A filter-passing agent that produces lethal myocarditis in anthropoid apes, mice, guinea pigs and rabbits has been described by Helwig and Schmidt1 of the A. A. F. Regional and Convalescent Hospital, Miami Beach, Fla. In November 1944 the body of a well nourished adult male gibbon was brought to their laboratory. The animal had always been well, until one morning it suddenly dropped dead without previous indication of illness. The animal had not shown paralysis. Necropsy revealed a dilated heart, pericardial effusion, pulmonary edema and a bilateral hydrothorax. Microscopic examination showed an intense diffuse myocarditis and pulmonary edema, the remaining viscera being normal. Six weeks later a 5 year old well nourished male chimpanzee from the local Anthropoid Ape Research Foundation also died suddenly. The previous history also had been negative, and the same gross and microscopic findings were recorded as with the gibbon.
Fluid from the chest cavity
VIRUS MYOCARDITIS. JAMA. 1945;129(3):213. doi:10.1001/jama.1945.02860370035012