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
