Seroprevalence of Dengue, Zika, and Chikungunya in Humans and Macaques in SE Asia

Overview

This study assessed antibody prevalence against dengue, Zika, and chikungunya viruses in humans and nearby macaques in Thailand and Cambodia. Humans showed significantly higher seropositivity rates (38.5%–74.4%) compared to macaques (0%–8.0%), suggesting limited macaque involvement in urban arboviral transmission cycles.

Background

Arboviruses transmitted by Aedes mosquitoes, including dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV), cause substantial disease burdens in Southeast Asia. While these viruses maintain urban transmission cycles primarily via human-mosquito-human interactions, the role of sylvatic reservoirs such as macaques remains unclear. Nonhuman primates can act as reservoirs or amplification hosts for arboviruses, but data on their involvement in periurban transmission are limited. Understanding human and macaque seroprevalence can clarify potential spillover or spillback dynamics at the human-animal interface.

Data Highlights

Key Findings

• Human seropositivity rates for DENV, ZIKV, and CHIKV ranged from 38.5% to 74.4% across study sites.
• Macaques living in close proximity to humans showed low seropositivity rates (0%–8.0%) for these arboviruses.
• Seroprevalence differed between Thai and Cambodian cohorts, indicating geographic variability.
• Age was the only significant predictor of human seropositivity in multivariate analyses.
• Low macaque seropositivity suggests limited role in sustaining or amplifying urban arboviral transmission cycles.
• Detected macaque antibodies may reflect spillback infections from humans rather than primary sylvatic reservoirs.

Clinical Implications

These findings highlight that human populations remain the primary reservoirs for dengue, Zika, and chikungunya viruses in Southeast Asia, with macaques playing a minimal role in urban transmission. Surveillance and control efforts should continue focusing on human-mosquito-human cycles. However, monitoring sylvatic populations remains important to detect potential spillback events and emergence of novel viral variants.

Conclusion

The study demonstrates significantly higher arboviral antibody prevalence in humans compared to nearby macaques, supporting a limited role for macaques in urban transmission cycles. Continued investigation of human-animal interfaces is essential to understand arboviral ecology and inform public health strategies.

References

1. Original Study 2019-2022 -- Prevalence of Antibodies Against Dengue, Zika, and Chikungunya Viruses in Humans and Nearby Macaques in Thailand and Cambodia