Identification of white spot syndrome associated baculovirus (WSBV) target organs in the shrimp Penaeus monodon by in situ hybridization

Pendc'us monodon non-occluded baculo 111 (PmNOB 111) is a strain of white spot syndrome associated baculovii-us (WSBV) isolated from diseased black tiger shrlrnp F! monodon.In order to identify the target organs of WSBV, the tissue sectlons of experimentally infected shrimp sampled at 0, 16, 22, 40, 52, and G4 h post-infection were h\ bridized in situ with PmNOB 111 DNAspecific probe labeled with digoxigenin.WSBV-positlve cells initially observed at 16 h postinfection in the stomach, gill, cuticular epidermis and hepatopancreas.At 22 h post-infection, the lymphoid organ, antenna1 gland, muscle tissue, hematopoietic tlssue, heart, midgut and hindgut were found to be WSBV-positive.T h e nervous tissue and compound eyes did not have WSBV-positive cells until 40 h post-infection.Thus various tissues from the mesoderm and ectoderm, such a s connective tissue.epithelium, nervous tissue and muscle, can all be infected by WSBV.By 52 or 64 h post-infection, ~t was found that the stomach, 9111, cuticular epidermis, lymphoid organ, hematopoietic tissue and antennal gland were all h ~d v i l y Infected with WSBV and that these tissues had become necrotic.The whlte spot syndrome itself first appeared at 40 h post-infection, and the shrimp began to dle at 64 1 1 post-infection.The probe demonstrated no reactlon to LVSBV-negative tissue.