The European Centre for Disease Control and Prevention said on Tuesday that avian influenza A H7N9 reports in China have risen to a total of 251 cases.
Most H7N9 cases resulted in severe respiratory disease, and 56 patients have died from the influenza strain in China. The ECDC said final outcomes are not always reported after the initial notification.
The ECDC said that 116 cases have been recorded since October from nine Chinese provinces and Taiwan. In response, the ECDC updated its Rapid Risk Assessment on human infections of influenza A H7N9.
Ocasional human-to-human transmission of the virus could not be ruled out by the ECDC, but there is not an indication that it is sustained. The increase in cases may be a factor of the increased number of exposed people, enhanced transmissibility of the virus and a seasonal transmission pattern.
The ECDC said the most likely culprit of increased infection is a zoonotic avian influenza that is circulating among poultry in south-eastern China. The virus presents a pandemic threat to humans.
The persistence of the virus in poultry shows a long-term threat as a zoonosis or pandemic virus. The Rapid Risk Assessment recommended that preporations be made to respond to both possibilities.