Persistence of virus-neutralizing antibodies in horses inoculated with two doses of a live equine herpesvirus type 1 vaccine with different vaccination intervals

The antibody response in horses inoculated with 2 doses of a live equine herpesvirus type 1 vaccine with different vaccination intervals (1 to 3 months) was evaluated with regard to the persistence of virus-neutralizing (VN) antibodies. The durations for which the geometric mean VN titers were maintained significantly higher than those before the first vaccination (P<0.05) were up to 5 months in horses that received the vaccination with a 1-month interval (n=17) and 7 months for those that received it with a 2-month (n=17) or 3-month interval (n=14 or 17). The vaccination program with the 2-month interval was the most effective in maintaining VN antibodies for a long duration with the smallest gap of antibody decline between the first and second vaccinations.     

Acoustic characterization of biological backscatterings in the Kuroshio-Oyashio inter-frontal zone and subarctic waters of the western North Pacific in spring

The acoustic characteristics of biological backscattering in the western North Pacific were studied to verify expert knowledge on species composition in the echosigns. The survey was conducted in the Kuroshio-Oyashio inter-frontal zone and the subarctic waters in April 2003. The species composition of backscatterings was identified by using midwater trawl, Isaacs-Kidd midwater trawl and Bongo net. The differences of mean volume backscattering strengths between 120 and 38 kHz (ΔMVBS₁₂₀₋₃₈) were calculated for the backscatterings. Six types of backscatterings were classified based on the results of net samples and the ΔMVBS₁₂₀₋₃₈. The ΔMVBS₁₂₀₋₃₈ of each group was as follows: copepods 13.7–17.3 dB, krill 11.6–15.3 dB, Japanese anchovy −1.6 to 1.1 dB, a myctophid, Diaphus theta −0.8 dB, sand lance 6.1 dB and larvae and juveniles of pelagic and mesopelagic fish −9.6 to −4.0 dB. The results suggest that biological backscatterings in the Kuroshio-Oyashio inter-frontal zone and subarctic waters of the western North Pacific in spring can be characterized by using ΔMVBS.