HLTB21H3 Study Guide - Final Guide: Etiology, Histology, Syphilis
10 Apr 2012
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Transmission- the movement of parasite from host (direct or indirect-vec- tors) Vector- animate intermediaries ex. flies, fleas, ticks etc. Parasite- obtain resources needed for their growth and reproduction, par- asite may harm host, but may not outright kill them (ex. malaria parasite, red blood cell killer) Virus- smaller then bacteria, must be in living cell to reproduce. Macro parasite- do not require microscope to see. Incubation period- the period in which the disease is not active. Carriers- infectious but asymptomatic individuals, can infect others but don"t experience symptoms themselves. 3 factor model: host + agent + environment. Multiplier r- predicts how fast a disease with spread thru the population. Herd immunity- reduce number of susceptible individuals below a critical point. Reducing virulence- clean water, clean needle exchange, and condom use, immunization. Hunter gathers- small groups, human to human transmission were ab- sent. Agriculture revolution: change from hunter-gatherer to farming, irriga- tion, banking, urbanization, domestication of animals.
