Abstract
A survey on neutralizing antibody against Akabane virus was conducted on a total of 11, 574 nonvaccinated cattle in Hiroshima Prefecture over a period from 1972 to 1985.
Positive rate of Akabane antibody was 81% in 1973, 71% in 1975, 46% in 1976, 45% in 1977, 74% in 1978, 68% in 1979, 62% in 1980, 52% in 1981, 50% in 1982, 57% in 1983, 52% in 1984, and 83% in 1985.
A change in antibody positive rate to over 71 % was observed in years when the positive rate of Akabane antibody was reduced to 45% to 52%.
An increase in positive rate to over 48% was recognized in a cycle of 2-4 years, where as that to over 63% was in a cycle of 5-7 years.
An increase in Akabane antibody-positive cattle started in August to November in each year. The highest rate was recognized in September. Among mother cows of calves with the abortion-arthrogryposis-hydroencephaly syndrome, the antibody-positive rate was 87% in 1972, 1973, and 1977.
Anti-Akabane antibody was found in precolostral serum in 33%(3/9) of the normal calves in 1977.
