Hatching pattern and coexistence of Aedes aegypti and Aedes albopictus (Culicidae) in a subtropical city, Argentina, after three decades of coexistence.

Aedes aegypti and Aedes albopictus are mosquito vectors of numerous arboviruses of sanitary importance. Presently in Argentina, neither Ae. aegypti nor Ae. albopictus, have displaced the other species in the places where they coexist, since the introduction of the latter in 1998. In this study, we evaluated whether these species coexist at different scales (ovitrap, microhabitat and habitat) in the city of Eldorado, Misiones province, northeast Argentina. We also analyzed the seasonal variation and climate variables related to the delay in egg hatching of both species. Mosquitoes were collected weekly, from June 2017 to May 2018, using ovitraps placed in urban areas. We conclude that Ae. aegypti and Ae. albopictus coexist in the study area, at the ovitrap, microhabitat and habitat scales. Furthermore, no pronounced pattern of delayed hatching has been observed for either species; however, eggs of Ae. albopictus laid during colder weeks and less rainfall needed a greater number of immersions to hatch, while for Ae. aegypti those laid during weeks with low rainfall and high temperatures showed the longest delay in hatching response.

First Detection of Madariaga virus in Mosquitoes Collected in a Wild Environment of Northeastern Argentina.

Madariaga virus (MADV), previously known as South American eastern equine encephalitis virus (SA EEEV; family Togaviridae, genus Alphavirus), is a mosquito-borne virus associated mainly with equine disease. In 2010, the first human outbreak by MADV was reported in Central America, but the mosquito vectors and vertebrate hosts involved in the outbreak were not identified. In Argentina, the first epizootic of MADV was in 1930, and since then, several epizootics by MADV have been reported. However, the potential vectors and hosts involved in the transmission cycle remain unknown. In the present study, MADV was detected in Culex (Culex) spp. mosquitoes and the phylogenetic analysis showed that the MADV fragment amplified grouped with the lineage/subtype III of the SA EEEV complex. Our results provide information about the natural infection with MADV in mosquitoes collected in a wild environment of Argentina and its genetic relatedness.