Simian virus 16 associated with an epizootic of obscure neurologic disease

Abstract

An epizootic of obscure neurologic disease associated with Simian Virus 16 (SV16) occurred in 4 groups of monkeys that included 179 rhesus (Macaca mulatta) and 7 vervet (Cercopithecus aethiops) monkeys. A total of 71 rhesus monkeys and 3 vervet monkeys died of the disease during the epizootic, and an additional 88 rhesus monkeys were killed to prevent further spread of the disease. In the rhesus monkeys, the disease was characterized by convulsive seizures of short duration and sudden death with no obvious pathologic changes observed at necropsy. In the vervet monkeys, the disease tended to be more prolonged with associated skeletal muscle paralysis of varying severity. Myocarditis with pericardial and peritoneal effusions was observed in all 3 affected vervet monkeys and nonsuppurative encephalitis in 1 of these animals. SV16 was isolated from 4 of 10 brains cultured and from other organs in 2 additional animals. The disease was apparently introduced into the colony by newly imported animals.