Hosts were considered positive for infection if at least one of the host samples, i.e., oropharyngeal or cloacal swabs, tested positive by virus isolation or rRT-PCR ( Table 2 ). The prevalence of influenza in hosts varied across the sampling sites, and analyses of prevalence revealed that differences exist across the sites for both virus isolation and rRT-PCR detection methods (p#0.0001 and p#0.00001, respectively). A significant difference in prevalence across the sites was also detected for the environmental samples (feces, fecal digestors, water, and water troughs) and when all samples, regardless of type, were tested by both detection methods (p#0.00001 for all comparisons). In Dhaka, the overall prevalence varied by site, but this difference was mostly due to low prevalence at the Pet bird market, Farm-1, and the Lake. That is, prevalence was approximately equal at the markets ( Table 2 ). Weighted average of prevalence for the markets in Dhaka was 47.3% and 23.0% for samples tested by virus isolation and rRT-PCR, respectively.