Complement-fixing and Neutralizing Antibodies Against Japanese B Virus in the Sera of Okinawan Horses

Abstract

Sera from 9 Okinawan horses in areas where encephalitis was present among humans were tested for complement-fixing antibodies against antigens prepd. from viruses of Japanese B, Western equine, and Eastern equine encephalitis. Sera of 5 Okinawan goats and serum obtained on Guam from a normal horse were also tested. All Okinawan horse sera fixed complement in the presence of Japanese B virus in a final dilution of 1:16 or more. The sera gave negative results against Western equine virus; 3 sera were negative with Eastern equine virus. Sera of the goats were negative although not wholly so with the Eastern virus -The normal horse serum had no activity against any of the 3 antigens. The results indicated that all Okinawan horses had contact with Japanese B virus. This conclusion was reached also with neutralization tests.