An emerging bird flu that is mysterious and deadly is haunting China. With four fresh H7N9 cases reported in Jiangsu Province and no indication as to how three Chinese adults caught the little-noted avian flu virus that killed two of them in March, the global medical community is hoping the new flu will calm down until China’s health system can determine how it spread.
“I can tell you this thing is real and definitely has the markings of being a killer,” says Jason Tetro, coordinator of the Emerging Pathogens Research Centre in Ottawa, which on Monday examined gene sequences from three of China’s H7N9 cases.
“I don’t wish to cause panic,” Tetro said in an interview, noting that if the subtype were proven to have emerged from a small farm, he wouldn’t be much alarmed. Infecting a big poultry reservoir, on the other hand, might well enable H7N9 to access Asia’s wild bird population. The upstart subtype could then become as menacing as H5N1, which since 2005 has officially taken 371 lives in 622 cases, mostly in China, Southeast Asia and Egypt, according to the World Health Organization. The additional Chinese cases have convinced Tetro that “close contact with birds” has been involved. “And I think the CAFOs [industrial chicken farms] have definitely contributed to the evolution of this virus,” he says.
Already, “the internal genes of H7N9 are very close to those of H5N1,” says Mike Coston, a widely read American flu blogger, in an interview. (Coston’s Avian Flu Diary noted on March 14 that a paper in the U.S. Centers for Disease Control’s Emerging Infectious Disease Journal had identified the Shanghai area as one well suited to breed a new genetic subtype of influenza.)
In a development unwelcome to Chinese authorities, many Chinese microbloggers are associating the H7N9 deaths with the still-unexplained swine carcasses that last month floated down the Huangpu River, which provides Shanghai’s drinking water. (Local health officials announced on Monday that the dead pigs contained no bird flu virus.)