St. Louis encephalitis (SLEV) and West Nile (WNV) arboviruses, which circulate in Argentina, are maintained in enzootic transmission cycles involving Culex mosquitoes (vectors) and birds belonging to orders Passeriformes and Columbiformes (amplifier hosts). The objective of this work was to determine the circulation of both viruses among wild birds in a semiarid ecosystem in the Province of La Rioja through a serologic survey. During spring 2013 and fall 2014, a total of 326 wild birds belonging to 41 species were captured in areas close to the cities of La Rioja and Chilecito, in the Province of La Rioja. While exposure to SLEV and WNV was analyzed in birds’ serum through neutralizing antibody detection, viral circulation was estimated through apparent seroprevalence of neutralizing antibodies. The exposure of the avian community to viruses was 3.02% for SLEV and 1.89% for WNV, while 1.19% corresponded to coinfections. Our study confirms for the first time the circulation of SLEV and WNV in wild birds in the Province of La Rioja. Moreover, it is the first study to register neutralizing antibodies for flavivirus in the species Leptotila verreauxi (White-tipped Dove) (WNV) and Melanerpes cactorum (White-fronted Woodpecker) (SLEV). These results suggest that in semiarid ecosystems from northwestern Argentina the requirements and conditions for amplification and enzootic maintenance of SLEV and WNV would be present.

在阿根廷传播的圣路易斯脑炎 (SLEV) 和西尼罗河 (WNV) 虫媒病毒在涉及库蚊的地方性传播循环中得以维持蚊子（媒介）和鸟类属于 Passeriformes 和 Columbiformes（放大器宿主）。这项工作的目的是通过血清学调查确定这两种病毒在拉里奥哈省半干旱生态系统中的野生鸟类中的传播情况。2013 年春季和 2014 年秋季，在拉里奥哈省拉里奥哈市和智利西托市附近地区共捕获了 41 种 326 只野生鸟类。虽然通过中和抗体检测分析了鸟类血清中 SLEV 和 WNV 的暴露情况，但通过中和抗体的表观血清阳性率估计了病毒循环。禽类社区对病毒的暴露对于 SLEV 为 3.02%，对于 WNV 为 1.89%，而 1.19% 对应于合并感染。我们的研究首次证实了拉里奥哈省野生鸟类中 SLEV 和 WNV 的传播。此外，这是第一项在该物种中注册黄病毒中和抗体的研究Leptotila verreauxi（白头鸽）（WNV）和Melanerpes cactorum（白额啄木鸟）（SLEV）。这些结果表明，在阿根廷西北部的半干旱生态系统中，存在 SLEV 和 WNV 扩增和地方性动物维持的要求和条件。