Abstract
In 1986, 1987 and 1988, from June to November of each year, 108, 125 and 60 sentinel cattle respectively were located in various parts of Hiroshima Prefecture, Japan, and utilized to isolate arboviruses, such as bovine ephemeral fever virus and Chuzan virus. Four strains of a virus, one in 1986, two in 1987 and one in 1988, were isolated in HmLu-l cell culture, derived from baby hamster lung, from the blood specimens of cattle which showed slight fever and leukopenia. All the isolates were sensitive to ether, chloroform and deoxycholate, labile at pH 3.0 but stable at pH 7.4 and 8.0. They passed readily through membrane filter of 450 and 200 nm pore size, passed through 100 nm filters with some titer loss, but did not through 50 nm filters. Replication of the isolate was not inhibited by 5-iode-2-deoxyuridine. The bullet-shaped virus particles were observed in the preparations from the isolate by electron microscopy. The isolates were serologically indistinguishable from one another and showed cross reaction with Fukuoka virus, a member of the family Rhabdoviridae, which was previously isolated from biting midges and mosquitoes in Japan. All these findings support the identification of the isolates as Fukuoka virus. Neutralizing antibody incidences to the virus were observed in five of the 14 sentinel cattle herds, showing positive rates of 16.7-69.2%, in June 1987, and in 10 of the herds, showing positive rates of 9.1-76.9%, in November 1987. neutralizing antibody to the virus in bovine sera collected in various parts of Hiroshima Prefecture, Japan in 1983 and 1987 indicated positive rates of 8.4 and 28.9%, respectively. The etiological significance of the virus in the bovine disease remains to be investigated.
