Diagnostic and Preventive Practices for WSSV in Japan

Keiichi Mushiake

Goto Station of Japan Sea-Farming Association
Arakawa, Tamanoura, Minami-Matsuura, Nagasaki 853-0501, Japan

ABSTRACT

White spot syndrome (WSS), considered equivalent to PAV (penaeid acute viremia) in Japan, has become the most serious problem not only in farming industry, but also in hatcheries for sea ranching of kuruma prawn, Penaeus japonicus. The prevalence of WSSV (white spot syndrome virus), the causative agent of WSS, was examined in wild kuruma prawn broodstocks by nested PCR (polymerase chain reaction). As a result, WSSV was detected at the highest prevalence (10.1%) in the ovary of female prawn. This result indicates that spawners are source of infection for this viral disease in kuruma prawn. In 1997, selection of brooders based on detection of WSSV from the ovary before spawning by PCR was carried out. However, WSSV occurred in postlarvae obtained from brooders caught between July and August. In 1998 and 1999, eggs were selected based on WSSV detection by PCR from receptaculum seminis of spawned broodstock. Consequently, WSSV did not occur in their offsprings in both years. These results strongly indicate that selection of eggs based on PCR result from receptaculum seminis of spawned broodstock is a practical way of controlling WSSV in hatcheries.