The re-emergence and spread of the H7N9 influenza virus in eastern and southern China has been traced through poultry trade routes in a genetic analysis by Chinese, US and Australian researchers.
The scientists say that unless control measures, such as permanent closure of live poultry markets, are put in place, the virus could persist and spread beyond the region.
A study in the journal Nature says the virus has persisted and diversified in chickens and spread across China.
The second wave of the H7N9 outbreak which began in late 2013 has resulted in at least 318 human cases and more than 100 deaths, more than twice that of the first wave.
Yi Guan of the University of Hong Kong, Professor Edward Holmes of the University of Sydney and colleagues monitored the evolution and spread of H7N9 over 15 cities across 5 provinces.
They identified a large number of new genetic variants which have become established in chickens and have spread across the country, most likely due to poultry movement along trade routes.
The researcher propose that control measures such as permanent closure of live poultry markets, central slaughtering and preventing inter-regional poultry transportation during disease outbreaks, are needed to reduce the threat of H7N9.
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