Poultry markets in China 'are vast bird flu reservoir'
Closing live poultry markets in China dramatically curtailed the spread of a novel strain of bird flu this year, according to an analysis.
The report, published in the Lancet, showed shutting the markets cut the number of new cases of H7N9 bird flu by 97%.
It said the future of the markets, a millennia-old culture in China, needed to be reassessed.
Experts said the markets can become a reservoir of viruses.
There have been 137 cases of H7N9 bird flu and 45 deaths, according to the World Health Organization.
However, most were in the months immediately after the virus was found to be moving from infecting animals to people.'Robust evidence'
Live poultry markets rapidly became linked with the outbreak. Nearly 800 markets were then shut across Shanghai, Hangzhou, Huzhou, and Nanjing.
It allowed scientists to analyse the role of the markets in the spread of the virus.
Dr Benjamin Cowling, one of the researchers at the University of Hong Kong, said: "Our findings confirm that live poultry market closure is a highly effective intervention to prevent human disease and protect public health.
End Quote Dr Benjamin Cowling University of Hong Kong
The H7N9 virus has continued to circulate and now has the potential to re-emerge in a new outbreak of human disease this winter”
"Without this robust evidence, policymakers would struggle to justify further closures of live poultry markets because of the millennia-old culture of trading live birds and the potential huge economic loss on the poultry industry in China."
The Lancet report said the markets should be "rapidly" closed in areas where the bird flu emerged and that discussions on the role of the markets "should be renewed".
Guillaume Fournie and Dirk Pfeiffer, of the Royal Veterinary College in the UK, said: "If birds spend a sufficient amount of time in live poultry markets to become infected and transmit the virus to other susceptible birds, sustained virus circulation in the live poultry markets can occur.
"Live poultry markets can then become a permanent source of infection for poultry flocks and for people who are in loose contact with infected poultry."
Two cases of H7N9 bird flu have been reported in October.
Dr Cowling said: "These are the first laboratory-confirmed cases of H7N9 this autumn, five months after the outbreak earlier in 2013.
"This is of great concern because it reveals that the H7N9 virus has continued to circulate and now has the potential to re-emerge in a new outbreak of human disease this winter."