Studies on the Uganda I/CDC strain of Plasmodium malariae in bolivian Aotus monkeys and various anophelines.

A strain of Plasmodium malariae (Uganda I/CDC) was isolated from an infant who had been infected via blood transfusion from a donor who had entered the United States 8 yr previously. After passage through a splenectomized chimpanzee, the parasite was studied in 29 splenectomized Aotus azarae boliviensis monkeys. Maximum parasitemias were higher in Aotus monkeys without previous Plasmodium infection than in Aotus monkeys with a history of P. vivax infection. Animals with a history of infection with both P. vivax and P. falciparum had lower maximum parasitemias than did monkeys in either of the 2 preceding groups. The highest rates of mosquito infection were most often obtained during the 10-day period just after the parasite count rose above 500/mm3 of blood. The most susceptible mosquito was Anopheles freeborni followed by An. stephensi, An. gambiae, An. dirus, and An. maculatus. Two attempts to transmit the Uganda I/CDC strain of P. malariae to other monkeys by sporozoite inoculation were unsuccessful.