Surveillance for Asiatic filoviruses and zoonotic paramyxoviruses at a perceived wildlife-human interface

Emerging zoonotic viruses pose a global health threat. In Thailand, evaluating human-wildlife interfaces is critical for identifying potential zoonotic virus spillover, particularly in areas with high-risk contact with roosting bats. We conducted cross-sectional sampling of humans (n = 234) and bats (n = 272) at a cave site in central Thailand where guano farmers, national park workers, and cave visitors may be exposed to bat-borne viruses. Molecular and multiplex serologic methods were used to identify current and previous infections with zoonotic paramyxoviruses and filoviruses, while multivariable regression was used to identify human behavioral correlates of seroreactivity. We detected serological evidence of orthoebolaviruses in two cave-roosting bat species, Mops plicatus and Hipposideros larvatus, and evidence of exposure to small terrestrial mammal-borne parahenipaviruses in humans. Individuals working in the extractive industry were more likely to be seroreactive to parahenipaviruses, including Gamak virus (OR = 3.41, 95% CI: 1.39-8.57, P < 0.001). Parahenipaviruses have been detected in shrews in eastern China and South Korea; therefore, we used ecological niche modeling of Crocidura shrews to predict the potential host range of novel parahenipaviruses in Thailand. Four Crocidura species were predicted to occur in the study province. This study provides the first evidence of Asiatic filoviruses in bats in Thailand and human exposure to parahenipaviruses in Southeast Asia. These findings underscore the importance of zoonotic disease surveillance and support expanding sampling across animal species and serial time points to maximize detection of emerging zoonotic viruses and improve understanding of transmission dynamics at high-risk human-wildlife interfaces across ecological settings throughout Thailand and Southeast Asia.