Micro Unit 9 Transmission and Reservoirs

3 types of reservoirs - human

Actively carry virus or microbe (infection) and carriers (no outward signs and symptoms)

3 types of reservoirs - animal

Zoonoses - emerging pathogens come from crossing barrier (only associated with specific species —> now humans are infected)

3 types of reservoirs - environmental (Non living)

Soil, water, food

Transmission

Movement of pathogen to host

3 types of contact transmission - direct

Host comes in contact with pathogen (drank contaminated water or ate contaminated food, stepped on nail)

3 types of contact transmission - indirect

Come in contact with pathogen on surface and picked up infection that way (fomites) contaminated instruments (catheter, IV lines *TB

3 types of contact transmission - droplets

Short distance for transmission (less than 1 meter from someone), cough, sneeze, laugh

Vehicle transmission

Picking up a pathogen through poor food, water, and air (droplets small enough to float to people further away from 1 meter) *legionnaire’s disease, COVID

Vector Transmission

Animals that carry pathogens from one host to another (arthropods) insect has infection and because they bite (biological transmission: different stages or arthropod life cycle means that being bit doesn’t mean you have pathogen *could’ve been infected in egg stage so you need to eats eggs egg to be infected), touch (mechanical: fly walks on food *doesn’t have pathogen only carries it on feet)

Biological vector transmission

Active, arthropod has to bite and transfer pathogen via saliva