Blood meal analysis: unveiling the feeding preferences of Aedes aegypti and Aedes albopictus in a dengue-endemic area

Studies have suggested animals as possible reservoir hosts for flaviviruses transmitted by Aedes mosquitoes; however, there is limited evidence for the dengue virus in Malaysia. One of the possible ways to determine the zoonotic potential for any pathogen transmission is through blood meal analysis which can provide valuable insights into the feeding preferences of the mosquitoes. Unfortunately, limited information is available on the feeding preferences of Aedes mosquitoes in Malaysia. Thus, this study aimed to identify the blood-feeding preferences of Aedes aegypti and Aedes albopictus from different ecotypes in Selangor, Malaysia. The field mosquitoes were collected using a modified backpack aspirator and CDC light trap. The collected mosquitoes were initially classified based on degrees of blood digestion according to the Sella scale before extracting the DNA. The presence of vertebrate DNA was detected using nested PCR, and samples positive for vertebrate DNA were further subjected to species-specific PCR targeting the common animals found at the study locations. In general, 51 of 187 field caught Aedes mosquitoes were positive for the presence of vertebrate DNA in their blood meal. The most frequent blood meal source was human (38.2%), followed by monkey (12.7%), bovine (10.9%), chicken (7.3%) and dog (3.6%). The human blood index (HBI) of Ae. albopictus collected across the four different ecotypes revealed that, Ae. albopictus collected near human dwellings showed 100% anthropophilic tendency. Interestingly, there were two Aedes mosquitoes, Ae. aegypti (n=1) and Ae. albopictus (n=1) positive for both human and monkey blood. Since sylvatic dengue continues to flourish in Southeast Asia, this finding from blood meal analysis shows the potential for zoonotic transmission by Aedes mosquitoes in these locations. However, further research must be carried out to understand the role of animals as potential reservoir hosts for the dengue virus, especially through the detection of the virus in the blood meal.