Observation on pathogenicity and epizootiology of Penaeus monodon baculovirus (MBV) in cultured shrimp in Taiwan

Studies on the epizootiology of MBV infection in P. monodon showed that the incidence of MBV in postlarval and juvenile P. monodon cultured in Taiwan increased from 15-17% in 1984-1986 to 80-85% in 1988. The infection rate of MBV in P. monodon broodstock populations investigated in 1988 was approximately 50%. A survey on cultured P. penicillatus in 1987 revealed 20-25% MBV infection rate.Studies of hatchery-reared postlarval P. monodon showed that MBV infection initiated mortality. Results from these pathogenic studies showed that environmental stressors significantly affect the survival of MBV-infected postlarvae, juvenile (s) and adult P. monodon and P. penicillatus. Histopathological observations performed in the present study revealed that mortality of P. monodon broodstocks may be caused by secondary infection of pathogenic bacteria.