Distribution and identification of Aedes mosquitoes, vectors of Dengue virus in Abéché, Chad

Aedes mosquitoes, vectors of dengue, chikungunya, Zika, and yellow fever, represent a significant threat to public health due to their role in transmitting these diseases. Their emergence in Chad, driven by increasing urbanization and demographic expansion, raises considerable concerns. The aim of this study is to better understand the diversity and the role of Aedes mosquitoes in dengue transmission in the city of Abéché, Chad. This is a cross-sectional study conducted over four months, from July to October 2024. Mosquitoes were collected using human bait techniques in nine neighborhoods of Abéché. The samples were then subjected to morphological identification, followed by viral RNA extraction and RT-PCR analysis to detect dengue virus. The results show that out of 370 mosquitoes captured, 85.9% (n = 318) belonged to Aedes genus, of which 95% (n = 305) were Aedes albopictus and 4.6% (n = 13) were Aedes aegypti. There is no evidence of dengue virus in all analyzed mosquitos’ samples. This study highlights the significant presence of Aedes mosquitoes, particularly Aedes albopictus, in the city of Abéché, Chad, where they constitute the dominant species. Despite their high abundance and known role as vectors of dengue, none of the analyzed mosquitoes tested positive for the dengue virus. These findings underscore the importance of continued entomological surveillance and further research to better understand the distribution, dynamics, and potential role of Aedes mosquitoes in disease transmission in Chad. Such efforts are crucial for developing effective vector control strategies and mitigating the risk of dengue outbreaks in the region.