Epidemiology of Viral Diseases

Question 1

Virus epidemiology is the study of ________

Answer 1

Determinants, Dynamics, Distribution, and frequency of viral diseases in populations

(DDDF)

Question 2

The risk of infection and/or disease in an animal or animal population is determined by:

Answer 2

1. Characteristics of virus
2. The host and host population
3. Behavioral, environmental, and ecological factors that affect transmission

Question 3

What is the role of viral epidemiology?

Answer 3

1. Understand etiology of diseases
2. Determine factors affecting host susceptibility
3. Modes of transmission
4. Impacts of viruses on health, economy, and society
5. Study non infectious and infectious diseases
6. Large scale testing of vaccines and drugs

Question 4

What benefits comes from epidemiology of viruses?

Answer 4

1. Understand nature of diseases
2. Able to direct treatments, control, and prevention
3. Early warning signs, able to track disease
4. Assess social and economic impacts of disease
5. Assess efficiency and cost of disease control and prevention

Question 5

What is case fatality rate?

Answer 5

of death among clinically sick animals (not among entire population!!!)

Ex: # of sick animals is 25, number of dead animals is 10 (10/25 x 100)

Question 6

What is mortality rate?

Answer 6

of animals in a population that die from a disease over a period of time

Question 7

What is morbidity rate?

Answer 7

of animals in a population that develop CS attributable to a particular virus over time

Question 8

What is incidence rate?

Answer 8

a measure of the occurance of infection or disease in a population over time

Ex: a year or a month

• helps determines frequency or duration of a disease

Question 9

What is prevelance?

Answer 9

The # of occurances of a disease (OLD AND NEW CASES) in a population at a particular point in time

• helps determine frequency and duration of a disease

Question 10

What is a sporadic viral disease?

Answer 10

Disease that occurs occasionally, singly, or in scattered instances

or in irregular and haphazard manner

Question 11

What is an enzootic/endemic viral disease?

Answer 11

Constant presence of a viral disease within a given geographic area or population group

Ex: up north, alot of lyme dz bc alot of ticks

Question 12

What is an epizootic/epidemic viral disease?

Answer 12

viral disease that occurs in more cases than expected in a given area or among a specific group

peaks in a disease incidence that exceeds the expected incidence

Question 13

What is a pandemic / panzootic viral disease?

Answer 13

Occurs over a very wide area (several countries or continents)

affects a large proportion of the population

Question 14

Types of asymptomatic carriers?

Answer 14

1. Incubatory acute carriers
2. Convalescent chronic carriers
3. Inapparent carriers

Question 15

What is an incubatory acute carrier?

Answer 15

animal that sheds virus during incubation period of the disease

Question 16

What is a convalescent chronic carrier?

Answer 16

Animal that sheds a virus during recovery of a disease

Question 17

What is a inapparent carrier?

Answer 17

Carrier state may exist in an animal with an infection that is inapparent throughout its course

Question 18

What is an exotic disease?

Answer 18

a disease not known to occur in a particular country or area

Question 19

________ refers to the time during which an infected animal sheds virus

Answer 19

Period of contagiousness

Question 20

What is seroepidemiology?

Answer 20

Using serological data as the basis of epidemiological investigation

Question 21

What is molecular epidemiology of viruses?

Answer 21

using molecular biological data as a basis of epidemiological investigation

Question 22

Most viruses are transmitted by the _________ route

Answer 22

Horizontal/Lateral

Question 23

What is horizontal transmission?

Answer 23

Spread of an infectious agent from one person to another

Question 24

Licking, rubbing, sexual contact and biting is an example of ________ transmission

Answer 24

Direct contact

Question 25

What is droplet transmission?

Answer 25

direct contact transmission by saliva or mucus that travels LESS THAN 1 METER Ex: sneezing, coughing ** not considered airborne if < 1 meter

Question 26

What is a fomite?

Answer 26

Inanimate object contaminated with the virus and is capable of transmission to another individual

Question 27

What is airborne transmission?

Answer 27

Indirect-contact transmission spread of infectious agents by droplet nuclei in dust that travels MORE THAN ONE METER, long distances

Question 28

Vector transmission is also known as ____________

Answer 28

Arthropod-borne transmission

Question 29

Mosquitos and other biting insects may serve as a mechanical vectors for _________ virus

Answer 29

Fowlpox

Question 30

What is an arbovirus?

Answer 30

Virus transmitted to humans by arthropods such a mosquitos and ticks

Question 31

What is an urban cycle?

Answer 31

Virus cycles between humans and insect vectors

Question 32

What is a dead end host or incidental host?

Answer 32

Infectious agent does not develop sufficient viremia and can't be transmitted to another host

Question 33

What is a bridge vector?

Answer 33

An arthropod that acquires a virus from an infected wild animal and transmits it to the secondary or human host

Question 34

Example of common-vehicle transmission?

Answer 34

Fecal oral transmission Fecal contamination of food and water Or virus contaminated meat or bone products

Question 35

What is iatrogenic transmission?

Answer 35

infection transferred during medical or surgical practice

Question 36

How can iatrogenic transmission occur?

Answer 36

1. Contaminated instruments / body surface 2. Introduction of a pathogen through contaminated prophylactic or therapeutic preparations

Question 37

________ is also known as hospital acquired infection

Answer 37

Nosocomial

Question 38

What is nosocomial transmission?

Answer 38

Occurs when an animal is in a vet hospital Ex: parvovirus in clinic

Question 39

What is vertical transmission?

Answer 39

From mom to embryo, fetus, or newborn From milk, colostrum, fecal contamination

Question 40

Viruses that are transmitted by the _______ route have low environmental stability

Answer 40

Respiratory

Question 41

Viruses transmitted by _______ route has a high stability

Answer 41

Fecal-oral

Question 42

True or False: Enteric viruses have been shown to be more stable in environment than respiratory viruses

Answer 42

TRUEEE

Question 43

What is herd immunity?

Answer 43

When most of the population is vaccinated, it protects the non-vaccinated people

Question 44

What is an amplifying host?

Answer 44

Host with high levels of the infectious virus that can be transmitted to another host

Question 45

_________ is when the virus is transmitted between non-wild or domestic animals and the primary insect vectors

Answer 45

Epizootic cycle (rural cycle)

Question 46

_______ is natural transmission of viruses between wild animals/birds and primary insect vectors

Answer 46

Sylvatic / Jungle/ Enzootic cycle