Studies of a Chloroquine-Resistant Strain of Plasmodium vivax from Papua New Guinea in Aotus and Anopheles farauti s.l.

Abstract

AMRU-1, a chloroquine-resistant strain of Plasmodium vivax from Papua New Guinea, was established in Aotus monkeys as a potential model for chemotherapeutic studies. The course of infection in 16 untreated, splenectomized, Colombian, and Panamanian animals was reasonably reproducible with parasitemias being maintained above 1,000/mm3 for an average of 13.7 days. Moderate to high parasitemias (1,200-68,800/mm3) were recorded in these monkeys, with a mean maximum parasitemia of 20,587.5/mm3. The sibling species Anopheles farauti 1, A. farauti 2, and A. farauti 3 were infected with gametocytes of this strain; these gametocytes completed the sporogonic phase, producing sporozoites that were infective to Aotus monkeys. Maximum infections in mosquitoes occurred 3-4 days prior to the peak parasitemia in the monkeys. Using these 3 species of Anopheles, sporozoite-induced infections were obtained in monkeys in 9 of 15 attempts with an average prepatent period of 32 days. The findings show that a suitable model system could be developed to assess the activity of antimalarial drugs against the blood stages and possibly the liver stages of the AMRU-1 strain.