DETECTION OF IHHN VIRUS IN Penaeus stylirostris AND P. vannamei IMPORTED INTO HAWAII

Abstract

Infectious hypodermal and hematopoietic necrosis (IHHN), a newly recognized virus disease of penaeid shrimp, was found in populations of blue shrimp ( Penaeus stylirostris ) and white shrimp ( P. vannamei ) imported into Hawaii as postlarvae from commercial penaeid hatcheries in Costa Rica and Ecuador. In addition, the disease was detected in populations of post‐larval P. stylirostris imported from commercial and government‐run penaeid hatcheries in Florida and Tahiti, which had obtained all or part of their brood stock from Central or South American sources. IHHN has been found to be a disease of P. monodon as well, but has only been observed in this species when its history has included concurrent culture with stocks of P. stylirostris or P. vannamei. IHHN was found in Hawaii to be a highly lethal disease of juvenile P. stylirostris , frequently resulting in mortality rates that approached 90% of the affected population. Two populations of P. vannamei were shown to carry the disease, but detection of infections or mortalities due to IHHN in P. vannamei were unusual. These findings indicate that IHHN virus was imported into Hawaii with penaeid populations that originated directly or indirectly from South or Central America, and suggest that the virus is now or has been enzootic in penaeid culture facilities that produce P. stylirostris and P. vannamei in that region, and in Florida and Tahiti.