Evaluating sampling strategies for the detection of avian influenza viruses in the environment

Highly pathogenic avian influenza (HPAI) viruses threaten humans, livestock and wildlife, highlighting the urgent need for early warning surveillance. Environmental RNA (eRNA) monitoring provides a safer, cost-effective and non-invasive alternative to direct pathogen testing, yet the effectiveness of different sample types for avian influenza viruses (AIVs) is unclear. We evaluated four eRNA-based sampling methods in urban waterfowl ponds over approximately one year. All methods combined with RT-qPCR and metagenomic sequencing detected AIV, but detections were asynchronous, likely reflecting low viral concentrations or detection limits. These results highlight both the promise and the current limitations of eRNA-based AIV surveillance.