Current Status of Viral Diseases in Asian Shrimp Aquaculture

The giant or black tiger shrimp, Penaeus monodon, was formerly the dom- inant cultured shrimp species in Asia. Since approximately 2002, it has been essentially replaced by the domesticated American whiteleg shrimp P. vannamei. The change in dominant species has affected disease concerns. For both species, white spot syndrome virus (WSSV) and yellow head virus (YHV) are the most lethal. For P. monodon, the next most important dis- eases are hepatopancreatic parvovirus (HPV) and monodon baculovirus (MBV). For P. vannamei, they are taura syndrome virus (TSV) and infec- tious hypodermal and hematopoietic necrosis virus (IHHNV). TSV was introduced to Asia in 1998 by careless importation of shrimp stocks for aquaculture but has not been reported to cause problems with local crus- tacean species. IHHNV, which is endemic in Asia, is harmless to P. mon- odon but poses a constant threat to IHHNV-free stocks of P. vannamei if they are hatched and reared in Asia under non-biosecure conditions. An emerging disease for P. monodon is monodon slow growth syndrome (MSGS), a component of which seems to be Laem-Singh virus (LSNV). Infectious myonecrosis virus (IMNV) is a P. vannamei disease, first report- ed from Brazil but now reported in Indonesia where it was probably intro- duced by careless importation of shrimp aquaculture stocks. So far, IMNV has not been reported in other Asian countries. Penaeus vannamei nodavirus (PvNV) is a new pathogen first reported from Belize in 2004 with gross and histological signs that are indistinguishable from those of IMNV. The disease has not yet affected Asian culture. A more recent disease of P. vannamei in Asia is abdominal segment deformity disease (ASDD), possi- bly caused by a yet unknown local virus.