S. Li et Ptk. Woo, VACCINATION OF RAINIBOW TROUT, ONCORHYNCHUS-MYKISS (WALBAUM), AGAINSTCRYPTOBIOSIS - EFFICACY OF THE VACCINE IN FRESH AND SEA-WATER, Journal of fish diseases, 20(5), 1997, pp. 369-374
Adult rainbow trout, Oncorhynchus mykiss (Walbaum), maintained in eith
er fresh or sea water were vaccinated with a live Cryptobia salmositic
a vaccine. All vaccinated fish were protected 4 weeks later against th
e cryptobiosis, while unvaccinated rainbow trout developed the disease
(e.g. high parasitaemia and severe anaemia) after challenge with viru
lent C. salmositica. There was also no disease in vaccinated fish when
they were transferred from fresh to sea water immediately after vacci
nation. Complement fixing antibodies (CFAbs) were detected in vaccinat
ed fish and the CFAbs lysed parasites under in vitro conditions. The a
ntibody titres increased rapidly at one week postchallenge in vaccinat
ed fish in fresh water and vaccinated fish transferred from fresh wate
r to sea water after vaccination. However, the production of CFAbs was
delayed by one week in vaccinated fish in sea water and the antibody
titre was significantly lower than that in fish maintained in fresh wa
ter.