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Infectious Disease. Infectious Disease. Caused by invading organisms (bacteria, virus, fungi) Selective pressures Influences the frequencies of certain alleles which affect immune response. History of infectious disease.
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Infectious Disease • Caused by invading organisms (bacteria, virus, fungi) • Selective pressures • Influences the frequencies of certain alleles which affect immune response.
History of infectious disease • Prior to the 1920s infectious disease was the #1 limiting factor to human populations. • Bubonic Plague • 1918 Influenza • TB • Malaria
History of infectious disease • Since the 1940s the use of antibiotics has reduced mortality resulting from infectious disease. • Between 1980 and 1992 deaths from infectious disease increased by 58% which might be due to the over prescription of antibiotics.
History of infectious disease • Smallpox • 10-15% of all deaths in parts of Europe during the 1700s • Modern medical technology has successfully eliminated this disease. • In 1977 the World Health Organization (WHO) declared the smallpox virus extinct, save for a few colonies in labs in both the US and Russia.
Vectors • Agents that serve to transmit disease from one carrier to another. • Ex: the mosquito is a vector for malaria
Endemic vs. Pandemic • Endemic: • Something which is continually present within a population. Pandemic: Extensive outbreak of disease affecting large numbers of people over a wide area, potentially a world wide phenomenon
Pathogens • Any agents (especially microorganisms like viruses or bacteria) that infect a host or cause a disease.
Zoonotic • Diseases which are transmitted to humans through contact with nonhuman animals.
Impact of Infectious Disease • Humans and pathogens exert selective pressures on each other • Microorganisms evolve • A pathogen cannot kill its host too quickly • Selection acts to produce resistance in hosts
The Human Genome Project • One of the (many) goals of this project is to find DNA variants associated with disease and to design treatments targeting those genes. • Some of these variants cluster in particular populations there have been efforts to ID ancestry to predict risks, this has been referred to as “Race Based Medicine”
“Raced Based Medicine” • The result has been the use of the imprecise term “race” to design treatment plans and protocol. • Problems: • Clinically observed or self ID’ing of “race” is often at odds with genetic profiles. • If treatment is assigned based on self reported race rather than genetic tests serious illnesses may be missed/misdiagnosed
“Raced Based Medicine” • Problems: • The use of the term “race” as a basis of treatment ignores real differences that lead to ill health • Categorizing drugs along racial lines is likely to lead to the same problems that resulted from categorizing people into racial groups. • Note: This doesn’t mean researchers should stop looking for the underlying genetic factors,, it just means that the search should focus on gene complexes rather than the idea of “race”