exam 2 6140

One health:

"the collaborative efforts of multiple disciplines working locally, nationally, and globally, to attain optimal health for people, animals and our environment", as defined by the One Health Initiative Task Force.

Pandemic

(of a disease) prevalent over a whole country or the world.

How does the current status, spread, and death toll from COVID-19 compare with the great influenza pandemic of 1918?

-1918 pandemic: Most deadly epidemic in history -Infected 1/3 of the world; 5% of the world died -killed 50 to 100 million people worldwide in 1 year. -Extreme virulence, dead in 1-2 days. -H1N1 variant- like the swine flu can test the RNA from the frozen bodies

Describe the conflicting or confusing results with estrogen replacement therapy (pp. 74-75; 84-85)

-1978 large cohort study (probably some selection bias due to women taking HRT were healthier, even without the therapy --Increase breast cancer --Lower hip fractures risk --Lower heart disease risk --1999 38% were on HRT --Observational study -1991 huge clinical trial --Women's health initiative --Stopped in 2002 because ---Increased heart attack ---Increased stroke ---Increased blood clots ---Increased breast cancer ---Decreased hip fractures ---Decreased colon cancer

Contrast incidence rates with prevalence. How is it that the rate of HIV can be higher in African-American males in Utah, yet the vast majority of cases are in Caucasian males.

-Caucasian men having sex with caucasian men. -Not a lot of African-born immigrants living in Utah than Caucasian males, although RATES are higher in African-American males. -Still needs to be focused on caucasions and African-American males. -African it is passed in heterosexual relationships. -LGBTQ+ groups.

What is the difference between association and cause-effect?

-Cause/Effect Relationship: a direct relationship in which occurrence B happens in response to the presence of exposure A --Need to be able to show a positive correlation on an x/y axis -Coincidence: when 2 events occur together without one causing the other -Association: 2 events occur together in a significant pattern, but this does not mean one causes the other

List the 6 concerns with clinical trials mentioned in the lecture.

-Drop out rate --Differential drop-outs, control groups may have more dropouts than experimental groups. -Subjects may not follow prescribed behavior throughout the study period -Subjects may not report or recall exposures/behaviors accurately -Expensive -They take a long time -Sample size often small -Ethics (if a test drug turns out to be toxic or harmful)

List 5 factors that lend validity to study results

-Eliminate bias and error as discussed above --e.g. large study population, randomization, blinded, good measurement, no conflict of interest, eliminate recall or selection bias. -Strong association or statistics --e.g. high relative risk or odds ratio or very low p-value -Dose-response relationship -Known biological explanation -Consistent results from several studies

What is elephantiasis? How does one get it?

-Filariasis -Caused by roundworm spread by mosquitoes -Clogs the lymph vessels and inhibits circulation so legs and hands get swollen.

Know how the new COVID rapid antigen assay compares to the gold standard RT-PCR test.

-Gold standard= RT-PCR test -Rapid Antigen Test --Screening test with results in 15 minutes ---Specificity- 100% ---Sensitivity- 84-97.6% ----Actually have the disease -----2.4-16% of individuals that they don't actually have the disease but they DO in reality

What is the difference between incidence and prevalence?

-Incidence: number of new cases in a given time period/population at risk --10 new cases in one year out of 100 lactating cows --Incidence of mastitis in 2017: 10/100 = 0.1 = 10% per cow per year -Prevalence: number of cases/population at risk --2 infected cows. The population at risk: 200 cows --Prevalence of tuberculosis: 2/200 = 0.01 = 1%

List the human behaviors that increase zoonosis in modern times (see slides: drivers of disease slide & illegal wildlife trade)

-Increasing population density. -Climate changes. -International travel. -RNA viruses are constantly changing: --Influenza viruses. --Coronaviruses.

Know examples of common screening tests.

-Infectious disease --STIs --Whooping cough --Hepatitis C - blood donation -Behavioral --ADHD --Autism --Mental health -Chronic disease --Cholesterol test --Breast, cervical, prostate, colon -Health promotion --Pregnancy test --High blood pressure --Osteoporosis

Describe at least 3 demographic variables (slide #25)

-Microbiology -Virology -Clinical Medicine/Pathology -Social and Behavioral Sciences, Demography -Toxicology -Biostatistics --Sporadic --Endemic --Epidemic --pandemic

escribe 2 ways that flu virus can change or mutate to give new strains.

-Mutation: --RNA polymerase makes an error about every 10 thousand nucleotides (viral genome = 13,588 bp). --This causes antigenic drift, which is a slow change over time. -Reassortment: --The RNA genome consists of eight segments. --If more than one type of influenza virus infects a single cell, exchange of RNA segments may produce an antigenic shift, or sudden large change in the virus.

A unique feature about influenza disease is that the infected host sheds virus 1-2 days before onset of disease signs/symptoms. Why does that increase the spread of disease?

-RNA viruses like influenza virus are constantly changing so continued vigilance is required! -You spread it before you have it- peaks with the fever.

Know reasons and application for screening tests

-Screening--the presumptive identification of unrecognized disease or defects by the application of tests, examinations, or other procedures that can be applied rapidly. -Positive screening results are followed by diagnostic tests to confirm the actual disease.

Characteristics of a good screening test or a successful screening program.

-Simple --Easy to learn and perform --Can it be done by a non-physician? -Rapid --The success of the program depends on results -Inexpensive --Health departments and underdeveloped regions expense? -Safe --No harm to participants -Acceptable --To target group --Example: testicular cancer vs breast cancer screening

Know when screening tests are justified: Social, Scientific, Ethical (treatment availability, the magnitude of the issue, cost-benefit, prevalence, potential participation.)

-Social --Health problem should be important for the individual and the community ---What is the magnitude?!? ---Is it a major health problem for the community? (example Malaria screening at USU --Diagnostic follow-up and intervention should be available to all who require them --There should be a favorable cost-benefit ratio ---Will the public participate in the test? --Public acceptance must be high ---Genetic testing? -Scientific --Early detection efforts are most likely successful when... ---The natural history of the condition is adequately understood. ----This knowledge permits identification of early stages of the disease and appropriate biologic markers of progression ---Prevalence of the disease or condition is high ----High cholesterol and high blood pressure are effective indicators for... ----Reliable screening test? -Ethical --It is ideal if the screening program is implemented so that... ---It can alter the natural history of the condition in a significant proportion of those screened. ---Suitable, acceptance tests for screening and diagnosis of the condition as well as acceptable effective methods of prevention are available ----What about screening individuals in late-stage HIV? ----Screening individuals, that lack insurance or physician care? (GOOD QUESTION)

What happened with Vioxx in regard to ethics? (pp. 78-80)

-There is evidence that drug companies sometimes suppress negative findings. --Harmful side effects have frequently become obvious after drugs were approved. ---Most recent famous example is Vioxx, removed from the market in 2004. They knew about the harmful problems yet still sold the product

Explain epidemiology's mission in terms of "explain, predict, control". (slide #23)

-To describe the health status of populations. -To explain the etiology of disease. -To predict the occurrence of disease. -To control the occurrence of disease. --Intervention or Prevention

List different ways the W.H.O. and CDC report epidemiological and trend data

-cases per day -per 100,000 population -per million -highlight regions with any positive cases -cumulative number of cases, etc.

List 13 control measures that work before infection

1. Immune system 2. Hand washing 3. Immunization 4. Disinfection 5. Water purification 6. Vector control Deet, rodent, control, etc 7. Quarantine 8. Food processing and cooking 9. Food storage ...

6 control measures applied after infection.

1. Immune system 2. Quarantine 3. Antitoxin 4. Antibiotics 5. Antimicrobial drugs 6. Supportive care (oxygen, hydration, etc.)

HIV/AIDS:

1983, deadly, borne, sexually transmitted, presumed from primate origin

Opioid addiction:

1995-2010? (Non-infectious disease)

West Nile Virus:

1999, endemic west nile region forever, first seen in the US in 1999. Spread quickly across the country. Can be fatal especially in >70. Still no human vaccine.

How many eggs can the roundworm Ascariasis lay in one night?

200,000 eggs per day. Transmission by ingesting eggs in food or water. Eggs are passed onto the soil via the feces of infected people

Bird flu:

2003, first isolated in 1996, outbreak in 2003; >700 cases reported since. High mortality rate. Fear of pandemic. Fortunately human-to-human contact is rare, so most cases are people who work with poultry.

SARS (1):

2003, up to 10% fatal. Originated in China, spread through the orient. Contained and eradicated by 2004.

Swine flu:

2009, spread across globe in 30 days, raised fears but turned out not highly lethal and later classified as seasonal flu

Ebola:

2014, emerging? Periodic outbreaks since 1976. The worst was the 2014 epidemic in Guinea, Sierra Leone, Liberia; 63% deadly, killing 11,325 people 2014-16. Ongoing in Dem ROC. reporting outbreaks July 2018, May 2020, and June 2020. Vaccine approved in 2019.

Zika:

2015, serious not deadly. Causes microcephaly in babies via vertical transmission.

COVID-19:

2019, china initially Dec. 2019, pandemic by Jan. 2020 in almost every country by March 2020 and still as of end of Sep 2020.

How was the Utah Opioid epidemic identified as such? [Hint: The growing concern was noticeable, but the magnitude and epidemic nature would not have been identified without epidemiology.]

23 individuals die in Utah each month to overdose (primarily oxycodone. In 2014, 32% of adults were prescribed an opioid pain reliever (~11% of adults experience daily pain according to the CDC) After collecting data opioid epidemic outpaces deaths due to firearms, falls, and motor and vehicles COMBINED!

What is the status of the COVID-19 vaccine? (the answer to these questions is debatable and changes daily)

23Sep20 CDC (Dr. Robert Redfield) and NIH (Dr. Anthony Fauci) directors said the U.S. vaccine should be ready and approved for use in March/April. Political rhetoric online says Pres. Trump may over-rule FDA and call for less strict safety standards to get it out sooner. (CNN 24Sep20. More on political factors in public health unit #20) The leading candidates appear to be Sanofi-GlaxoSmithKline, Johnson & Johnson, AstraZeneca, and Moderna. A vaccine was released in Russian 04 Sep 2020. Most US vaccines- in stage 3 testing

helminth disease: Ascarids

25% of the world's population especially in the tropics and subtropics. Eggs are passed onto the soil via the feces of infected people. -50% of children in Southeastern U.S. infected at some time

Why were the syphilis experiments unethical?

400 black men with syphilis were observed over time but not treated in order to observe the course of untreated syphilis the subjects were misled as to the nature of their participation.

How many cases of Lyme disease were reported in Utah in 2014? Why was it investigated? How does this demonstrate the political aspect of epidemiology and PUBH?

5 cases in Utah. It was investigated and the public health department just wanted the ticks. There is lots of lyme disease. It is increasing. Lyme disease is primarily a zoononitic disease. Deer and mice and ticks are transmitting it.

According to Dr. Tarbet, _70% of new and emerging human diseases in the past 3 decades were of zoonotic origin.

50% of physicians could not diagnose a zoonotic illness. Highest probability for emergence of new infectious diseases is associated with RNA viruses, especially those found at the human-animal interface.

Use cardiovascular/heart (CDH) disease, HIV, and TSS as examples of disease distribution among populations, i.e. race, gender, etc.

???

Cause-effect relationship

A cause-effect relationship is a relationship in which one event causes another to happen. ... Whenever the cause occurs, the effect must also occur. There must not be another factor that can explain the relationship between the cause and effect.

Confounding variables

A confounding variable, also called a confounder or confounding factor, is a third variable in a study examining a potential cause-and-effect relationship. A confounding variable is related to both the supposed cause and the supposed effect of the study.

Variables vs Controlled variables

A control variable is any factor you control or hold constant during an experiment. A control variable is also called a controlled variable or constant variable. ... In contrast, there may be variables you can't easily control, such as humidity, noise, vibration, and magnetic fields.

Randomized clinical trial

A controlled medical experiment in which subjects are randomly chosen to receive either an experimental treatment or a standard treatment (or placebo).

What is dose-response?

A dose-dependent response can help establish a cause-effect relationship.

Placebo

A harmless pill, medicine, or procedure prescribed more for the psychological benefit to the patient than for any physiological effect.

Know which way to move the 'cut-off' point to get more sensitivity or more selectivity.

A lower cut point (move left) makes the screening test more sensitive. A higher cut point (move right) makes the screening test more specific

B cell

A lymphocyte that produces proteins that help destroy pathogens.

Spike protein:

A peplomer is a glycoprotein spike on a viral capsid or viral envelope. These protrusions bind only to certain receptors on the host cell. They are essential for both host specificity and viral infectivity. The tail fibers of some bacteriophages, especially the T4-like phages, are modified peplomers.

antibody

A protein that acts against a specific antigen

Prospective studies

A study that monitors people who might become exposed to harmful chemicals in the future. In prospective studies, individuals are followed over time and data about them is collected as their characteristics or circumstances change. Birth cohort studies are a good example of prospective studies.

Test variable

A test variable is a user-defined, name-value pair that stores and refers to information throughout a test and between tests.

cohort study

A type of epidemiologic study where a group of exposed individuals (individuals who have been exposed to the potential risk factor) and a group of non-exposed individuals are followed over time to determine the incidence of disease

Case-control study

A type of epidemiologic study where a group of individuals with the diseases, referred to as cases, are compared to individuals without the disease, referred to as controls

RNA virus:

A virus in which the genetic material is RNA. The RNA may be either double- or single-stranded. There are 6 classes of viruses. The DNA viruses constitute classes I and II. The RNA viruses make up the remaining classes.

contagious

Able to be passed easily from one person to another. has an R0 value

What has acquired immunity? How is it acquired? What is the key component and where are these found in the body?

Acquired immunity= antibodies that are specific to a disease

What are some advantages and disadvantages of clinical trials?

Adv: Shows cause rather than just association Dis: Expensive Takes lots of time

What is the mode or transmission for Hantavirus? What is the reservoir? How does this relate humans to environment and veterinary medicine?

Aerosolized urine or feces in the four corners area of UT, AZ, etc. on the reservations. It comes from deer mice.

What is the mode of transmission for Hantavirus?

Air molecules of scat?

disease

An abnormal state in which the body is not functioning normally

Experimental group

An experimental group (sometimes called a treatment group) is a group that receives a treatment in an experiment. The "group" is made up of test subjects (people, animals, plants, cells etc.) and the "treatment" is the variable you are studying.

Cyclical Fluctuations

An increase or decrease in the frequency of a disease or health condition in a population over a period of years or within each year.

What 3 areas does One Health attempt to consolidate?

Animal health Human health Environmental health

Genetic shift

Antigenic shift is the process by which two or more different strains of a virus, or strains of two or more different viruses, combine to form a new subtype having a mixture of the surface antigens of the two or more original strains.

Who is required to get IRB approval?

Any clinical trial

Review from prior lecture(s): Study how dose response can strengthen an association or predict cause-effect.

As the dose increases the p value should also increase showing the dose response

How can you reduce selection bias in a prospective cohort study?

Ask yourself, "Who is responding?"

Correlation vs Association

Association refers to the general relationship between two random variables while the correlation refers to a more or less a linear relationship between the random variables.

The influenza virus can change significantly from one year to another and has the capacity to turn into a major killer. In 1918, there was a pandemic of flu that killed approximately how many people worldwide?

At least 50,000,000

Explore and discuss the difference between risk assessment and risk perception, using alcohol, automobiles, nuclear power as examples.

Automobiles-- low perceived, high actual Alcohol-- low perceived, high actual Nuclear energy-- high perceived, low actual Is often different between age groups and education Study the figure on pg 97 in the book!!!

Chiroptera

Bats are mammals of the order Chiroptera. With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more manoeuvrable than birds, flying with their very long spread-out digits covered with a thin membrane or patagium.

Bias

Bias is a disproportionate weight in favor of or against an idea or thing, usually in a way that is closed-minded, prejudicial, or unfair.

Epidemiology

Branch of medical science concerned with the incidence, distribution, and control of diseases that affect large numbers of people. the study of the distribution and determinants of disease frequency in human or animal populations. the branch of medicine which deals with the incidence, distribution, and possible control of diseases and other factors relating to health.

Know what a p-value is and how it is used for clinical trials and for all comparison studies.

Can be used to compare trials

What type of study is reported for breast and lung cancer in these slides? a) descriptive research b) case-control study, c)intervention study, d) cohort study?

Case control

Which type requires new data to be gathered and which ones can use existing data on file?

Case-control (existing data) Cohort-control (gathered data)

infectious

Caused by or capable of being transmitted by infection.

long-term trend

Changes in the occurrence of disease over a long period of time.

For what population is Zika most serious?

Children! :( microcephaly

What 3 species have the highest number of viruses shared with humans?

Chiroptera primates rodents

What type of study was the WHI study (1991-2002)

Clinical Trial

Which type is required to approve new human or veterinary medicine through the FDA?

Clinical trials (intervention) (IRB- institutional review board)

What are the main determinants for the Hantavirus outbreak in the 4-corners region? [Recall that more details are in unit 6 with Dr. Tarbet]

Close quarters with animals? The mice are located in the areas where they live rather than just in the mountains.

Understand what CI is and how it is used in public health publications.

Confidence Interval "Margin of error" The circle reprecents the mean and the tails are the margain of errors. If the confidence intervals overlap then it is likely that there is no statistical significance. From his slides Odds ratio 2.5 (0.5, 4.5) confidence interval Also could say ratio of 2.5 + 2.0 If it's 0.5 it's negative association, meaning the exposure actually protects from disease (people with the disease were more likely to have exposure, like exposure to vitamins or good hygiene maybe) If it's 4.5 it's positive association, meaning the exposure is associated with the disease (i.e. people with disease were more likely to have exposure) If it's 1.0 they are not associated.

How many variables do we seek to have in a clinical trial?

Control group Trial group

Proof-reading:

DNA polymerase proofreading is a spell-checking activity that enables DNA polymerases to remove newly made nucleotide incorporation errors from the primer terminus before further primer extension and also prevents translesion synthesis.

In 2004 the H3N8 flu virus jumped from horses to __________.

DOGS! At a horse/dog race track. Confused by another disease- took virus coast to coast in 2 years. In shelters they found it.

According to the highly-respected journal "Science", what is wrong with epidemiologists' interpretation of association results? What is the minimum ratio Science recommends to consider important? (FYI: Dr. Day thinks the ratio should be even higher before drawing important conclusions.)

Data in epidemiological studies is derived from nonexperimental settings This makes comparisons difficult and adds uncertainty to the result A July 1995 article in Science (p. 164 - 169) criticized epidemiologists and the news media for placing too much emphasis on studies which show relatively low ratios The authors suggest one should be skeptical for studies with RR of 3 or less

Demographic

Demography is the statistical study of populations, especially human beings. Demographic analysis can cover whole societies or groups defined by criteria such as education, nationality, religion, and ethnicity.

Which type of epi. study is likely to yield an answer in the shortest period of time? Why?

Descriptive, case-control

What is a P-value used for?

Determining statistical significance.

Give 3 examples of selection bias, including 2 from this lecture.

Dewey presidency (telephones in 1948) vs Truman Fitness surveys done by students in HPER building HRT in women who already care about their health (pros vs cons)

Pandemic:

Disease that occurs over a wide geographic area and affects a very high proportion of the population.

Which of the following consists of the answers to the who, when, and where questions? A) Frequency; B) Incidence; C) Prevalence; D) Distribution

Distribution

List 3 essential characteristics of an effective vaccine. List the 5 other desired characteristics of a vaccine.

ESSENTIAL 1. Safety 2. Effectiveness 3. Stability DESIRED 1. Cost 2. Admin nasal or oral 3. Stable at room temp or tropical temps 4. One dose is effective 5. Long-shelf life

How is epidemiology important in disease prevention?

Epidemiology is concerned with the distribution and determinants of health and diseases, morbidity, injuries, disability, and mortality in populations. POPULATION-BASED DISEASE CONTROL

Are there ethical concerns an issue with non-intervention studies such as case-control studies? (Hint: these are retrospective)

Errors may exist in reporting or recall The control group may not be truly comparable

risk perception (perceived risk)

Evaluation of risk present at the time the maneuver is made.

What is the main goal of epidemiology?

Examines disease occurrence among population groups, not individuals

True or False? Disease frequency is usually expressed as prevalence rate.

False

Be able to discuss cost-benefit analysis (pp. 98-99) and use breast cancer screening for women in their 40's as an example (pp. 85-86).

Financial, effort, and emotional cost Compared to what is the benefit? Example: Breast cancer screening at age 40 Benefit: May save some lives by catching cancer early Costs: Radiation exposure False positives emotional cost 2008 data showed some positives resolve themselves so screening could lead to unnecessary treatment Financial cost Effort by patients and doctors Final decision = begin routine screens at age 50 unless high risk, i.e. family history of breast cancer Study Schneider p. 98, and pp. 85-86

What 2 main keys are used to diagnose pinworm infection?

Finding eggs around the anus Scotch tape test

List 2 "collateral damage" effects of a pandemic (i.e. social aspects that complicate the medical aspects of a pandemic)

First, panic and fear can cause global governance to be challenged and people's behavior and activities to be unpredictable. Second, a pandemic means that the supply chains for critical products like drugs and medical supplies will be threatened.

Draw a dose-response curve on a grid with an X and Y-axis.

Good support for cause/effect

In 2009, a pandemic occurred caused by what virus and what strain? Was it highly lethal like the Asian bird flu? How fast did it spread across the globe?

H1N1(swine flu) is a type A influenza virus spread across globe in 30 days, raised fears but turned out not highly lethal and later classified as seasonal flu

controllable risk

Health risk factors over which individuals have some measure of control.

Describe the "Love canal" (Hooker chemical) incident and how epidemiology was used to identify determinants of disease.

Higher rates of cancer above a 'fun area' where companies disposed of chemicals in this area.

Review from prior lecture(s): Know when specificity and sensitivity are desired.

If the diagnostic (confirmatory) test is expensive or invasive: Use high specificity Minimize false positives Can have false negatives If the penalty for missing a case is high (e.g., the disease is fatal and treatment exists, or disease easily spreads): Minimize false negatives (maximize positives) Use high sensitivity Can have false positive (play it safe)

What modes of transmission do worms use?

Immigration, travel, AIDS

acquired immunity

Immunity that is present only after exposure and is highly specific.

How was dr Semmelweis's career affected after his claims on the importance of handwashing?

In 1865, the increasingly outspoken Semmelweis supposedly suffered a nervous breakdown and was committed to an asylum by his colleagues. He died 14 days later, at the age of 47, from a gangrenous wound on his right hand which might have been caused by a beating from the guards. Semmelweis's practice earned widespread acceptance only years after his death when Louis Pasteur confirmed the germ theory, and Joseph Lister, acting on the French microbiologist's research, practiced and operated using hygienic methods, with great success.

Control

In an experiment, the standard that is used for comparison

attack rate

In epidemiology, the attack rate is the percentage of the population that contracts the disease in an at risk population during a specified time interval. It is used in hypothetical predictions and during actual outbreaks of disease.

Describe the proper PUBH way to cough or sneeze (the "patriotic" way).

In our sleeves! It's a polite thing today.

How do we minimize confounding variables in animal testing? (Hint: consider genetics, environment, etc.)

In the lab: in-bred mice, all exactly the same genetic material

Explain the interaction between incidence, prevalence, and prognosis. Give examples.

Incidence: Prevalence: depends on incidence and prognosis Prognosis: --------------------------- -If prognosis is good and patients heal quickly, prevalence goes down. -If prognosis is bad and patients die quickly, prevalence goes down. -If prognosis is chronic, and patients stay sick for a long time, prevalence goes up.

Which cancer has the highest incidence? Which cancer has the highest death rate?

Incidence: female breast cancer Highest death rate: lung and bronchus cancer ***there are better treatments for breast cancer than lung cancer

Contrast incidence and prevalence.

Incidence= measures NEW cases of disease and is expressed as a proportion prevalence= measures EXISTING cases of disease and is expressed as a proportion

Know how sample size and random variation affect P-values.

Increased sample size means more significant p-value as it is less likely the association is by chance.

infant botulism

Infant botulism is a rare bacterial infection that occurs in the large intestine of babies. It develops when a baby ingests C. botulinum spores, which are present in honey and soil. Infant botulism causes muscle weakness, which can lead to difficulty eating and breathing.

What influence has syphilis case study had on the conduct of clinical trials?

Informed consent Institutional review boards (IRB)

Which type of epidemiologic study is most likely to yield a valid result? Why? Which is the 2nd most valid?

Intervention, then cohort-study

Which type requires intervention (such as treatment) during the course of the study?

Intervention: randomized, double-blind, placebo-control

Review from prior lecture(s): Understand P-values, what they mean, and how they are used.

Is it low enough to say the two results are really different? P < 0.05, 95% confidence that they are really different (not just by chance) P < 0.01, 99% confidence that the difference is real (not just by chance)

How do you explain the W.H.O.'s data for 14-21 Sep 2020 showing a 6% increase in COVID cases at the same time as 10% decrease in deaths?

Is it possible that the virus is becoming less deadly? Or I read somewhere that it could be a result of the social distancing and because people are remaining at a safer distance less of a lethal dose of the virus is getting transmitted and it is easier for the host to handle

Give an argument in favor of strict FDA regulation and an argument in favor of looser FDA regulation.

It may be faster but not as safe.

Why might you discourage pesticides against sand flies as a public health official?

It may leak into their water system?

How could selection bias have affected the difference in earlier studies?

It was a cohort study and some of the women already had good health practices

How was child-bed fever being spread?

It was being spread from patient to patient in the hospitals.

List 4 ways clinical trials reduce confounding variables?

Large sample size Randomly selected Wide variety of locations, environments, etc Gender matched Control all variables except the ONE being tested*

How is bias prevented in an intervention (clinical trial) study?

Large sample size Randomly selected test subjects (from a wide variety of locations and environments) Gender matched Control all variables except the ONE being tested

Know how sample size relates to statistical power.

Larger sample size increases statistical power.

Know what P-value of < 0.05 and <0.01 mean and which is better.

Less than 0.01

How might the data in Figure 7-1 on life expectancy differ if it were life expectancy at age 5 rather than at birth? (p. 92. Hint: Underdeveloped countries have high numbers of children die in the first years of life)

Life expectancy at birth vs life expectancy at age 5 So in underdeveloped countries like India, it's much higher after age 5, but if you include all the babies in the average the number is small.

Contrast a live vaccine with a killed vaccine. What are the advantages of each?

Live (attenuated) vaccine- it is stronger than the killed vaccine. The inhaled version is given to those over 18 years old. The killed vaccine can't give you the vaccine no matter what (purified protein).

Understand why the crude death rate in Florida looks different than Alaska, but the adjusted rate is not so different. (p. 91)

Many people retire to Florida and young people live in Alaska

How did this change medicine after the 2002 Women's' Health Initiative (WHI) study compared with 1960-2002? [Hint: in 1999 38% of post-menopausal women used HRT]

Many women stopped using HRT?

What is B-cell? What important protein does is produce?

Memory b-cells are the cells that remember the pathogen and kill the pathogen. The vaccine is a weakened infection (attenuated) or a killed vaccine that presents proteins from the pathogen to the immune system so you make Ab and have memory B-cells against that pathogen.

MERS:

Middle Eastern Respiratory Syndrome. Similar to SARS.

MMWR

Morbidity and Mortality Weekly Report

List One Health connections (env, man, animal) that led to Hantavirus outbreaks in the U.S. 4-corners area in early 2000's. Be able to retell the story of how the environment, man and animals interact to cause the outbreak.

More rain More mice People migrating and moving to locations

What is the reservoir for Hantavirus?

More rain= more food More food= more mice Hantavirus spread through scat Inhaled hantavirus harmful to lungs

Are these cancers affected by multiple determinants or mostly by a single determinant? Are cultural factors disease determinants?

Multiple determinants and many genetics contribute to these diseases. Conditions associated with health -Physical activity -Nutrition -Environmental poisoning -Seat belt use -Provision and health services

random variation

Natural variation in the output of a process, created by countless minor factors

Describe the Tuskegee syphilis study from the textbook (pp. 75-77).

Nazi experiments on humans

What is a negative association?

Negative: follows opposite trends

Is most data for epidemiological studies derived from experimental or non-experimental data? What is the difference?

Non-experimental. They focus on what is happening at the current time period.

What type of epidemiological study could be done now using known cases of Lyme disease to show a connection between out-of-state hiking and Utah Lyme disease cases? Describe how you would perform this study and what math equation you would use to make your conclusion.

None of the ticks were positive with Lyme disease. Most cases can be tracked to another state such as in northeastern US. We would use case-control study and use the odds ratio.

Demographics. Fact: Utah has the lowest lung cancer rate in the U.S. Question: Is this true of all cancers? (see slides #11-12)

Not true of all cancers.

Know the top 5 perceived risky activities, and evaluate which is NOT high risk according to experts. (p. 96)

Nuclear power is not high risk, interesting...also ... Top 5 risky activities Motor vehicles Smoking Alcoholic beverages Handguns Surgery

What does an Odds Ratio of <1 mean?

OR = 1 implies no association. Assuming statistical significance: OR = 2 suggests cases were twice as likely as controls to be exposed. OR<1 suggests a protective factor. Statistical significance...no overlap of confidence intervals

Know the difference between the odds ratio and relative risk and when each should be used.

Odds ratio- commonly used in case-control studies OR=odds of exposure in those with disease/odds of exposure in those w/o disease OR>1 increased frequency of exposure among cases OR=1 No change in frequency of exposure OR<1 decreased frequency of exposure Relative risk- commonly used in cohort studies RR=rate of development of disease of persons exposed/ rate of development of disease of persons not exposed. RR>1 increased risk of outcome RR=1 no risk of outcome RR<1 reduced risk of outcome

Tell the story of Wakefield's fraud. Why is it important today?

On 2 February 2010, The Lancet formally retracted Wakefield's 1998 paper.[100][101] The retraction states that, "The claims in the original paper that children were 'consecutively referred' and that investigations were 'approved' by the local ethics committee have been proven to be false."[18] The following day the editor of a specialist journal, Neurotoxicology, withdrew another Wakefield paper that was in press. The article, which concerned research on monkeys, had already been published online and sought to implicate vaccines in autism.[102] In May 2010, The American Journal of Gastroenterology retracted a paper of Wakefield's that used data from the 12 patients of the article in Th e Lancet.[103] On 5 January 2011, BMJ editors recommended that Wakefield's other publications should be scrutinized and retracted if need be.[49] False claim that MMR vaccine was linked to autism. Retracted 12 years later. After millions of $ in confirmatory and follow-up research was done. Wakefield had conflicts of interest, some ties to a legal firm that stood to gain financially by this. He was stripped of his post. He was debarred from scientific organizations, but got no jail time for his fraud.

What statistical calculations are used for intervention studies?

P-value, ANOVA,

Study John's Hopkins study about the rate of false negatives in the RT-PCR assay, and know what it says about the ideal time to get tested

Per CDC, the rapid test has a 100% match for specificity (detects negatives), and an 84.0-97.6% match for sensitivity (detects positives) Note: A recent John's Hopkins study said the gold standard RT-PCR test gives false negatives... 67% false negatives when tested on day 4 after exposure, 20% false negatives at the ideal test time, which is 3 days after symptoms arise or 8 days after exposure. May 13 issue of Annals of Internal Medicine. Ann Intern Med. 2020;173(4):262-267.

Describe critical aspects of a clinical trial

Phase 1 New drug or vaccine in a few volunteers to see if it's toxic Phase 2 100s of subjects. Check for efficacy and toxicity. Phase 3 Given to 1000s of subjects

When calculating the rate of a disease, which of the following is generally the denominator of the calculation? A) Population infected; B) Population at risk; C) Total state population; D) Total world population

Population at risk

What is a positive association?

Positive: follows the same trends

Name 2 control measures that can be applied both before AND after infection.

Quarantine Hand Washing

RNA polymerase:

RNA polymerase (green) synthesizes RNA by following a strand of DNA. RNA polymerase is an enzyme that is responsible for copying a DNA sequence into an RNA sequence, during the process of transcription.

What is the random variation?

Random variation—results due to chance and not to a relationship between the variables of interest If the random variation is greater than exposures it is not statistically significant

morbidity

Rate of disease in a population

Recall bias

Recall bias is a type of information bias common in case-control studies where the cases (or their families) are more likely to recall a prior exposure than the controls.

Fictitious example data: People found with common colds lasting more than 3 days were asked about Vitamin C intake. They found an odds ratio of 0.0079 for ingesting the FDA recommended allowance of vitamin C, compared with the healthy control group. What does this odds ratio mean about colds and vitamin C?

Reduced vitamin C intake people are at a higher risk for more colds.

Which of the following is calculated by dividing the ratio of exposed subjects to nonexposed subjects in the case group by the ratio of exposed subjects to nonexposed subjects in the control group? A) Incidence rate; B) Prevalence rate; C) Odds ratio; D) Relative risk.

Relative risk

Is Vioxx on the market today? Why or why not?

Removed from the market in 2004.

What is an IRB?

Review Board The IRB ensures that... The study is well-designed its benefits outweigh the risks Subjects truly give informed consent Clinical trials are halted if the treatment group is clearly showing better or worse results than the control. (pp. 76-77)

What 3 emerging diseases are similar. In other words, what recently emerging diseases were similar to COVID-19?

SARS Ebola Zika? MERS

How do opioid deaths compare with motor vehicle accidents? Would this be observed without epidemiology looking at and tracking infectious as well as non-infectious disease?

SO MUCH HIGHER.

What is the cause of Leishmania and how is it transmitted? Is it zoonotic?

Sand flies carry leishmania. He studied those sand flies. It replicates in the skin, having a constant immune reaction in the skin. Zoonotic and protozoan paradise but there are several species. He tries to figure out how to push down the population of sandflies. They would go into villages in India to find out how they interact with people. Their animals are in close proximity to where the people are living.

Seasonal Fluctuation

Seasonal patterns that will normally repeat themselves during a year for most organizations.

Selection bias

Selection bias is the bias introduced by the selection of individuals, groups or data for analysis in such a way that proper randomization is not achieved

How was Dr. Semmelweis's handwashing protocol received by his peers?

Semmelweis's observations conflicted with the established scientific and medical opinions of the time and his ideas were rejected by the medical community. Semmelweis could offer no acceptable scientific explanation for his findings, and some doctors were offended at the suggestion that they should wash their hands and mocked him for it.

Disease distribution

So "distribution" covers time (when), place (where), and person (who), whereas "determinants" covers causes, risk factors, modes of transmission (why and how).

How big are ticks? Can you see all varieties easily? In the Lyme disease example, was it shown that no Lyme disease can originate in Utah? What was the percent chance that it can? What type of field work was used to show this ultimately?

Some are small and some are larger. In Illinois they would find many of them. They needed to get the ticks There was a man that wore a cap to attract the ticks. They focused on the recreational areas to collect ticks. They wanted to find those specific types of ticks in those areas.

What is the "compassionate use clause"?

Some unproven trial drugs have been allowed to be used to treat terminal patients on a limited trial basis -Hydroxy-chlorqunine vs COVID-19 -HIV experimental drugs in the 1980s

Why are ethical concerns less with a cohort study? (hint: designed controls vs groups chosen by exposures already present)

Sometimes it is hard to isolate which of many factors are responsible for health differences Differential drop-outs are worrisome

What does a p-value of <0.05 mean?

Statistically significant!

Recalling the series of 30 global map slides (not on CANVAS PPT), how long did it take the pandemic flu of 2009 to move across the entire globe after it was first identified? How does this relate to the 2019-2020 COVID-19 pandemic?

The 2009 H1N1 influenza (flu) pandemic occurred against a backdrop of pandemic response planning at all levels of government including years of developing, refining and regularly exercising response plans at the international, federal, state, local, and community levels. At the time, experts believed that avian influenza A (H5N1) viruses posed the greatest pandemic threat. H5N1 viruses were endemic in poultry in parts of the world and were infecting people sporadically, often with deadly results. Given that reality, pandemic preparedness efforts were largely based on a scenario of severe human illness caused by an H5N1 virus. Despite differences in planning scenarios and the actual 2009 H1N1 pandemic, many of the systems established through pandemic planning were used and useful for the 2009 H1N1 pandemic response. CDC's response to the 2009 H1N1 pandemic response was complex, multi-faceted and long-term, lasting more than a year. This document seeks to document for the public the key events of the pandemic as they unfolded and CDC's response. The following is a summary narrative of highlighted CDC-related events from the 2009 H1N1 pandemic.

descriptive epidemiology

The aspect of epidemiology concerned with organizing and summarizing health-related data according to time, place, and person

What is the cause of the disease that was known as "childbed fever" in the 1840's?

The cause was puerperal fever.

What were the main determinants for the 2015-2016 Zika outbreak originating in Brazil? [Hints: vector, geography, lifestyle, gender. Note: the W.H.O. predicted it would spread throughout the Americas by end of 2016, but in Nov. 2016 W.H.O. announced the end of the epidemic]

The children are born with microcephaly. The disease is caused by vertical transmission. Flu-like symptoms.

Control group

The control group is defined as the group in an experiment or study that does not receive treatment by the researchers and is then used as a benchmark to measure how the other tested subjects do.

Dose-response

The dose-response relationship, or exposure-response relationship, describes the magnitude of the response of an organism, as a function of exposure (or doses) to a stimulus or stressor (usually a chemical) after a certain exposure time.

Cohort studies are often prospective (but can be retrospective). Describe how a cohort study is done prospectively. [Hint: cohort study groups are selected based on exposure not based on disease]

The investigator has no control over exposure.

odds ratio

The likelihood of a disease among individuals exposed to a risk factor compared to those who have not been exposed ad/bc Odds" refers to the probability of occurrence of an event/probability of the event not occurring.

How did handwashing affect the survival rate of birth mothers in 1844-1849?

The mortality rate went from 10-15% in that ward month to month down to 1-2%, and even a couple of months there were no mortalities. Another source says it was reduced from above 30% down to 2%.

Incidence

The number or rate of new cases of a particular condition during a specific time. the sum of all new episodes of illness of a certain disease divided by population size

How can selection bias occur in a prospective cohort study?

The poor people did not own telephones! So Truman actually won, not Dewey Democrats are often more poor (according to Dr Day) Republicans are often more wealthy (according to Dr Day)

P-value

The probability level which forms basis for deciding if results are statistically significant (not due to chance).

Negative predictive value

The probability that a person with a negative test result is truly disease free refers to what value? NPV = TN / (FN + TN)

Positive Predictive value

The probability that a person with a positive test result is truly positive refers to what value? PPV = TP / (TP + FP)

Effective vaccines are possible, but each year scientists must develop a new variation of the vaccine. Why?

The strains can mutate

4 specific aims of an IRB.

The study is well-designed its benefits outweigh the risks Subjects truly give informed consent Clinical trials are halted if the treatment group is clearly showing better or worse results than the control. (pp. 76-77)

Random variation

The tendency for the estimated magnitude of a parameter (e.g., based upon the average of a sample of observations of a treatment effect) to deviate randomly from the true magnitude of that parameter. Random variation is independent of the effects of systematic biases.

Can random variation be greater than the effect of the test variable in an experiment?

There is not a significant difference. The significant difference - defined by t-test, ANOVA, or statistical evaluation to show that differences between groups are much bigger than the random variation between samples within groups. A P-value of <0.05 is normally given, and P < 0.001 is much better.

What type of HRT studies were done about 1976-1999?

There was a large cohort study (probably biased) and a huge clinical trial

Are worm diseases important in the U.S.? How important?

They are especially important to the poor-er populations.

Why are worm diseases of increasing concern in the U.S.?

They are increasingly in the poverty-stricken parts of the United States

Case control studies are always retrospective. Why?

They identify cases and collect data to determine exposures The exposed and non-exposed groups are followed, usually for a period of many years.

What is the danger of reporting associations to the public?

They skew the information from "may account for" to "contribute to this"

How was the Sept. 2018 norovirus outbreak in Utah related to epidemiology? [Was epidemiology used to trace the origin of the epidemic, and/or to predict and prevent spread?]

They talked to the caterer and the people at the event where food was served at a church picnic. They gathered data to understand this more. The norovirus was spread from people to people.

What helminth disease is of concern from litter sandboxes or grass areas where lots of dogs play?

Toxocara- live in the intestines of cats and dogs. Microscopic eggs found yards, playgrounds, sandboxes.

What are some serious outcomes of worm diseases (hint: toxocara)

Toxocara: can reach the brain in turn damaging learning and cognition.

What is the mode of transmission for most helminths?

Transmitted by food, water, vectors, direct contact

A group that is exposed to the intervention is called the ______ group.

Treatment group

True or False? Cohort studies start out by measuring exposure and watching for the development of disease.

True

True or False? In a therapeutic clinical trial, both the experimental group and the control group are composed of patients who have the disease for which a therapy is being tested.

True

Relative Risk (RR)

Used in cohort studies to determine how strongly a risk factor is associated with an outcome. Risk of outcome in exposed/risk of outcome in unexposed. 1 is the null. RR = [a/(a + b)] / [c/(c + d)] "Risk" refers to the probability of occurrence of an event or outcome. Statistically, risk = chance of the outcome of interest/all possible outcomes.

Why is incidence more useful in identifying the cause of a disease?

Used to assess risk factors and causes for disease development

When is it most useful to use prevalence?

Useful in assessing the societal impact of disease and planning for healthcare services.

How can you reduce selection bias in a retrospective case-control study?

Using random methods when selecting subgroups from populations. Ensuring that the subgroups selected are equivalent to the population at large in terms of their key characteristics (this method is less of a protection than the first, since typically the key characteristics are not known).

What examples of public health policies or practices do you see that involve One Health?

Vaccines Public health officials working with other systems

Besides vector transmission, in what 2 ways can Zika be transmitted? [Hint: a) virus is found up to 6 months after infection in what human tissue? b) vertical transmission]

Vertical transmission Sexually transmitted

Virus shedding;

Viral shedding occurs when a virus replicates inside your body and is released into the environment. At that point, it may be contagious. For the coronavirus that causes COVID-19, it's not known exactly when this occurs after someone is infected.

Which of these terms can be described as a measuring scale or gradient, and which are just a yes/no: Virulence, pathogen, infectious, contagious?

Virulence: scale Pathogen: type Infectious: Yes/no Contagious: scale

How is selection bias almost always present in a retrospective case-control study?

Well if they already choose to take a specific drug or behave a certain way. They choose that way.

Compare and contrast risk perception of women voters, college students, and experts regarding pesticides and motor vehicles. What trend do you see? (p. 96)

Well it looks like we all have very different opinions about what is safe or risky.

Thought question: How are epidemiologists and epidemiology important in 2020 in tracking, identifying, and eliminating the local and national opioid epidemic? [Note: Utah is a prototype but this affects states in which all of our many MPH students reside.]

West Virginia has been a problem and they've been talking about it since 2002.

Describe the disease trends as they relate to endemic and epidemic outbreaks of a disease. How do you decide when an outbreak is "epidemic"? (Hint: "epidemic threshold". Anthrax example.)

When they come above a threshold. Depends on each of the diseases.

Why is the who, when, and where questions useful in determining the causes of disease? Give examples.

Who: unit of study can be individuals, farms, ponds, sheds, villages, states, etc. (obesity rates in the photo below). "Does it deal with geography?" "Does it deal with the climate?" "Is it because of their diets?" "Financial?" "female or children?" When: seasonal variation, sporadic occurrence, endemic, outbreaks, pandemics Where: spatial clusters are detected, the next step is to identify risk factors for disease Inferences are made from the distribution Risk factors and associations identified Causality is usually difficult to prove

How can you as an MPH implement concepts of One Health?

Working with people, environment, nutrition, medical workers, animals, vaccines

Are helminth diseases normally deadly?

Worm diseases are chronic and debilitating, but rarely fatal.

Pathogen

a bacterium, virus, or other microorganism that can cause disease.

cost-benefit analysis

a decision-making process in which you compare what you will sacrifice and gain by a specific action

Rate

a measure, quantity, or frequency, typically one measured against some other quantity or measure.

Endemic

a population when that infection is constantly maintained at a baseline level in a geographic area without external inputs

Define conflict of interest. How are Wakefield and Vioxx examples of this?

a situation in which a person is in a position to derive personal benefit from actions or decisions made in their official capacity.

Conflict of interest

a situation in which the concerns or aims of two different parties are incompatible

specificity of a screening test

ability to designate an individual who does not have a disease as negative. A highly specific test means that there are few false positive results.

sensitivity of a screening test

ability to designate an individual with disease as positive. A highly sensitive test means that there are few false negative results, and thus fewer cases of disease are missed. The specificity of a test is its ability to designate an individual who does not have a disease as negative.

Zoonotic:

able to move through the animal-human barrier; transmissible from animals to humans

Population

all the inhabitants of a particular town, area, or country.

Intervention study

an experiment in which something is altered or changed to determine its effect on something else

Highly pathogenic flu (H5N1 avian in 2003 and H7N9 in 2017) crossed from it's normal reservoir of __________ to humans. It infects the lower respiratory tract and has high mortality (about 60%). A big PUBH fear is if this virus adapts to human-to-human transmission it may likely cause a deadly pandemic.

birds

risk assessment

calculating risk, or the degree of likelihood that a person will become ill upon exposure to a toxin or pathogen.

latrogenic

caused by treatment

dose-response

correlation between the amount of a drug given and its effects

mortality

death rate

Which type is the cheapest to conduct?

descriptive

Information on the distribution of disease gives clues about the ____________________ of disease.

determinants

__________ studies are the most convincing type of clinical trials.

double-blind

epidemic threshold

epidemic threshold is used to confirm the emergence of an epidemic so as to step-up appropriate control measures

virulent

extremely poisonous

Nosocomial

hospital acquired infection

distribution of disease

how a disease is spread out in a population, often using factors such as person, place, and time

Significant

important and meaningful

Significant difference

in an experiment, a difference that is unlikely to have occurred because of chance alone and is inferred to be most likely due to the systematic manipulations of variables by the researcher

control group

in an experiment, the group not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment

helminth disease: Pinworms

life cycle in the intestine, emerge at nighttime to lay up to 15,000 eggs near the anus. Intolerable itching causes the victim to scratch thus reinfecting themself and others. Pain causes nightmares, so nightmares are a diagnostic tip for pinworms. .02-20% prevalence. Most common helminth disease in the US

helminth disease: Toxocara

live in the intestines of cats and dogs. Microscopic eggs are shed in the animal's feces, contaminate yards, playgrounds, and sandboxes. Can reach brain-damaging learning and cognition. 5-10% of US people have been exposed. Also another proponent of OneHealth

Frequency

measures compare one part of the distribution to another part of the distribution, or to the entire distribution. number, and number in relation to the population

double blinded

neither the participants or the researchers involved should know which treatment the patients are actually getting

B cell memory

not dependent on repeated exposure to antigen, represents the secondary antibody response, higher affinity then the parent B cell

sporadic

occurring at irregular intervals or only in a few places; scattered or isolated.

Surveillance

ongoing systematic collection, analysis, and interpretation of health data that are essential to the planning, implementation, and evaluation of public health practice

The 2003 avian flu virus has occasionally infected humans with a high fatality rate. If it mutates to spread easily between humans rather than just from animal to humans, it could cause a(n) ______________.

pandemic

Prevalence

percentage of people within a population who have a specific mental disorder

What does informed consent mean and who does it protect?

permission granted in the knowledge of the possible consequences, typically that which is given by a patient to a doctor for treatment with full knowledge of the possible risks and benefits.

mammogram

radiographic image of the breast

Epidemic

rapid spread of disease to a large number of people in a given population within a short period of time

Clinical trial

requires randomized controlled trials before any new drug is approved.

What epidemiological study type does FDA regulate?

requires randomized controlled trials before any new drug is approved.

observable risk

risks that are known and have immediate effects

Retrospective studies

studying participants with a disease and tracing behaviors to determine cause In retrospective studies, individuals are sampled and information is collected about their past

Reliability (precision)

the ability of a measuring instrument to give consistent results on repeated trials

immunity

the ability of an organism to resist a particular infection or toxin by the action of specific antibodies or sensitized white blood cells.

Screening

the application of a test to all individuals in a defined population.

Genetic drift

the change in the frequency of an existing gene variant in a population due to random sampling of organisms. The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces.

Validity

the extent to which a test measures or predicts what it is supposed to

Rates

the frequency of occurrence of an event during a given time frame for a designated population

Incubation period:

the period between exposure to an infection and the appearance of the first symptoms.

Define ethics in your own words

the principles of right and wrong that guide an individual in making decisions

Population at risk

those in the population who are susceptible to a particular disease or condition

Determinants

underlying factors that ultimately bring about disease a quantity obtained by the addition of products of the elements of a square matrix according to a given rule.

idiopathic

unknown cause

Does HRT increase breast cancer?

yes

Is there a vaccine for dog flu? Horse flu?

yes

does HRT increase heart disease risk?

yes