What is 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:

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.