Prevalence of avian influenza (H9N2) in commercial quail, partridge, and turkey farms in Iran, 2014-2015.

Avian influenza virus (AIV) H9N2 subtype is endemic in Iran and causes substantial economic loss to the growing poultry industry within the country. In this study, a cross-sectional analysis was carried out to determine the sero-prevalence of H9N2 in several commercial farms between the years 2014 and 2015. The comparison of the mean of serum titers and the ratio of sero-positive birds between all units were analyzed using one-way ANOVA test. In 2014, a total of 77 farms (58 turkey farms, 14 quail farms, and 5 partridge farms) and 894 birds (682 turkeys, 154 quails, and 58 partridges) were sampled while in 2015, a total of 69 farms (54 turkey farms, 8 quail farms, and 7 partridge farms) and 856 birds (675 turkeys, 105 quails, and 76 partridges) were sampled. Of that, 52 of 77 sampled farms (67.5%) and 437 of 894 samples (48.9%) were positive for H9N2 in 2014 while. Forty-one of 69 farms (59.4%) and 307 of 856 sera (35.9%) were positive in 2015. Furthermore, the mean titer of partridge farms was significantly lower than that of turkey farms (p < 0.01) and the mean percentage of sero-positive turkey farms was significantly higher than partridge farms (p < 0.01) in 2014. In 2015, no significant difference was observed between the mean sera titer amongst farms and percentage of sero-positive birds (p > 0.05). Our results indicated that H9N2 is circulating in these farms. Since many more such farms are being established for operations, in addition to the threat of emergence and continuous reemergence of the disease in these farms, enhanced veterinary biosecurity measures on farms are required for mitigation.