After a spate of deaths from bird flu among patients in China, the World Health Organization has warned all countries to watch for outbreaks in poultry flocks and to promptly report any human cases.
Several strains of avian flu are spreading in Europe and Asia this winter, but the most worrisome at present is an H7N9 strain that has circulated in China every winter since 2013.
China has reported over 225 human cases since September, an unusually high number. The nation' Lunar New Year vacation starts soon, and as it does, live poultry shipments increase, and holiday travelers often spread the flu.
The fatality rate is not yet known, because some victims are still hospitalized. But Dr. Margaret Chan, the health organization' director general, said this week that China had had more than 1,000 cases in the last four years, of which 39 percent were fatal.