Comparison of experimental Rickettsia tsutsugamushi infections in silvered leaf (Presbytis cristatus) and cynomolgus (Macaca fascicularis) monkeys.

Both silvered leaf and cynomolgus monkeys were infected with the Gilliam, Karp and Kato strains of Rickettsia tsutsugamushi. The two species developed similar clinical syndromes, but the antibody responses were greater in cynomolgus monkeys. In both species of monkeys, the Gilliam strain induced more severe clinical manifestations. At 10 months post-infection, silvered leaf monkeys were immune to homologous intradermal (id) challenge. Cynomolgus monkeys, at 15 months post-infection, were relatively resistant to homologous intravenous challenge, but not to a homologous or heterologous id challenge.