Infection: Emerging Diseases

Emerging infectious diseases, or EIDs, are a category of contagious illnesses that have become public health concerns during the past 20 years and are expected to become more common or spread to more countries in the near future.

EIDs include several different types of infections:

• Diseases involving newly identified organisms (AIDS, SARS).
• Diseases involving mutations or changes in a known disease organism (avian flu).
• Diseases that spread to a geographical area where they were previously unknown (Lyme disease, West Nile virus, hantavirus infection).
• Diseases that have become more difficult to treat because of resistance to commonly used antibiotics (drug-resistant tuberculosis).

There are several reasons why a disease can become an EID:

• Mass travel and tourism. Diseases like SARS and AIDS spread rapidly because of the popularity and speed of air travel.
• Bioterrorism, or the intentional spread of deadly diseases as a method of warfare.
• Evolution of the disease organisms themselves.
• Breakdowns in public health, such as malnutrition, poor sanitation, or refugee situations.
• Overuse of antibiotics in treating bacterial infections.
• Importing animals that may be infected with previously unknown organisms for study in laboratories or as pets.
• Changes in human vulnerability to disease. For example, smallpox could reemerge as a disease because routine vaccination against it was discontinued in the 1970s.

SEE ALSO AIDS; Avian influenza; Ebola and Marburg hemorrhagic fevers; Hantavirus infection; Lyme disease; Severe acute respiratory syndrome; Tuberculosis; West Nile virus infection