A multispecies convergence zone: viral diversity and zoonotic spillover potential at Cambodia’s cross-border rodent trade hub

Live animal trade interfaces may increase opportunities for zoonotic pathogen exposure through multispecies aggregation and repeated human-animal contact, yet systematic multi-host surveillance remains limited. We investigated a cross-border rodent trade hub in Chrey Thom, Cambodia, where rodents from multiple provinces were consolidated for export to Vietnam. This multispecies convergence zone provided an opportunity to characterize viral diversity, detection frequency, and behavioural factors associated with spillover potential. From 2015 to 2018, we conducted repeated cross-sectional surveillance over four years among rodents, domestic animals, and humans using consensus polymerase chain reaction (PCR) assays targeting nine viral families. Zoonotic-exposure questionnaires were administered to community members and febrile hospital patients. We estimated detection frequencies by host group and described reported behaviours and exposure awareness. Among 2,618 specimens from 1,005 animals and 342 humans, 15.3% of specimens and 21.5% of individuals were positive, all among animals, with 12 distinct viruses identified. Rodents and poultry had the highest detection rates, at 34.7% and 33.9%, respectively. Coronaviruses predominated in rodents (34.4%), including an HKU1-like betacoronavirus. Rattus losea had 76.2% positivity, and Seoul virus was detected in the atypical host Rattus argentiventer . In poultry, PREDICT-CoV-100, infectious bronchitis virus, and Newcastle disease virus were detected; infectious bronchitis virus was molecularly documented in Cambodia for the first time. Influenza A(H5) was detected in ducks and A(H9) in chickens. No viruses were detected by PCR in humans. High-risk animal-contact behaviours were common in both participant groups, and only 10.7% recognized zoonotic transmission routes. Diverse viruses of zoonotic or veterinary relevance were detected in animals at this cross-border rodent trade hub. Frequent viral RNA detection in traded rodents and poultry, combined with common human-animal contact and limited awareness of zoonotic transmission routes, supports integrated One Health surveillance at wildlife trade interfaces. These data provide a rare pre-COVID baseline for assessing how evolving trade pathways may influence future interface-level spillover risk.