The geographic distribution and parasite infection rate of Anopheles crucians


Anopheles crucians Wiedmann (s. l.) is an anopheline species complex that is distributed broadly across North and Central America and the Caribbean. It is a potential vector of Plasmodium falciparum and Plasmodium vivax, as well as a number of arboviruses. More recently, it has been implicated as a vector of Dirofilaria immitis, a microscopic nematode worm that is the causative agent of heartworm disease. Although the members of this species complex are morphologically indistinguishable as adults, it is possible to assign individuals at the species level within the complex using a previously described polymerase chain reaction (PCR) assay based on amplification of the internal transcribed spacer 2 region (ITS2). An understanding of species composition and distribution could be critical in elucidating the role that this complex may play as a vector of D. immitis. Here we describe our initial efforts to determine the distribution, composition, and parasite infection rate of members of the An. crucians complex within a community in the Southeastern United States. We employed PCR amplification of the rDNA ITS2 sequence to differentiate over 240 individuals from the An. crucians complex collected from 10 different sample locations in Lowndes county GA. We observed individuals of this complex in sympatry in multiple locations throughout the county with several of these locations exhibiting three of the species (A, C, D) in sympatry. We also employed a PCR-based assay to amplify the D. immitis-16S rRNA gene within individual mosquitoes in order to determine if there are differences in parasite infection rates between different members of this species complex. This work represents a new step in understanding An. crucians ecology in the state of Georgia. An understanding of species distribution and vector competence within the An. crucians complex could allow for the development of improved vector control strategies.


Valdosta State University Graduate School

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