Banca de DEFESA: SERGIO LISBOA MACHADO

Diversity and structure of mosquito communities (Diptera: Culicidae) and detection of circulating arboviruses in 
remnants of the Atlantic forest, state of Rio de Janeiro, Brazil

Culicidae, Atlantic Forest, conservation area, disease risk, vectors, arboviruses

The Atlantic Forest is an exceptionally biodiverse region that stretches across parts of Brazil, Paraguay, and Argentina. Human activities, such as deforestation, coupled with climate change, have the potential to severely harm this environment. These actions lead to habitat destruction and, as a result, cause ecological imbalances. They also disrupt mosquito communities, known as culicids, many of which act as vectors for pathogens responsible for diseases like Yellow Fever, Zika, and Chikungunya. When human activities encroach upon the natural habitats of mosquitoes, conditions become more conducive to their reproduction and survival, as some taxa exhibit adaptability to various environments, occurring in different types of larval habitats, thus increasing the risk of arbovirus transmission. This study, therefore, aimed to analyze the ecological aspects of Culicidae while simultaneously detecting the circulation of arboviruses in various remaining fragments of the Atlantic Forest across the municipalities of Casimiro de Abreu (Fazenda Três Montes), Silva Jardim (Sítio Terra Boa), Nova Iguaçu (Sítio Boa Esperança), and Cachoeiras de Macacu (Reserva Ecológica do Rio Guapiaçu) in
the state of Rio de Janeiro, and to assess the risk of emergence and transmission of arboviruses. Sampling was conducted monthly over three consecutive days between 2018 and 2023. Adult specimens were captured using CDC and Shannon light traps, as well as the protected human attraction technique (TAHP) using Castro traps. Immature specimens were collected with the aid of entomological shells, ovitraps, and polyethylene pipettes. Larvae and pupae were then pipetted and transferred into 250 ml plastic bags. This combination of traps provided a comprehensive and representative sampling of the diversity of adult mosquitoes present in the study area. Arbovirus detection was carried out through viral RNA extraction. From the start of the study up
until May 2024, 18,434 insects (1,418 pools) were processed. At Fazenda Três Irmãos, located in Silva Jardim, our observations of ecological indices revealed a significant positive correlation between the species Haemagogus leucocelaenus and Aedes terrens with abiotic variables such as temperature and relative humidity. Haemagogus janthinomys showed a positive and statistically significant correlation with rainfall
levels. The months of December 2020, November 2021, and January 2022 were identified as periods with the highest occurrence of culicid eggs in this location. Notably, the most abundant species found was Haemagogus leucocelaenus, with the majority of individuals recorded at altitudes of 2m and 6m. We detected the Yellow
Fever virus in seven pools and the Zika virus in five pools, both in 2019. Haemagogus  janthinomys was found to be of low abundance, possibly due to the species' requirement for multiple immersions for its eggs to reach the embryonic stage. Our findings indicate that abiotic factors such as higher temperature, relative humidity, and precipitation levels contribute to the multiplication of Culicidae and should be considered when developing strategies for the control and prevention of disease spread.