Occurrence of PAV (Penaeid acute viremia) in seed production of kuruma prawn

In 1996, a hatchery of Japan Sea-Farming Association obtained kuruma prawn (Penaeus japonicus) eggs for seedling culture from wild broodstocks, among which some were found to be rod-shaped DNA virus (PRDV) infected by PCR tes t. Eggs were washed once with filtrated seawater and reared in the hatchery . During the culture, those post-larval groups in which PRDV were detected were excluded. Although no PRDV was found in the seedlings prior to the tra nsportation to the nursery by PCR test, PAV occurred among them during the culture in the nursery facilities. In 1997, the hatchery again obtained pra wn eggs from wild broodstocks. However, in this year, PCR-check was applied to select non-PRDV infected spawners. Furthermore, eggs were disinfected w ith iodine before being served for rearing. No PAV infection occurred throu ghout the culture in the hatchery and the nursery facility in this year. Th ese results strongly suggest that the infection source of PAV occurred in 1 996 originated from spawners.