Epidemiology Flashcards
Disease outbreak
Occurrence of cases of disease in excess of what
would normally be expected in a defined community, geographical area or season.
Epidemic
A disease tending to affect a disproportionately large
number of individuals in a community at the same time.
Endemic disease
restricted to a locality or region
Pandemic
Disease occurring over a wide geographic area (multiple
continents) and affecting an exceptionally high proportion of the
population.
horizontal transmission
infection spread via food, water, air, contact, vectors etc
vertical transmission
infection spread through generation
Fooborne diseases are mainly transmitted through which route
the Faecal-oral and the Vertebrate reservoir.
Different spread route
Saliva - Droplet and airborne (respiratory)
e.g. Mycobacterium tyberculosis, etc.
Faecal-oral (food plays important role)
e.g. cholera, E. coli, Campylobacter jejuni, Salmonella, rotavirus, etc.
Direct Person-to-Person (including venereal)
e.g. EBOLA, yaws etc
Zoonoses: Vector-borne
e.g. malaria, Dengue transmission by mosquitoes
Zoonoses: Vertebrate reservoir (food plays important role) - Infectious agent colonizing animal reservoir (separate animal host)
Zoonoses: Vector + vertebrate reservoirs
Insect-borne transmission can be more complex – involving alternate host
Zoonoses: Vertebrate reservoir (food plays important role)
explain
(1) Causing infection/infectious disease in vertebrate reservoir
e. g. Brucellosis in cattle and sheep, rabies in dogs, etc.
(2) As commensal or subclinical infection in animal reservoir
e. g. Salmonella and Campylobater jejuni in poultry
Faecal-oral (food plays important role)
explain
- Faecal contamination of food and/or drinking water
- While reproducing in gut -> affect the mucosa -> large areas that do not absorb nor retain fluids
- Body fluids leak into gut -> watery diarrhoea
- Flushes bacterium/virus -> 109/g faeces
