Mosquito community structure, host-feeding patterns, and molecular xenomonitoring of zoonotic Brugia in Klang Valley, Malaysia

Information from the abstract

Lymphatic filariasis remains a public health concern in Malaysia, with zoonotic Brugia species occurring at the animal-human interface and presenting a potential risk of spillover to humans. This study investigated mosquito community structure, host-feeding patterns, and the presence of zoonotic Brugia in a non-endemic area of Malaysia. Entomological surveys were conducted in two locations; Bukit Gasing (forested area) and Pulau Carey (coastal area), between April–July 2024 and November 2024–February 2025 using Human Landing Catch and Mosquito Magnet traps. A total of 1584 mosquitoes representing 16 species were collected, morphologically identified, and analyzed using dissection and PCR targeting the cytochrome c oxidase I ( COX1 ) gene to detect Brugia pahangi and Brugia malayi . Community analysis revealed significant differences in mosquito assemblages between sites (stress = 0.015, F 1,6 = 4.11, R 2 = 0.41, p = 0.021). Pulau Carey was characterized by Culex and Mansonia species, whereas Bukit Gasing was associated with Aedes and Armigeres kesseli . Ar. subalbatus overlapped across the two sites. No significant difference in within-site variability was observed ( p > 0.05). Mosquito dissection showed one infective-stage (L3) of B. pahangi in Ar. subalbatus from Pulau Carey. Molecular screening detected B. pahangi in 5 of 68 pools of Ar. subalbatus (overall minimum infection rate = 3.16 per 1000 mosquitoes; 95% CI 1.0–7.4) from the same area. B. malayi was not detected in any of the samples. Two of the five positive pools yielded high-quality sequences (GenBank: PV611840, PV612037) and showed clustering with Southeast Asian B. pahangi strains from animal and vector sources. Blood meal analysis showed that 47.87% of mosquitoes contained detectable vertebrate DNA, with Ar. subalbatus (H′ = 1.01) and Cx. quinquefasciatus (H′ = 1.08) exhibiting the highest host diversity, feeding across multiple vertebrate hosts including humans, cats, dogs, and monkeys, suggesting their potential role as bridge vectors facilitating contact between human and animal hosts. Although evidence of sustained transmission was not established, the detection of B. pahangi DNA, an infective-stage larva, diverse vector blood meals, and clustering of isolates with sequences from human and animal hosts suggests the potential for zoonotic filarial transmission risk in non-endemic settings. These findings highlight the value of integrated entomological surveillance alongside molecular techniques for detecting early signals of zoonotic filarial circulation in at-risk regions.

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Related topics: Parasitic Diseases Research and Treatment · Mosquito-borne diseases and control · Malaria Research and Control