Infectious Epi
incidence formula
# of new cases in pop./# of people in pop.
recall
______________ is influenced by: -How recent the activity took place -The impact, importance, or the uniqueness of the activity -The consistency of an event -If there was media coverage
general cohort
________________ cohort: -Benefit: Enhanced generalizability. -Limitation: Cannot analyze rare exposures
special cohort
________________ cohort: -Benefit: allows examination of rare exposures -Limitation: limited generalizability.
retrospective cohorts
benefit of _____________ cohort: are less expensive than prospective designs and generate results more rapidly.
prospective cohorts
benefit of _______________ cohort: allows for the quality control of exposure and outcome measurements and protects against temporal ambiguity.
ecologic studies
benefit of ________________________: Population data is typically publically available on a variety of governmental websites. Studies can be conducted inexpensively and easily because data collection is not required by the researchers.
Cross-Sectional Studies
benefit of ________________________: These studies are inexpensive and easier to conduct compared to the other analytic study designs.
case reports
benefit of ________________________: useful for the description of rare diseases or new treatments.
case reports
limitation of ______________________: The description of a single individual prohibits epidemiological inference
Cross-Sectional Studies
limitation of ________________________: Impossible to demonstrate a temporal association and, thus, impossible to prove causality.
case series
limitation of _________________________: A weak study design that does not allow for comparison between diseased and non-diseased individuals
ecologic study
limitation of _________________________: Cannot make individual level inferences based on population level data (ecologic fallacy). Cannot determine if those who are truly exposed have higher occurrence of disease.
case series
Data from a series of cases, with no control or comparison group is captured.
exposures
In cohort studies, _________________ measured at baseline can be followed up to look for an occurrence of disease.
Hill's Causal Criteria
Includes: Strength Consistency Plausibility Biologic Temporality Coherence Specificity Analogy Experiment
Agent Host Environment
List parts of the epidemiological triad
prevalence
Measures the proportion of the population who has the disease at a given time (point prevalence) or during an interval of time (period prevalence).
incidence
The number or rate of new cases of a particular condition during a specific time.
relative risk formula
[a/(a+b)]/[c/(c+d)]
case series
benefit of _______________________: Occasionally, there will be situations where there are no non-ill individuals or a very small number of cases. In these situations a _____________________ can provide person, place, and time associations.
Double blinded trial
both investigators and patients are blinded to the exposure group.
prevalence formula
# of people w/ disease/# of people in population or (a+c)/(a+b+c+d)
Intention to Treat Analysis (ITT)
All individuals who are randomly assigned to a treatment are analyzed, regardless of whether they complete or receive treatment
Intention to Treat Analysis (ITT)
Benefits of __________: -Benefits of randomization are preserved -Maintains statistical power of the original study -Good and poor compliance differs by important prognostic factors, ________ helps ensure the study results remain unbiased -Provides information on the effectiveness of a treatment under everyday conditions
determinants
By understanding _____________________ and their interrelationship, we can identify and implement interventions for disease prevention, treatment, and control.
Validity
Cannot be assessed statistically. Instead, an epidemiologist must rely on clinical and biologic characteristics, external literature, and judgment to assess it.
recall bias
Case-control studies are particularly susceptible to _______________, where the recall of the controls may be less accurate than the recall in the cases
ecologic studies
Correlational studies that are population-based rather than individual-based
Hill's Causal Criteria
Criteria for causality differ philosophically and practically. Epidemiologists typically use what?
target and source
Establishing the _____________ and _____________ population for a case control study is an important aspect of the study design
Source
Ex: Immunization rates in Sierra Leon post Ebola Crisis _________________ population: Major City Hospitals (type of population?)
Study
Ex: Immunization rates in Sierra Leon post Ebola Crisis _________________ population: People we can reach for survey in hospitals during the study time frame. (type of population?)
Target
Ex: Immunization rates in Sierra Leon post Ebola Crisis _________________ population: Sierra Leonean population (type of population?)
case-control studies
Goal of these studies: To compare the exposure characteristics of cases with a representative sample of the target population within which the cases occurred.
information bias
In case-control studies, exposure is assessed retrospectively, leading to the increased risk of ____________________
Case-Crossover Studies
In this design, cases serve as their own controls. The design evaluates exposure during a period of time before disease onset (control period). Example: use of disinfectant in hospital wards to prevent healthcare associated infections
Nested Case-Control Studies
Limitations of these studies: It is necessary to select different controls for each outcome of interest.
Case-Cohort Studies
Limitations of these studies: Potential increase in information bias because exposure information may have been collected at different times and the sub cohort may have been established after baseline.
Case-Crossover Studies
Limitations of these studies: Study assumes that no temporal trends exist. If such trends do exists, the design must be extended (case-time-control design).
Nested Case-Control Studies Case-Cohort Studies Case-Crossover Studies
List 3 other ways to choose controls
cohort studies
Non-diseased, at-risk individuals are enrolled into a study and followed up for a period of time. Exposures measured at baseline can be followed up to look for an occurrence of disease.
incidence
Refers to the number of new cases that develop among susceptible individuals. Incidence can be expressed as a proportion of at-risk individual who develop disease by a certain time (cumulative incidence) or as a function of follow-up time contributed (incidence rate)
Case-Cohort Studies
Select controls from a random subset of the entire cohort at baseline and use this group as a control for each of the case groups. If a new type of outcome needs to be studied, only cases need to be tested.
selection bias
Selection of study participants in a way that favors a certain outcome
True
T/F: Avoid matching on many variables. Unless the variable is a strong confounder, it makes little difference. We usually use 1:1 or 2:1 matching. Increasing beyond 4:1 matching shows little to no benefit in terms of power.
True
T/F: DO NOT match on a variable you are interested in analyzing as an exposure. Matching removes the differences between groups by a certain variable. In this case, you measure of association will be 1 and show no difference in exposure.
epidemiological triad
The _____________________________ provides a framework for emphasizing the relationship between three components: the host, the agent, and the environment
external validity
The ability to apply inferences about the particular target population to other target populations.
Person
The attributes of the ________________ include individual level characteristics believed to influence disease
intervention
The exposure of interest (or ___________________) is randomized and administered to patients based on a strict study protocol.
Randomized Clinical Trial (RCT)
The investigator assigns participants to receive a treatment (experimental group) and others to receive another treatment, often a placebo or the current gold standard of care (control group).
population-based
The most basic "_________________________" study pulls controls from the same population as cases (i.e. geographically or from the same hospital).
prevalence
The number or proportion of cases of a particular disease or condition present in a population at a given time.
information bias
The relationship between the exposure and the outcome is distorted because of how data are measured.
human hosts
These differ in susceptibility to infections due to genetic, environmental, behavioral, and other factors
RCTs
These studies are initiated to make inferences about a specific target population. To do so they use eligibility criteria.
Cross-Sectional Studies
These studies capture information regarding an exposure and an outcome simultaneously, usually through a survey instrument; they may also collect retrospective data.
case reports
These studies evaluate a single case of disease. It may evaluate transmission, natural history, and/or a new/novel treatment.
Randomized Clinical Trial (RCT)
These studies evaluate the effect of planned interventions in an experimental manner
ecologic studies
These studies look at how levels of exposure correspond to levels of disease within a population
Epidemiologists
They investigate associations between exposure and outcomes. The ultimate goal is to prove a causal association.
case-control studies
This allows the _____________________ study to overcome some of the limitations of cohort studies: -It is possible to study rare diseases because resources can be used more efficiently -More than one exposure can be assessed at a time because the study population was not restricted based on exposure -More resources can be expended per person because a large sample size in not required
prospective cohorts
This cohort is one in which a cohort is assembled in the present time and followed up into the future.
retrospective cohorts
This cohort takes advantage of records and specimens collected in the past and assesses outcome that have occurred before the present time. Often times, databases or medical records are used for this design.
place
This describes the geographical characteristics of our population, whether this be a county, a state, a school, or a place of work.
epidemiology
This is a population science and we take a multifaceted approach to describe the populations we study
Source population
This is a subset of the target population that can be enumerated and further studied
time
This is the essential third parameter of our population that provides us with more specificity in our measurements.
the agent
This is the infecting pathogen. They have characteristics influencing infectivity, including evolution of resistance to antibiotics and antivirals.
Study population
This population is comprised of those individuals in the source population contributing information to the epidemiological investigation
cohort study
This study is best suited for diseases with high incidence among the exposed and high prevalence of exposure in the population. If disease is rare, an unrealistically large one would be required
the environment
This t is the setting in which transmission occurs. It is important to recognize that certain ones influence the agent's survival and infectivity
prevalence
Typical measurement of a survey or cross-sectional study.
accuracy formula
(TP + TN)/(TP + TN+ FP + FN)
accuracy formula
(a+d)/(a+b+c+d)
general cohort
(type of cohort) Used to analyze common exposures. Participants pulled from general population.
special cohort
(type of cohort) Used when exposures under study are rare. Study populations can be drawn from groups sharing similar characteristics such as hospitals or occupational groups (i.e. factories, oil rig workers, so on).
probable
*If sample is sufficiently large ________________ cases can be excluded from analysis to maximize accuracy of results.
secondary
*When later conducting analysis it is important to eliminate _________________ cases for risk factor analysis, especially when the goal is to identify source of the outbreak
gown
- STANDARD PRECAUTION To protect from splashes /sprays of large quantities of BBF/S E - CONTACT PRECAUTION To protect contamination of personnel clothing
Non-differential misclassification
A bias that occurs when the misclassification of the disease is the same for all categories of the exposure or the misclassification of the exposure is the same for all categories of the disease.
infectious disease
A disease that is caused by a pathogen and that can be spread from one individual to another.
30%
About _______% of infected people are asymptomatic for norovirus
96%
About _______% of non-bacterial outbreaks are probably Norovirus-related
Review; case; food; clinical
Actions to Confirm the Diagnosis: - ________________ preliminary information - Get ___________ history - Collect ______________ specimens (in the case of a foodborne outbreak) - Obtain _________________ specimens - Send clinical/food specimens to CDC reference laboratories, when warranted
Enteropathogenic E.coli (EPEC)
Acute and chronic endemic and epidemic diarrhea in infants
Case-Cohort Studies
Advantages of these studies: -Efficient way to analyze relationship of exposure and outcome. -Allows flexibility to test hypotheses not thought of at beginning of cohort -Reduces selection bias by drawing cases and controls from the same population
Case-Crossover Studies
Advantages of these studies: All personal-level factors are similar and cannot confound the analysis
Nested Case-Control Studies
Advantages of these studies: Offer potential for integrating technology and research questions that increase the value of conducting lengthy cohort studies. With repeated testing, can determine if an exposure occurred before disease onset (temporality).
intermediate
Areas with ________________________ levels of infection of HAV: • Developing countries, countries with transitional economies, and regions where sanitation conditions are variable • Children escape infection in childhood and reach adulthood with no immunity • Higher number of susceptibles makes outbreak and epidemics more likely
low
Areas with low levels of infection of HAV: • Developed countries with good sanitary and hygienic conditions • Infection rates are low • Disease may occur in adolescents and adults in high risk groups (IV drug users, MSM, travelers to endemic areas, isolated populations) • When virus is introduced into communities, generally stopped early with good hygiene practices
entire population
As epidemiologists, the interventions that we purpose deal with _____________________________ and include the majority of public health measures, policies, and guidance affecting the population.
-Person, place, and time of the outbreak -Suspected etiologic agent -Mode of transmission
As soon as preliminary data offer information about the scope and magnitude of an outbreak a hypotheses is formed to describe what?
direct transmission
Can happen through: -Sexual (via mucous-membranes; ex: Syphilis, HIV, Gonorrhea) -Contact (skin to skin; ex: Herpes Simplex; Perinatal (transplacental or vertical ex: Rubella, HIV, Hepatitis B, Syphilis) -Parenteral (needle stick) ex: HIV, Hepatitis B & C
Nested Case-Control Studies
Cases and controls pulled from an existing cohort or clinical trial.
Rapid diagnostic test Traditional Lab testing
Cholera is diagnosed through what methods?
slaughter; slaughter; contaminated ingredients
Food contamination that leads to enteric bacterial diseases occur due to bacteremia prior to _____________________, contamination of meat by fecal material after ___________________, use of _____________________________ during food processing. cross contamination in the food processing plant, and cross contamination in the kitchen during food prep
recall bias
Food histories are not 100% accurate; they are subject to what?
Oocysts
For Cryptosporidium, _________________ appear in the stool at the onset of symptoms and are immediately infectious; Excretion of them occurs for several weeks after symptoms resolve and a large # of them are shed in human and animal stool
Antibiotics
For Salmonella, after enterocolitis, fecal excretion persist for several days or weeks; ___________________ do not decrease the duration of excretion
1:1
For ___:___ matched pair analysis, the odds ratio formula is f/g and the test for statistical significance is the McNemar chi-squared test
conditional logistic regression
For matched pair analysis with 2, 3, or 4 controls per case, we must perform __________________________ or a similar method
1 − 1/R0
For simple models and a 100%-effective vaccine, the proportion of the population that needs to be vaccinated to prevent sustained spread of the infection is given by what equation?
epidemiologically linked
For some diseases a person is considered a confirmed case if they have clinically compatible symptoms and are "_______________________ ________________" to a confirmed case.
HANDWASHING
For the prevention of food borne outbreaks, enforce ______________________ of food handlers and educate them
SARS-COV2
For this disease, certain activities like singing, speaking loudly or playing a musical instrument, such as the saxophone, these droplets can be aerosolized (become smaller) and therefore can stay longer in the air (see choir outbreak)
spores
For transmission of intestinal botulism in infants and adults, it occurs after ingestion of botulism ____________ rather than by ingestion of a preformed toxin
Rn = R0 x s s= proportion of susceptible persons in the populations
Formula for Rn = of actual number of transmissions (number of susceptible persons are decreasin
SARS-COV2
Furthermore, the virus can be transmitted via fomite transmission. ___________________ can survive in the environment depending on the surface so persons can become infected when touching high contact surfaces such as door knobs, elevator buttons and toilet handles and then touching their faces..
12-60hrs
Gastroenteritis typically develops how long after being infected with the norovirus?
gram negative
General shift towards ____________________ flora in hospitals
External validity
Generalizability
airborne
Give the mode of transmission for the following disease: measles
sexual contact
Give the mode of transmission for the following disease: HIV/AIDS
airborne droplet
Give the mode of transmission for the following disease: SARS
saliva
Give the mode of transmission for the following disease: diptheria
bodily fluids
Give the mode of transmission for the following disease: ebola
airborne droplet
Give the mode of transmission for the following disease: influenza
airborne droplet
Give the mode of transmission for the following disease: mumps
airborne droplet
Give the mode of transmission for the following disease: pertussis
fecal-oral route
Give the mode of transmission for the following disease: polio
airborne droplet
Give the mode of transmission for the following disease: rubella
airborne droplet
Give the mode of transmission for the following disease: smallpox
case reports
How are Potential Outbreaks Identified? An individual, physician, lab technician, or infection control nurse, notice a higher than expected number of cases of disease and report the cluster to the health department. These are known as what?
Person Place Time
How do epidemiologists describe populations?
RT-PCR IgM and IgG antibodies
How do you diagnose Ebola?
B/c it is a lipid enveloped RNA virus
How does Ebola virus survive in the environment?
Blood and Body Fluids (BBF)
How is Ebola transmitted?
24-60hrs
How long do norovirus symptoms typically last?
3-8 days
How long does the Influenza virus disease last?
Laboratory testing
However, if a case definition is sufficiently specific, it may not be necessary to test all specimens for confirmation. _______________________ is expensive and time consuming; it is often not the best expenditure of resources
Animal reservoirs
Humans are also susceptible to diseases that have human ________________ reservoirs. These disease are transmitted from animal to animal with humans as incidental hosts.
300 million cells
Humans shed about how many skin cells (squames) per day?
◦ Means of transmission ◦ Reservoir of the organism
ID epidemiologists typically classify disease by two important epidemiological characteristics; what are they?
IRR formula
IRe/IRue
Norovirus
Is highly contagious and spread: • Person-to-person spread • Environment or fomite contamination • Aerosolization of vomitus • Fecal-oral route i.e. consumption of fecally contaminated food or water
Randomized Clinical Trial (RCT) Cohort Studies Case-Control Studies Cross-Sectional Studies
List the types of analytic study designs
Case reports Case series Ecologic study
List the types of descriptive study designs
Food contamination Milk Food Handlers (rare carriers) Water Contact with Infected Animals
List the types of foodborne transmission that may lead to enteric bacterial diseases
N95 Mask PAPR Powered Air Purifying Respirators
List the types of personal respirators for airborne precautions
Target Source Study
List the types of populations
Human Animal (zoonoses) Soil Water
List the types of reservoirs
- Typical signs and symptoms - Modes of transmission - Foods in past outbreaks
List what you should know about the causative agent
high
The following are people who are at __________ risk for Ebola: -Handling bush meat (wild animals hunted for food) -Contact with infected bats (CARRIERS) -Removal and burial of human remains (funeral rituals), postmortem examinations -Healthcare providers, family and friends who get exposed to blood or body fluids of sick patients. -Waste management: Clothes, bedding, needles, syringes/sharps or medical equipment contaminated with the virus -Diagnostic laboratory activities (see Marburg virus)
Botulism
The following are reservoirs for ____________________: -Spore forming clostridium bacteria -Spores -Toxin
Botulism
The following are risk groups for ____________________: -Foodborne: Individuals who can or preserve foods in the home -Intestinal: Infants younger than 6 months & Infants younger than 1 yr. who are fed honey -Wound: Injection drug users
Ebola
The following are signs & symptoms of ______________: -Fever (greater than 38.6°C or 101.5°F) -Macular Rash Severe headache -Muscle pain -Weakness -Diarrhea, might be bloody later in the disease process -Vomiting -Abdominal (stomach) pain -Unexplained hemorrhage (bleeding or bruising) but never in the first days of illness
Norovirus
The following are signs and symptoms for what virus? - Acute onset of watery nonbloody diarrhea - Vomiting (esp. in children) - Abdominal cramps - Nausea - Low grade fever
control measures
The following are some examples of what? -Recalling or destroying remaining contaminated food products -Restricting infected workers from high-risk occupations -Correcting procedural practices identified as inadequate or improper
control measures
The following are some examples of what? -Recommending a prophylactic therapeutic agent and/or vaccine -Enforcing hand washing -Educating the public regarding risk and prevention
Botulism
The following are symptoms in adults of __________________: • Early symptoms • Fatigue, weakness, and vertigo • Followed by: • Blurred vision, dry mouth, difficulty in speaking • Disease may progress to weakness in arms and neck, then respiratory muscles and muscles of the lower body are affected • Illness may lead to respiratory failure and death if ventilators are not provided (CFR: 5-10%)
Botulism
The following are symptoms in infants (< 1yr) of __________________: • Typically starts with constipation • May include: poor suck, altered cry, weakness, loss of head control • Ranges from mild illness and ranges to (descending) paralysis and respiratory failure • Mortality rare: 0.1%
Vibrio
The following are the 3 types of illness for ____________: - Gastrointestinal - Primary septicemia - Wound
Ebola
The following are the Epidemiologic risk factors for what disease? within the past 21 days before the onset of symptoms, such as contact with blood or other body fluids or human remains of a patient known to have or suspected to have EVD; residence in—or travel to—an area where EVD transmission is active (Guinea, Sierra Leone and Liberia); or direct handling of bats or non-human primates from disease-endemic areas.
HAV
The following are treatment recommendations for what? • Palliative only. Replenish fluids • Avoid prescription of unnecessary medications • Hospitalization unnecessary in absence of acute liver failure
Ebola
The following is the clinical criteria for what disease? which includes fever of greater than 38.6 degrees Celsius or 101.5 degrees Fahrenheit, and additional symptoms such as severe headache, muscle pain, vomiting, diarrhea, abdominal pain, or unexplained hemorrhage
Crypto
The following risk groups are for ________________: -Children younger than 2 years of age -Animal handlers -International Travelers -MSM -Close personal contacts of infected individuals -10-20% of AIDS patient developed infection at some point during illness
Internal validity
The goal of obtaining inferences from a study population that are applicable to the target population.
reservoir
The habitat in which an infectious agent usually lives, grows, and multiplies. This habitat can include humans, animals, and the environment.
portal of exit
This is the path by which a pathogen leaves its host. This usually corresponds to the site where the pathogen is localized.
Target population
This is the population we will want to make inferences about or generalize to
Matching
This is the primary method of ensuring that cases and controls share similar characteristics.
Virulence
This is the severity of the disease after infection occurs and is measured as the proportion of clinical cases that develop severe disease or die (Case Fatality Rate).
Herd immunity
This is typically achieved through vaccination. The concept of it dictates that not all individuals have to be immune to a disease to halt epidemics, but a significant proportion of the population has to be protected against the disease. This number is known as the ____________________ threshold.
portal of entry
This is where the pathogen is able to enter into a susceptible host. These include ingestion, inhalation, and percutaneous entry
case definition
This lists the clinical criteria by which public health professionals determine whether a person's illness is to be included as a case in an outbreak investigation.
carrier
This may be an individual who is: - colonized - infected and asymptomatic - in incubation period before disease, pre-symptomatic - convalescent from acute disease This status may be short or lenghty
Clinical infection
This may result in signs and symptoms. Some of these may be less obvious or very minor. At the end of the spectrum is the individual with no signs, no symptoms who has a asymptomatic infection or subclinical infection
vehicle transmission
This occurs via an inanimate object, material, or substance that is contaminated with the infectious agent
Standard Precaution
This precaution applies to 1) blood; 2) all body fluids, secretions, and excretions, except sweat, regardless of whether or not they contain visible blood; 3) non-intact skin; and 4) mucous membranes.
Universal Precaution
This precaution says to treat all human blood and certain human body fluids as if they were known to be infectious for HIV, HBV and other blood-borne pathogens
Quarantine
This separates and restricts the movement of people who were exposed to a contagious disease to see if they become sick
Isolation
This separates sick people with a contagious disease from people who are not sick.
case definition
This should always contain information regarding person, place, time, and clinical features.
Indirect transmission
This transmission involves airborne and droplet
Normal flora
This type of Flora protects against infectious diseases originating at mucous membranes
Norovirus
This virus can survive high chlorine levels and is HIGHLY contagious
Norovirus (NOV)
This virus has a temperature tolerance from freezing to 60 C
SERIAL INTERVAL
Time of onset between primary and a secondary case
Frequency Tables
Use _______________________ to express: - # of individuals presenting with specific symptoms - # of individuals who ate a specific food or had a specific exposure - # of individuals who ate a particular meal, if multiple meals are suspected
low
Use of PCR tests with ________ specificity (FP high) can result in unnecessary investigation and treatment of persons with false-positive PCR test results and inappropriate chemoprophylaxis of their contacts
Cholera
Vibrio Cholerae is the scientific name of the bacteria that causes what known disease that affects the small intestine?
severity
Virulence is the _____________ of the disease after infection occurs and is measured as the proportion of clinical cases that develop severe disease or die (Case Fatality Rate).
Ebola- lipid enveloped RNA virus
Virus shed in human body fluids or animal feces survives under dry conditions only hours to days in the environment but will survive for weeks if stayed hydrated (e.g. in blood samples) (clinical specimens)
• Humans are the only reservoir • Vaccination causes long term immunity • The disease is easily detectable in humans
WHAT MAKES A DISEASE A GOOD CANDIDATE FOR VACCINATION AND ERADICATION?
Hand Sanitizer
Washing hands with soap and water is the best way to reduce the number of germs on them. If soap and water are not available, use an alcohol-based _________________ _______________ that contains at least 60% alcohol
case control
When to use ____________________ studies: 1. When the exposure is unknown 2. When the outbreak is large 3. When the disease is uncommon 4. The exposed population cannot be enumerated
Household Exposed children and providers Exposed, unprotected healthcare workers (HCW)
What contacts of pertussis should receive prophylaxis?
Microscopy (Identification of oocysts) ELISA PCR
What diagnostic tools are used for Crypto?
Ebola
What disease is a viral hemorrhagic fever?
No positive test in an healthy person
What do you want from a confirmatory test?
find everyone with disease (no disease with negative test; no false negative)
What do you want from a screening test?
Cholera and other Vibrio Illness Surveillance System
What does COVIS stand for?
Hepatitis A Virus (HAV)
What does HAV stand for?
herd immunity threshold
What does HIT stand for?
Severe Acute Respiratory Syndrome
What does SARS stand for?
Viral Hemorrhagic Fevers
What does VHF stand for?
RT-PCR
What is a good tool for diagnosis of norovirus in humans? (hint: it examines stools and emesis)
Measure of transmissibility
What is a secondary attack rate an example of?
Foodborne: • by ingestion of food • from contaminated animals • food products contaminated by infected animal or person
What is another form of transmission for enteric bacterial diseases not including person 2 person?
- Median illness duration of 12-60 hrs. - Incubation period of 24-48 hrs. - More than 50% of people vomiting. - No bacterial agent
What is the Kaplan criteria for diagnosis during outbreaks?
H7N9
What is the NEW strain of "bird flu" that affected Asia in 2013?
R0 Guinea: 1.7 (CI:1.44 to 2.01) R0 Liberia: 1.83 (CI: 1.72 to 1.94) and R0 Sierra Leone: 2.02 (1.79 to 2.26)
What is the R0 for Ebola in Guinea, Liberia, and Sierra Leone?
0, Bodily fluids, exposure to contaminated needles and other objects (assuming no control measures)
What is the R0 for Ebola in the US?
1-4, Sharing needles, sexual contact
What is the R0 for HIV?
12-18, Airborne
What is the R0 for Measles?
12-17, Droplets, Airborne
What is the R0 for Pertussis?
maximum in catarrhal stage
What is the communicability of pertussis?
Standard
What is the correct form of isolation that is needed (Standard, Contact, Droplet, Airborne)? Annette is admitted for a severe fever, hepatitis and renal failure. She just returned from trekking in the Brazilian Amazon. She is diagnosed with malaria and yellow fever
Standard Contact Droplet
What is the correct form of isolation that is needed (Standard, Contact, Droplet, Airborne)? Benjamin, 2 months old, has a severe cough. His physician suspects whooping cough or Respiratory Syncytial Virus (RSV) bronchiolitis. He was admitted to a pediatric intensive care unit in a private room.
Standard Contact -Contact precaution if nasty boil is still seeping and not successfully drained yet
What is the correct form of isolation that is needed (Standard, Contact, Droplet, Airborne)? John had a nasty boil under his arm. He has some fever, chills, vomiting and diarrhea. He is so sick that he is admitted in a hospital. A blood culture shows that he has Staphylococcus aureus growing from a blood culture.
Standard Droplet Airborne
What is the correct form of isolation that is needed (Standard, Contact, Droplet, Airborne)? Peter went to see his physician for a chronic cough. He is sick enough to justify being admitted. He is going to be worked up in the next few days, meanwhile what is recommended?
Standard Contact
What is the correct form of isolation that is needed (Standard, Contact, Droplet, Airborne)? Typhoid Marie broke her leg. She is admitted to the broken foot ward of the hospital. Her stool is checked because of her past history of typhoid fever. Salmonella typhi is still present in her stool.
Serologic (IgM)
What is the diagnostic method for HAV?
1-2 weeks, range of a few days to 4 weeks
What is the duration of Crypto?
less than 2 months
What is the duration of HAV?
R0 - 1/R0
What is the equation for the herd immunity threshold?
C
What is the following Human influenza type? • Mild Illness • No epidemics
B
What is the following Human influenza type? • No subtypes • Humans only • Epidemics Yearly
A
What is the following Human influenza type? • Subtypes based on surface protein • Humans and animals • Epidemics yearly • Ability to cause pandemics
Phase 2
What is the following WHO pandemic phase? an animal influenza virus circulating among domesticated or wild animals is known to have caused infection in humans, and is therefore considered a potential pandemic threat
Phase 3
What is the following WHO pandemic phase? an animal or human-animal influenza reassortant virus has caused sporadic cases or small clusters of disease in people, but has not resulted in human-to-human transmission sufficient to sustain community-level outbreaks
Phase 5
What is the following WHO pandemic phase? human-to-human spread of the virus into at least two countries in one WHO region
Phase 4
What is the following WHO pandemic phase? human-to-human transmission of an animal or human-animal influenza reassortant virus able to cause "community-level outbreaks
Phase 1
What is the following WHO pandemic phase? no viruses circulating among animals have been reported to cause infections in humans
Phase 6
What is the following WHO pandemic phase? the pandemic phase, is characterized by community level outbreaks in at least one other country in a different WHO region in addition to the criteria defined in Phase 5. Designation of this phase will indicate that a global pandemic is under way.
case definition
What is the following an example of? Situation: 25 children who attend Happy Times daycare have presented with rash and fever over the past two weeks. _______________________: A case will be defined as a child (person) attending Happy Times daycare (place) from X date to Y date (time) presenting with rash and fever (clinical features).
seasonal variation
What is the following an example of? For example, vector-transmitted diseases such as malaria, dengue or St. Louis encephalitis depend on mosquito vectors for transmission. Since mosquitos are only present during warm parts of the year, disease only occurs during warm parts of the year.
3-5 days
What is the incubation period for Campylobacter?
7 days (range 2-14 days)
What is the incubation period for Crypto?
1/2 day to 3 days
What is the incubation period for E. Coli?
8-10 days (range 2-21 days)
What is the incubation period for Ebola?
7-10 days (range: 2-25 days or longer)
What is the incubation period for Giardia?
28-30 days (range 15-50 days)
What is the incubation period for HAV?
6-48hrs
What is the incubation period for Salmonella?
1-3 days
What is the incubation period for Shigella?
12-48hrs, range 6hr-8 days
What is the incubation period for foodborne botulism?
3-30 days
What is the incubation period for infant botulism?
12-48hrs
What is the incubation period for norovirus?
1-5 days
What is the incubation period for the Influenza virus?
4-14 days
What is the incubation period for wound botulism?
2-3 days, range a few hours-5 days
What is the incubation period of Cholera?
12-72 hours
What is the incubation period of Vibrio Vulnificus?
6-21 days
What is the incubation period of pertussis?
5 virions
What is the infectious dose of Influenza?
poultry, unpasteurized milk
What is the leading Bacteriological Causes of the following Foodborne/Enteric Illness in USA: Campylobacter jejuni
eggs, poultry, beef, pork, produce
What is the leading Bacteriological Causes of the following Foodborne/Enteric Illness in USA: Salmonella sp.
cattle (handling) and beef, produce, water (recreational and drinking)
What is the leading Bacteriological Causes of the following Foodborne/Enteric Illness in USA: Shigatoxin E.coli (STEC)
salads, produce (food handler)
What is the leading Bacteriological Causes of the following Foodborne/Enteric Illness in USA: Shigella
Large droplets
What is the mode of transmission for pertussis?
Disease
What is the most appropriate classification for the following? (Contamination, Exposed, Colonization, Carrier, Asymptomatic Infection, Disease?) A week later Jane has a headache, mild fever, a light rash that lasted only a few days. The virus is no longer present in her blood but she has developed antibodies to the West Nile virus
Contamination -Should he be treated? NO
What is the most appropriate classification for the following? (Contamination, Exposed, Colonization, Carrier, Asymptomatic Infection, Disease?) Bob had diarrhea, dehydration and fever. He received some intravenous fluid and recovered rapidly. A blood culture showed the presence of Staphylococcus epidermidis, a common skin contaminant. A second culture taken within 20 minutes was negative
Asymptomatic Infection
What is the most appropriate classification for the following? (Contamination, Exposed, Colonization, Carrier, Asymptomatic Infection, Disease?) Jane went to give blood. Polymerase Chain Reaction (PCR) test performed as routine screening showed that she had West Nile virus present in her blood.
Disease
What is the most appropriate classification for the following? (Contamination, Exposed, Colonization, Carrier, Asymptomatic Infection, Disease?) John had a nasty boil under his arm. He has some fever, chills, vomiting and diarrhea. He is so sick that he is admitted in a hospital. A blood culture shows that he has Staphylococcus aureus growing from a blood culture.
Exposed
What is the most appropriate classification for the following? (Contamination, Exposed, Colonization, Carrier, Asymptomatic Infection, Disease?) Michael was a drinking companion of Billy who was diagnosed with the infectious form of tuberculosis. They spent a lot of time together. They slept under the interstate or in empty containers.
Colonization -No treatment indicated, actually would do more harm than good
What is the most appropriate classification for the following? (Contamination, Exposed, Colonization, Carrier, Asymptomatic Infection, Disease?) Peter went to see his physician for a sore throat. She took a sample from his throat. Thinking it could be a viral pharyngitis and since Peter was not very sick, she did not prescribe antibiotics. Two days later the results of the culture came back showing the presence of Neisseria meningitis. Does he need treatment?
Carrier
What is the most appropriate classification for the following? (Contamination, Exposed, Colonization, Carrier, Asymptomatic Infection, Disease?) Typhoid Marie had typhoid fever. Later Salmonella typhi was isolated from her stools although she had recovered completely and was healthy.
Dehydration in children and elderly
What is the most common complication of norovirus?
waterborne
What is the most common mode of transmission for Cryptosporidium?
Campylobacter
What is the most frequent enteric bacterial diseases in the US?
the intestinal tract
What is the primary habitat for Salmonella?
Fruit bats
What is the reservoir for Ebola?
humans
What is the reservoir for HAV?
Humans only (adolescents and adults)
What is the reservoir for pertussis?
humans and various animals ◦ Infects over 45 invertebrate species, birds, fish, reptiles, and mammals
What is the reservoir of Crypto?
food/water; feces
What is the source and anatomical source of Crypto?
Pertussis
What is whooping cough or 100 day cough called?
surface water, water systems
What is/are the reservoir(s) for the following? Legionella
soils & animal gut -horses
What is/are the reservoir(s) for the following? Tetanus
rodents
What is/are the reservoir(s) for the following? plague
Animals but not humans
What is/are the source(s) of infection for the following? Hantavirus
Humans & other animals
What is/are the source(s) of infection for the following? Influenza, plague
Humans only
What is/are the source(s) of infection for the following? Mycobacterium tuberculosis, measles, chickenpox, smallpox, Shigella
Animals
What is/are the source(s) of infection for the following? Salmonella, Brucella
fecal-oral
What kind of person 2 person transmission happens in enteric bacterial diseases?
Avian (bird) flu
What type of flu is the following? • Influenza viruses that occur naturally among wild birds • Transmitted from birds to humans • No human immunity • No vaccine
Seasonal (common) flu
What type of flu is the following? • Transmitted person to person • Most people have some immunity • Vaccine available
Pandemic flu
What type of flu is the following? • Virulent human flu that causes a global outbreak • Spread easily from person to person • No human immunity
Nigeria Senegal DR Congo
What was the hot zone of Ebola?
2009
What year was the H1N1 (Influenza A) Swine Flu pandemic?
>
When R0 ____ (> or <) 1 the infection will be able to spread in a population
<
When R0 ____ (> or <) 1 the infection will die out in the long run.
Varies on a case by case basis, involving many considerations: -Severity of the illness -Vulnerability of exposed population -If the suspected exposure is ongoing -Cost of the intervention -Political Considerations
When do we enact extreme control measures?
results
When do you publish ___________________? 1. When the disease or exposure is rare or novel 2. If the disease or exposure has presented in atypically 3. If the means of control was novel or atypical
Review what you know about cases Identify most likely agents
When the Causative Agent is Unknown, what should you do?
unknown
When the Causative Agent is Unknown: Review what you know about cases -Symptoms, severity of disease -Events attended or anything unusual -Foods consumed and methods of food preparation Identify most likely agents 1. Apply knowledge of incubation period 2. Apply knowledge of food item consumed or other mode of transmission 3. Apply knowledge of clinical presentation
water (drinking water and recreational water)
While this parasite can be spread in several different ways, _________________ is the most common way to spread the parasite, Cryptosporidium
State; error; false
Why do we Confirm Diagnoses? -________________ labs may not have the proper expertise or equipment to diagnose rare or emerging diseases. -There is the potential for _____________ in specimen collection. -______________ conclusion may be drawn regarding a cluster of cases.
1. Reveal if control measures were successful or not. 2. The potential for the rise of secondary epidemics.
Why do we continue to monitor surveillance data?
-Can provide important and interesting information about the origins of the outbreak -Can confirm the existence of the suspected etiologic agent.
Why perform supplemental investigations?
B/c the guidelines for how to use the gear (PPE) were insufficient
Why were so many health care workers affected by Ebola?
Campylobacter jejuni
Wildlife reservoir of ________________________: • Wild birds, migratory birds — cranes, ducks, geese, and seagulls • Domestic bird species • Rodents • Insects on their exoskeleton
wash your hands
You do this activity: - Beginning and end of day - Before & after each patient contacting - Before and after gloving - Anytime after contact with: • Blood & body fluid • Secretions /excretions • Mucous membranes • Damaged skin • Contaminated environment • Contaminated equipment
match
You should _______________ on variables that are potential confounders AND are distributed very differently between the cases and an unmatched group of controls.
New
__________ information usually provides additional insight into the exposure of the disease; ex: Maybe a particular food or swimming in a pool is identified only after a case control study is performed. The food item would need to be taken of shelves and the pool would need to be closed to the public.
HAV
____________ is a potential problem in large collections of people with overcrowding, inadequate access to sanitation and access to clean water. If cases do occur, improve sanitation and safety of water supplies. Mass vaccination should not be used as a substitute to environmental measures
Ebola Hemorrhagic Fever
_____________ was first discovered in 1976 near the Ebola River in what is now the Democratic Republic of the Congo. Since then, outbreaks of this disease among humans have appeared sporadically in Africa.
Oysters and clams
______________ and ________________ tend to CONCENTRATE norovirus in their tissues, through contamination of their harvest areas; norovirus is also transmitted in cold foods, salads, sandwiches, bakery products, liquid items such as salad dressings etc
case
_______________ definitions should become more specific as the investigation continues and more data become available regarding: -Person, place, and time association -Clinical criteria -Classify cases based on certainty
Laboratory
_______________ tests may confirm the same strain of a pathogen in an environmental sample and an individual, confirming source of agent
Ebola vaccine
________________ Vaccine: Ervebo® is administered as a single-dose injection, and is a live, attenuated vaccine that has been genetically engineered to contain a protein from the Zaire vrius
Confirmed
________________ case of pertussis: • a case that is culture positive and in which an acute cough illness of any duration is present; • or a case that meets the clinical case definition and is confirmed by positive PCR; • or a case that meets the clinical case definition and is epidemiologically linked directly to a case confirmed by either culture or PCR
probable
________________ case of pertussis: • meets the clinical case definition for typical disease, is not laboratory confirmed and is not epidemiologically linked to a laboratory-confirmed case, • OR meets the clinical case definition for atypical disease and is confirmed by positive Direct Fluorescent Antibody (DFA)
Cholera
________________ is communicable for as long as stools test positive for V. cholerae - Symptomatic individuals: usually until a few days after recovery - Asymptomatic individuals: usually between 7-14 days
Humans
________________ only natural hosts for Shigella
Typical
________________ pertussis disease: A cough illness lasting at least 2 weeks with one of the following: paroxysms of coughing, inspiratory "whoop," or post-tussive vomiting, without other apparent cause (as reported by a health professional)
carriers
________________ play an important role in transmission, as they do not know they are infected and consequently do not seek treatment for the disease
Confirmed
_________________ cases are generally those with laboratory findings of the suspected organism.
Botulism
_________________ is under-recognized and under-reported; Worldwide incidence is unknown.
Contact
_________________ isolation precautions include: - Clean Hands - Gown - Gloves - Private room (*) - Gloves when entering room, - change glove after infectious contact - Gown when entering room if substantial contact will occur
Droplet
_________________ isolation precautions include: - Clean Hands - Surgical Mask - Eye Protection - Private Room - Mask when entering room
Airborne
_________________ isolation precautions include: - Clean hands - N-95 or PAPR - Negative Pressure/Door Closed
standard precaution
_________________ precaution: 1. Wash * Touch * Wash 2. If red, wet or dirty wash * glove * touch * unglove * wash 3. Know what is clean, know what is dirty, keep them apart
Oocysts
__________________ are highly resistant to chemical disinfectants used to purify drinking water
Pasteurization
__________________ is a sanitation process in which milk is heated briefly to a temperature high enough to kill pathogens, followed by rapid cooling
atypical
__________________ pertussis disease: A persistent cough illness lasting greater than 2 weeks with or without paroxysms and inspiratory whoop
Deterministic Models
___________________ Models: Fixed input rates and therefore the model's prediction will be "pre-determined"
restaurant
___________________ inspection may prove the source of the contaminated food
Norovirus
___________________ outbreaks have been associated with sources of contaminated water, including municipal water, well water, stream water, commercial ice, lake water and swimming pool water.
Investigators
___________________ should also be aware of background levels of disease
Influenza
___________________ syndrome: Fever, chills, myalgia, headache, Nasal congestion Sore throat, dry cough, Malaise, fatigue
Case Definition
____________________ Format includes: "We defined a case as..." -Person, place, time -Subcategories indicate status of a case and specificity -Confirmed (ex. laboratory) vs probable (epidemiologically linked or meeting a case definition except for laboratory information) -Primary (contracted infection from original source) vs Secondary (contracted infection from person infected through original source) -Consider existing surveillance case definition
Probable
____________________ cases are those who have certain symptoms meeting a clinical case definition, but do not have laboratory confirmation.
Laboratory
____________________ confirmation is important to determine what specific agent is responsible for the outbreak.
Handwashing
____________________ removes resident and transient flora
Stochastic Models
_____________________ Models: Input parameters vary by chance, rates may vary randomly and therefore the models provides a range of outcomes or the probability of the outcome occurring.
Hillandale
_____________________ farm cooperated early on with FDA and USDA and no major violations were found on the farms.
Supplemental
_____________________ studies may provide information that forces a modification in prevention and control measures
study design
______________________ is chosen based on: -Size and availability of the exposed population -The speed with which results are needed -Available resources
Bordetella pertussis
______________________ isolated in 1906 by Jules Bordet and Octave Gengou, who also developed the first serology test and vaccine
Descriptive
_______________________ Epidemiology: 1. Frequency Tables 2. Incubation Period 3. Epidemic Curve 4. Spot Maps 5. Attack Rates
communication
_______________________ is key to an effective outbreak investigation
Case finding
_______________________ techniques: -Enhanced surveillance, including review of existing surveillance data -Surveying hospitals, emergency rooms, or physicians -Obtaining credit card receipts or shopper card information -In some cases, use of internet, social media, or other media resources
Cryptosporidium; Crypto
_________________________ is a microscopic parasite that causes the diarrheal disease cryptosporidiosis. Both the parasite and the disease are commonly known as "________________."
Cryptosporidium
___________________________ is a leading cause of waterborne disease among humans in the United States.
Norovirus (NOV)
a contagious gastrointestinal illness; Single-stranded RNA virus
Causative Agent
a pathogen, such as a bacterium or virus that can cause a disease
carriers
a person with an inapparent infection who is able to transmit disease
Communicability
ability to spread from one individual to others and cause disease
Source of infection
actual person, animal, object from which infection was acquired. Example: Potato salad
Odds ratio formula
ad/bc
Cholera
an acute intestinal infection caused by ingestion of contaminated water or food that causes severe diarrhea, dehydration, and if not treated properly, death.
outbreak
an incident in which two or more persons have the same disease, have similar clinical features, or have the same pathogen-thus meeting the case definition*- and there is a time, place, or person association among these persons.
Inactivated vaccines
contain killed pathogens, which induce a weaker immune response
Differential misclassification
different amounts of error in study groups. Results in bias in one direction or another
bacterial disease
disease caused by bacteria that destroys all living cells or releases chemicals that upset homeostasis
water borne
examples: Cholera, Hepatitis A by ________________ transmission
Botulism
food poisoning
fomites
inanimate objects laden with disease causing agents (skin cells, hair, clothing) ex: Varicella
carrier
individual which is colonized + more
case series
larger collection of cases of disease, often grouped consecutively and listing common features such as the characteristics of affected patients
Infectious period
length of time a person can transmit disease.
prospective cohorts
limitation of _____________ cohort: are expensive and follow-up often must occur for a number of years, often times making the study untenable.
retrospective cohorts
limitation of _____________ cohort: rely on data that has already been collected, meaning investigator do not have any say on how exposure and disease are defined.
resident flora
microorganisms that usually occupy a particular body site
contact
mode of transmission: Direct or indirect (direct=skin/sexual contact; indirect=contaminated objects like infected fomite, blood, or body fluid)
vector borne
mode of transmission: I.e., mosquito, tick, snail
food or water borne
mode of transmission: Ingestion of contaminated food or water
airborne
mode of transmission: Inhalation of contaminated air
perinatal/vertical
mode of transmission: Similar to contact infection, but contact may occur in utero during pregnancy or delivery
COVIS
o CDC database o Vibriosis is reportable by law in 26 states and territories o _______________ report includes: - clinical information - exposure history - seafood trace back information
Single blinded study
patients are blinded to exposure group.
Efficacy
performance of the vaccine under ideal and controlled circumstances
Latent period
period of infection without being infectious. This may occur right after exposure or late in the disease.
source of contamination
person, animal, object from which environmental media are contaminated. Example the cook is the source of contamination of the potato salad.
Reservoir
person, animal, plant, environmental medium (soil, water) in which microorganism: - normally lives & multiplies, - on which it depends primarily for survival, - where it reproduces itself in such a manner that it can be transmitted to the susceptible host.
Colonization
presence of a microorganism on/in a host, with growth and multiplication of the organism, but without interaction between host and organism (no clinical expression, no immune response).
s
proportion of susceptible persons in the populations
Non-differential misclassification
random error, or the same amount of error in each group. Results will always be biased towards the null.
Differential misclassification
rate of misclassification differs in different study groups
Acellular Pertussis vaccine
subunit vaccine that contain purified, inactivated components of B. pertussis cells
recombinant vaccines
subunit vaccines produced by genetically engineered microorganisms
R0
the average number of people likely to catch the illness from a single infected person in a totally susceptible population
Incubation Period
the period between exposure to an infection and the appearance of the first symptoms
viral shedding
the release of virus particles that can potentially spread the infection to others
Incubation period
the time between exposure to an infectious agent and the onset of symptoms or signs of infection
vector transmission
transmission of an infectious agent by an insect, arthropod, or animal; ex: Malaria, Dengue, Lyme Disease, Zika, Yellow fever
Edward Jenner
used cowpox inoculation to prevent smallpox (immunization)
Effectiveness
vaccine performance under 'real-world' conditions
SARS-CoV
viral respiratory disease of zoonotic origin caused by the SARS coronavirus (_______________)
Influenza
virus replicates in all respiratory tree, particularly terminal bronchi, bronchioles and alveoli
Non-differential misclassification
when measurement error and any resulting misclassification occur equally in all groups being compared
Fastidious
will only grow when specific nutrients are included
recombinant vaccines
• Antigens may also be produced by genetic engineering technology • 5 currently available in the U.S. • Viral: hepatitis B, human papillomavirus, influenza (one brand), live attenuated influenza • Bacterial: Salmonella typhi (Ty21a)
Live attenuated vaccines
• Can be viral or bacterial • Derived from "wild," or disease-causing, viruses or bacteria • Attenuated (weakened) in a laboratory • Must replicate in a vaccinated individual to produce a response
Enterohemorrhagic E.coli (STEC)
• Hemorrhagic colitis caused by E.coli 0157:H7 • less frequently O26:H11 • cytotoxins resembling Shigella dysenteriae, type 1: shigalike or verotoxins
Influenza Antigenic Shift
• Major Changes • Changes occur quickly • Completely new subtype or virus • No immunity • Type A viruses only • Pandemic
Influenza Antigenic Drift
• Minor Changes • Often not even recognized by the human immune system • Natural mutation over time • Continuous process • Vaccine strains must be updated each year • Type A & B viruses Seasonal epidemics
inactivated vaccines
• Produced by growing the bacterium or virus in culture media, then inactivating it with heat and/or chemicals • Not alive, cannot replicate • Cannot cause disease from infection even in an immunocompromised person Ex: polio, hepatitis A, rabies
active immunity
• Protection produced by the person's own immune system • Often a lifetime immunity
passive immunity
• Protection transferred from another animal or human • Effective Protection that wanes with time
Polysaccharide vaccines
• Unique type of inactivated subunit vaccine • Pure polysaccharide vaccines • Able to stimulate B cells without the assistance of T-helper cells • Repeat doses of polysaccharide vaccines usually do not cause a booster response • Conjugate polysaccharide vaccines • Polysaccharide is chemically combined with a protein molecule
resident flora
Flora: Survives on the skin more than 24 hours; low virulence
Phase 4 (Post marketing surveillance)
What clinical trial is the following? Evaluation in the real clinical setting
Phase 1
What clinical trial is the following? First in humans, safety
Phase 2
What clinical trial is the following? First in patient dose, dosage form
SARS
"____________ patients are most likely to be contagious when they have symptoms, such as fever or cough. Patients are most contagious during the second week of illness" (CDC)
infectivity formula
(# infected / # susceptible) X 100
Virulence formula
(# of severe disease or deaths / # with disease (cases)) X 100
Pathogenicity formula
(# with clinical disease / # of infected) X 100
Traveler's Diarrhea
-Not common in US -Associated with many enteropathogens -Usually ingestion of contaminated food or water
Initial case definition
-This approach emphasizes sensitivity over specificity. -As additional information on the cases, exposure, and the symptoms is gathered, an updated, more EPID6214 Fall 2021 specific case definition is introduced.
Spot Maps
-useful for visualizing clusters -not indicative of higher incidence where spots are more dense - no accounting for population (denominator) -many apparent clusters are due to chance and are not necessarily indicative of proximity to causal factors
Steps of an Outbreak Investigation
1. Verify an outbreak is occurring 2. Confirm the diagnosis 3. Assemble an investigation team 4. Create a tentative case definition 5. Count cases 6. Perform epidemiologic analyses 7. Perform supplemental laboratory of environmental investigation (if indicated) 8. Develop hypothesis 9. Introduce preliminary control measures 10. Decided whether observation or additional studies are indicated 11. Perform additional analyses or plan and perform additional study 12. Perform new investigation-derived control measures and/or ensure the compliance of existing control measures 13. Communicate prevention information and findings 14. Monitor surveillance data
transient flora
Flora: catheter, bedpan, urinal, patient care casual contact; Enterobacteria, Gram - bacilli, Pseudomonas...
hypothesis
A hypothesis should be developed regarding: -Time -Person -Place -Etiologic agent -Mode of transmission
Vibrios
A leading cause of GI illness and septicemia from seafood consumption; Wound infections due to this bacteria are increasing
Antigen
A live or inactivated substance capable of producing an immune response
commensal
A relationship between two organisms in which one organism benefits and the other is unaffected
confounder
A variable that is associated with the exposure and independently influences the occurrence of the outcome.
resident flora
Flora: mostly Gram + , very few Gram - ;Staphylococci, diphteroides
infection
Infectivity is the ability of an agent to cause _______________ in a susceptible host and is measured as the proportion of exposed persons who become infected.
misclassification
Information bias results in ________________________
hypothesis
Initial __________________ based on: -Initial case reports -Interviews/questionnaires of index cases -Laboratory findings
Adolescents and adults
After immunization of disease, who is susceptible to pertussis?
Cluster
Aggregation of cases in a given area over a particular period without regard to whether the number of cases is more than expected.
cytotoxins
All Shigella produce _____________________, particularly S. dysenteriae
biological characteristics
All are dependent upon the condition of the host: age, gender, genetics, climate and weather, nutrition, stress, sleep, smoking, stomach acidity, hygiene
VHF
All types of ____________ are characterized by fever and bleeding disorders and all can progress to high fever, shock and death in many cases
hypothesis
Initial __________________ help clarify: -What is known -What is missing -Actions needed to gather missing information
communication
An effective outbreak investigation will involve _____________________ between: 1. Members of the investigation team 2. Stakeholders in the investigation -Hospital staff, physicians or infection control nurses -Daycare workers, school principles, teachers, parents 3. The public
Pandemic
An epidemic occurring on a global or semi-global scale
Endemic
An epidemic whose incidence remains stable over a long period of time. This forms a baseline for comparison to determine if a new epidemic is EPID6214 Fall 2021 occurring.
infectious disease
An illness due to a specific infectious agent or its products that arises through transmission of that agent from an infected person, animal or reservoir to a susceptible host, either directly or indirectly, through an intermediate plant or animal host, vector or the environment.
actually occurring
An important early step in any outbreak investigation is to verify that an outbreak is _________________________-.
Carrier State
An individual with an inapparent infection who is able to transmit that infection is considered to be a carrier.
zoonotic disease
An infectious disease is transmitted between species (sometimes by a vector*) from animals other than humans to humans or from humans to other animals.
cholera
Approximately 80% of _________________ infected individuals do not demonstrate any symptoms.
high
Are the following a part of a high or low risk group for HAV? Anyone not previously vaccinated or infected
Yes, one is Zebov
Are there 2 vaccines for Ebola rn?
high
Areas with ____________ levels of infection of HAV: • Developing countries with poor sanitary conditions and hygienic practices • Most children infected by age 10 • Infections in childhood results in very few symptoms • Epidemics uncommon because older children and immune • Symptomatic disease rates are low
Giardia
Anyone may become infected with ____________ those at highest risk are: ◦ Travelers to countries where giardiasis is common ◦ People in childcare settings ◦ Those who are in close contact with someone who has the disease ◦ People who swallow contaminated drinking water ◦ Backpackers or campers who drink untreated water from lakes or rivers ◦ People who have contact with animals who have the disease ◦ Men who have sex with men
simple
Assumptions for _____________ models: • Everyone is susceptible at beginning of outbreak/epidemic • Assume no heterogeneity • Random mixing
systematic stool examination
Asymptomatic carriage of Salmonella can be detected by __________________________ examination
Noroviruses
At least 50% of all food borne outbreaks of gastroenteritis can be attributed to what?
Descriptive Information Laboratory Data Environmental Data
List the information used in developing a case definition
◦ Itchy skin ◦ Hives ◦ Swelling of the eyes and joints
List the less common symptoms of Giardia
community-wide; person 2 person
Before the HAV vaccine, most diseases occurred in __________________________ outbreaks and infection transmitted ___________________ in households
preformed
Botulism occurs from consumption of _________________ toxin in foods
chicken
Campylobacter jejuni Grows best at 37°C to 42°C body temperature of _________________ (41°C to 42°C)
Nausea Vomiting Diarrhea
Clinical features of foodbrone botulism include?
Giardia
Communicability of this disease is that it can transmitted during the entirety of infection, which can last months
Wright County Egg
Company that had observations of concern highlighted by the FDA: • Failure "to eliminate rodent hiding places and nesting sites," and failure to properly seal its henhouses. • Failure to eliminate sources of water in the manure pits below the henhouses. • Failure to require employees to "change protective clothing when moving from house to house." • Failure to keep uncaged chickens out of the egg-laying operation.
publication
Considerations for ___________________ 1. Establish who will be the primary and senior author 2. Clearly define roles of individuals for the manuscript
Louis Pasteur
Created first rabies vaccination (live attenuated vaccine) on a nine year old boy
40%
Cruise ships have an overall high attack rate, up to ________%
human
Cryptosporidium parvum and C. hominis are the most relevant species for ___________________ health; Both can cause a self-limiting diarrhea in immunocompetent individuals, but can cause potentially life-threatening disease in the immunocompromised.
Nitazoxanide
Diarrhea from Crypto can be controlled by a 3-day course of what?
Enteroinvasive E.coli (EIEC)
Diarrhea with fever in all ages
disease Vaccines DONT PREVENT infection
Do vaccine prevent disease or infection?
identify
During the course of an outbreak investigation, the investigator should take steps to ________________ additional cases not known or reported at the time on the initial report
Incubation Period
Each disease has typical __________________________ but varies widely. Requires replication of the organism to some threshold level for producing symptoms.
-Rate of growth of the organism in the host -Dosage of the infectious agent -Portal of entry/route of inoculation -Immune response of the host
Each infectious disease has a characteristic incubation period dependent on: ? -? -? -? -?
prophylaxis
Epidemic Measures for HAV: 1. Determine mode of transmission (person-to-person or common vehicle) 2. Make special efforts to improve sanitation and hygiene practices 3. Outbreaks in institutions may warrant mass ____________________ with HAV vaccine or IgG
outbreak
Epidemic limited to a localized increase in the incidence of disease
information bias
Error that arises from systematic differences in the way information on exposure or disease is obtained from the study groups.
E. coli
Escherichia coli
Exposure
Estimating Risks Associated with "_________________": Compare attack rates among exposed and unexposed
Non-differential misclassification
Example: In a case-control study of alcohol consumption and risk of hepatocellular carcinoma, both cases and controls underreport exposure to alcohol
transient flora
Flora: Acquired during contacts with contaminated areas mouth, nose, perineal area, genitals, anal area
transient flora
Flora: Easily removed with soap and water
resident flora
Flora: Not easily removed, hours of scrubbing; complete sterilization impossible
Attack Rate (AR)
Expresses occurrence of disease among a particular at-risk population for a limited period of time, often due to a specific exposure. -Can be event or exposure specific
R
Factors influencing ______: • Transmission mode (airborne, large droplets, blood and body fluids, other) • Infection-control practices in place (see Ebola West Africa) • Incubation period short versus long, duration of infectiousness (SARS vs. HIV) • Extent of contact an infectious person has with others (infectious period) or duration of infectiousness (see Ebola West Africa) • Percent of the population that has been vaccinated (if a vaccine exists)
transient flora
Flora: Survive on skin less than 24 hours; may have high virulence
EpiInfo
Field statistical epidemiology software developed by the CDC for outbreak investigations
Prepare Investigation
Goal of ____________________________: each investigator knows their role and has the tools to successfully complete his or her deliverables
Influenza Antigenic Drift
Gradual changing of amino acid composition of influenza antigens Results in decreased ability of host memory cells to recognize them
Shigella
Gram negative rods of Enterobacteriaceae family that is divided into 4 major O antigenic group: A: S. dysenteriae B: S. flexneri C: S. boydii D: S. sonnei
Salmonella enterica
Gram-negative, food-borne pathogen that causes human diseases ranging from mild gastroenteritis to severe systemic infections
Salmonella enterica
Group 1 of Enterobacteriaceae where there is majority of human isolates
Botulism
Growth and toxin formation for foodborne _______________ to occur require: • an anaerobic environment • moisture • Neutral-to-alkaline pH • Energy source such as sugar or protein
Enterohemorrhagic E.coli (STEC)
Hemorrhagic colitis and hemolytic uremic syndrome in all ages and thrombotic thrombocytopenic purpura in adults; bloody diarrhea
Whooping cough
Highly contagious respiratory infection caused by the bacteria Bordetella pertussis
Case Reports Surveillance
How are Potential Outbreaks Identified?
onset
Infectiousness of Ebola starts by ______________ of disease (not before) (again unlike influenza)
wet, red or dirty
If it is ________, ___________, or ____________ wash, glove then wash after removing gloves
decrease
If proportion of immunes is > HIT then infection should _______________
5-10 years
Immunity for Pertussis wanes approximately ______-______ years after vaccination
intermediate and low
In high transmission areas, little risk. In ____________________________ transmission areas risk factors include: • Poor sanitation • Lake of safe water • Use of recreational drugs • Living in a household with an infected person • Being a sexual partner of someone with acute HAV • Traveling to areas of high endemicity
Special Cases
In some cases, a single case of a severe disease demands investigation. Some example are: human rabies, anthrax, foodborne botulism, polio, and bubonic plague.
Cholera
In untreated severe disease: - Rapid dehydration - Acidosis - Circulatory collapse - Hypoglycemia in children - Renal failure that can lead rapidly to death
Enterotoxigenic E.coli (ETEC)
Infantile diarrhea in developing countries and travelers' diarrhea
Host
Infected or potentially infected person or animal
secondary attack rate
Infected/Susceptible after contact with a primary case (Quantified for many infections highest for airborne transmissions, Rabies e.g. 30% after bite from a rabid dog)
Universal Precaution Standard Precaution
Infection control includes what 2 precautions?
Giardia
Infection with _________________ is associated with: ◦ Drinking water from unfiltered surface water sources or shallow wells ◦ Swimming in bodies of freshwater ◦ Eating contaminated food. Transmission also occurs person 2 person and through anal-oral intercourse
infectious agent toxic transmission intermediate
Infectious Disease: An illness due to a specific _______________________ or its _______________ products that arises through _______________________ of that agent from an infected person, animal or reservoir to a susceptible host, either directly or indirectly, through an ____________________ plant or animal host, vector or the environment.
Infectious agent
Infectious microbe or parasite that produces disease, pathogen
surveillance
It consists of: -Ongoing, systematic collection of health data -Data analysis, -Interpretation of data, -Dissemination of the information, AND -Linking the health data to public health practice
phenolics
It has been suggested that double-strength phenolics may be effective for norovirus
Positive polymerase chain reaction (PCR) for B. pertussis
Laboratory Criteria for Diagnosis: -Isolation of Bordetella pertussis from clinical specimen -?
Airborne Droplet Contact (direct and indirect) **Another that is not as important for isolation guidelines include vector-borne
List the main modes of transmission that isolation guidelines in institutions are based off of
Giardia; Giardia
Life Cycle 1. Infections occurs when _____________ infected cysts are ingested by a susceptible host. 2. Cysts are hardy and can survive well in the environment, particularly in cold water. 3. Trophozoites live and multiply in the small intestine. 4. Trophozoites and cysts are shed in stool 5. Animals are infected with ______________, but their role in transmission is unclear
Rabies WNV H1N1, H5N1, H5N1 etc. (pandemic flu) Salmonella serotypes (Except Salmonella typhi) Yersinia pestis Tuberculosis (Mycobacterium tuberculosis, M. bovis) Baylisascaris procyonis
List 3 types of zoonotic diseases
◦ Diarrhea ◦ Gas ◦ Greasy stools that tends to float ◦ Stomach or abdominal cramps ◦ Nausea/vomiting ◦ Dehydration
List at least 4 acute symptoms of Giardia
-Frequent, non-bloody, watery diarrhea -Abdominal cramps -Fatigue -Fever -Nausea/Vomitting -Weight Loss -Dehydration
List at least 4 symptoms of Crypto
• Fever • Fatigue • Loss of appetite • Nausea • Vomiting • Abdominal pain • Dark urine • Clay-colored bowl movements • Joint pain • Jaundice • Malaise
List at least 4 symptoms of HAV
-Alcoholism -Cancers, particularly on chemo or radio-therapy, leukemia, lymphoma, Hodgkin's -Diabetes -Gastric disease -Hemochromatosis -Immune suppression (HIV) -Kidney chronic disease -Liver disease -Long term steroid use -Old age
List at least 4 underlying conditions that increases the risk for serious V. vulnificus infection
Pneumonia Seizures Encephalopathy Hospitalization Death
List some complications of pertussis
Human rabies Anthrax Foodborne botulism Polio Bubonic plague
List some diseases where a single case of severe disease demands investigation
-Closing a business: pool, restaurant, daycare center, so on. -Mass vaccinations -Boil water advisory
List some examples of extreme control measures
-Water temperature -Air temperature -Harvest technique -Cooling method -Post-harvest processing method
List some factors that affect Vibrio illnesses
Mechanical Biological
List the 2 types of vector transmission
Infectivity Pathogenicity Virulence Carrier state/inapparent infection Immunogenicity Herd immunity
List the Biologic Characteristics of Organisms
◦ Person-to-person ◦ Animal-to-person ◦ Waterborne (including recreational waters) ◦ Foodborne
List the fecal-oral transmission route for Cryptosporidium
Mosquirix
Malaria vaccine: Plasmodium falciparum vaccine vaccine to generate antibody and T-cell immune response recombinant protein Phase 3
human reservoirs
Many common infectious diseases have ___________________ reservoirs. These are diseases that are transmitted person to person without intermediaries, including STDs, measles, mumps, and many other respiratory infections.
temporal; seasonal
Many diseases undergo ___________________ variation in incidence. When this variation depends on the time of year, the variation is called _____________________.
asymptomatic
Many infections of Giardia are _____________________ (symptomatic/asymptomatic)
seasonal
Many respiratory illnesses have a __________________ variation, including influenza and pertussis. However, the reason why is still unclear.
Live attenuated vaccines
May cause severe/fatal reactions as a result of uncontrolled replication of the virus • Only occurs in the immunocompromised Ex: Measles, mumps, rubella, yellow fever
acceptable
Milk can be contaminated and infect persons with Mycobacterium bovis, Listeria monocytogenes, Q fever (Coxiella burnetii), Brucella, Campylobacter, Salmonella, Escherichia coli O157:H7 etc. Milk is tested following pasteurization to confirm that bacteria have been killed to an _____________________ level.
Giardia
The following are complications of _______________ in children: ◦Delayed mental and physical growth ◦Slow development ◦Malnutrition because of failure to absorb fat, lactose, vitamins A and B12
500
More than ___________ health care workers (only 3 outside the hot zone) have contracted Ebola since the outbreak began in December 2013, and 269 have died, (WHO, Nov 2014).
Model
Most Common __________________ Structures: SI: Susceptible - Infectious (HIV) SIS: : Susceptible - Infectious - Susceptible (STIs) SIR: Susceptible - Infectious - Recovered/Removed (=Immune) (MMR) SIRS: Susceptible - Infectious - Recovered - Susceptible (Pertussis, Flu, COVID-19?) SEIR: Susceptible - Exposed- Infectious - Recovered/Removed (=Immune) (MMR) SEIRS: Susceptible - Exposed - Infectious - Recovered - Susceptible (Pertussis & Flu)
RN
NET OR EFFECTIVE REPRODUCTION NUMBER
Negative predictive value
NPV = TN / (TN + FN)
Vibrios
Naturally occurring bacteria in salt-water (halophilic-SALT LOVING); highest levels in warmer months
herd immunity
Necessary conditions for ____________________: ◦ Agent restricted to single host species ◦ Relatively direct transmission ◦ No reservoir outside human host ◦ Infections induce solid immunity
supportive
Norovirus treatment is only ___________________ and there is only short term and strain specific immunity
Epidemic
Occurrence of more cases of illness than expected in a given area or among a specific group of people over a particular period of time. Causes usually presumed to have a common cause or be related to one another in some way.
Airborne
Occurs when aerosolized droplet nuclei less than 5 microns (< 5 µ) are expelled into the air via cough or sneeze; Nuclei have the ability to stay suspended in the air for a greater amount of time; ex: Measles, TB, varicella, smallpox
Droplet
Occurs when aerosolized droplet nuclei more than 5 microns (> 5 µ) are expelled into the air via cough or sneeze; Droplet nuclei usually travel less than three feet. Exposure does not usually occur outside of this distance; ex: Mumps, pertussis, and influenza
Differential misclassification
Occurs when the accurate measurement of a disease depends on the exposure and results in a biased estimate of effect.
colonization
Often the term ________________________ is applied for relationship host-agent in which the immune response is difficult to elicit.
supportive
Only ____________________ treatment is used for Ebola: Fluid management to prevent shock, blood transfusions, oxygen, ventilations, pain control and ulcer prophylaxis
mud party and petting zoo
Outbreaks of E. Coli in Louisiana are due to what?
Crypto
Outbreaks of ______________ occur: -Contamination of public water ◦At least 3 major outbreaks -Daycare centers worldwide Recreational use of water ◦Swimming pools, water slides, pools, and lakes -Consumption of infected foods and water
botulinum toxin
Outbreaks of foodborne botulism occur when food is prepared under conditions that permit the formation of _________________ _____________.
2-6 months
Outside the body oocysts may remain infective for ___-____ months or longer in a moist environment
Positive predictive value
PPV = TP / (TP + FP)
Pertussis pathogenesis
Pathogenesis of _________________: • Toxin mediated disease •Attach to cilia of respiratory epithelial cells • Inflammation interferes with clearance of pulmonary secretions
disease
Pathogenicity is the ability of a microbial agent to induce ________________ is measured as the proportion of infected persons who develop clinical disease.
DROPLET & CONTACT
Patient Placement for what? • Private room preferred • or cohort with same infection • or at least 3 feet between beds • Use common sense: do not mix immunocompromised patient with infected one
AIRBORNE
Patient Placement for what? Private room with ventilation control
10
People who recover from Ebola infection develop antibodies that last for at least _______ years.
environmental reservoirs
Plants, soil, and water in the environment are also reservoirs for infectious disease.
existing
Practically, it is important to ensure ________________ control measures are adhered to. Issues can arise when those responsible for implementing control measures are not convinced the measure is sound or they do not trust the information.
Airborne Precautions
Precautions include: 1-ROOM WITH VENTILATION CONTROL • Negative air pressure • >6 air exchange /hour • HEPA filtered or exhaust out 2-PERSONAL RESPIRATOR 3-PATIENT wears surgical mask if coughing & when transported
team; surveillance; supervisor's; supplies; state and local
Prepare the Investigation -Identify outbreak investigation ____________ -Share __________________ information -Get appropriate __________________ approval -Gather __________________ and equipment -Review scientific information -Notify __________________ departments
Contamination
Presence of a microorganism on a body surface or an inanimate object.
newborn
Prevention of pertussis in this group is the main goal due to when this group becomes infected they have the most severe infection
Crypto
The following are complications of people who develop ________________: People with weakened immune systems may develop serious, chronic, and sometimes fatal illness from this GI infection. Exs: ◦ Persons infected with HIV/AIDS ◦ Cancer and transplant patients taking immunosuppressive drugs ◦ Those with inherited diseases affecting the immune system
Annual Variation
Prior to the development of vaccines, diseases such as measles, mumps, and varicella, would propagate through the population, leaving no susceptible individuals. As new individuals were born, the number of susceptible would go up and epidemics would occur again. These factors led to ___________________ variation in disease incidence
Antibody
Protein molecules (immunoglobulins) produced by B lymphocytes to help eliminate an antigen
norovirus
The following are complications that may happen with _____________________: Severe dehydration is possible and may be fatal to the very young/old.
Appropriate Ethical Intelligible Omni competent Unambiguous Coded Unbiased Piloted
Questionnaire Design- Guidelines include? AEIOU CUP
-Is the item needed? -Can I analyze it? -Can it be answered accurately? -Will it be answered accurately?
Questionnaire Design—Criteria
Influenza Antigenic Shift
RNA exchange between different viruses Occurs during coinfection of a host cell More likely to produce pandemic strains
negative association
RR/OR<1 means?
no association
RR/OR=1 means?
positive association
RR/OR>1 means?
shifts
Reasons as to why there are ________________ in Colonization Flora: - Modification of the skin environment due to skin changes still poorly understood - Invasive procedures provides portal of entry to different flora: - Antibiotic therapy:
Antibiotic Chemoprophylaxis
Recommended for all close contacts of pertussis, regardless of age and immunization status
hydrogen peroxide
Relatively new "accelerated, stabilized ___________________ __________________" .... Good activity against Feline calicivirus, good success in norovirus outbreak management aboard ships
communicate; contribute
Remember—one of your responsibilities as an epidemiologist is to ______________________ findings and _____________________ to the literature.
True
T/F: Diseases with only a human reservoir are good candidates for vaccination and disease eradication.
Cholera
Risk Groups of ________________: Increased Risk: - Lowest SES groups, particularly people without access to clean water and adequate sanitation - Persons with blood group O are more vulnerable to severe cholera if infected Reduced Risk: - Breastfeeding infants
True
T/F: HAV vaccine should be considered for all high-risk populations
True
T/F: HAV vaccine should be given ASAP, but no more than 2 weeks after exposure
True
T/F: Immunity of HAV is life long and there is no chronic carriage
True
T/F: Immunization decreases pertussis cases but did not change cycles
True
T/F: Norovirus does not multiply in foods
2x2 table
STUDY
True
T/F: Over time the number of immunes will increase and the number of susceptible persons will decrease therefore; R0 > Rn
FALSE; STEAMING DOES NOT INACTIVATE NOROVIRUSES
T/F: Steaming inactivates noroviruses
foodborne
Salmonella, E. coli, Shigella by _____________________ transmission
external validity
Selection bias affects _______________________ of the study.
sensitivity
Sensitivity = TP / (TP + FN)
True
T/F: Stool samples are best collected 48-72 hours after exposure (i.e. acute phase of norovirus), but stools are positive up to 7-10 days after onset
incubation period
Take the average and range of all cases to describe the ____________________
Phase 3
What clinical trial is the following? Efficacy, adverse drug reactions
low
Shigella has a ___________ infective dose: 10-200 bacteria by mouth
Influenza virus
Single stranded RNA virus: • Evolve rapidly Lipid envelope with 2 important glycoprotein • Hemagglutinin HA • Neuraminidase NA
Resident Flora Transient Flora
Skin Hand Flora includes what 2 types of flora?
severe
Some control measures for are already established and incorporated into state and federal legislation. This is especially true for ___________________ disease.
specificity
Specificity = TN / (TN + FP)
Hand Sanitizers
These can quickly reduce the number of germs on hands in some situations, but they do not eliminate all types of germs: Not effective on spores (particularly Clostridium difficile)
authorities
State public health codes require physicians and laboratories to report certain infectious disease to public health _____________________
CDC
States report nationally notifiable diseases to the ___________ through the NNDSS
antigens
Studies of _______________ that produce protective immunity after natural infections often lead to development of vaccines.
variant viruses
Swine flu viruses do not normally infect humans but when they do these viruses are called '_____________________'
True
T/F: 2 oral vaccines (Dukoral and Shanchol) are prequalified by the WHO and available in many countries for Cholera
True
T/F: A single reported case of botulism is enough to initiate an outbreak investigation
True
T/F: Children are infected with Giardia more frequently than adult
Botulism
These conditions for ________________ to occur most often present in lightly preserved foods and inadequately processed, home-preserved foods, and home-canned foods
viral shedding
The Norovirus has _____________ __________________: -Up to 72 hours after recovery -Up to 2 weeks in both symptomatic and asymptomatic people
persons experiencing homelessness
The Updated Vaccine Recommendations 2019 stated that what other specific population should received the HAV vaccine?
media
The _________________ can be a useful tool in communicating with the public: -Effective medium to communicate to the public what they need to know. -Can be less than scientific or overzealous in communication of information.
journalist
The ______________________ limited by the amount of time of his/or her broadcast or the length of his or her column. Thus, it is important to be concise and provide the media with a cohesive message.
communicability
The _______________________ of HAV begins a week or two before symptoms manifest (most infective) and diminishes rapidly afterwards
true positive rate
The ability of a diagnostic test to correctly identify individuals with disease; it is the proportion of individuals with the disease who are correctly identified by the test as positive (i.e., have the disease). Also called sensitivity.
true negative rate
The ability of a diagnostic test to correctly identify individuals without disease; it is the proportion of individuals without the disease who are correctly identified by the test as negative (i.e., do not have the disease). Also called specificity.
Sensitivity
The ability of a test (case definition) to correctly identify those with the disease
Specificity
The ability of a test (case definition) to correctly identify those without the disease
Immunogenicity
The ability of an organism to produce an immune response after an infection that is capable of providing protection against reinfection with the same or a similar organism
secondary attack rate
The attack rate in susceptible people who have been exposed to a primary case.
1. Small enumerable exposed groups 2. Large enumerable exposed groups 3. Large or small groups where the exposure situation can be pinpointed, but the exposure population cannot be enumerated 4. The exposed population is not known or enumerable
The characteristics of the exposed population are determined after interviewing initial cases and fall into four categories?
sensitivity and specificity
The creation of a case definition must always weigh what?
hypothesis
The development of a ___________________ is an early stage of outbreak investigation.
2-4
The duration of Giardia is self-limiting infections usually resolving in ______ - _______ weeks
Influenza
The duration of viral shedding for ___________________ is from 1 day before onset to 5 days after onset
New Orleans
The first reported human Baylisascaris case in ______________________ raised concerns that very little was known about this zoonotic disease in the increasing urban racoon population
prevention
The primary goal of an investigation is always _________________
Natural History of Disease
The progress of a disease process in an individual over time, without intervention
pathogenicity
The proportion of individuals with asymptomatic infections is a measure of what?
Herd Immunity
The resistance of a group to an attack by a disease to which a large proportion of the members of the group are immune.
80%
The secondary attack rate for pertussis is up to _____%
Epidemic Curves
These plot the number of cases by the time of disease onset.
Inapparent Infections
These potentially play a large importance in the propagation of epidemics. The understanding of the transmission of a disease during an epidemic can help control transmission
Standard Precautions
These precautions are designed to reduce the risk of transmission of microorganisms from both recognized and unrecognized sources of infection in hospitals
efficacy and effectiveness
There are many factors that influence this critical percent (herd immunity), including ________________ and ____________________ of the vaccine and infectivity of the disease.
Cryptosporidium
There are many species of __________________________ that infect animals, some of which also infect humans. The parasite is protected by an outer shell that allows it to survive outside the body for long periods of time and makes it very tolerant to chlorine disinfection.
"Sky is falling" syndrome
There are risks and benefits of involving others early on in Outbreak Investigations. What is one?
Colonization Protects the Host
There are several mechanisms for protection: - Non specific stimulation of immune responsiveness - Specific cross reactive immunization - Competitive bacterial interference
N95 Mask PAPR Powered Air Purifying Respirators
These airborne precautions are for Personnel: • In AIRBORNE ISOLATION ONLY • To prevent inhalation of droplet nuclei • Main leak comes from poor fit around face
Standard Precautions
These are an expansion of universal precautions: -Precautions should be taken for any contact with Blood and Body Fluid (UP) -AND for any contact with secretions and excretions, mucous membranes, damaged skin, contaminated environment and equipment
Isolation Quarantine
These are necessary Public Health measures to prevent exposure to people who have or may have a contagious disease.
Hand sanitizers
These are not effective when hands are visibly dirty
Surgical Masks
These are used for DROPLET PRECAUTIONS to prevent large droplets (>5mu m) on/from patient and for patients to prevent emission of droplet (large and droplet nuclei)
Surgical Masks
These are used for STANDARD PRECAUTIONS for personnel to protect from splashes /sprays of blood and body fluids (BBF), secretions (S) and excretions (E)
Eye Protection Face Shield
These are used in risk of spray or splash: - of blood, - body fluid, - secretion - excretion in FACE OR EYE
Frequency Tables
These can be used to describe the general patterns of the outbreak.
carrier
Think about ______________ as: - Potential Source for infection - Explanation for persons who don't show signs or symptoms
Inapparent Infections
This an infection that can be documented by isolation of an organism by culture, positive PCR, or demonstration of an immune response in persons who remain asymptomatic.
Shigella
This bacteria is ale to penetrate cells
Wright County Egg
This company is still allowed to sell eggs, but they must go to a "breaker" facility where the eggs are removed from their shells and heated to kill salmonella for use in prepared foods such as cake mixes
exposed
This definition relies on mode of transmission and other information that may not be all known
initial case definition
This definition will start broadly as opposed to narrowly, with the goal of identifying as many cases as possible.
SARS-COV2
This disease is mainly transmitted through droplets > 5 micron which will fall on the ground within 6 feet
Asymptomatic infection
This does not mean that "all is quiet". It may cover some very active processes as in the asymptomatic phase of HIV infection, tuberculosis infection, hepatitis B carrier state.
Filoviridae
This enveloped RNA virus can lead to Ebola
vehicle transmission
This includes transmission via water-borne, foodborne, and fomites
Rn
This is a reproduction number and is the average number of successful transmissions per infectious person
carrier
This is an individual that harbors a specific microorganism in the absence of discernible clinical disease and serve as a potential source of infection.
vector
This is any agent that carries and transmits an infectious pathogen to another living organism
botulinum toxin
This is one of the most lethal substances in existence; this toxin is produced by the bacterium Clostridium botulinum
zoonosis
This is termed "_________________" refers to an infectious disease that is transmissible under natural conditions from vertebrate animals to humans. Examples: brucellosis (cows and pigs), plague (rodents), tularemia (rabbits), and rabies (bats, raccoons, dogs, and other mammals).
Pathogenicity
This is the ability of a microbial agent to induce disease is measured as the proportion of infected persons who develop clinical disease
Infectivity
This is the ability of an agent to cause infection in a susceptible host and is measured as the proportion of exposed persons who become infected
R0
This is the basic reproduction number; If an infectious person is introduced into a totally susceptible population, average of secondary infectious persons resulting from this infectious person
Surveillance
This is the continuous monitoring of the occurrence of a disease (or other important health event) in a population.
reservoir
This is the long-term host of the pathogen of the infectious disease. Hosts often do not get the disease carried by the pathogen or it is carried as an asymptomatic subclinical infection.
mode of transmission
This is the means by which an infectious agent infects a susceptible host
Test positivity
This is the number of positive tests/ total number of tests per day
oocysts; oocyst
Transmission of Cryptosporidium results from the ingestion of ________________; one single _________________ is enough to make a person ill with crypto
Person to Person Large Droplets Airborne Contact, fomites
Transmission of Season Flu?
Vibrio
Transmission of _______________: - Ingestion of raw or undercooked shellfish (ie oysters, clams) - Direct skin exposure to seawater or raw seafood drippings
botulism antitoxin
Treatment for botulism should include supportive care and careful administration of what?
Biological
Type of vector transmission: : the vector uptakes the agent, replicates and/or develops it, and then regurgitates the pathogen onto or injects it into a susceptible animal
Mechanical
Type of vector transmission: the disease agent does not replicate or develop in/on the vector, it is simply transported by the vector from one animal to another
90
Up to ________% of Salmonella infections in the US are foodborne
blood
Upon recovery from Ebola, virus clears fast from _____________ but is longer persistent in kidneys, gonads and other organs
standard
Use ______________________ precautions at ALL times for ALL patients
Campylobacter jejuni (gram-negative & don't like oxygen)
Well adapted to birds who are carriers
Compartmental
What Model classification is the following? -Populations are divided into categories/compartments -Tracks infectious process in populations, can be either deterministic or stochastic
Transmission dynamics or "Dynamic transmission" models
What Model classification is the following? Includes contacts (hence transmission) between individuals. Risk or force of infection depends on number of infectious persons in the population and therefore changes over time...
Network
What Model classification is the following? Network of individuals is explicitly modelled, especially for STDs
Static
What Model classification is the following? Risk or force of infection is "pre-determined". Used when risk of infection is known, not good when evaluating interventions i.e. to reduce the prevalence of infectious persons with vaccinations or treatment interventions because the risk of infection might change
Individual based or microsimulation
What Model classification is the following? Tracks infection process for every individual of the population, most likely stochastic models
-Chronic, severe diarrhea -Malnutrition -Dehydration -Death
What are some complications of Crypto that may happen to people with HIV?
Diarrhea, Nausea, Abdominal pain, Vomiting, Myalgia, Fatigue, Headache Low fever, Chills
What are some gastroenteritic symptoms that may develop after getting infected with the norovirus?
cough & mild URTI
What are some of the symptoms of pertussis in the catharrhal stage?
cough w/ inspiratory whoop & vomit; minimal fever
What are some of the symptoms of pertussis in the paroxysmal stage?
Handwashing Sanitary disposal of feces Protection of water supply Food prep Control of vectors (specifically flies)
What are some prevention methods of Shigellosis?
Organize questions to facilitate recall Offer "not sure" response
What are some solutions to Foodborne Questionnaires or food histories?
DTaP (pediatric) Tdap (adolescent and adult)
What are the 2 Pertussis-containing vaccines?
R0 and Rn (Reproduction Numbers not Rates)
What are the 2 measures for measure of transmissibility?
Hand washing Avoid contaminated water
What are the 2 methods of control for Crypto?
Active Passive
What are the 2 types of immunity?
Preschool and school children
What are the core transmission groups for influenza?
• Ingestion of food or water contaminated with feces of infected person (Vehicle) • Person-to-person transmission • Indirect through environmental fomites • Waterborne outbreaks
What are the fecal-oral routes of transmission for HAV?
Restaurant and catered meals (36%), nursing homes (23%), schools (13%) and vacation settings or cruises (10%)
What are the most common settings for food-borne outbreaks of norovirus?
• Sewage contamination of well water • Recreational waters: (swimming pools etc.) • Commercial ice • Lake and river water (see Colorado river rafters, Grand Canyon, Summer 2002)
What are the most common settings for waterborne outbreaks of norovirus?
Education Proper water treatment and distribution systems and sewage disposal Pre-exposure immunization
What are the prevention methods for HAV?
Humans and environment (brackish water or estuaries)
What are the reservoirs for Cholera?
Humans Wild and domestic animals such as cats, dogs, cattle, and beavers
What are the reservoirs of Giardia?
Primates such as gorillas and chimpanzees *become infected and can have high case fatality rate
What are the vectors for Ebola?
subclinical or inapparent infection
an infection with signs and symptoms too mild to be recognized, except by special tests
matching
any attempt to force a sample to resemble specified attributes of the population
herd immunity formula
𝑉 = 1 − (1/𝑅0) -where V equals the herd immunity threshold and 𝑅0 equals the basic reproductive number
