Vaccination against parainfluenza 1 virus (typus muris) infection in order to eradicate this virus in colonies of laboratory animals.

Parainfluenza 1 virus (typus muris), commonly known as Sendai virus, is still contaminating mouse colonies in Japan. This presents a serious problem to keep mouse colonies pathogen-free. It seems that the infection is spread by dust and the virus remains active a considerable time in the mouse breeding rooms after all mice are removed. In order to eradicate the infection of this virus, vaccination was attempted to inoculate newly born young mice successively for about six months and during and after these periods the movements of the infection were under observation. The vaccine used for this experiment was inactivated virus vaccine with mineral oil-Arlacel adjuvant. The induction of antibody level by the inoculation of this vaccine was evidenced to be very efficient and the duration of the immunity was also very satisfactory. However, after the cessation of the vaccination, the infection of the virus reappeared gradually after some period of temporary ease.