Experimental louse-borne relapsing fever in the grivet monkey, Cercopithecus aethiops. I. Clinical course.

Fifteen grivet monkeys, Cercopithecus aethiops, were infected with an Ethiopian strain of Borrelia recurrentis, the causative agent of louse-borne relapsing fever. An initial spirochetemia occurred in all. Inactivity, fever, and leukocytosis accompanied the infections. Eight of the monkeys experienced 1 relapse and 1 monkey had 2 relapses. The relapses tended to be less severe than the initial infections. The only deaths, however, occurred in 2 of the 3 monkeys with severe relapses. The clinical course of the experimental infection in grivet monkeys closely resembles that of natural infections in man.