Abstract
High HI antibody titiers were revealed in monitoring of antibody to Newcastle disease (ND) virus in Osaka Prefecture. It was confirmed that this phenomenon occurred only this year after retrospective study and the high antibody titers were observed from June to September of this year after prospective chohort study. Epidemic of ND disseminated by racing pigions were occurred in Japan, 1985. It can be epidemiologically considered that the latent ND infection of chickens occurred in Osaka Prefecture.
