Traders who might promote conditions favorable for sustaining HPAIV H5N1 in LBMs (20) were predominant in 13 of the
Hanoi LBMs included in the survey (solid triangle in Fig. 1). In contrast, traders operating in the Hanoi hub, and all traders
operating in Bac Giang markets, kept their poultry in LBMs for only a short period, so virus maintenance was unlikely (20).