Abstract
Serological relationship among several strains of the Flacherie virus of the silkworm isolated from various areas in Japan (Nagano, Saitama, Hyogo, and Shimane Prefectures) has been determined by means of serological neutralization technique. Strong cross neutralization has been demonstrated between any pairs of virus strains and anti-virus serum, so far as tested. It is concluded that the Flacherie virus group of the silkworm in Japan may be consisted of serologically related strains.
The protective effect of the anti-Flacherie virus rabbit serum against per os virus infection to the larvae of the silkworm has been demonstrated. When the anti-Flacherie virus rabbit serum was ingested by the newly hatched larvae just before per os inoculation of the virus (at 1, 000 infectious units per one larva) all larvae survied, whereas all larvae that had not been treated with the antiserum died by the 10th day after the virus inoculation.
