288 - Detection of Dengue Virus Serotype-1 in Aedes aegypti mosquitoes collected during an outbreak in Araraquara, Brazil using Integrated Aedes aegypti Monitoring (MI-Aedes) technology
Abstract: Araraquara is a medium-sized municipality in São Paulo state, Brazil, that reported 23,847 cases of dengue in 2019. In 2022, a similar scenario was experienced, with approximately 16,395 cases and 17 deaths. The purpose of the study was to describe the infection rate in mosquitoes caught in traps distributed in the urban areas of the city. Methods: From epidemiological week (EW) 02 to 22 of 2022, 909 Mosquitrap installed in the municipality were weekly inspected. Aedes aegypti (males and females) were collected and analysed to examine the presence of Dengue Virus. Confirmed human cases were obtained through a database made available by the municipality. Results: During the 20-week study period, the MFAI (Mean Female Aedes Index) ranged from 0.22 (EW 6) to 1.04 (EW 18), and 2611 dengue human cases were confirmed. The highest number of cases occurred from EW 09 to 11, and a second peak occurred from EW 20 to 22. 5233 mosquito samples were collected and 241 samples were positive for DENV, showing an infection rate of 4.36%. EW 17 and 18 had the highest infection rates, with positivity rates above 8%, and EW 12, 15, 16, and 19 also presented high positivity rates, showing percentages above 7%. EW 3, 5, and 6 yielded no positive results. Discussion: The recurrence of a DENV1 epidemic reveals the seasonal profile of the disease in Brazilian endemic cities, such as Araraquara. Factors like the high density of Aedes and its distribution in the municipality most likely contributed to the high number of human cases during the first half of 2022. The increase in cases and positivity in mosquitoes was not limited to a single area, demonstrating the virus's ability to spread rapidly throughout the city's urban areas.
