Viruses isolated from bats in Japan.

Virus isolation has been attempted from the blood, spleen, liver and kidneys of bats. Nine viruses (1.1 per cent) have been isolated so far from 838 bats collected in different places in Japan. Two of the isolates (TOK-1350 and TOK-1362) were isolated from Vespertilio supernas collected in Fukushima Prefecture. They killed suckling mice within 3-5 days after intracerebral inoculation. The remaining seven isolates were all filtrable through Millipore filters (0.22 micron) and were pathogenic for suckling mice but not adults. One of seven strains (KY-5) was ether resistant and another (TOK-292) was partially ether resistant and both were resistant to sodium deoxycholate (SDC); another (KY-663) was partially resistant to SDC. The sucrose acetone (SA) antigen of each new isolate did not show haemagglutination (HA) with goose red cells, even after protamine or ultrasonic treatment. Complement fixing (CF) activity was found in four of the seven strains. Both TOK-949 and VS-820 were collected at the same place and probably have the same CF activity. The remaining five strains are apparently different. Both YF-17D and Rio Bravo gave high HI titre with antisera against KY-5, TOK-949, TOK-1280, VS-820 and VeJ-822. They thus seemed to be flaviviruses although they were distinct from Japanese encephalitis virus (JEV) strains. From 1 to 10 per cent of bat sera contained antibody against JEV.