Epidemiological characterization of avian influenza virus circulation in pigeons and quail across different production systems in Chattogram, Bangladesh

Pigeons and quail contribute to poultry production, nutrition, and livelihoods in Bangladesh; however, their role in avian influenza virus (AIV) circulation remains poorly understood. These poultry species are widely reared and traded alongside chickens and ducks in household farms, commercial systems, and live bird markets, where inadequate biosecurity may create an overlooked ecological niche for AIV circulation, reassortment, and potential zoonotic spillover. Between November 2021 and April 2022, we conducted a cross-sectional study in Chattogram, Bangladesh, to estimate the prevalence and subtype-specific distribution of AIV and to identify factors associated with AIV positivity in pigeons and quail. A total of 300 birds (108 pigeons and 192 quail) were sampled from households, commercial farms, and live bird markets. Oropharyngeal and cloacal swabs were collected from each bird and tested for the AIV matrix gene using real-time reverse transcription polymerase chain reaction, followed by subtype-specific detection of H5, H7, and H9. Data collected from bird owners and traders included bird demographic characteristics, bird source, and health status using a structured questionnaire. The overall prevalence of AIV was 14.3% (95% confidence interval [CI]: 10.6-18.8). Quail had a higher prevalence (18.2%, 95% CI: 13.0-24.4) than pigeons (7.4%, 95% CI: 3.3-14.1). Among detected subtypes, H9 was most prevalent (11.3%, 95% CI: 7.9-15.4), followed by hemagglutinin (HA)-untyped (2.7%, 95% CI: 1.2-5.1) and H5 (0.3%, 95% CI: 0.001-1.8), while H7 was not detected. Quail had higher odds of AIV positivity than pigeons (adjusted odds ratio [aOR] = 4.1, 95% CI: 1.8-10.6); clinically sick birds (aOR = 2.9, 95% CI: 1.4-6.2) and birds sampled from household farms (aOR = 2.8, 95% CI: 1.2-6.5) also had higher odds of AIV positivity. These findings indicate that pigeons and quails, which are understudied poultry species, may contribute to the maintenance and transmission of AIV within mixed poultry production and marketing systems in Bangladesh. Integrating these species into routine AIV surveillance is therefore necessary to strengthen early detection, inform control strategies, and reduce the risk of zoonotic spillover.