Encephalomyelitis in Monkeys

Abstract

When a massive dose of either eastern or western virus of equine encephalomyelitis is instilled intranasally into a young rhesus monkey, it will in most instances succumb to a fatal infection. Symptoms of the 2 forms of virus have been similar except that as in other animals the eastern has run a shorter course. "Dropping virus into the eye has not resulted in either disease or measurable antibodies. Eastern virus injected intralingually and western virus introduced by stomach tube have proved fatal, but we have not diseased healthy animals by keeping them caged with sick ones." Hyperimmune horse serum has provided passive protection against nasally instilled virus. Incomplete protection has been furnished by serum administered within 3 hrs. of infection. In numerous trials no beneficial effect has resulted from such a serum given at and after the time of first temp. rise, even when this serum was equivalent in amount to the injection of 500 cc. into a 150-lb. man. "Animals twice vaccinated with crude chick embryo vaccine have in all but one instance been completely protected against massive doses of intranasal virus. This vaccination has produced antibodies which were present in high titer after eastern, in lower titer after western vaccine injection.".