BIOL 372 Lecture Notes - Lecture 2: Aids, Hiv, Chlamydia Trachomatis
Document Summary
The triad of disease causation: the cause of all diseases can be subdivided into three categories. Nonparasitic environment- diet, lifestyle, chemicals, radiation: causes in two or all three of these categories may act simultaneously and may interact to generate disease. This is why it is useful to picture the three causes as vertices of a triangle, and a disease placed inside of it closest to the most important cause or causes. Essential (primary) causes- a cause that is required for the disease to occur (without it, you cannot have the disease. Exacerbating (secondary) causes- a cause that is not required for the disease to occur. This term isn"t commonly used anymore in this context, mostly used in cases of lice or bedbugs. Hookworm species that infect humans: necator americanus, ancylostoma duodenale. Manifestations: anemia, malnutrition, retarding of growth, reduced brain function. Geographic distributions: necator: americas, sub-saharan africa, east asia, indonesia, ancylostoma: middle east, north africa, south asia.
