Epidemiology (7) - End E1 Flashcards
What are some signs of salt poisoning?
initially thirst, constipation, skin irritation, lack of appetite
nervous signs: ear twitching, aimless wandering, bumping not objects, dog-sitting - may move around foot with a pivot
What is epidemiology?
the study of determinants, dynamics, and distribution of diseases in a population
The risk of infection and/or disease is determined by what?
characteristics of the virus, the host, and host population
behavioral, environmental, and ecological factors that affect virus transmission from one host to another
Viruses survive in nature only if they _____
are able to pass from one host to another, whether of the same or another species
What are the 2 primary transmission routes?
horizontal transmission
vertical transmission
What is direct contact? It is [horizontal/vertical] transmission
licking, rubbing, biting, sexual acts
horizontal
What is indirect contact? It is [horizontal/vertical] transmission
fomites, such as bedding, instruments, halters, grooming equipment
horizontal
What are fomites?
carrying infectious agents and hence transferring them from one individual to another
What is a common vehicle? It is [horizontal/vertical] transmission
virus contaminated meat, water supplies
horizontal
What is airborne? It is [horizontal/vertical] transmission
droplet, aerosol, dander
horizontal
What is arthropod borne? It is [horizontal/vertical] transmission
mechanical and biological
horizontal
What are examples of vertical transmission?
intra-uterine
milk
integration proviral DNA into germline of fertilized egg (not in mammals)
T/F: Milk is an example of horizontal transmission
FALSE - vertical
What does iatrogenic mean?
caused by the doctor
What does nosocomial mean?
caused by the clinic
What is zoonotic?
infections transmissible from animals to humans
What is acute self-limiting infection?
high efficiency of transmission (many individuals infected over a short period of time)
virus excretion of short duration to limit reduction of susceptible (no latent infections)
immunity forces variants - through antigenic drift and shift
mechanism 1
Antigenic [shift/drift] has been associated with the major pandemics of human influenza in the last century
SHift
Antigenic shift is facilitated by a _______
segmented genome
causes a new strain
Antigenic DRIFT is caused by ______
small mutations
What is persistent/latent infection?
prolonged period of excretion reduces the population necessary for transmission
promotes transmission for non-herding species by venereal route (intercourse)
antibody and virus can co-exist
mechanism 2
Infectious bovine rhinotracheitis is an example of a _______ infection
persistent/latent infection - herpes virus
What is resistance of the virus to the environment?
survival favors famine transmission or transmission in meat products
virus is not highly infectious; hence number of susceptible animals does not fall as animals born compensate for those infected
mechanism 3
What is perpetuation through a host?
vector host is often an arthropod in which the virus replicates
infection in arthropod is persistent - can be passed vertically
biological transmission indicates the virus replicates in the arthropod, compare mechanical transmission through contaminated mouthparts
mechanism 4
West Nile encephalitis transmitted by mosquitoes is an example of ______
perpetuation through a host
What is biological transmission?
involves replication of the virus in the arthropod vector
How does an arthropod vector acquire the virus?
by feeding on the blood of a viremic animal
What is a reservoir host?
the natural host of a virus
What is a carrier?
the host that harbors infections and can spread to others
What is a dead end?
host is severely infected, but the level of viremia is too low for blood sucking vector to pick up the virus
What is perpetuation through congenital/veritcal transmission?
virus may be transmitted transplacentally without necessarily causing either death or fetal abnormalities
virus may be recognized as “self”
virus can be transferred through milk
viral genome may be integrated into the genome of gametes
mechanism 5
When a virus has the ability to maintain a line of transmission in a new species, it may be described as having the ability to ______
“jump species”
Mechanisms for virus perpetuation often involve _____
wildlife
What is a reservoir?
the species/environment in which an infectious pathogen naturally lives and reproduces
Based on the limited data available, the risk of animals spreading COVID-19 is considered to be [high/low]
low
Some viruses survive better as _____ in a ______ climate
aerosols
humid
What is sequencing in the context of molecular epidemiology?
it provides a means of identification of viral strains with a specificity that surpasses serological methods
The entire viral genome may be sequenced if the pathogen is _____
novel
ex: canine influenza
______ is an example of sequencing used in epidemiology.
Viral genomic sequencing
What are the 5 mechanisms that perpetuate a virus?
- acute self-limiting infection
- persistent infection
- resistance of the virus to environment
- involvement of a host
- congenital/vertical transmission
Who said “the single biggest threat to man’s continued dominance on this planet is the virus”
Joshua Lederberg
What infection replicates rapidly and at a high titer?
acute self-limiting infections
There are different types of hosts that contribute to the maintenance, transmission, and occurrence of viral diseases. They are ____
primary host
reservoir host
incidental (dead end) host
An integrated approach to disease control is through
using vaccines
use of molecular epidemiology and genomic sequencing
modeling
using surveillance
staying informed via websites that monitor disease occurrence and outbreaks
