Global Connections & Countermeasures Flashcards
what kind of diseases are the majority of emerging infectious diseases
zoonotic
animal origin, primarily wildlife
reservoir hosts
living organisms or inanimate matter (soil) in which an infectious agent normally lives and multiplies
usually does not cause significant disease in host
susceptible hosts
a person or animal not possessing sufficient resistance against a particular pathogen to prevent contracting infection/disease when exposed to the agent
usually causes disease in host
carriers
an infected individual not showing signs of a disease
potential source of infection
can be persistently infected for life
what are the dynamics of a zoonotic disease outbreak
- pathogen evolution
- cross species transmission
- animal to human spillover
- human to human transmission
- international spread
what factors contribute to zoonotic disease outbreak
- host distribution/density
- pathogen prevalence
- infection intensity
- pathogen release from reservoir
- pathogen survival and spread
- human exposure
many factors must line up in order for a pathogen to spread from a reservoir to cause outbreak
what are the 3 main drivers of disease emergence
- land use changes
- human demography and behavior
- climate and weather
endemic disease
typical occurrence (incidence) of a disease in a geographic area
epidemic disease
occurs when the number of disease cases exceeds endemic amount
what are countermeasures to disease outbreak
- active and passive surveillance
- human behavior change and education
- gov policy
- animal control
- medical countermeasures
influenza A
segmented RNA virus
classified by H and N surface proteins
influenza A hosts
broad
natural reservoirs are WATER FOWL
how has influenza evolved
highly mutable, can recombine and reassort with other influenza strains to form new subtypes
creates evolutionary advantage
avian influenza
H5N1
hosts: high mortality in birds and marine mammals
low pathogenicity H5N1
majority of strains
causes GI disease only
high pathogenicity H5N1
created from spillover of LPAI H5s or H7s to chickens
causes systemic disease primarily in CNS and respiratory systems
avian influenza transmission
migration
ecological interactions
mammal adaptations
avian influenza management
prevent human spread
carcass removal and disposal
stamping out of infected chickens
farm biosecurity
where is Rift Valley Fever a problem
africa
reservoir for Rift Valley Fever
mosquito vectors
susceptible hosts for Rift Valley Fever
livestock (sheep, cattle, goats) and humans
livestock: major cause of abortion storms
risk of Rift Valley Fever
food safety; can contaminate national food supply
control of Rift Valley Fever
risk predictions based on climate forecasting, vector control, vaccination of livestock and humans
