DIFFERENTIATION OF BP-TYPE BACULOVIRUS STRAINS USING IN-SITU HYBRIDIZATION

BP-type viruses infect wild and farmed shrimp species in the Americas and can cause high mortality in larval stages. Histologically, BP dise ase is characterized by the presence of occlusion bodies (OBs) in the nucleus of hepatopancreatic epithelial cells. By in situ hybridization using different molecular probes, we tested shrimp infected with BP-t ype viruses collected from several geographical areas. In one shrimp, a case of double infection by 2 different BP-type viruses was noted. T his has not been previously reported. The molecular probes recognized only the Pacific strain of BP. This specificity of the probe was confi rmed by in situ hybridization tests with some infected shrimp collecte d from the Atlantic and Pacific coasts. The probes reacted only with i nfected shrimp obtained from the Pacific coast. These results suggest the existence of at least 2 different BP-type viruses and show that sp ecific probes can be used to differentiate between them.