The experimental transmission of Plasmodium malariae to Anopheles labranchiae atroparvus.

Abstract

The Vs strain of P. malariae proved very infective for laboratory-bred A. l. atroparvus; of 31 batches fed on 11 gametocyte carriers, 24 (77·4%) became infective. Oöcysts were first seen 5 days after the blood meal; development was slow, 5–14 days, after which they measured 6–64μ. The greatest number of oöcysts per gut was 60 (average 24) in one batch; the average for all batches was 3·5. Sporozoites first appeared in the salivary glands on day 15; they measured 12–14μ in length in fresh preparations, and 10·5μ in stained preparations. Sporogony developed in 15–20 days, in mosquitoes kept at 19°–30°C. From 1 to 98·6% of A. l. atroparvus in the various batches became infected, but not in accordance with the density of male gametocytes. The ability of male gametocytes to originate sporogony in A. l. atroparvus extends from 8 to 404 days of patency. The highest degree of infectivity was 98·6% of one batch of mosquitoes, fed during the second week of patency. Success in infecting mosquitoes depends upon the quality of the gametocytes, the susceptibility of the mosquitoes, and the number of mosquitoes in each batch used.