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Re-emergent Equine Diseases

Apr 14, 2015
The terms “emergent” and “re-emergent” frequently are used interchangeably without apparent appreciation of the meaning of each term as a descriptor of a specific infectious disease. It is important to make a distinction between the terms insofar as they are not synonymous. “Emergent” refers to the first recorded appearance and recognition of a disease in a population for which there are no previous published reports. “Re-emergent” diseases, on the other hand, are those that have been experienced in the past but either have reappeared in a more virulent form or have occurred in a different epidemiological setting.
 
A wide range of factors involving infectious agent, host, or the environment can contribute to the occurrence of an emergent or re-emergent disease. These can include microbial change and adaption, host susceptibility to infection, modulation of climate, altered ecosystems, population demographics, trends in international trade, and land use. The number of emergent and re-emergent diseases of humans, animals, and plants continues to increase as more sophisticated technologies become available that enable detection of previously undiscovered infectious agents in the host and the environment.
 
There are various examples of re-emergent diseases, some of which are host restricted to members of the family Equidae, whereas others can infect different domestic and/or wildlife species besides the horse. The majority of the better-known examples are viral diseases. The emergence of a strain of equine influenza virus, influenza-A/equine/ Jilin/89 (H3N8), in China in 1989 gave rise to very high morbidity and associated case-fatality rates in the equine population exposed to this particular strain of virus. Very fortunately, the Jilin/89 strain of H3N8 virus did not spread outside of China.
 
Source: TheHorse