| The Southern Province of Zambia has historically had hyperendemic transmission of Plasmodium falciparum, primarily by Anopheles arabiensis. Although malaria admissions to the Macha Mission Hospital have declined significantly since 2003 when artemisinin combination therapy was adopted as the national standard treatment for uncomplicated malaria, P. falciparum continues to pose a significant public health risk in the region. To further combat malaria transmission, a large-scale insecticide treated bed net (ITN) campaign began in the Southern Province during the 2006-2007 rainy season. It is unknown how such vector control measures will impact anopheline foraging behavior in the Macha area. Therefore, the work presented in this dissertation aimed to (1) determine the degree of anthropophily and endophily in the An. arabiensis population during the year of ITN introduction, (2) evaluate the foraging behavior of An. arabiensis following ITN introduction, (3) ascertain the usefulness of Centers for Disease Control (CDC) light traps as a replacement for human landing catches (HLCs) in an area with high ITN use, and (4) examine the behavior of the potential secondary malaria vectors, An. coustani and An. squamosus. In order to examine the host seeking, blood feeding, and resting behaviors of the anophelines in Macha, mosquitoes were collected by pyrethrum spray catch and CDC light trap, as well as by human- and cattle-baited collections during the 2006-2007, 2007-2008, and 2008-2009 rainy seasons. Collections were performed in four village-areas during the year of, and the two years following, ITN distribution. A novel PCR based diagnostic was designed to identify the host source of mammalian blood meals out to 60 hours post feeding, aiding in the determination that An. arabiensis remains decidedly anthropophilic despite high rates of ITN use. Additionally, paired indoor/outdoor HLCs demonstrated that An. arabiensis in Macha appears to be relatively cxophagic, biting both right after sunset and right before sunrise, potentially circumventing the protective effects of ITNs. Furthermore, it was established that CDC light traps are an efficient replacement for HLCs in Macha even when positioned next to an ITN, catching on average 1.91 (95% CI: 1.16-2.28) times as many An. arabiensis per night as a landing catch pair. In conjunction with these studies, the anthropophilic tendencies of An. coustani and An. squamosus were observed. These species made up a large proportion of the anophelines collected by HLC and displayed high human blood indices. Overall, the entomological studies presented in this dissertation expand our knowledge of anopheline foraging behavior in Macha in the presence of ITNs. The work establishes an important framework from which to evaluate continued vector control efforts. |
