Epidemiology of Viral Diseases

Question 1

Definition of Virus Epidemiology

Answer 1

Study of the determinants, frequency, dynamics, and distribution of viral diseases in populations.

Question 2

The risk of infection/disease in an animal is determined by what factors?

Answer 2

Characteristics of the virus

Host and host population

Behavioral, environmental and ecological factors that affect virus transmission

Question 3

The study of epidemiology helps:

Answer 3

Knowledge of diseases
Dz treatment, control, prevention
Warning systems and tracking
Social/economical impacts
Cost and efficacy of dz control/prevention

Question 4

The case fatality rate:

Answer 4

Number of deaths among the clinically ill animals

Question 5

The mortality rate:

Answer 5

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

Question 6

The morbidity rate:

Answer 6

Number of animals in a population that develop clinical signs over a period of time

Question 7

The number of new cases that occur in a population over a period of time:

Answer 7

Incidence

*useful for describing acute dz

Question 8

The number of occurrences of a disease in a population at any point in time:

Answer 8

Prevalence

Question 9

If a disease is constant within an area or population it is:

Answer 9

Enzootic

Question 10

If a disease occurs occasionally and irregularly it is:

Answer 10

Sporadic

Question 11

If a disease is occurring more than expected in an area/population over a period of time it is:

Answer 11

Epizootic

Question 12

If a virus epidemic occurs over a very wide area it is:

Answer 12

Panzootic

Question 13

T/F: shedding of disease by asymptomatic carriers can be continuous or intermittent.

Answer 13

TRUE

Question 14

A disease that is not known to occur in a particular region is:

Answer 14

exotic

Question 15

The use of serological data as the basis of epidemiological investigation

Answer 15

seroepidemiology

Question 16

Contact (direct and indirect), vectors, vehicles, and iatrogenic and nosocomial are methods of _______ virus transmission.

Answer 16

Horizontal

Question 17

Most viruses are transmitted by the horizontal/vertical route?

Answer 17

horizontal

Question 18

T/F: Droplet transmission is considered to be indirect contact transmission, since the parties involved aren’t actually touching.

Answer 18

FALSE - droplet transmission is considered direct contact because the droplets (sneezing, coughing) travel less than one meter.

Question 19

A fomite is an inanimate object that is contaminated with and transmits infectious agents. Fomites are a type of _______ _______ transmission.

Answer 19

Indirect contact

Question 20

Airbone droplets that travel more than one meter, and may last in the air for prolonged periods, are what kind of transmission?

Answer 20

Indirect contact

Question 21

T/F: Arthropod transmission is also known as Vector transmission.

Answer 21

TRUE - arthropods can be mechanical or biological vectors

Question 22

What is a name for viruses that can be transmitted to humans by arthropods?

Answer 22

Arboviruses

Question 23

What are the typical mechanisms of transmission of arboviruses?

Answer 23

Enzootic cycle (Slyvatic cycle)
Epizootic cycle (rural cycle)
Urban cycle (between humans and insects)

Question 24

In what kind of host can the level of virus become high enough to make infectious an insect vector that feeds on it?

Answer 24

Amplifying host

Question 25

Common-vehicle transmission includes fecal contamination of _____ and _____ supplies, and virus contaminated meat/bone products.

Answer 25

Food and water

Question 26

What are 2 pathways for iatrogenic transmission?

Answer 26

Via contaminated medical instruments or body surfaces.

Via contaminated prophylactic/therapeutic preparations (contaminated vaccines)

Question 27

T/F: Vertical transmission occurs from mother to baby before, during, or shortly after parturition.

Answer 27

TRUE

Question 28

During the _______ period of infection, clinical signs are first seen after the incubation period.

Answer 28

Prodromal

Question 29

The disease is at its height with severe clinical signs in the ______ phase.

Answer 29

Acute

Question 30

The _______ period is when the body gradually returns to its pre-disease state and health is restored.

Answer 30

Convalescent