First report on the diversity and geographical distribution of mosquitoes of the genera Haemagogus and Sabethes (Diptera: Culicidae), the main vectors of jungle yellow fever in Paraguay.

Abstract

Sylvatic yellow fever virus is transmitted by mosquitoes Haemagogus and Sabethes genera, which predominantly inhabit forested areas but can also be found near human dwellings in rural zones. In Paraguay, outbreaks of the disease were reported between 2007 and 2008, prompting the initiation of systematic sampling starting from those years to monitor the vectors transmitting the yellow fever virus. This study aims to identify the primary vector species and determine their geographic distribution in Paraguay, based on administrative divisions and ecoregions. Sampling was conducted in 17 departments, the capital district of Asunción and in 7 ecoregions in daylight hours using manual aspirators and entomological nets. Sampling was sporadic (2008-2016) and regular, risk-based from 2017. The collected data were georeferenced and processed using QGIS software. A total of 288 observations were documented, with a higher prevalence in the departments of Alto Paraná (26.74%), San Pedro (21.18%), and Caaguazú (12.50%). Sixteen species were identified, 9 of which belong to the genus Sabethes (89.58%) and 3 to the genus Haemagogus (10.42%). In the Western region or Chaco, only Hg. spegazzinii was found, while species of the genus Sabethes predominated in the Eastern region. The results further indicate that the ecoregions of the Atlantic Forest of Alto Paraná and the Cordillera de los Altos show the highest concentration of these vectors. This study represents the first compilation of the geographic distribution of Haemagogus and Sabethes mosquitoes in Paraguay and makes significant contributions to national surveillance by identifying three priority ecoregions for yellow fever monitoring. The information provided is essential for delineating risk areas and strengthening prevention and control strategies for sylvatic yellow fever, particularly in vulnerable zones.