The LMVR insectaries are one of the strengths of the LMVR's research program and a major resource for the NIH and the malaria and leishmaniasis research communities in general. Dr. Tovi Lehmann joined the LMVR in late 2004 as Facility Head for insectary operations. He is assisted by two experienced technicians and four young, enthusiastic high school students. The mosquito rearing area of the LMVR insectaries is located on the 2nd floor of the NIAID Twinbrook III Laboratories and includes five insectary modules reserved for mosquitoes. It addition, a secure containment area permits the safe infection and dissection of mosquitoes with malaria parasites. Over the last two years the LMVR insectaries has significantly increased work on the sandfly vectors of leishmaniasis. An insectary module on the 2nd floor supports the breeding and handling of uninfected sandflies. A new insectary for the holding and manipulation of infected sandflies has been activated on the 3rd floor of Twinbrook III. The LMVR insectaries maintain five species of Anopheles, some of which are sub divided into genetically selected lines and mutant strains. In addition the facility maintains Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus. On occasions the insectary rears Toxoryhncites amboinensis to support research by the NIAID laboratory working on dengue and West Nile vaccines. Two genera including four species of sandflies are reared in the LMVR. In addition the insectaries maintain Ixodes, Dermacentor and Amblyomma ticks. On occasion, the insectary has supported colonies of Cimex and Rhodnius. The Insectary Team maintains a colony of chickens, now housed in the Twinbrook III animal facility. Chickens are regularly infected with the avian malaria Plasmodium gallinaceum;this parasite has been used at the NIH for over 50 years and has proven to be a particularly useful model system for research on this important parasite. Chickens are also used as a source of regular blood meals for mosquito colony maintenance. In addition to supporting mosquito research in the International Studies Section, there are significant projects requiring mosquitoes in the Mosquito Immunity and Vector Competence Unit of Dr. Barillas-Mury, and the Vector Biology Section of Dr. Ribeiro. The Malaria Genetics Section under Dr. Wellems is involved in conducting a genetic cross between drug sensitive and drug resistant strains of Plasmodium vivax. The genetic recombination of these parasites must take place in the gut of a mosquito vector and the resulting sporozoites carrying either of the two parental genotypes or the recombination genotype are used to initiate infection in a monkey host. In the past the LMVR insectaries have supported such genetic crosses using various parasite genotypes in P. falciparum and chimpanzees and Aotus monkeys. The cloned parasites derived from such crosses have proven exceptionally valuable in the Laboratory's studies of drug resistance in malaria. The Malaria Vaccine Development Branch (MVDB) uses the LMVR vector containment facility for infecting mosquitoes with P. falciparum and testing the efficacy of various antibodies in the quest for a transmission blocking vaccine. The MVDB has recently initiated studies with transgenic parasites and is testing drugs against the relapsing forms (hypnozoites) of the malaria parasite. Such studies require the use of sporozoite-initiated infections in a monkey model. Mosquitoes for these studies are reared and maintained in the LMVR insectaries. Research on the development of vaccines for leishmaniasis has focused primarily on antigens derived from sandfly saliva. The life cycle of the parasite requiring the sandfly vector is conducted in the secure LMVR insectary on the 3rd floor of Twinbrook III. The sandfly colony closely supports and collaborates with the sandfly/leishmaniasis programs in the LPD and at the WRAIR facility at Forest Glen. Studies are underway to select Plasmodium gallinaceum adapted to a normally poor vector, An. stephensi, with 2% susceptibility. The goal of these experiments is to determine if such adaptation incurs fitness costs on the parasite and if these costs are the prime boundaries of parasite specificity. After 14 generations of plasmodium passage, no evidence for adaptation to the new vector was evident. It was concluded that there was no existing variation in plasmodium stock with respect to its ability to infect this mosquitoes and that denovo mutations were probably too rare to allow such adaptation given the number of generations and population effective size of the parasites. Studies are underway to select An. stephensi for susceptibility to Pl. gallinaceum. The goals of these studies are to understand the variation in infection prevalence in this system and assess the costs associated with susceptibility of this vector to this plasmodium. Studies revealed that selection resulted in 90% susceptibility in 5 generations of selection, suggesting a major locus or few loci. These studies explain the low infection of this system (above) as a result of variation in vector susceptibility exposed to homogenous parasite population. Studies to evaluate the biological costs of susceptibility to mosquito fitness and survivorship are underway. Studies are underway to identify the barriers to the development of Plasmodium falciparum in Culex quinquefasciatus. Cu. quinquefasciatus is an important man-biting vector of several arboviruses in the tropics and a major pest mosquito. It regularly feeds on humans with malaria but has never been shown to become infected or to transmit the parasite. Experiments comparing development of the parasite in An. gambiae and Culex have shown that midgut invasion occurred in both vectors, but oocyst formation failed in Culex.
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