EESA10H3 Lecture Notes - Lecture 7: Cervix, Pneumonic Plague, Septicemic Plague
1 Mar 2018
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Document Summary
"infectious disease" is a host-centred concept: human body is a habitat and host to many organisms, associations that harm or bother us are infectious diseases; agents are pathogens. Some form spores, which are resistant to physical and chemical influences. Immune system distinguishes "self" from "foreign. : active immunity -- on first exposure to antigen, body produces antibodies, vaccination, antigen preparation --> active immunity, antibody preparation --> passive immunity, herd immunity -- practical protection. If enough members of a group are immune, hard to maintain chain of infection: evolution of strategies for managing transmission of disease, segregation of sick or exposed persons. Fecal-oral pathway: one person"s infectious diarrheal disease becomes next person"s disease of fecal origin. If sewage is not well controlled, waterborne transmission dominates. Fecal-oral transmission also via soil and by hand-to-mouth transmission: cholera, typhoid fever, dysentery; giardiasis, cryptosporidium (zoonoses); hepatitis a, Norwalk virus, and polio: non-fecal organisms also transmitted in water or soil, guinea worm disease, tetanus.
