Download Infectious Disease

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 selfreported 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.