DNA barcodes: helping elucidate the role of mosquito species in flavivirus transmission in the southern area of Mar Chiquita Lake, central Argentina.

BERRON C; RE, V; LIJTMAER, DA; DIEZ, NG.; STEIN, M ; VISINTIN, A ; TUBARO, PL; ALMIRÓN, WR; CONTIGIANI, M

Kunming, Yunnan

Conferencia; 5th International Barcode of Life Conference; 2013

Saint Louis encephalitis virus and West Nile virus (Flaviviridae. Flavivirus) are mosquito borne-viruses that can cause neurological diseases in humans. Generally, transmission cycles of both viruses involve birds and ornithophilic mosquitoes of Culex genus. In the southern area of Mar Chiquita Lake, central region of Argentina, serological evidence in resident birds indicates circulation of both viruses. Additionally, West Nile Virus RNA was recently detected in specimens of the Culex genus. In this sense, the advent of modern molecular techniques has enhanced our capabilities to understand vector-host interactions and disease ecology. We studied the mosquito feeding patterns in order to contribute to elucidate the vector species. The project was based on three components: the generation of the barcode library for the mosquitoes of the study site, the identification of the engorged female mosquitoes using the barcodes and the identification of the mosquito blood meal sources using the barcodes of the birds of Argentina and other potential hosts available on BOLD. Most of the mosquito voucher specimens and all the engorged females were collected southwest of Mar Chiquita Lake (~30.9ºS, 63.0ºW) during 2009-2010. Mosquitoes were processed at the Institute of Virology ?Dr. J. M. Vanella? (INVIV, Córdoba, Argentina) and the Museo Argentino de Ciencias Naturales (Buenos Aires, Argentina) and molecular laboratory procedures were carried out at the INVIV and the Canadian Centre for DNA Barcoding (Guelph, Canada). Species of the mosquitoes of the region were successfully separated using DNA barcodes and could be used to identify females. This method was also useful to find out the origin of 226 blood meals. Mosquitoes belonging to Ochlerotatus, Psorophora and Mansonia genera fed exclusively on mammals (7 host species identified), while mosquitoes belonging to Culex genus fed primarily on birds (22 host species identified). A few species of the latter genus fed exclusively or mainly on mammals with a little portion of blood meals taken from birds (Taraba major), while other species fed almost exclusively on birds, being T. major the main host targeted. Although not conclusive, this analysis provides important clues about what Culex species might be involve in the enzootic cycles of these viruses, as well as potential species that could be involved in their transmission from birds to mammals. The role of T. major in flavivirus transmission should be addressed in future studies.