Exposure of free ranging birds to St. Louis encephalitis and West Nile viruses (Flavivirus) in agriculture and cattle raising landscapes in Argentina

ANA PAULA MANSILLA; DIEGO GALLEGO; AITUÉ FARANA; MIKEL LARREA; ROMINA GALLARDO; BRENDA KONIGHEIM; DIEGO ARIAS BUILES; JUAN MANUEL GRANDE; LUIS ADRIÁN DIAZ

New Orleans

Congreso; The American Society of Tropical Medicine and Hygiene Annual Meeting; 2018

American Society of Tropical Medicine and Hygiene

Anthropogenic changes affect biological communities of host and vectors driving arbovirus activity. In general, urban and agricultural landscapes host less avian and mosquito diversity and frequently these are dominated by few species. The St. Louis encephalitis (SLEV) and West Nile viruses (WNV) are infectious agents that have emerged and re-emerged worldwide. The aim of this work was to evaluate activity of SLEV and WNV in bird communities in agricultural and cattle raising landscapes. Field work was carried out in four different sites in La Pampa province (Argentina) between February and June 2017 (summer and fall). Avian sera samples were analyzed by plaque reduction neutralization test. Generalized Linear Models were performed to determine the effect of bird species and sampling site on the infection of SLEV/WNV. Neutralizing antibodies against SLEV were found in 45 out of 348 samples (12.9%) while WNV seroprevalence overall was 3.4% (12/348). House Wren (Troglodytes aedon), House Sparrow (Passer domesticus), Monk Parakeet (Myiopsitta monachus), Rufous Hornero (Furnarius rufus), Rufous-collared Sparrow (Zonotrichia capensis) and Picui Ground-dove (Columbina picui) were the most exposed avian species to SLEV. On the other hand, Shiny Cowbird (Molothrus bonariensis), Rufous Hornero (Furnarius rufus), Monk Parakeet (Myiopsitta monachus), and Picui Ground-dove (Columbina picui) showed the highest seroprevalence values for WNV. The sampling site was a significant variable affecting the chance to detect an infected bird by SLEV/WNV. Sites located in northern area showed higher seroprevalence values than those located southern. Our data confirm the geographic expansion of WNV in Argentina from center region to southern latitudes. Northern area of La Pampa is subject of intense agricultural activities (soy, corn, wheat) whilst southern area has a mixed of agricultural and cattle raising activities. These preliminary data indicate a potential positive effect of agricultural activities over the SLEV/WNV activity.