Dumpsites emerge as hotspots for mosquito arbovirus vectors in Thailand

Dumpsites in rural Thailand carry the heaviest burden of mosquito species capable of transmitting arboviruses, according to a new study of zoonotic interfaces in two border provinces. The research, published open access in Parasites & Vectors, surveyed seven types of sites where humans, animals and mosquitoes overlap, and found that waste dumps supported the largest populations of known vector species, including Culex gelidus and Culex vishnui, the two most abundant mosquitoes collected across the entire study.

The study was conducted in four districts: Pong Nam Ron and Soi Dao in Chanthaburi province, and Mae Fah Luang and Wiang Kaen in Chiang Rai province. The researchers sampled houses, temples, dumpsites, orchards, forest edges, forest interiors and bat caves, using snapshot sampling with two to three daily replicates of multiple trap types — light traps, Biogents Pro traps, Gravid Aedes traps and Prokopack aspirators — over 48 hours per interface. Sampling took place in both the dry and wet seasons of 2024 to capture seasonal variation in mosquito presence and abundance.

In total, Culex gelidus accounted for 45.6 percent of collected vectors (6,195 individuals) and Culex vishnui for 24.6 percent (3,348 individuals), with both species most prominent at dumpsites. Aedes albopictus, the third most abundant vector at 9.0 percent (1,014 individuals), was found across all interfaces, with high abundances in forests in all districts and at the Mae Fah Luang dumpsite. The authors analysed mosquito presence, absence and abundance across interfaces and seasons using generalised linear mixed models with Tukey post hoc tests, and calculated rarefied diversity indices for host-seeking communities at each interface.

Diversity patterns reinforced the risk picture: host-seeking communities at dumpsites were consistently low in diversity, as were forest interiors in Pong Nam Ron and Wiang Kaen. Low diversity combined with high abundance can indicate conditions favouring a few vector species, and the authors note that dumpsites support mosquito populations that feed both day and night and attract animal species, presenting a zoonotic risk to workers and neighbouring farmland communities. Forest sites were also identified as high-risk settings owing to the predominance of Ae. albopictus, though the authors stress that further investigation into its potential as a bridge vector and its role in sylvatic transmission is required.

The background to the study reflects growing concern that rapid climate change, land-use shifts and urbanisation are altering vector ecology in Thailand, a biodiversity hotspot with high risk for spillover of zoonotic mosquito-borne viruses. While the vectors of endemic Flaviviruses such as Japanese encephalitis virus and dengue virus are well characterised, the authors argue that current surveillance is needed where humans and animals increasingly overlap. This is the first investigation of arboviral vector ecology in Thailand to include dumpsites, and the team recommends longitudinal monitoring of rural interfaces to inform vector control and One Health preparedness. As an early-access, peer-reviewed accepted article, the findings are citable with a permanent DOI, with a final version of record to follow.

Subject of Research: Ecology and abundance of mosquito arboviral vectors across zoonotic interfaces in Thai border provinces

Article Title: Mosquito arboviral vectors at zoonotic interfaces in border provinces in Thailand

Article References: Brown, R., Phanitchat, T., Penjan, P., Jakkosung, A., Ritthison, W., Phanthanawiboon, S., Pientong, C., & Overgaard, H. J. (2026). Mosquito arboviral vectors at zoonotic interfaces in border provinces in Thailand. Parasites & Vectors. https://doi.org/10.1186/s13071-026-07667-9

Image Credits: AI Generated

DOI: 10.1186/s13071-026-07667-9

Keywords: mosquitoes, arboviruses, Thailand, dumpsites, Aedes albopictus, Culex gelidus, zoonotic spillover, vector surveillance, dengue, Japanese encephalitis, One Health, forest interfaces