Research on Anopheles gambia mosquitoes in Mali and at the NIH Over the past year, Dr. Tovi Lehmann has been working with his team in Mali on the identification of the hidden shelters of African malaria mosquitoes during the Sahelian dry season. This project (funded by the Tamaki Foundation) has involved training Malian dog handlers and their dogs to identify shelters by scent-detection and then searching selected areas (GPS anchored) around two villages in Mali. Over 20 putative shelters were identified by the dog teams and characterization of these shelters is currently ongoing. The verification of these shelters will continue in the upcoming year and Dr. Lehmann plans at least 1 upcoming trip (November 2013) to determine (together with the Mali team) the best verification strategy to be used. Additionally, Dr. Lehmann has been supervising 2 complementary studies on the long-distance migration of malaria vectors (partly funded by the Gates Foundation through a grant to Dr. Frank Collins at Notre Dame). These studies are 1) on-the-ground monitoring of vector density and composition and 2) aerial sampling of mosquitoes. The transect study includes 8 villages along two transects spanning 100 km each, and surveys are conducted synchronously across all 8 villages every 2 days or every 2 weeks, depending on changes in density observed on the ground;this project will also continue in the next year. The aerial sampling of mosquitoes is aimed at detecting seasonal migrations of these mosquitoes at altitudes of 40-150 m. This project was initiated by Dr. Diana Huestis, who worked with the Malian field team to optimize the methodology. This project thus far has yielded capture of 9 Anopheles gambiae females at high-altitude (>100 m above ground) and several other mosquitoes. Dr. Huestis may plan a trip to further work with the team and possibly train them in a new method to conduct aerial sampling. Over the past year, Dr. Tovi Lehmann has been analyzing data on mosquito population dynamics and its spatial distribution. The data cover nearly 5 years of sampling in our focal village in Mali. This analysis has resulted in 1 publication which is already in-press (below) and a draft of a second manuscript is currently in progress. In collaboration with Dr. Molina-Cruz and Knoeckel (LMVR), Tovi has written part of a review article on Culicine mosquitoes and malaria (in Review), with Dr. Diabate (Burkina Faso) and colleagues, as well as Drs. Ribeiro (LMVR) and Palley (UMD) Tovi has contributed to studies on mating behavior of Anopheles gambiae. Additionally, Dr. Lehmann has been supervising postdoc Diana Huestis and postbac Monica Artis. Together, Dr. Lehmann and Dr. Huestis have designed and supervised experiments to evaluate the measurement of flight activity in cages using sound recording as well as the development of flight persistence assay that can be used in the lab and in the field (in Mali). Dr. Lehmann and Dr. Huestis have also been working on a collaborative SNP study which investigates genetic diversity and possible origins of mosquito populations at the beginning of the wet season. During this year, Dr. Huestis has conducted a laboratory study on the effect of changes in photoperiod on longevity (and other phenotypes) of newly-established mosquito colonies from Mali. The manuscript of this project is currently being drafted and a follow-up study, which adds the seasonal component of temperature, is currently ongoing and will continue into the next year. Dr. Huestis also works with Ms. Monica Artis, (INRO postbac) on the analysis of cuticular hydrocarbons of malaria mosquitoes using chromatography (GC). Testing that during the dry season composition of CH differ from that during the wet season is currently underway and will continue in the upcoming year. Additionally, this past year, Ms. Artis led an experiment to test the effect of oviposition deprivation on longevity of malaria mosquitoes, and is currently drafting the manuscript of these results. Research on Asian Anopheles vectors of malaria in Cambodia and at the NIH In order to determine the role of different Anopheles species in transmitting artemisinin-resistant P. falciparum in Cambodia, Becky Miller and Brandy St. Laurent have been working through thousands of anopheline samples from Thmar Da, Western Cambodia, where distinct populations of artemisinin-resistant P. falciparum circulate. They have identified more than five different Anopheles species carrying parasites in this area and molecular analysis reveals that the anopheline fauna of the area is extremely diverse. In order to quantify how well artemisinin-resistant and susceptible P. falciparum strains infect different laboratory-adapted anopheline species from Cambodia. Brandy and Becky have initiated infection experiments with laboratory adapted An. dirus isolated from different countries in Southeast Asia. We currently have only An. dirus in the insectary at NIH to represent Cambodian anophelines. Dr. St. Laurent also completed an extensive An. dirus rearing experiment to ensure that the laboratory lines were healthy and standardized enough for meaningful infection experiments. During the last year in Cambodia, Dr. St. Laurent has characterized at the molecular level and colonized 12 species of Anophelines malaria vectors. For many of these species, it is the first successful colonization. These colonies will form the critical basis for studies on the possible role of these species in the transmission of drug resistant Plasmodium falciparum.
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