Epidemic Jungle Fevers Among Okinawan Colonists in the Bolivian Rain Forest

Abstract

SummaryAn epidemic of jungle fever which involved almost one-half of 400 Okinawan pioneers who were attempting to settle in the jungle rain-forest of the Bolivian lowlands adjacent to the Brazilian Matto Grosso is described. Fifteen of the cases ended fatally.A new virus, one of the Group A arthropod-borne viruses, serologically related to Semliki Forest virus, has been isolated from the blood of two of the patients. This, the Uruma virus, was responsible for 10 to 15% of the cases of jungle fever; the etiology of the remaining cases remains undetermined. Serological survey of indigenous communities reveals that this virus or a serologically related agent is endemic to the region. The Semliki Forest-Uruma-Mayaro-Chikungunja serological group of agents appears to be a world-circling group of tropical Group A arthropod-borne viruses pathogenic for man.The problem of jungle fever, or pyrexias of unknown origin, in similar attempts of nonindigenous populaces to clear and settle in tropical jungle, and the problem of multiple etiology of any epidemic that develops among them, are discussed.