epidemiology of viral diseases Flashcards
epidemiology
is the branch of science that studies the frequency, distribution, and determinants of disease in populations
purpose of epidemiology
- acquisition of information
- planning and monitoring
- assessment of the economic effects
arbovirus
multiply in the arthropod vector
cases
those animals suffering from a clinically diagnosable disease
case-fatality rate
the number (%)of deaths among the clinically ill animals
carrier
any animal that sheds an infectious agent without demonstrating clinical signs
incubatory (acute) carriers
animals that excrete agent during the disease’s incubation period
covalescent (chronic) carriers
animals that shed agent when they are recovering from disease
communicable period
the time during which the infectious agent may be transferred, directly or indirectly, from an infected animal to another animal
contagious disease
an infectious disease in which the pathogen may be transmitted from one host to another by direct or indirect contact
dead-end host
one that is not involved in maintaining a virus
disease
any disturbance of the normal structure or function of any part, organ, or system of the body that results in a characteristic set of symptoms and signs
endemic
the constant or usually expected occurrence of a disease within a give geographic area or population
epidemic
major increase in disease incidence affecting either a large number of animals or spreading over a large area
exotic
a disease not known to occur in a particular country or geographic area
field isolate
fresh virus isolate from the natural host
fomites
inanimate objects other than vehicles involved in the transfer of infectious agents from one host to another
incidence
the number of new cases that occur in a population over a specified period of time
incubation period
the period of time between infection and the development of clinical signs and symptoms
infection
invasion and multiplication of microorganisms in body tissue
morbidity rate
percentage of animals in a population that develop clinical disease attributable to a particular pathogen over a specified period of time
mortality rate
percentage of animals in a population that die from a particular disease over a specified period of time
pandemic
a geographically widespread epidemic
pathogen
any disease causing virus or microorganisms
pathogenicity
ability of an organism to cause disease
population
aggregation of animals
prevalence
the number of occurrences of disease, infection, or related attributes in a population at a particular point in time
reservoir
the organism or environment that normally harbors a pathogen
screening
this is systematic diagnostic testing to detect asymptomatic or subclinical animals or individuals who appear healthy, for the purpose of control or prevention of disease
source
the place from which a pathogen passes directly to a susceptible host
sporadic disease
a disease that occurs irregularly and hapharzadly
sylvatic
occurring in or affecting wild animals
threshold level
the minimum concentration of a pathogen in the host’s circulation that allows successful transmission to an arthropod vestor
wild-type virus
denotes the original virus circulation in nature from which mutants arise
zoonosis
a disease that primarily affects vertebrate animals but that
seroepidemiology
is the use of serological data as the basis of epidemiological investigation
contact transmission
this is the spread of infectious agents by direct or indirect contact
vestor transmission
an arthropod that carries pathogenic organisms from infected host to another
extrinsic incubation period
the time the pathogen spends in the arthropod vector
vehical transmission
this is the transmission of infectious agents by a medium
iatrogenic transmission
infection that is transferred during surgical and medical practice
nosocomial infections
infections acquired within the veterinary hospital or clinic
epidemiologic triad is made up of:
- host
- agent
- the environment
herd immunity
refers to immunity conferred on a group or population as a result of the presence of immune individual within the population
