GRAY , EM; BRADLEY, TJ; University of California, Irvine; University of California, Irvine: Metabolic and Energetic Effects of Plasmodial Infection in Aedes aegypti

Plasmodium species are the causative agents of malaria. They are transmitted between the vertebrate and mosquito hosts via the bite of the latter. The developmental cycle of Plasmodium spp. in the mosquito is well established, but its pathogenicity to the mosquito remains unclear. We wish to understand the metabolic effects of plasmodial infection on female mosquitoes from the moment they take an infected blood-meal to the time when they become infective. Two phases during malarial development should be metabolically costly to the host: the oocyst growth phase on the midgut and the invasion of the salivary gland cells by the sporozoites. In the Aedes aegypti and Plasmodium gallinaceum host-disease complex, the timing for these phenomena is well known. Oocysts grow during the first week following an infective blood-meal, each producing and liberating thousands of sporozoites into the hemolymph. These sporozoites enter, and are visible in, the mosquito salivary glands 2 weeks following the blood-meal. Through the analysis of carbon dioxide release with flow-through respirometry and quantification of glucose uptake, we have examined the energy metabolism of infected and non-infected mosquitoes at these critical times. Diurnal patterns of metabolic rate and activity have also been examined in the context of possible behavioral changes caused by the infection. Our studies are designed to determine if infection with Plasmodium imposes metabolic costs on the host, with possible implications for the insects� fitness. Supported by NSF grant IBN-0079501