Infectious Disease Caused by invading organisms such as bacteria, viruses, or fungi. Throughout evolution, disease has exerted selective pressures on human populations. Disease influences the frequency of certain alleles that affect the immune response.

Impact of Infectious Disease Before the 20th century, infectious disease was the number one limiting factor to human populations. Since the 1940s, the use of antibiotics has reduced mortality resulting from infectious disease.

Impact of Infectious Disease In the late 1960s, the surgeon general declared the war against infectious disease won. Between 1980 and 1992 deaths from infectious disease increased by 58%. Increases in the prevalence of infectious disease may be due to overuse of antibiotics.

Endemic Continuously present in a population. Sufficient numbers of people must be present Small bands of hunter-gatherers were not faced with continuous exposure to endemic disease

Pandemic An extensive outbreak of disease affecting large numbers of individuals over a wide area; potentially a worldwide phenomenon. – Ex: Smallpox

Why It Matters One goal of the human genome project is to find DNA variants associated with disease and to design treatments that target those genes. Because some of these variants cluster in certain populations, there have been efforts to identify ancestry to predict risks. This has been referred to as race-based medicine.

Why It Matters The result has been the use of the imprecise term race to design treatment protocols. There are several problems with this effort: – Clinically observed or self-identification of race or ethnicity is often not congruent with genetic profiles. – If treatment is assigned for a person based on self- reported race rather than a genetic test, serious illnesses may be missed. – The use of race as a basis for treatment ignores real differences that lead to ill health.

Why It Matters Example: A drug is designed to treat hypertension in African Americans. If the drug is automatically prescribed and other drugs are not considered, the patient may not benefit at all. If the drug is the best choice for a white person, but is viewed as an “African American drug,” it may not be prescribed as needed.

Why It Matters Categorizing drugs along racial lines is likely to lead to the same problems that resulted from categorizing people into racial groups. This doesn’t mean that the quest for underlying genetic factors involved in disease should be halted; it just means that the search should focus on gene and gene complexes rather than race.