Epidemiology of Viral Diseases Flashcards
Definition of Virus Epidemiology
Study of the determinants, frequency, dynamics, and distribution of viral diseases in populations.
The risk of infection/disease in an animal is determined by what factors?
Characteristics of the virus
Host and host population
Behavioral, environmental and ecological factors that affect virus transmission
The study of epidemiology helps:
Knowledge of diseases Dz treatment, control, prevention Warning systems and tracking Social/economical impacts Cost and efficacy of dz control/prevention
The case fatality rate:
Number of deaths among the clinically ill animals
The mortality rate:
Number of animals in a population that die from a disease over a period of time
The morbidity rate:
Number of animals in a population that develop clinical signs over a period of time
The number of new cases that occur in a population over a period of time:
Incidence
*useful for describing acute dz
The number of occurrences of a disease in a population at any point in time:
Prevalence
If a disease is constant within an area or population it is:
Enzootic
If a disease occurs occasionally and irregularly it is:
Sporadic
If a disease is occurring more than expected in an area/population over a period of time it is:
Epizootic
If a virus epidemic occurs over a very wide area it is:
Panzootic
T/F: shedding of disease by asymptomatic carriers can be continuous or intermittent.
TRUE
A disease that is not known to occur in a particular region is:
exotic
The use of serological data as the basis of epidemiological investigation
seroepidemiology
Contact (direct and indirect), vectors, vehicles, and iatrogenic and nosocomial are methods of _______ virus transmission.
Horizontal
Most viruses are transmitted by the horizontal/vertical route?
horizontal
T/F: Droplet transmission is considered to be indirect contact transmission, since the parties involved aren’t actually touching.
FALSE - droplet transmission is considered direct contact because the droplets (sneezing, coughing) travel less than one meter.
A fomite is an inanimate object that is contaminated with and transmits infectious agents. Fomites are a type of _______ _______ transmission.
Indirect contact
Airbone droplets that travel more than one meter, and may last in the air for prolonged periods, are what kind of transmission?
Indirect contact
T/F: Arthropod transmission is also known as Vector transmission.
TRUE - arthropods can be mechanical or biological vectors
What is a name for viruses that can be transmitted to humans by arthropods?
Arboviruses
What are the typical mechanisms of transmission of arboviruses?
Enzootic cycle (Slyvatic cycle) Epizootic cycle (rural cycle) Urban cycle (between humans and insects)
In what kind of host can the level of virus become high enough to make infectious an insect vector that feeds on it?
Amplifying host
Common-vehicle transmission includes fecal contamination of _____ and _____ supplies, and virus contaminated meat/bone products.
Food and water
What are 2 pathways for iatrogenic transmission?
Via contaminated medical instruments or body surfaces.
Via contaminated prophylactic/therapeutic preparations (contaminated vaccines)
T/F: Vertical transmission occurs from mother to baby before, during, or shortly after parturition.
TRUE
During the _______ period of infection, clinical signs are first seen after the incubation period.
Prodromal
The disease is at its height with severe clinical signs in the ______ phase.
Acute
The _______ period is when the body gradually returns to its pre-disease state and health is restored.
Convalescent
