Test 1 Flashcards
Epidemiology is a science about
Frequency and distribution of disease related events and determinants of disease and health in populations
In definition of epidemiology the terms “distribution” and “determinants” refer to..
Frequency, patterns (profiles) and causes of disease related events in populations
In the definition of epidemiology, “determinants” generally refers to what 3 things
- Disease agents
- Causes of disease
- Risk factors of disease
In what way do host determinants define the differences between animals
In susceptibility to disease agents
What 3 things do environmental factors influence
- Susceptibility of the host to disease agents
- Distribution of cases of the disease in different parts of the population
- Exposure of the host to disease agents
The primary determinants are
Factors that have major effect in inducing the disease
The secondary determinants are factors that..
Predispose the host to the disease or modify the influence of primary factors
The exogenous disease determinants are
All factors originating from external environment, that cause- or have influence on a disease
The endogenous determinants are
Factors related to the properties of the host that may have influence on disease occurrence
What theory does epidemiology use in assigning associations and risk
Probability theory
‘Rapidly in rapidly out’ strategy is
Survival strategy of pathogens
Ability of agent to induce antibody production in the host is
Antigenicity
Ability of agent to survive adverse environmental conditions is its
Stability
An infection in which the pathogen remains inactive for a long period of time before becoming active is termed..
Latent infection
An infectious disease that is transmitted from animals to humans (or from humans to animals)
Zoonosis
An organism that transmits the disease-causing organism from the reservoir to the host
Vector
Capacity of agent to cause disease in infected host
Pathogenicity
Capacity of agent to enter and multiply in host and produce infection
Infectivity
If an animal is infected with a virus and a mosquito bites it - gets contaminated with the virus and proceeds to bite and infect a person. In this scenario - what is the vector?
Mosquito
Which of these pathogens are microbial agents?
A. Single cell fungi
B. Helminths
C. Protozoa
D. Arthropods
E. Bacteria
Bacteria
Severity of disease that the agent causes in infected host reflects the ? of the agent
Virulence
The natural habitat of a pathogen is termed the ? of the infection
Reservoir
The transmission of a disease via a fomite (non-living object involved in transmission) is known as
Indirect transmission
A disease model describing the causality of well-defined infectious diseases is
Infection chain
What does the P value express in statistical analysis
The probability that a relationship between variables has been found by chance
TRUE OR FALSE
Evan’s postulates have a difficulty dealing with multiple etiological errors, multiple effects of single causes, carrier states, non-agent factors and quantitative causal factors
False
A disease model allowing to describe associations between different disease determinants together with their association with the disease is
Web of causation
The assumptions of Koch’s postulates are not fulfilled in case of
A. Quantitative causal factors
B. Well-defined infectious agents
C. Multi-causal etiology
D. Carrier state of host
E. Multiple effects of one cause
Quantitative causal factors
The combination of disease determinants that leads to the induction of disease is named
Sufficient cause
TRUE OR FALSE
The existence of a statistical association between the factors and the disease is decisive in determining the causality of a factors
(Statistical association = causal relationship)
False
Describe 3 of the Koch’s postulates
- When inoculated into a susceptible animal the agent has to cause specific disease
- The agent causing the disease must be present in all cases of the disease
- The agent has to be isolated and grown in pure culture
What is meant by ‘Cause of a disease’
Any event, condition or characteristic that plays a significant role in the development of the disease
The disease determinant that has to be present to induce the disease is named
A necessary cause
What is an important principle of Evan’s postulates
That the causation of the factor is based primarily on the study of disease and exposure in groups of animals
Which of the following are components of the infection chain model
A. Mode of transmission
B. Agent
C. The environment
D. Source of infection (reservoir)
E. Necessary cause
Mode of transmission (A) and Source of infection (D)
A causal model utilising the concept of necessary and sufficient cause is
Wheel of causation
What are the two assumptions of Koch’s postulates
- There must be one specific cause for the disease
- One specific cause must result in only one specific disease
The epidemiologic triad of disease causation refers to:
A. Agent, host environment
B. Source, mode of transmission, susceptible host
C. Time, place, person
D. John Cena, Marilyn Monroe, Esta Nahkur
Agent host and environment (A)
The level of independency in measurements and evaluations of the person who records and/or analyses the trait (variable) in question defines
Objectivity of data
If a diagnostic technique measures the properties of the body that best reflect the true health status of the individual, the technique is considered
Valid
What are the two types of statistical variables?
Qualitative and quantitative
Which of these variables is an example of a categorical data
A. 75.2kg
B. Height
C. Colours
D. Number of animals
Colours (C)
A categorical variables is also
Qualitative
Which of these variables is an example of a continuous data
A. Breed
B. Infection status (yes/no)
C. Height (Cm)
D. Body condition index (1-5)
Height (cm)
Discrete variable is also a
Quantitative variable
Which of these variables is an example of ordinal data
A. Weak, moderate, severe
B. Red, green, blue
C. Fever (yes/no)
D. Bodyweight (kg)
Weak, moderate, severe (A)
What are summarised, numerical and pictorial (graphical) information about variables are called
Descriptive statistics
All of these are measures of central location except
A. Mode
B. Arithmetic mean
C. Geometric mean
D. Range
E. Median
Range (D)
The measure of a central location that is most affected by one extreme value is the..
Arithmetic mean
All of the following are measures of dispersion except
A. Standard deviation
B. One percentile
C. Interquartile range
D. Variance
E. Range
One percentile (B)
TRUE OR FALSE
Standard deviation and variance have the same units
False
TRUE OR FALSE
For a given set of measurements, the deviation and the standard deviation have identical units
True
What is a histogram?
A graphical expression of a frequency distribution
TRUE OR FALSE
Values of one variable may have more than one modes
True
What is the purpose of descriptive epidemiology (3)
- To understand variations in disease frequency geographically and over time
- To understand how disease varies among animal groups
- To provide clues about source, and modes of transmission of disease agents
Epidemic curve expresses
Dynamics of disease in time
Epidemic curve, where the first peak is followed by one or more peaks with relatively similar time interval, is characteristic to what
Probagating epidemic
Large number of animals falling ill in a short period of time is characteristic to
Pointsource epidemic
A disease is called endemic when
Disease occurs with relatively small fluctuations in frequency through long time period
Disease is called epidemic when
The disease occurrence overcomes significantly the usual level observed in a population
The disease is called sporadic when
Disease occurs rarely and without regularity
What kind of disease is it when there are usually no more than 2-4 cases per week, and last week there were 13 cases
Epidemic
What kind of disease is it when there are fewer than 10 cases per year and last week was only one case
Sporadic
What kind of disease is it if there usually are 40-50 cases per week, and last week were 48 cases
Endemic
What kind of exposure is propagated epidemic usually the result of
Animal to animal
Increases and decreases in the frequency of a disease over a period of some years or a year are
Cyclic trends
TRUE OR FALSE
To describe the dynamics of the disease in time, we use time-series analysis and presentation of data on frequency polygons or bar charts
True
The main sources of errors in long time trends of disease frequency (3)
- Changes in registration and reporting
- Changes in host population structure
- Changes (differences) in recognition (diagnostics) of a disease
To describe the geographical distribution of the disease, we use
A. Histograms
B. Cartograms
C. Nanograms
D. Pictograms
Cartograms (B)
TRUE OR FALSE
Demographic characteristics are restricted to host characteristics (age, sex, species etc)
False
TRUE OR FALSE
Socio-economic status of an animal is made up of variables like economic status and/or educational level of the owner, animal keeping practises and traditions
True
Demographic characteristics influence the hosts
A. None of these
B. Both - susceptibility to disease and opportunities for exposure
C. Susceptibility to disease
D. Opportunities for exposure
Both (B)
Epidemiological data are related to (4)
- Factors influencing the animal productivity
- Animal productivity
- Factors influencing the animal health
- Animal diseases
Epidemiological data are related to (4)
- Factors influencing the animal productivity
- Animal productivity
- Factors influencing the animal health
- Animal diseases
The parameters describing the data quality are
A. Validity
B. Refinement
C. Reliability
D. Precision
E. Correctness
A + B + C + D