Live poultry markets (LPMs) are a recognized source of influenza viruses. Since 2001 and 2003,
respectively, a first and second monthly “rest-day” has been implemented in Hong Kong’s LPMs, when
stalls are cleared of unsold poultry and disinfected. We assessed the incremental effectiveness of
each rest-day and the banning of live quail sales in 2002 in reducing influenza A H9N2 subtype
isolation rates for chickens and minor poultry, by using a multivariable Poisson generalized linear
model. There was a 58% reduction (p = 0.001) in virus isolation after 1 monthly rest-day in minor
poultry compared with 27% (p = 0.22) in chickens. Combining 1 rest-day with the removal of quails
further reduced virus isolation in chickens but not in minor poultry. However, an additional rest-day
each month did not appear to affect isolation rates for either species.

Effect of Interventions on Influenza A (H9N2) Isolation in Hong Kong’s Live Poultry Markets, 1999–2005.pdf