H7N9 Influenza Virus Spreading Across China
Second outbreak, with 318 human infections and 100 deaths, twice as big as first outbreak
THURSDAY, March 12, 2015 (HealthDay News) -- Avian flu (H7N9 influenza) is gaining strength in China and has the potential to emerge as a life-threatening virus for humans across the globe, a new report suggests. The study was published in the March 11 issue of Nature.
H7N9 influenza first appeared in eastern China in March 2013 when the virus spread to humans from infected poultry, according to the U.S. Centers for Disease Control and Prevention. A second wave of the H7N9 outbreak that began in late 2013 has resulted in at least 318 human infections and more than 100 deaths -- more than twice that of the first wave, the study authors noted.
Yi Guan, from the University of Hong Kong, and colleagues monitored the evolution and spread of H7N9 over 15 cities across five provinces in China. The researchers identified a large number of new genetic variants that have become established in chickens, and tracked the march of those viral mutations across the country as chickens were sold and transported.
"With the recent reports of H7N9 infections in Xinjiang in the far northwest of China, it is probable that the H7N9 virus is now present across most of China," the study authors write. "As this virus does not cause obvious symptoms in chickens and only limited surveillance has been conducted, the prevalence of this virus is likely to be higher than we document here," they added. The study authors propose measures that can be taken to slow or halt the spread of the avian flu. These include permanently closing all live poultry markets, halting the transportation of poultry between regions during a disease outbreak, and shutting down large poultry slaughtering plants.