Infections with the Uganda Palo Alto, Malayan Camp-CH/Q, Vietnam Oak Knoll, and Vietnam Smith strains of Plasmodium falciparum in owl monkeys (Aotus trivirgatus griseimembra) with concomitant microfilaremias usually, but not always, followed a more benign course than infections with the same strains in monkeys free of filarial infections. Four distinct microfilariae were identified in systematic examinations of 26 monkeys, 5 with self-limited infections with P. falciparum, 9 with normally benign self-limited infections with P. vivax, and 12 without previous malaria. The microfilariae found included: Dipetalonema (Dipetalonema) gracile, Tetrapetalonema (Tetrapetalonema) barbascalensis, T. (T.) panamensis, and an unidentified species designated “Aotus C.” Among 23 monkeys studied completely, 14 were infected with a single species, 4 had double infections, and 5 had triple infections. T. barbascalensis was identified in 16 monkeys, T. panamensis in 11. Although data were very limited, there was a suggestion that infections with P. falciparum were less intense in monkeys infected with T. barbascalensis, either alone or with other filariae, than in subjects infected only with T. panamensis.
Present address: Department of Pharmacology, The Medical Center, University of Alabama in Birmingham, Box 191, University Station, Birmingham, Alabama 35294. Send reprint requests to this address.