Molecular Detection of Dengue and Chikungunya Viruses from Wild-caught Aedes Mosquitoes Across Arboviral Endemic Regions of Ethiopia

Background Arboviral infections, especially dengue fever and chikungunya, are emerging diseases that pose a significant public health challenge in Ethiopia. These viruses are primarily transmitted by widely spread Aedes aegypti mosquitoes. Research on arboviruses using molecular techniques is limited in Ethiopia but is important for informing public health decisions. This study aimed to molecularly detect Dengue and Chikungunya viruses in wild-caught Aedes mosquitoes across the arboviral endemic regions of Ethiopia. Methods Larvae and adult stage Aedes mosquitoes were collected using Pasteur pipettes and improved Prokopack aspirators from four study sites between October 2022 and June 2023. The mosquitoes were pooled by species, date of collection, and collection site into 1 mL prefilled DNA/RNA Shield tubes with bead beats. The pooled mosquitoes were homogenized using the FastPrep-24™ Classic bead beating homogenizer. The RNA was extracted using the QIAamp Viral RNA Mini Kit according to the manufacturer's instructions. Then, the extracts were screened for DENV and CHIKV on the QuantStudio 5 Real-Time PCR system. Results were interpreted based on the Ct values, and maximum likelihood estimation (MLE) to determine the dengue infection rate in the population. Results A total of 3,510 Aedes mosquitoes were collected, with the majority identified as Ae. aegypti (88%). Three mosquito pools tested positive for DENV (one pool from Dire Dawa and two pools from Afar). All DENV isolates were identified as DENV-3. We found a low MLE in both Dire Dawa and Afar sites. Conclusions We detected DENV-3 in three pools of adult Ae. aegypti collected from the Afar and Dire Dawa sites where recent dengue outbreaks have been reported, using a molecular approach and estimating the MLE for each site. This finding provides valuable information for public health decision-making to prevent future outbreaks. Further studies are recommended to gain insights into other circulating arboviruses from Aedes mosquitoes in Ethiopia.