Veterinary Epidemiology Quiz1 Part 1

kelseyfmeyer's version from 2015-08-26 15:45


Question Answer
What is CDC?Centers for Disease Control and Prevention
What is OIE?World Organisation for Animal Health (known by its French acronym Office International des Epizooties – OIE)
What is USDA- APHIS?United States Department of Agriculture- Animal and Plant Health Inspection Service
what is USDA –FSIS?United States Department of Agriculture - Food Safety and Inspection Service
what is AVMA?American Veterinary Medical Association
Epidemiology is?the greek of the word means... "the study of what is upon the population". SO, it is the Study of the occurrence and distribution of disease in populations (animal or human) (Emphasis on establishing the causal factors that influence disease occurrence)
what is a population?the totality of individuals that share common attributes (sex, breed, ethnicity, location)
What is EBM (evidence based medicine)?"the conscientious, explicit and judicious use of current best evidence in making decisions about the care of the individual patient.”
EBM uses POPULATION DATA to better understand these 4 areasdx, prevention, tx, prognosis
What is endemic(human)/enzootic(animal)?Usual (constant) frequency of disease in a population. A disease is endemic when it occurs with predictable regularity in a population. (Note: Endemics can become epidemics if host-agent-environmental factors change)
What is Epidemic (epizootic)?Often synonymous with the term outbreak and typically used for infectious diseases. An epidemic disease is a disease that is rapidly spread and many individuals acquire disease over a short period.
What is Pandemic?A widespread epidemic/epizootic……involving more than one country. There is a more specific def. made by the WHO(World Health Organisation), which requires...: There must be a disease new to a population – or at least a disease that had not surfaced for a long time. This disease must be caused by disease-causing agents that infect humans, causing serious illness. AND, The agents must spread easily and sustainably among humans causing high morbidity and high mortality
The WHO (world health organization) defines their "phase 6- pandemic phase" asthe 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.
"sporatic" disease occurance is defined as...A disease that is NOT NEW & occurs infrequently (without regularity) in a population. Cases occur in small numbers, illness is not apparently connected with similar illnesses in any other animals/persons, and it is not rapidly spread
explain epidemic vs sporaticWhilst an epidemic can be 1 case of a new disease, it is rapidly spread between animals /humans... BUT!!! A sporadic case refers to a person/animal whose illness is not rapidly spread and not apparently connected with similar illnesses in any other animals or humans
what is Public health surveillance?Public health surveillance is the ongoing, systematic collection, analysis, interpretation, and dissemination of data regarding a health-related event for use in public health action to reduce morbidity and mortality and to improve health (CDC,2001).
what is passive surveillance?System in which Vet agencies make no active efforts to collect disease info (But Problem: Some info on disease frequency but not accurate.)
what is Active surveillance?Uses structured disease surveys to collect high quality disease info quickly. A survey: Trained veterinary staff examine only a sample of the population. (more costly but more accurate)
what is a host?An individual (animal or human) that harbours an Infectious agent or is exposed to a potential causal agent of disease which is usually infectious. Typically used in reference to infectious diseases although in general hosts are also susceptible to noninfectious and chronic diseases.
What is a demographic?Personal characteristics of an individual or group (age, sex, breed, occupation)
what is a case?Individuals with a particular disease that meet selected criteria stated by the case definition
what are Causal factors or determinants?A factor that directly influences the occurrence of disease. Synonymous with risk factor or exposure factor
what is infection?Defined as the encounter of a potentially pathogenic agent with a susceptible human /animal host and the host shows an immunologic response to infection.
what is disease DEFINED as?a clinically apparent infection — infection accompanied by overt illness.

Disease reporting

Question Answer
what are the three corners of the epidemeologic triangle? What is this triangle used for?Host-Agent-Environment. It is used as A model to explain why diseases occur in a population.
Temporal (in time) disease occurance reporting uses what kinda terminology (list...)Endemic (enzootic), Epidemic (epizootic), Pandemic (panzootic), Sporadic
how would you describe endemic in terms of temporal patterns?dz occurs at expected frequency, present in population or region at all times, and Usually low and predictable level
how would you describe epidemic in terms of temporal patterns? how do you depict the occurrence of the dz?disease occurs at greater than expected frequency. Occurrence depicted graphically as "Epidemic curves"
how would you describe pandemic in terms of temporal patterns?sporatic
The shape of an epidemic curve tells us what two major things?These are histograms depicting the no. of new cases (Y) axis over time (X) axis. Using this info, we can get info on probable time of exposure based on the incubation period, and also info on if the outbreak was due to a common or point source
what are the 3 basic curves of disease occurrence on the epidemic curve?(1) Point epidemic (point source) (2) Continuous common source epidemic (3) Propagating epidemic
what is a "point source" epidemic curve? what does the curve look like on the graph?animals or persons are subjected to the same BRIEF exposure over a limited, defined time period, usually within 1 incubation period. The graph looks like Curve commonly rises rapidly and contains a definite peak at the top, followed by a decline once the point source is removed, no new cases occur (see slide 14)
what is a "continuous(common) epidemic" epidemic curve? what does the curve look like on the graph?Exposure to the source is prolonged over an extended period of time and may occur over > one incubation period. On the graph, The down slope of the curve may be very sharp if the common source is removed or gradual if the outbreak is allowed to exhaust itself (see slide 16)
what is a "propagating epidemic" epidemic curve? What does the curve look like on the graph?Occurs when disease is introduced through a single (primary) source of infection in 1 animal and then transmitted to other animals. The graph has multiple peaks and regressions (see slide 20)
what is the frequency of an endemic like?disease occurs at expected frequency
what is the frequency of an epidemic like?disease occurs at greater than expected frequency
what is the frequency of "sporatic disease" occurance like? What is distinct about them?only a small number of cases are observed during a short period of time, Disease occurs rarely and without regularity, and there are no secondary cases
look at slide 24 for sporatic vs endemic vs epidemicepi and sporatic look similar, except sporatic is much fewer cases
what does a time series analysis do?Uses the information on patterns of disease occurrence obtained from temporal occurrence data...the temporal occurrence data will identify periods of high/low risk (trends) of disease occurrence--> allows casual associations to be explored
what are the three trends of time-series analysis?short-term, cyclical (including seasonal), secular trends
what is a secular trend?a long term trend, where the Data reflects an Overall inc or dec in incidence occurring gradually over long time periods
what is a cyclical trend like?Rise and fall of disease over greater than 1 year Associated with regular, periodic fluctuations in level of disease occurrence
what are some factors which would make a cyclical trend a seasonal trend?things like host density (all migrating together or sthing), Management practices, Vector borne diseases (fly season), Infectious agent survival due to environmental factors
Disease occurrence can be affected by host factors such as...age, sex, breed
What is Incidence?a measure of the frequency with which new cases occur over a specified time period (other explanations given are:)The proportion of a population, initially free of the outcome of interest, that develops the disease over a given period of time. Incidence refers to NEW cases of disease
What is prevalence?The number of cases that are present in a given population (other explanations given are:) Proportion of the population at a given time that have the factor of interest
what is attack rate?Measure of the proportion of the population that develops disease at the start of an outbreak among the total exposed
What is the math problem for incidence?I(per 1,000)= the number of new cases in a population during a particular period of time, DIVIDED BY the number of individuals at risk of developing the disease during that period of time. All of this is multiplied by 1000.
how are units of population expressed?Unit of population expressed as whole numbers and in the smallest multiples of 10
What is the math problem for prevalence?# of individuals having a disease at a particular point in time DIVIDED BY # of individuals in the population at risk at that point in time
how is incidence expressed, versus prevalence?incidence is usually expressed numerically in reference to population at risk (X out of a 1000 or whatever mult of 10). Prevalence is usually expressed as a proportion between 0 and 1, OR a %, OR As a unit of population at risk
what is point prevalence?Number of cases in a population, at a particular point in time.
what does incidence account for that prevalence doesnt?prevalence, (unlike incidence), does not take into account the duration of disease. It is a snapshot at this point in time.
What is period prevalence?How many people have had the disease during a certain time period, for example over 1 calendar year. It is a combination of point prevalence and incidence
what is the math equation which relates incidence and prevalence?Prevalence=Incidence x Duration of disease
check out prevalence vs incidence example starting on slide 53helpful
what is a cluster analysis?Geographical information systems used to measure disease occurrence in time and space... This allows us to ID geographical clustering of disease and define as endemic, epidemic, sporadic, pandemic based on timelocation
what is data modelling used for?used to test hypotheses and plan health policies
what is a case definition?set of uniformly applied criteria for a particular disease

Causal relationships

Question Answer
What is Infection?ability of the agent to establish itself in a host
what is Pathogenic?ability of agent to produce disease in host
what is Virulence?Measure of severity of disease due to agent
Resistance to disease in populations is called...?herd immunity
The stronger the association between a presumed causal factor and disease or outcome, the more likely a cause and effect relationship exists.This is which criteria for establishing a cause?Strength of association
non-statistical strength of association means?it happened by chance, no real cause or relation
Positive statistical association may indicate...?causality
A negative statistical association may indicate...?a protective factor
example/explanation of a causal factor being Necessary and sufficient?Certain dose of virus required for infection
example/explanation of a causal factor being Necessary but not sufficient?Occurrence of disease requires two or more factors are present
example/explanation of a causal factor being Sufficient but not necessary?Passive smoking can cause feline lymphoma, but other causes of feline lymphoma exist
example/explanation of a causal factor being Neither sufficient nor necessary but can contribute to existing disease?High fat diet and Cardiovascular disease
what is Temporal Precedence?The evidence provided demonstrates that your cause happened before your disease occurrence.
Dose-response relationship...what must you remember about this criteria of causal factors?disease may not develop until exposed to a certain level [ex: exposure/smoke]
"Reversible association" criteria of causal factors means/asks...Does the removal of a factor results in a decreased or increased frequency of disease? (ex: Cessation of smoking leads to reduction of inflammatory & haemostatic markers for cardiovascular disease)
what is the strongest type of epidemiologic study providing EVIDENCE (NOT PROOF) that an association might be causal? What are the less strong types?A Randomized clinical trial is Best evidence for causality! Other trials which are not randomized, so are less strong are: cohort and case control, cross sectional, cases series, case report
Relative Risk ratios are used in what studies? Odds Ratios are used in what studies? what do they both measure?RR is used in cohort studies. OR is used in case-control studies. They measure the STRENGTH of the association between the causal/exposure factor and disease which is a Major criteria for judging causal inferences