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 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”