The Penaeid Shrimp Viral Pandemics due to IHHNV, WSSV, TSV and YHV: History in the Americas and Current Status

At least four virus caused pandemics have adversely affected the global penaeid shrimp farming industry since 1980. These viruses in the approximate order of their discovery are Infectious hypodermal and hematopoietic necrosis virus (IHHNV), Yellow Head Virus (YHV), Taura Syndrome Virus (TSV), and White Spot Syndrome Virus (WSSV). The socioeconomic impact of the diseases caused by these viruses have been so severe in some shrimp producing countries of Asia and the western hemisphere (Americas) that they were listed by the World Animal Health Organization (or ‘Office International des Epizootics,’ OIE) as posing a significant disease threat to cultured and wild crustaceans as a consequence of international trade or movement of infected crustaceans. IHHNV, TSV, and WSSV have had major impacts on cultured and wild shrimp in the Americas. Despite some unconfirmed reports, YHV has not been found in wild or cultured penaeid shrimp in the Americas. Nonetheless, YHV is considered to pose a significant threat to wild and cultured shrimp in the Americas because of the experimental demonstration of high susceptibility of American penaeids to the virus. Additional virus-caused diseases found in shrimp have been recognized recently. For example, Infectious Myonecrosis (IMN) has severely affected shrimp farms in northeast Brazil in 2003. This emerging disease was shown to have a viral etiology and the virus was named IMNV for the disease it causes. This paper reviews aspects of the biology and epizootiology of WSSV, TSV, IHHNV, YHV, and the emerging disease IMN.