Molecular xenomonitoring for identifying Plasmodium parasites and blood meal sources in mosquitoes of the southern Rift Valley Lakes, South Ethiopia

Detecting Plasmodium parasites and host blood meals in the abdomens of fed mosquitoes enables timely decisions for effective malaria control. Hence, this study aimed to detect the Plasmodium parasite DNA and identify sources of blood meals in the abdomens of freshly fed Anopheles mosquitoes in South Ethiopia. A cross-sectional entomological survey was conducted in 12 malaria-endemic Kebeles near the southern Rift Valley Lakes, Abaya and Chamo, as a baseline for a trial evaluating house screening and/or ivermectin treatment for domestic animals to control malaria. Four hundred sixteen houses were selected for the Centers for Disease Control and Prevention (CDC) light trap collections. The species of mosquitoes were identified using morphological and molecular methods. The polymerase chain reaction (PCR) technique was employed to Plasmodium parasites detection and blood sources identification. Plasmodium vivax (2.0%; 9/446) and P. falciparum (0.2%; 1/446) were detected in the abdomens of mosquitoes. Out of 446 tested Anopheles specimens 85% (378/446) were fed on six vertebrate hosts, while 15% (68/446) tested negative for these hosts. Goat blood was the most common, accounting for 67% (299/446), followed by human blood (23%; 102/446). Cow blood was identified in 19% (84/446) of the fed mosquitoes, while dog blood was present in 13% (57/446). Chicken and pig blood were detected rarely. The overall human blood meal index was 23%, including mixed blood meal sources. Anopheles arabiensis was the most prevalent species, comprising 85% (380/446) of the nine Anopheles species identified, followed by An. pharoensis 7% (33/446) and An. tenebrosus 3% (13/446). Detecting Plasmodium parasites in the mosquitoes’ abdomens can enhance preparedness for malaria control. Anopheles mosquitoes obtain blood from various sources, with goats being the most common, followed by humans. Interventions targeting these mosquitoes may prioritise animal sources.