Several conclusions can be drawn from this study. First, prevalence in the migratory waterfowl that visit the Lake is extremely low (1.7%), which suggests that AIV might not be maintained in birds at the lake ecosystem. Second, Farm-1 is a contaminated area, but the transmission within the flock appears to be at a minimum level as shown by the low prevalence at the site compared to that in the markets (rRT-PCR: 4.2% vs. 23.0%; Table 2 ). Third, although environmental samples collected near the birds (e.g., cockatiels, parrots, munia, quail) at pet bird markets tested positive for infection, only two samples were influenza A and the rest were subtyped as NDV. The 2 influenza-positive samples were subtyped as H9N2 and were collected from quail feces during the same visit to the pet bird market. Thus, the role of pet bird markets in perpetuating and spreading AIV remains unclear. Lastly, AIV is circulating in the 3 retail markets that were sampled in Dhaka. Chickens are the primary birds at these markets, but influenza has also been isolated from the ducks at all 3 locations. Therefore, there exists the possibility of interspecies transmission of influenza and an increased probability of reassortment between various lineages and subtypes. In fact, others have postulated that live bird markets are the ideal environment for influenza transmission because of the high density and variety of hosts within a localized area [19, 29, 30] . Indeed, reassortment of H9-subtype viruses in bird markets has been previously reported [18, 19, 20] .