Evidence incriminating Anopheles maculatus as a potential vector of Plasmodium knowlesi and Plasmodium inui

In Indonesia, 29 anopheline species are vectors of human malarias. Many of these morphologically indistinguishable vectors are in species complexes requiring molecular analysis to identify. Data on vectors in North Sumatra remain limited. This study investigated mosquitoes of the Maculatus Subgroup in Ujung Bandar Village, Langkat Regency, to identify them and their potential roles in malaria transmission. Mosquitoes collected via human landing catches (July 2022 – June 2023) were analysed using ITS2 PCR assays and a phylogenetic analysis. Screening for Plasmodium DNA was performed on mosquito heads and thoraces using RT-qPCR targeting the 18S rRNA, followed by species-specific nested PCR. All 234 specimens morphologically identified An. maculatus s.l. were confirmed as An. maculatus s.s., being genetically consistent with populations from Indonesia and mainland Southeast Asia. Four (1.7%; 95% CI: 0.5–4.3%) An. maculatus specimens were positive for Plasmodium genus DNA, with one specimen positive for the DNA of both Plasmodium knowlesi and Plasmodium inui. This represents the first detection of zoonotic malaria parasite DNA in wild-caught An. maculatus. These findings suggest that An. maculatus may be a potential vector of both zoonotic and human malarias in North Sumatra.