Objective To analyze clinical and epidemiological characteristics of two cases of H5N6 avian influenza infection in Dazhou City in July 2021, to identify the transmission routes, and assess the risk of H5N6 avian influenza virus spread, to provide a reference for control and prevention of avian influenza.
Methods Medical records of the H5N6-infected cases were collected in Dazhou City in July 2021, epidemiological investigations of their close contacts were conducted, and throat swabs from close contacts and dead poultry samples were collected for nucleic acid detection using real-time fluorescent RT-PCR.
Results Epidemiological investigations revealed that both cases had a history of poultry exposure. One patient had long-term poultry breeding and routine cleaning of poultry pens, while the other had selected ducklings at a live poultry market 6 and 9 days before symptom onset. Clinically, both patients developed fever and cough after poultry exposure, with H5N6 nucleic acid positivity detected in bronchoalveolar lavage fluid samples on day 10 and 15, respectively. Among 149 environmental samples collected from live poultry markets in H County and K County, 120 tested positive for influenza A virus, with positive rate of 80.54%.
Conclusion This study reports the first human H5N6 avian influenza cases in Dazhou City, both linked to poultry and poultry environment exposure. No human-to-human transmission was identified. Live poultry markets are high-risk areas for H5N6 transmission, highlighting the need for enhanced disinfection measures to prevent human infections.