Yellow fever and arbovirus surveillance in sylvatic areas from Misiones province, Argentina

GOENAGA, S.; LEVIS, S.; ROSSI, G. C.; LESTANI, E.; AGOSTINI, I.

Congreso; 66th Annual Meeting of American Society of Tropical Medicine and Hygiene; 2017

Yellow fever (YF) is a viral hemorrhagic fever endemic to tropical regions. In South America, the sylvatic cycle of Yellow fever virus (YFV) is maintained by viral circulation between monkeys and diurnally active mosquitoes that breed in the forest canopy. In Argentina, circulation of YFV was detected during 2007-2009, where a sylvatic outbreak affected monkeys and humans. However, the transmission cycles are not completely understood, and identification of vectors and reservoirs remains poorly known. Since 2015, we have captured mosquitoes in four protected areas of the Atlantic Forest of Misiones province, Argentina. In order to evaluate the YFV enzootic circulation, mosquitoes were tested for YFV and other arbovirus. During the day, we captured adult mosquitoes from human bites, focusing on Sabethes and Haemagogus genera, because of their known implication in the YFV transmission. Specimens were sorted according to location, date and species. RT-PCR for YFV, generic Flavivirus, Alphavirus and Bunyavirus from supernatant of mosquitoes pool homogenates were performed. Inoculation into Vero and C6/36 cells for virus isolation attempts were done from those pools positives for genome detection. A total of 696 mosquitoes sorted in 134 pools were analyzed. Sabethes mosquitoes were the most abundant genus (40%, 10 species), followed by Trichoprosopon (18%, 4 species). Among the mosquitoes taxa implicated in YFV transmission, only 5 captured specimens belonged to Hg. leucocelaenus, 2 belonged to Sa. chloropterus and 36 specimens belonged to Ae. serratus. No specimen of Sa. albiprivus, Ae. aegypti or Ae. albopictus were captured. No YFV genome was detected in any of the analyzed mosquitoes pools. Nevertheless, several arbovirus genomes were detected, such as Mercadeo virus, Madariaga virus, and one new flavivirus strain. Currently, isolation attempts are still ongoing. Even though YFV was not detected in our survey, the current YF outbreak in Brazil could spread to bordering countries representing a threat for public health. Continuous maintenance of surveillance is crucial to detect the potential spread of YFV to Argentina.