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Research Project: Xenosurveillance Using Arthropod Vectors to Characterize Vector-borne Disease Epidemiology

Location: Foreign Arthropod Borne Animal Disease Research

Project Number: 3022-32000-024-015-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Aug 1, 2023
End Date: Jul 31, 2027

Mosquitoes interact profoundly with other organisms within the ecosystems they inhabit. Because the females of most mosquito species must take a blood meal from another animal in order to produce viable eggs, and because female mosquitoes usually feed from multiple hosts over the course of their lives, mosquitoes can be effective vectors for pathogens. Many mosquito-vectored pathogens are zoonotic, transmitted via mosquitoes among non-human animals, occasionally spilling over to humans or livestock. The transmission dynamics of these zoonotic mosquito-vectored pathogens are influenced, in large part, by the host-feeding patterns of mosquitoes. Interactions between mosquitoes and their host animals create networks that can enable pathogens to move between vertebrate hosts. The host associations of mosquitoes vary by species: some species are relative generalists, but most specialize, to varying extents, on particular types of host animals. Characterizing the host associations of mosquito communities provides insight into how a pathogen may move within an ecosystem, potentially impacting humans or livestock. Concomitantly, by identifying the host species from which mosquito blood meals are derived, we glean information on the composition of the vertebrate community of the ecosystem from which the mosquitoes were collected. These data are particularly informative when they are combined with data on the infection rates of vectors and environmental or landscape variables, and together, these elements contribute toward an overall characterization of pathogen transmission dynamics, enabling informed assessment of public health or veterinary risks associated with that particular pathogen. The objectives of the proposed work are (1) to characterize the mosquito community of the study site based on molecular and morphological tools, (2) develop resources that enable effective morphological identification of mosquitoes to the species level at the study site, (3) characterize the vertebrate community and mosquito host associations at the study site. By characterizing the mosquito and vertebrate host communities at a USDA-selected study site, we will contribute detailed information on the composition of these communities and the interactions between both. These data will be integrated with data on virus transmission and infection in vectors and livestock hosts, environmental variables, and GIS data to develop a thorough understanding of virus transmission dynamics and potential risks to livestock production in the U.S.

In the proposed work, we will characterize the mosquito community, the vertebrate community, and the interactions between both at a study location determined by the USDA. In short, mosquito specimens will be collected at the study site using diverse sampling techniques, including several that target blood fed females. To characterize the mosquito community of the site, mosquitoes will be identified using a combination of morphological and molecular tools. High quality, intact, representative specimens of each species will be photographed using a focus-stacking system. From each photographed specimen, reference DNA sequences will be collected and submitted to publicly accessible databases, and high-quality images and reference DNA sequences will be associated with each other. Images will be used to create illustrated dichotomous keys to the adult mosquitoes of the study site. To characterize the vertebrate host community, we will use blood fed mosquitoes as a source of environmental DNA for the detection of vertebrate species. Mosquitoes will be collected using established and novel trapping methods. They will then be sorted by species using dichotomous keys and morphological identification as well as the presence of a blood meal. Mosquitoes will be photographed and select genes will be sequenced for genetic identification confirmation. Blood meals will be preserved and then the blood meal will be sequenced to identify the host and the presence of pathogens.