The global status of significant infectious diseases of farmed shrimp

A discussion of the global status of shrimp diseases might best begin with a review of those diseases that are listed by the International Office des Épizooties (OIE). The OIE is also known as the World Animal Health Organization. The OIE is an international organization formed in 1924 in Europe by 28 countries in an effort to more effectively manage certain diseases of livestock. As of June 2010, the OIE consists of 176 member countries. The OIE was designated in 1995 by the newly formed World Trade Organization as the scientific reference body for animal health as it relates to international trade issues. The OIE has, among its functions, the listing of diseases (terrestrial and aquatic) which may pose risks of being transferred to new regions or nations as a consequence of global trade. Because of their economic importance and their potential for transfer with live or dead crustacean commodities, the OIE listed nine crustacean diseases in 2009. Of these nine listed diseases, six are diseases of penaeid shrimp (five viral and one bacterial); the seventh is a viral disease of Macrobrachium rosenbergii, the eighth is a disease of farmed spiny (Panulirus spp.) lobsters and it is due to infection by a rickettsial-like bacterium and the ninth listed disease affects freshwater crayfish and it is due to infection by a phycomycetous fungus. Two of the nine diseases were listed by the OIE as “under study” in the 12thEdition of the OIE Aquatic Animal Health Code. These diseases were necrotizing hepatopancreatitis (NHP), a rickettsia-like bacterial disease of penaeid shrimp which was approved for full listing in May 2010 and milky hemolymph disease (MHD) of spiny lobsters, which also has as its etiological agent a rickettsial-like bacterium and which may remain “under study” pending further consideration for full listing or removal from the list. While OIE listing gives these diseases global recognition, especially in relation to trade of crustacean commodities (e.g. live, dead or commodity products made from crustacean hosts for one or more OIE listed disease agents), there are other emerging diseases that are not listed by OIE that are also important locally and in some cases globally, to the global shrimp farming industry. Included in this review are the current OIE listed diseases of penaeid shrimp and several examples of emerging diseases which are of potential importance globally.