The isolation of Akabane virus (Iriki strain) from calves in Taiwan

Abstract

Nonsuppurative encephalitis in calves aged 4–12 months, cow abortion and fetal deformities were endemic in dairy farms in Taiwan in recent years. A virological investigation emphasizing on Arthpodborn virus (Arbovirus) was conducted. Total of 11 strains of Akabane virus were isolated from endemic districts between June and July of 1992. Among them, seven viruses were isolated from blood samples of 15 calves showing nervous signs. Another 4 Akabane viruses were isolated from clinically healthy calves from three of six dairy farms investigated. All the six investigated farms had a recent history of abortion and fetal deformities. The isolates caused prominent cytopathic effects in HmLu-1 cells and could reach a high virus titers (5 × 10⁶ TCID₅₀/ml). As demonstrated by a cross neutralization test, the isolates had identical antigenicity to Iriki strain of Akabane virus, but were antigenically more distant to JaGar-39 and OBE-1 strain of Akabane virus. This is the first report on the isolation of Akabene virus in Taiwan, and also the second report on the isolation of Iriki virus in the world.