Epidemiology of Viral Diseases Flashcards
What is virus epidemiology?
Study of determinants, frequency, dynamics, and distribution of viral diseases in populations
What is the case fatality rate?
Number (%) of deaths among clinically ill animals
What is the Mortality rate?
Number (%) of animals in population that die from particular disease over a specific period to time
What is morbidity rate?
% of animals in population that develop clinical signs attributable to particular virus over defined period of time
The incidence is the number of _______ cases in population over a ________ period of time
- New
2. Specified
Prevalence is the number of _____ and _______ occurrences of disease, infection, or related attributes in population over _________ point of time
- Old
- New
- Particular
What is a sporadic viral disease?
Occurs occasionally, singly, or in scattered instances, and in irregular and haphazard manner
What is an enzootic viral disease?
Constant presence of viral disease w/in given geographic are or population group
What is an epizootic viral disease?
Occurrence of more cases of viral diseases than expected in given area or among specific group of people/animals over particular period of time
What is a panzootic viral disease?
Occurring over very wide area and usually affecting a large proportion of the population
Asymptomatic carriers have contracted infectious viral disease, but display _____ clinical symptoms
No
What is a contagious disease?
Spread form one persons/organism to another by direct or indirect contact
What is the period of contagiousness?
Time during which infected animal sheds virus
What is an exotic disease?
Not known to occur in particular country or geographical area
What is seroepidemiology?
Use of serological data as basis of epidemiological investigation
What is molecular epidemiology of viruses?
Use of molecular biological date as basis of epidemiological investigation of viral diseases
What are two types of virus transmission?
- Horizontal
2. Vertical
What is horizontal transmission?
Spread of an infectious agent from one person/animal or group to another person/animal or group
What are two types of contact transmission?
- Direct
2. Indirect
What are the 5 types of horizontal transmission?
- Contact
- Indirect contact
- Vector
- Vehicle-borne
- Latrogenic
- Nosocomial
What are arboviruses?
Viruses transmitted to humans by Arthropoda such as mosquitoes and ticks
What are 3 types of transmission cycles?
- Enzootic cycle (Jungle cycle)
- Epizootic cycle (Rural cycle)
- Urban cycle
What is an amplifying host?
The level of virus can become high enough that an insect vector such as mosquito will probably become infectious
What is common-vehicle transmission?
Fecal contamination of food and water supplies and virus contaminated meat and bone products
What is latrogenic transmission?
Transferred during medical or surgical practice
Nosocomial transmission is also know as what?
Hospital acquired infection
What is vertical transmission?
Transferred from dam to embryo, or fetus, or newborn before, during, or shortly after parturition
Viruses transmitted via respiratory route have _____ environmental stability, whereas those transmitted via fecal-oral route have ______ stability
- Low
2. Higher
Herd immunity is a form of immunity that occurs when the vaccination of a significant _______ portion of a population provides a measure of protection for individuals who have not developed immunity
Large
What is the 5 step course of a typical infectious disease?
- Incubation period
- Prodromal period
- Acute period
- Decline period
- Convalescent period
What are 2 types of vector transmission?
- Mechanical
2. Biological
