The effect of oral contraceptives in malaria infections in rhesus monkey.

Rhesus monkeys, Macaca mulatta, were treated with the oral contraceptives Brevicon (norethisterone with ethinylestradiol) and Ovral (norgestrel with ethinylestradiol), and subsequently inoculated with the simian malaria parasites Plasmodium cynomologi bastianellii or P. coatneyi. Parasitological, serological, and serum biochemical studies indicated that although there were some significant differences, in general the patterns of response to infection in both treated and control animals were similar. During the primary infection, however, Brevicon resulted in increased levels of parasitaemia, whereas Ovral resulted in decreased parasitaemias, as compared with the untreated control animals. There were no differences in the responses following secondary parasite infection.