Definition of Emerging infectious disease

Emerging infectious disease: An infectious disease that has newly appeared in a population or that has been known for some time but is rapidly increasing in incidence or geographic range.

Examples of emerging infectious diseases include:

• Ebola virus (first outbreaks in 1976 and the discovery of the virus in 1977),

• HIV/AIDS (virus first isolated in 1983),

• Hepatitis C (first identified in 1989, now known to be the most common cause of post-transfusion hepatitis worldwide),

• Influenza A(H5N1) virus (well known pathogen in birds but first isolated from humans in 1997),

• Legionella pneumophila (first outbreak in 1976 as Legionnaire disease and since associated with similar outbreaks linked to poorly maintained air conditioning systems),

• E. coli O157:H7 (first detected in 1982, often transmitted through contaminated food, has caused outbreaks of hemolytic uremic syndrome), and

• Borrelia burgdorferi (first detected in 1982 and identified as the cause of Lyme disease).

Another example of an emerging infectious disease is the new variant of Creutzfeldt-Jakob disease, which was first described in 1996. The agent is considered to be the same as that causing bovine spongiform encephalitis, a disease which emerged in the 1980s and affected thousands of cattle in the UK and Europe.