Emerging Infectious Disease

The term 'emerging diseases' has become synonymous with new, previously unknown infectious agents, or with known infectious agents which are either spreading geographically or increasing in incidence. An analysis by Jones et al (2008) showed that since 1940 there has been a steady increase in new diseases, and new diseases are continuing to emerge today. Most of these new diseases are of minor importance with respect to human or animal health, but occasionally important, highly pathogenic diseases arise, such as we have seen in recent years with SARS and Nipah virus, or with new variants or strains of known diseases such as avian H5N1 influenza, the current pandemic strain of H1N1 2009 influenza virus, and extremely drug resistant tuberculosis.