MICROM 301 Chapter 16.3:
Document Summary
Introduction: colonization, establishment and growth of microbe in a particular environment, normal microbiota has colonized host. If microbe has parasitic relationship with host, tern is infection: pathogen has infected host. Infection doesn"t always lead to illness: subclinical=symptoms do not appear or mild enough to go unnoticed. 2: additional infection that occurs as result of primary infection=secondary infection. Pathogenicity: primary pathogen, microorganism or virus that causes disease in otherwise healthy individuals, examples. 10 -100 cells of shigella species need to be ingested to establish infection. In contrast, salmonellosis does not spread as easily c) (1) 10^6 cells needed cause illness: difference in infectious doses reflects pathogens ability to survive in acidic conditions encountered as cells pass through stomach a) Infectious dose generally expressed as id50 (1) experimentally derived figure (2) indicates number of microbial cells administered that resulted in disease in 50% of test population: progression of infectious disease.
