AGR 306 Final Exam

What are the five uses of epidemiology?

1. Study a disease for the cause that is known 2. Study a disease whose cause is unknown/poorly understood 3. Planning and assessment of a disease (creating disease control programs) 4. Evaluating the cost-benefits of a disease control program 5. Gathering of information on the ecology and natural history of a disease

For this example, mark one answer that has the correct disease determinant for all three classifications. Disease is Enterotoxemia (overeating disease) in sheep Determinant is over consumption of grain A. Secondary, extrinsic, environment B. Secondary, intrinsic, environment C. Primary, intrinsic, agent D. Primary, extrinsic, environment

A

Ratios, proportions, and rates can be expressed in three forms. Which of these forms measures the amount of disease and death in the population as a whole? A. Crude B. Specific C. Adjusted D. Total

A

What is the specific term for the number of individuals known to have had the disease for at least part of their life? A. Lifetime prevalence B. Period prevalence C. Point prevalence D. Specific prevalence

A

What is the term for a disease where humans and animals are both affected? A. Zoonoses B. Bad luck diseases C. Duplicate diseases D. Common ground diseases

A

What is the terminology for the period between infection and maximum infectiousness? A. Generation time B. Extrinsic incubation period C. Incubation period D. Lifetime period

A

What measures the rapidity with which new cases of disease develop over time? A. Incidence rate B. Attack rate C. Prevalence D. Morbidity rate

A

What type of epidemiological investigation (main 4) uses laboratory animals? A. Experimental B. Analytical C. Theoretical D. Descriptive

A

When entering data via a keyboard, four possible error types can occur. A student typed in 976 when they were supposed to type 977. What type of error is this? A. Substitution B. Transposition C. Insertion D. Deletion

A

Which of the following is NOT one of the five main maintenance strategies for infectious agents? A. Avoidance by vertical transmission B. The development of resistance forms C. Rapidly in, rapidly out strategy D. Persistence within the host E. Extension of host range

A

Which of the following is not one of the three important factors of transmission of infection? A. Characteristics of environment B. Characteristics of pathogens C. Characteristics of hosts D. Effective contact

A

Which of the following would NOT be information gathered for the ecology and natural history of a disease? A. Age of animal B. Social environment C. Housing facility D. Location of other animals to infected animals such as wildlife

A

Match the geographical base map to the correct description. Answers may be used more than once or not at all. Also known as dot or location map Use different sized circles to demonstrate the level of mortality or morbidity rates Show outbreaks of disease in discrete locations using symbols Display quantitative data using shaded areas of the map True boundaries between different values are depicted by joining all points of equal value by a line Intensity of shade indicates level of disease occurrence A. Point map B. Proportional circle map C. Chloroplethic map D. Isoplethic map E. Distribution map

Also known as dot or location map- A Use different sized circles to demonstrate the level of mortality or morbidity rates- B Show outbreaks of disease in discrete locations using symbols- A Display quantitative data using shaded areas of the map- C True boundaries between different values are depicted by joining all points of equal value by a line- D Intensity of shade indicates level of disease occurrence- C

Match the type of genotypic change to the correct description. Alternation in the sequence of nucleic acids in the genome of a cell Reassortment of segments of a genome that occurs when two microbes exchange genetic material Involves the transmission of genetic material- usually in the form of a plasmid Transfer of a small portion of a genome from one bacterium to another Release of DNA from one bacterial cell ans then its entry into another cell of the same bacterial species A. Mutation B. Transformation C. Recombination D. Transduction E. Conjugation

Alternation in the sequence of nucleic acids in the genome of a cell- A Reassortment of segments of a genome that occurs when two microbes exchange genetic material- C Involves the transmission of genetic material- usually in the form of a plasmid- E Transfer of a small portion of a genome from one bacterium to another- D Release of DNA from one bacterial cell ans then its entry into another cell of the same bacterial species- B

Match the type of host to the correct description. An animal that maintains an infection in the latter's endemic area (Long term) A species that additionally is involved in the life cycle of an agent, typically outside of the typical endemic area A host in which an agent is transferred mechanically (without further development) An animal in which an agent is held, probably without replication, in a state of 'suspended animation' One that does not usually transmit an infectious agent to other animals An animal which, because of temporally-associated changes in population dynamics that produce a sudden increase in the host population size, may suddenly increase the amount of the infectious agent A. Paratenic host B. Incidental host C. Primary host D. Amplifier host E. Reservoir host F. Intermediate host G. Secondary host H. Hibernating host

An animal that maintains an infection in the latter's endemic area (Long term)- C A species that additionally is involved in the life cycle of an agent, typically outside of the typical endemic area- G A host in which an agent is transferred mechanically (without further development)- A An animal in which an agent is held, probably without replication, in a state of 'suspended animation'- H One that does not usually transmit an infectious agent to other animals- B An animal which, because of temporally-associated changes in population dynamics that produce a sudden increase in the host population size, may suddenly increase the amount of the infectious agent- D

Calculate the prevalence rate using the following information: Within a flock of 100 geese, on Saturday, 12 geese had injured legs, 2 had injured beaks, and 6 had injured wings. What is the prevalence rate of injured legs? A. 2% B. 12% C. 20% D. 6%

B

Evan's rules contain how many rules? A. 5 B. 10 C. 15 D. 20

B

Time series analysis is used to detect temporal trends. These trends can be detected by several methods. Which of the following is NOT a method for time series analysis? A. Regression analysis B. Standard deivation C. Plotting D. Calculation of rolling averages

B

What form of quantitative investigations involved taking periodical observations on health, productivity and environmental factors? A. Studies B. Monitoring C. Surveillance D. Surveys

B

What is the normal response rate for mailed questionnaires? A. 70% B. 50% C. 60% D. 40%

B

Which of the following is NOT one of the four major methods of arriving at a hypothesis? A. Method of concomitant variations B. Method of consistency C. Method of agreement D. Method of difference

B

Which of the following is not a base of disease-control programs? A. Factors associated with its occurrence B. Mortality and morbidity rates C. Amount of disease in that population D. Costs-benefit relationship

B

Which of the following will NOT influence response rate in mailed questionnaires? A. Subject and aim of the study B. Providing a pen to mailer C. Confidentiality D. The sponsor

B

[Blank1] is the tendency for a condition to cause the death of affected animals in a specified time, however, in cases of chronic diseases, it is more appropriate to report [blank2] instead.

Blank 1- Case fatality Blank 2- Survival

Causality is the relationship between [blank1] and [blank2].

Blank 1- Cause Blank 2- Effect

Genetic diseases can be categorized as [blank1] aberrations, [blank2] disorders that are simply inherited, or [blank3] diseases that have a complex genetic component.

Blank 1- Chromosomal Blank 2- Mendelian Blank 3- Multifactorial

Separated populations of animals can be classified two ways: a [blank1] herd is one where no animals move in or out of the herd except to slaughter and a [blank2] herd is one where there is limited movement, but often replacements are brought in.

Blank 1- Closed Blank 2- Open

A [blank1] study uses a group exposed to factors to compared to a group not exposed to those same factors. Another study type, [blank2] looks at the relationship between the proposed causative factors to the disease. [Blank3] study compares a group of diseased animals with a group of healthy animals while exposing them to a specific causative agent.

Blank 1- Cohort Blank 2- Cross-sectional Blank 3- Case-control

There are three major trends of temporal changes and fluctuations in disease occurrence. 1 = short-term, 2 - [blank1] which includes seasonal and 3 - [blank2]-term.

Blank 1- Cyclical Blank 2- Long

Quantitative data is subdivided into two types: [blank1] is data that is typically whole numbers, where [blank2] can generate measurements and can use decimals.

Blank 1- Discrete Blank 2- Continuous

[Blank1] epidemiology is the practice of epidemiology in response to large problems where immediate attention is needed. Another form of epidemiology is genetic epidemiology where the population evaluated is a group of [blank2] individuals.

Blank 1- Field Blank 2- Related

An [blank1] case is the first case to come to the attention of the investigators. It is also considered to be a [blank2] case.

Blank 1- Index Blank 2- Primary

Regarding pathogens, there are three important characteristics: 1 - [blank1] - amount of an organism that is required to initiate infection 2- [blank2] - affects transmission and change change 3 - [blank3] - amount of time that an organism can remain infective outside its host

Blank 1- Infectivity Blank 2- Virulence Blank 3- Stability

When testing questionnaires, [blank1] testing is used on colleagues and [blank2] testing is considered a pilot survey.

Blank 1- Informal Blank 2- Formal

Within the host, sex can be a disease determinant. Sex-[blank1] diseases are due to Mendelian inheritance, whereas, sex-[blank2] diseases occur in both sexes, but one sex is more frequent than the other. Sex-[blank3] diseases is due to DNA that is not found on the sex chromosome, but it only occurs in one sex.

Blank 1- Linked Blank 2- Influenced Blank 3- Limited

Epidemiology is the study of disease in [blank1] and of factors that determine its [blank2].

Blank 1- Population Blank 2- Occurrence

[Blank1] investigations of epidemiology were the mainstay of epidemiologists prior to WWII. Epidemiologists were referred during this time as medical [blank2].

Blank 1- Qualitative Blank 2- Detectives

In methods of data collection, [blank1] and observation are considered primary forms, whereas [blank2] is considered secondary.

Blank 1- Questionnaires Blank 2- Documentary sources

A [blank1] variable is one that is affected. A [blank2] variable is the one that causes the effect.

Blank 1- Response Blank 2- Explanatory

The transmission [blank1] is the probability of transmission per contact. The [blank2] rate is the average number of contacts per unit of time.

Blank 1- Risk Blank 2- Contact

There are serveral forms of modelling, [blank1] uses theoretical models of nature processes, whereas, [blank2] modelling uses equations. Another type of modelling, [blank3] uses experimental animals.

Blank 1- Statistical Blank 2- Mathematical Blank 3- Biological

To formulate a hypothesis, there are three elements that must be known: [blank 1], [blank 2] and [blank 3]

Blank 1- Time Blank 2- Population Blank 3- Place

A [blank1] is an animate transmitter of infectious agents, whereas, a [blank2] is an inanimate carrier of agents.

Blank 1- Vector Blank 2- Fomite

In a herd of 100 cows, brucellosis is found. Within 1 year, 3 cows die, while a total of 10 cows contract brucellosis. Calculate the case fatality (CF) rate A. 3% B. 6% C. 30% D. 33%

C

What is the specific term for the number of cases that are known to have occurred during a specified period of time (a month for example)? A. Specific prevalence B. Point prevalence C. Period prevalence D. Lifetime prevalence

C

When entering data via a keyboard, four possible error types can occur. A student typed in 1516 when they were supposed to type 5161. What type of error is this? A. Substitution B. Deletion C. Transposition D. Insertion

C

Which of the following is NOT one of Hill's criteria for establishing a causal association? A. Biological gradient B. Compatibility with existing knowledge C. Description of place D. Time sequence of the events

C

Which of the following is true regarding virulence? A. Refers to the quality of disease induction B. Expressed as the ratio of the number of clinical cases to the number of animals in the group C. Ability of an infectious disease in a particular host in terms of severity D. Quantified as the ratio of the number of individuals developing clinical illness to the number exposed to the infection

C

What are the three reasons why prevalence of disease could change?

Change in the incidence rate Change in the average duration of the disease Change in both incidence and duration

Match the sub-discipline forms of epidemiology to the correct description. Chronic disease epidemiology Environmental epidemiology Micro-epidemiology Computational epidemiology Clinical epidemiology Molecular epidemiology A. Application of computer science to epidemiological studies B. Study of long duration diseases such as cancer C. Study of disease using a small group of individuals and trying to compare it to a larger population D. Studies the relationship between environmental factors and disease E. Use of epidemiological research within a clinical setting to try to improve patient care F. Studies of antigenetic and genetic differences in viruses and other microorganisms

Chronic disease epidemiology- B Environmental epidemiology- D Micro-epidemiology- C Computational epidemiology- A Clinical epidemiology- E Molecular epidemiology- F

Match the method of transmission to the correct description. Contaminated feed or water Airborne transmission via contaminated air (or droplets/dust) Transmission without transmission factors and without participation of an external medium Introduction into the body by a puncture of skin or through a wound- could be classified the same as contact Transferred during surgical or medical practice Transmitted through sexual contact A. Aerial transmission B. Ingestion C. Iatrogenic transmission D. Coitus E. Inoculation F. Contact

Contaminated feed or water- B Airborne transmission via contaminated air (or droplets/dust)- A Transmission without transmission factors and without participation of an external medium- F Introduction into the body by a puncture of skin or through a wound- could be classified the same as contact- E Transferred during surgical or medical practice- C Transmitted through sexual contact- D

What geographical base maps displays quantitative data using shaded areas of the map? A. Distribution maps B. Proportional circle map C. Point map D. Choroplethic map

D

What specific epidemic is caused by an infectious agent in which initial cases excrete the agent and thus infect susceptible individuals? A. Common source epidemic B. Index epidemic C. Point source epidemic D. Propagating epidemic

D

What term stands for the number of secondary causes that occur per unit time? A. Transmission risk B. Contact rate C. Transmission contact D. Transmission rate

D

Which of the following is NOT a population group for the Reed-Frost model? A. Immune animals B. Infected animals C. Susceptible animals D. Dead animals

D

Match the four approaches of epidemiological investigation to the correct description Descriptive Analytical Experimental Theoretical A. Observations taken are used for diagnostic and statistical procedures B. First part of an investigation C. Uses mathematical models to try to duplicate patterns of disease occurrence D. Includes a control group and seen in clinical trials E. Includes observing and recording diseases and possible causal factors

Descriptive- B, E Analytical- A Experimental- D Theoretical- C

List four factors that affect the dissemination rate (the propensity of infection to spread to other herds).

Disease control strategies Environment Farmers behavior Animal movements

Which of the following would not be considered an epidemiological unit? If they are all considered epidemiological units - then select none of the above. A. All livestock housed at the MSU farm B. Flock of sheep at one farm in Western Kentucky C. Cattle that go through the Paris Stockyards D. Horses at a boarding facility in Ohio E. None of the above

E

You are new to an area and are wanting to start a herd of cattle. Your local extension agent tells you that there have been causes of a particular disease in the area. Give 4 examples of information that you would need to gather to determine the possible ecology and natural history of the disease.

Environment/Housing Climate Other animals in proximity Interaction of animals and humans Social environment

What are the five main maintenance strategies used by organisms?

Extension of host range Persistence to host environment Rapidly in, rapidly out approach Avoidance of the stage in the external environment Ability to produce resistance forms

A disease-preventing program may not include economic analysis. True or False

False

All four types of epidemiological studies are considered observational. True or False

False

Crude measures (ratios, proportions, rates) are an expression of disease and death in the population in a selected group. True or False

False

Every occurrence of disease with a known cause will occur exactly in the same fashion (timing, environment, etc.). True or False

False

Human survival rates and animal survival rates can be compared to one another without bias. True or False

False

In secular trends, if the interaction is biased to the host rather than the parasite, there will be a gradual increase in disease occurrence. True or False

False

Koch's postulates are based on deductive reasoning. True or False

False

Most epidemiological studies are based on deductive reasoning. True or False

False

Prevalence is reported on a scale from 1 to 10. True or False

False

Risk factors for a disease will always be causal. True or False

False

Spatial distribution refers to the times of occurrence of cases of a disease. True or False

False

The four causes developed by Aristotle were accepted in their entirety by the Scholastics (Christian medieval philosophers). True or False

False

There are two main internal hazards: desiccation and ultraviolet light. True or False

False

When administering mailed questionnaires, reminding respondents will increase the response rate. True or False

False

When considering the age of the host, young animals are always more likely to develop the disease and be infected the most - resulting in a worse infection. True or False

False

When writing a questionnaire, questions should only be closed questions with fixed number of options for answers. True or False

False

Match the description to the correct method of acceptance of the hypotheses (one of four methods described). Generally disregards opinions of others Relies on the opinions of experts Self-evident without actual evidence; a belief or feeling Objective observations that can be repeated by many Uses gut feeling Requires clarity, order and consistency A. Tenacity B. Scientific inquiry C. Intuition D. Authority

Generally disregards opinions of others- A Relies on the opinions of experts- D Self-evident without actual evidence; a belief or feeling- C Objective observations that can be repeated by many- B Uses gut feeling- C Requires clarity, order and consistency- B

In causal model 1, there are different factors that impact component causes. Match the description to the correct factor. Increases the level of susceptibility of the host Facilitate manifestation of a disease Associated with the definitive onset of the disease Tend to aggravate the presence of a disease A. Predisposing factors B. Precipitating factors C. Enabling factors D. Reinforcing factors

Increases the level of susceptibility of the host-A Facilitate manifestation of a disease- C Associated with the definitive onset of the disease- B Tend to aggravate the presence of a disease- D

What are the four factors that affect the shape of the epidemic curve?

Incubation period of the disease Infectivity of the agent Proportion of susceptible animals in the population Distance between animals (Animal density)

What are the three main routes of infection? For each route, describe how the organism enters the animal.

Oral route- the animal ingest the organism either through ingesting milk, feces or feed Respiratory route- the animal inhales the organism as the air is contamination Infection via the skin, cornea, and mucous membranes- the animal gets infected with the organism by cuts, abraded skin, bite or corneal scratches

What are the four main scales of measurement?

Ratio Interval Nominal Ordinal

Match the term to the correct description. The proportion of true positives that are detected by a method The proportion of true negatives that are detected by a method Indication of the extent to which an investigation or measurement conforms to the truth Degree of detail in the data A. Specificity B. Sensitvity C. Refinement D. Accuracy

The proportion of true positives that are detected by a method- B The proportion of true negatives that are detected by a method- A Indication of the extent to which an investigation or measurement conforms to the truth- D Degree of detail in the data- C

Why is calculating mortality and morbidity rates important to a livestock producer? Give at least two reasons.

To know how a disease will affect the herd. Example- if a disease has a high mortality rate, a livestock producer will have a general idea of how many animals of his/her herd may die if the disease becomes present in the herd

A false-negative is when the animal is not diagnosed with a disease when it does have it. True or False

True

An animal is not infectious as soon as it is infected. True or False

True

An silent infection is an infection in a host without clinical signs. True or False

True

Causal model 2 is often considered a web of causation. True or False

True

Contiguous populations of wildlife can be quantified by two methods - directly or indirectly. True or False

True

Datum is the singular form of the word. True or False

True

In causal model 1, a cause may be considered necessary, sufficient, neither, or both. True or False

True

It is possible to develop and use disease control methods before the causative agent of that disease is determined. True or False

True

It may not be economical for a disease-controlling program to completely eradicate the disease from a population. True or False

True

Most epidemiological studies are based on inductive reasoning. True or False

True

One issue with Koch's postulates is that it ignores the impact of environmental factors on disease. True or False

True

Opportunistic pathogens can be exogenous or endogenous. True or False

True

Seasonal trends refer to the periodic fluctuations in disease incidence that are related to particular seasons. True or False

True

Surveillance is a form of more intensive data recording compared to monitoring. True or False

True

Temporal distribution refers to the times of occurrence of cases of a disease. True or False

True

Match the term to the correct description. Usual frequency of occurrence of a disease in a population A disease that is continuously present at high levels and affects all age groups Occurrence of an infectious or non-infectious disease to a level in excess of the expected level Widespread occurrence of disease in excess of expected that affects a large proportion of the population A. Endemic B. Hyperendemic C. Pandemic D. Epidemic

Usual frequency of occurrence of a disease in a population- A A disease that is continuously present at high levels and affects all age groups- B Occurrence of an infectious or non-infectious disease to a level in excess of the expected level- D Widespread occurrence of disease in excess of expected that affects a large proportion of the population- C

What are three examples of closed question types?

Yes or no Multiple choice Likert scale