RECENT ADVANCES IN PENAEID VIRUS DISEASE INVESTIGATIONS

Abstract

ABSTRACTOf the approximately 30 known viruses affecting crustaceans, at least six viruses are known in cultured penaeid shrimp. New information is presented here on five of the six penaeid viruses. Baculovirus penaei (BP) in penaeids from widely separated geographic locations was compared by transmission electron microscopy (TEM) of BP‐infected hepatopancreatocytes. Regardless of source or host species, the cytopathology and virion morphology was similar, but differences were found in the dimensions of BP nucleocapsids as a function of geographic source. P. monodon‐type baculovirus (MBV) was discovered in P. monodon from Asia, but it has recently been found to also infect cultured p. merguiensis and p. semisulcatus from other sites in Asia and the Middle East, and possibly P. kerathurus in Italy. Cytopathology and histopathology resulting from MEV infection in each of the species appears identical. Infectious hypodermal and hematopoietic necrosis virus (IHHNV), a picorna‐like virus known previously to infect P. stylirostris, P. vannamei, and P. monodon, has been found to experimentally infect P. japonicus, P. duorarum, P. aztecus and P. setiferus. IHHN appears to be widely distributed in culture facilities in the Americas, Asia, and the Pacific Basin. HPV (hepatopancreatic parvo‐like virus) was discovered in 1983, in four species of cultured or captive wild penaeids in Asia and Australia. TEM studies of HPV‐infected hepatopancreatocytes show HPV virions and cytopathology to be identical in the affected species. REO, a reo‐like virus of cultured P. japonicus in France and Hawaii, infects hepatopancreatic epithelial cells and causes chronic disease and high accumulative mortalities in tanks and possibly grow‐out ponds.