HLTH 240b Lecture Notes - Lecture 2: Typhoid Fever, Immunogenicity, Models 1
18 May 2017
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Document Summary
Disease causation: event, condition, or characteristic that comes before the disease and without which the disease would not occur. Theories: 19th century, contagion, supernatural, personal behavior, miasma, malaria (bad air, 20th century, germ, lifestyle, environmental, multi-causal. Historical contributions to life expectancy: 19th: hygiene, 20th: medicine, 21st: Etiology of a disease: sum of all factors contributing to the occurrence of a disease, agent + host + environmental factors. Infectious disease process: chain of disease transmission, agent, possible outcomes of exposure to an infectious agent. Disease: clinically apparent infection: pathogenicity: proportion of infected who develop clinical disease. Clinical to cub-clinical ratio: virulence: proportion clinical cases resulting in severe clinical disease. Infection is present, but not enough for illness. Measles, mumps: convalescent carriers: transmit disease during convalescent period. Infection is present, but not enough for continued illness. Typhoid fever, common cold: asymptomatic carriers: transmitting disease without showing manifestations. Polio: chronic carriers: transmitting disease for long time or indefinite transmission.
