chapter 19 microbiology
______ studies take into account past events that may have led up to the onset of the disease. Cross-sectional Cohort Case-control
Case-control
_____________________is the study of the distribution and causes of disease in populations.
Epidemiology
Humans have been enormously successful in eliminating or reducing the occurrence of certain diseases through efforts in ______. antibiotic treatment reservoir and vector control robotic surgery vaccination deforestation improved sanitation
Escherichia coli
______ studies are used to assess the value of a particular intervention or treatment, and also to judge the cause-and-effect relationship between the risk factors and disease. Retrospective Experimental Analytical
Experimental
In a case-control study, which characteristics should the controls share with the cases? Gender Disease symptoms Socioeconomic status Age
Gender Socioeconomic status Age
Compared to the general population, some descendants of Northern European ancestry are genetically less susceptible to ______ because they lack a specific receptor on their white blood cells. smallpox HIV malaria
HIV
Young children are particularly susceptible to meningitis caused by _______; fortunately, use of a(n) ______ has dramatically reduced the incidence of meningitis in this age group. Haemophilus influenzae; vaccine Staphylococcus aureus; antibiotic Haemophilus influenzae; antibiotic Staphylococcus aureus; vaccine
Haemophilus influenzae; vaccine
Which of the following have directly resulted in emergence of certain foodborne illnesses? More people living in cities Importation of food Mass production of food Widespread distribution of food
Importation of food Mass production of food Widespread distribution of food
_________________ contact involves transfer of pathogens via inanimate objects such as doorknobs, drinking glasses, or clothing, otherwise known as fomites.
Indirect
Who performed an epidemiological study of a large cholera outbreak in London during the mid 1800s? Joseph Lister Louis Pasteur Alexander Fleming John Snow
John Snow
Which disease is most likely to increase as people move closer to forests and other traditionally wild areas? Lyme disease Botulism tuberculosis Huntington disease
Lyme disease
Humans can serve as reservoirs for most communicable diseases. Which situation is easier to control? Symptomatic infections Asymptomatic carriers
Symptomatic infections
In week one, there are 30 cases of a specific disease. At the end of week two there are a total of 80 cases. By the end of the third week, t here are 150 cases. What does the prevalence rate indicate? The disease is decreasing in the population The disease is spreading in the population
The disease is spreading in the population
Two locations are experiencing cases of an infection: a city of 6,000,000 people with 600 cases, and a town of 6,000 with 300 cases. Which scenario is likely of greater concern to epidemiologists? The town of 6,000 The city of 6,000,000
The town of 6,000
True or false: Diseases with a long incubation period can spread extensively before the first symptomatic cases appear.
True
True or false: Hospital laboratories must report on the isolation of pathogens with epidemiologic significance.
True
True or false: It is important to know the geographic location of disease acquisition so that the source of infections can be determined.
True
True or false: News media alert the public to the presence of infectious disease.
True
True or false: Pathogens that have environmental reservoirs are difficult or impossible to eliminate.
True
_______ transmission occurs when a disease-causing agent passes from mother to baby during the period immediately before and after birth. Horizontal Innate Hereditary Vertical
Vertical
Which of the following statements about urinary tract infections (UTIs) in humans is true? Women are more susceptible because their urethra is relatively short. Women are more susceptible because their urine is relatively neutral. Men are more susceptible because their urethra is relatively short. Men are more susceptible because their urine is relatively neutral.
Women are more susceptible because their urethra is relatively short.
A new serotype of Vibrio cholerae, designated 0139, has acquired the ability to produce ______. pili an endospore an endotoxin flagella a capsule
a capsule
When an epidemic spreads globally, it is ______. an outbreak endemic a pandemic sporadic
a pandemic
Which of the following studies aim to assess if any of the potential risk factors identified by the descriptive studies are relevant in disease transmission? analytical studies retrospective studies experimental studies cohort studies
analytical studies
Many sexually transmitted diseases are spread when an infected individual is unaware of his or her infection. These infections are ______. symptomatic zoonoses asymptomatic
asymptomatic
The ______________ rate is the proportion of susceptible individuals developing illness within a population exposed to an infectious agent.
attack
The proportion of susceptible individuals developing illness in a population exposed to an infectious agent is the ______. prevalence rate mortality rate attack rate
attack rate
The average number of secondary cases that develop from a single case in a susceptible population is known as the______________ ______________ ______________ (R0).
basic, reproductive, number
In a case-control study of an outbreak of a foodborne illness among school children, the best controls would be ______. parents of the ill children best friends of the ill children
best friends of the ill children
Mosquitos that harbor the malarial parasite Plasmodium transmit the parasite and play an essential role in its life cycle. These mosquitoes are ______ vectors of Plasmodium. mechanical biological
biological
What are ways by which droplet transmission of infectious agents can be minimized? by wearing gloves when shaking hands by having people cover their mouth when they sneeze or cough, preferably not with their bare hands by washing fruits and vegetables with soap and warm water by placing desks or beds more than 1.5 meters apart in densely populated building
by having people cover their mouth when they sneeze or cough, preferably not with their bare hands by placing desks or beds more than 1.5 meters apart in densely populated building
Transmission of pathogens via direct contact ______. can be as simple as a handshake or as intimate as sexual intercourse usually involves organisms with a high infectious dose is unavoidable often involves organisms with a low infectious dose may be reduced by routine handwashing
can be as simple as a handshake or as intimate as sexual intercourse often involves organisms with a low infectious dose may be reduced by routine handwashing
A person can harbor a pathogen with no ill effects, acting as a(n)____________________ of the disease agent.
carrier
An individual with no overt disease who harbors infectious organisms is termed a(n) ______. carrier vector reservoir transporter
carrier
A study that starts with the disease and attempts to identify the causative chain of events leading to it is a ______ study. case-control prospective experimental
case-control
The proportion of persons diagnosed with a specific disease who die from that disease is the ______. attack rate case-mortality rate case-fatality rate
case-fatality rate
The ________________-________________ rate is the proportion of persons diagnosed with a specific disease who die from that disease.
case; fatality
The spread of an infectious disease follows a series of steps called the ______________________ of infection.
chain
As more and more people use daycare, the incidence of contagious diseases such as giardiasis and shigellosis have increased. This is an example of ______ contributing to emergence of infectious disease. microbial evolution advances in technology changes in human society complacency
changes in human society
John Snow performed an epidemiological study in the 1800s to figure out the cause of an outbreak of the disease
cholera
A(n) _________________ study looks ahead to see if the risk factors identified by previous studies predict a tendency to develop the disease.
cohort
An epidemic in which the patients were all exposed to a single source of the infectious agent is called a________________ -______________ epidemic.
common;source
Diseases that can be transmitted from one host to another, such as influenza, are termed__________________diseases.
communicable
If Treponema pallidum, the causative agent of the sexually transmitted disease syphilis, gained the ability to survive for long periods of time in the environment, then transmission from one host to another ______. could be indirect as well as direct would still only be direct
could be indirect as well as direct
A chef is preparing a delicious meal. He uses a cutting board to first chop raw chicken (containing Salmonella) and then uses the same board to cut salad ingredients. This scenario is an example of ______. vertical transmission indirect transmission vector-borne transmission cross-contamination
cross-contamination
Which of the following studies surveys a range of people to determine the population's characteristics such as behaviors, exposure, and disease, without attempting to establish the cause of the disease? prospective retrospective common-source cross-sectional
cross-sectional
Which of the following studies surveys a range of people to determine the population's characteristics such as behaviors, exposure, and disease, without attempting to establish the cause of the disease? prospective retrospective cross-sectional common-source
cross-sectional
Analytical studies that do not try to establish the cause of a disease, but instead seek to identify risk factors for the disease, are called ____________ -_____________.
cross;sectional
The disease schistosomiasis requires a specific aquatic snail host. Because of this, construction of ______________ for power, such as on the Nile River, has allowed this disease to spread.
dams
A mortality rate refers to the relative number of ______. illnesses in a population deaths in a population
deaths in a population
In a ____________________ study, epidemiologists collect data that characterize individuals that are ill and the time and place of a disease outbreak, so that a list of possible risk factors may be compiled.
descriptive
If the chain of infection is known, then researchers and public health workers can ______. determine how to stop or slow the spread of the disease develop a vaccine to prevent the disease develop a therapy to treat the disease determine the identity of the causative agent
determine how to stop or slow the spread of the disease
A woman still recovering from shigellosis diarrhea has a bowel movement but doesn't wash her hands afterward. She then shakes hands with another woman, who later touches her mouth with her fingers and develops shigellosis. This is an example of ______. direct contact fecal-oral transmission zoonotic transmission indirect contact
direct contact fecal-oral transmission
The infectious ______________________ is the minimum number of a particular microbe required to cause disease.
dose
Experimental studies should ideally be ______, where neither the researchers nor the patients know who is receiving experimental treatment. cohorted double-blind
double-blind
A 1993 outbreak of cryptosporidiosis in Wisconsin that is estimated to have affected more than 400,000 people involved contaminated ______. irrigation water swimming pool water drinking water
drinking water
Smaller droplets discharged from people remain in the air as fluid evaporates from them. These airborne particles, called ____________ ____________, are composed of microbes attached to a thin coat of the dried material.
droplet; nuclei
Yellow fever is a viral disease transmitted by mosquitoes. In the event of an outbreak of yellow fever, the most likely successful method of control would therefore be to ______. treat wastewater cook foods thoroughly treat drinking water eliminate mosquitoes
eliminate mosquitoes
Infectious diseases that are newly recognized or have recently increased in incidence are called _____________ infectious diseases.
emerging
Diseases that are always present in a given population are said to be__________________ diseases.
endemic
The common cold is constantly present in the United States and is therefore an example of a(n) ______ disease. outbreak epidemic endemic sporadic
endemic
The common cold is constantly present in the United States and is therefore an example of a(n) ______ disease. outbreak epidemic sporadic endemic
endemic
An unusually high number of influenza cases are reported in a particular region. This constitutes a(n) ______. sporadic epidemic pandemic endemic
epidemic
Each state has a state ______ or equivalent who oversees a network of public health laboratories involved in infection surveillance and control as well as other health-related activities. epidemiologist population geneticist politician physician
epidemiologist
Also called "disease detectives,"_________________ collect and analyze data to describe the sources of disease and risk of infection.
epidemiologists
If human skin can serve as a reservoir for Staphylococcus aureus, then this pathogen will be shed along with the skin cells. Shedding skin cells are therefore the portal of ________________ for this pathogen.
exit
To evaluate the effectiveness of a treatment or an intervention in preventing disease, scientists generally conduct studies called ________________studies.
experimental
Temperature, water and nutrient supply, and availability of O2, are all examples of ______ that influence the epidemiology of disease by determining which organisms can exist and reproduce in a given environment. genetic factors of pathogens factors in the physical environment virulence factors host-pathogen interactions
factors in the physical environment
School children become ill with E. coli 0157:H7. The Centers for Disease Control and Prevention determines the same strain of bacteria is found in a cafeteria server who didn't wash his hands after using the toilet. This is an example of ____________ -oral transmission.
fecal
An inanimate object such as a doorknob that can transmit infectious agents is called a(n)__________.
fomite
Determining the profile of individuals who become ill is necessary to define those within a population who are most at risk. In order to do this, all of the following variables about individuals are measured EXCEPT ______. geographic location socioeconomic class age previous illnesses gender
geographic location
A disease is not likely to spread within a population if 90% or more of the individuals are immune to the disease agent. This type of immunity is called_______________immunity.
herd
The transmission of a disease-causing microbe from one person to another (other than mother to child immediately before or after birth) is ______ transmission. diagonal vertical horizontal
horizontal
Transfer of a pathogen from you to another person, or from the environment to you, is known as _______________, transmission.
horizontal
All of the following serve as common reservoirs of infectious agents in healthcare settings EXCEPT the ______. patient's own normal microbiota visitors hospital food healthcare environment healthcare workers
hospital food
A major feature of smallpox that made eradication possible is that ______. the virus had an environmental reservoir the virus was found in water supplies the virus was transmitted via the fecal-oral route humans were the only reservoir of the virus
humans were the only reservoir of the virus
The _________________ of disease reflects the number of new cases in a specific time in a given population.
incidence
The number of new cases of a disease in a population for a specific period is the ______. attack rate incidence prevalence
incidence
Malnutrition, overcrowding, and fatigue ______ people's susceptibility to infectious disease. increase decrease have no affect on
increase
In week one, 30 influenza cases are confirmed. In week two, 50 new cases are reported. In week three, 100 new cases are reported. The incidence rate is ______. unchanged increasing decreasing
increasing
The time it takes before a pathogen begins to cause symptoms of disease is called the __________________ period.
incubation
The first case of disease in an outbreak is called the ______________ case.
index
In a healthcare facility, a pathogen was transferred between patients via medical devices such as urinary catheters. This is an example of _______ transmission. direct indirect zoonotic epigenetic
indirect
When Enterococcus faecalis ______, it is typically harmless, but if it ______ it can cause disease. is ingested; enters the urinary tract enters the urinary tract; is ingested
is ingested; enters the urinary tract
Droplet transmission of infectious agents typically involves crowded situations because ______. large respiratory droplets typically fall to the ground no farther than a meter (approximately 3 feet) from release people tend to breathe more deeply in crowded situations and therefore the inhaled droplets are more likely to go deep into the lungs
large respiratory droplets typically fall to the ground no farther than a meter (approximately 3 feet) from release
An epidemic will die out when the basic reproductive number is ______. less than 2 less than 1 less than 0 greater than 2 greater than 1
less than 1
The ______ of disease acquisition identifies the general site of contact between the person and the infectious agent. person timing location
location
Many people of Black African ancestry are genetically not susceptible to ______ caused by Plasmodium vivax because they lack a specific red blood cell receptor used by the organism. malaria yellow fever trypanosomiasis
malaria
Because ______, older adults are more susceptible to diseases such as tetanus. they may fall down more often they tend to stay indoors many fail to update their immunizations
many fail to update their immunizations
Flies that land on feces can pick up intestinal pathogens such as E. coli O157:H7 or Shigella species and transfer them to food. In doing so, the flies are serving as ______ vectors. biological mechanical
mechanical
The epidemiological term that refers to illness is _______. mortality pathogenicity morbidity communicability
morbidity
Tuberculosis is ______ to be asymptomatic or mild in a healthy individual compared to someone who is immunocompromised. more likely less likely
more likely
The _________________ rate reflects the overall rate of death in a given population at risk.
mortality
The incidence of deaths in a population is reflected in the death rate, or______________ rate.
mortality
In the developed world, although uncommon, waterborne disease outbreaks can involve large numbers of people because ______. waterborne diseases are easily spread from infected persons to susceptible ones municipal drinking water regularly contains large numbers of pathogens municipal water systems distribute water to widespread areas
municipal water systems distribute water to widespread areas
Diseases that do not spread from one host to another are ______ diseases. non-communicable diseases communicable diseases contagious
non-communicable diseases
Cleaning and the use of disinfectants minimizes the spread of pathogens from other patients and therefore helps reduce ______ infections. vertical nosocomial vector-borne
nosocomial
When people talk, sneeze, laugh, cough, and sing, they discharge microbes in small liquid droplets that evaporate, leaving behind airborne particles called droplet ____________ .
nuclei
Women infected with Neisseria gonorrhoeae ______. often have no immune response to the bacterium often have no obvious symptoms, making them asymptomatic carriers carry the bacterium as part of the normal microbiota
often have no obvious symptoms, making them asymptomatic carriers
COVID-19 is an epidemic that has spread across the world, and therefore it is referred to as a(n)_________________.
pandemic
Used in experimental studies,_______________ a is a mock drug and it looks and tastes like the experimental drug but has no medicinal value.
placebo
Drinking water that has been contaminated with certain strains of E. coli may result in gastroenteritis. In this example, E. coli has gained access to a susceptible host via a ______. portal of entry portal of exit
portal of entry
If a pathogen normally grows in the nose of a human, and the human sneezes, the nose is considered to be the ______ for the pathogen. carrier portal of entry portal of exit
portal of exit
The incidence of a disease is the number of new cases in a specific time period in a given population. However, it is the ________________ which reveals the overall impact of a disease on that population because it includes all cases of the disease.
prevalence
The total number of cases of a disease at any time or for a specific period in a given population is the ______. incidence occurrence prevalence attack rate
prevalence
The Centers for Disease Control and Prevention (CDC) focus on all of the following activities EXCEPT ______. supporting infectious disease labs researching infectious disease publishing the MMWR primary patient care collecting data on diseases affecting public health
primary patient care
An epidemic that occurs when a disease is contagious, with one person transmitting it to several others, who then transmit it to several more, and so on, is called a(n)____________________ epidemic.
propagated
Epidemiologists are usually more interested in the ______ of a particular disease, as it compares to the population as a whole, rather than the sheer number of cases. symptoms rate physical appearance
rate
The natural habitat of a pathogen, which might include humans, non-human animals, or the environment, is called the _______________ of infection.
reservoir
A newly recognized disease occurs much more commonly in the winter months. Based on this information, the disease is more likely spread via ______. respiratory droplets than by a vector a vector than by respiratory droplets
respiratory droplets than by a vector
The single most important measure for preventing the spread of infectious disease is considered to be ______. routine handwashing regular use of antibiotics quarantine of sick patients annual vaccinations
routine handwashing
Cooperative surveillance coupled with global immunization programs and isolation of cases resulted in the eradication of ______. tetanus polio smallpox
smallpox
Clostridium tetani, the causative agent of tetanus, a disease that infects humans, is found widespread in soils. Therefore, the reservoir for this organism is ______. soils humans animals
soils
When cases of a disease occur only from time to time, the term_______________ is used to describe them.
sporadic
Infectious disease ______ is one of the most important aspects of disease prevention; it involves both recognizing and reporting disease cases to public health authorities. surveillance treatment vaccination
surveillance
People with ______ illnesses are an obvious source of infectious agents. symptomatic bacterial zoonotic asymptomatic viral
symptomatic
Pathogens can be transmitted via fomites, an example of which is a ______. human carrier dog or other pet tabletop
tabletop
Unlike asymptomatic carriers, individuals with symptomatic infections are more likely to ______. unknowingly shed the organism intermittently or constantly for months, years, or even a lifetime take precautions to avoid transmitting their illness to others
take precautions to avoid transmitting their illness to others
Factors in the physical environment that can influence the epidemiology of disease by determining which organisms can exist and reproduce include ______. host genetic background host gender temperature oxygen level water and nutrient supply behavioral practices
temperature oxygen level water and nutrient supply
A 20-year old male developed gastroenteritis after eating raw cookie dough. Upon culture of his stool, the causative agent was shown to be Salmonella enterica serotype Typhimurium. Presumably the Salmonella organisms were in the uncooked eggs in the raw cookie dough. What is the reservoir for the infection in this case? the eggs themselves the infected 20-year old Salmonella enterica serotype Typhimurium the chickens from which the eggs came the cookie dough
the chickens from which the eggs came
All of the following are emerging diseases EXCEPT ______. the common cold Zika virus disease Ebola disease Middle East respiratory syndrome (MERS)
the common cold
New types of eye infections have resulted from ______. the increased use of smartphones the introduction of contact lenses coupled with improper disinfection techniques too much time spent looking at computer monitors while sitting at desks
the introduction of contact lenses coupled with improper disinfection techniques
An epidemic of typhoid fever in a Swiss ski resort occurred only in ______, because the locals rarely drank water, preferring wine instead. locals tourists
tourists
Overcrowding in human populations is a major risk factor for infectious disease because ______. transmission is often easier under crowded conditions large populations include more immunocompromised individuals humans living at high densities are under greater stress, which depresses their immune systems large populations lack genetic diversity in their immune systems, making them more susceptible to pathogens
transmission is often easier under crowded conditions
A healthcare-associated infection (HAI) is one acquired in a ______. urgent care facility long-term care facility hospital doctor's office health club
urgent care facility long-term care facility hospital doctor's office
Humans have been enormously successful in eliminating or reducing the occurrence of certain diseases through efforts in ______. deforestation vaccination robotic surgery reservoir and vector control antibiotic treatment improved sanitation
vaccination reservoir and vector control antibiotic treatment improved sanitation
All of the following are major factors contributing to the emergence of disease EXCEPT ______. microbial evolution vaccinations children in daycare complacency
vaccinations
A living organism, most commonly an arthropod, that can carry a disease-causing microbe externally or internally, is called a(n)__________________.
vector
Any living organism that can carry a disease-causing microbe externally or internally is called a ______. vector fomite pathogen
vector
Mechanisms to prevent airborne transmission of pathogens include ______. ventilation systems that constantly change air air circulation through high-efficiency particulate (HEPA) filters keeping workspaces at least 1 meter (3 feet) apart reduction of air pressure in hospital microbiology laboratories running a sterilizing ultraviolet light whenever a room is occupied
ventilation systems that constantly change air air circulation through high-efficiency particulate (HEPA) filters reduction of air pressure in hospital microbiology laboratories
Transfer of a pathogen by a pregnant woman to her fetus, or from a mother to infant during birth or through breastfeeding, are examples of________________ transmission.
vertical
Animals such as skunks, raccoons, and bats are reservoirs of the rabies virus. Therefore, rabies is considered a(n)_________________ disease.
zoonoses
Diseases that exist in animal reservoirs but can be transmitted to humans are ______. epidemics vectors zoonoses
zoonoses
A party was attended by 250 people. All of them ate cake made with Salmonella-contaminated eggs, and only 50 people developed salmonellosis (vomiting and diarrhea). What is the attack rate? 20% 25% 50% 10% 100%
20%
An estimated ______ of patients admitted to a hospital develop a nosocomial infection. 50% 5% 25%
5%
The spread of the mosquito _______, a vector for dengue virus and chikungunya, illustrates the influence of the environment on the epidemiology of disease. That mosquito is native to ______, but human activities have allowed it to spread to many other parts of the world; in turn, the diseases it transmits have spread accordingly. Anopheles gambiae; Southeast Asia Aedes albopictus; Southeast Asia Anopheles gambiae; Southwest Australia Aedes albopictus; Southwest Africa Anopheles gambiae; Southwest Africa
Aedes albopictus; Southeast Asia
_________________studies are designed to determine which of the potential risk factors identified by the descriptive studies are relevant in the spread of the disease.
Analytical