A dangerous strain of bird flu that has been circulating in 2013 could be on the verge of snowballing into a global pandemic.
The Paris-based Organization for Animal Health said Wednesday that a farm in Shaanxi province has reported an outbreak of a highly dangerous pathogen, while a separate farm in Guangxi province has reported an outbreak of H5N6, another dangerous strain of bird flu.
The H5N6 virus killed 23,950 ducks out of a flock of 30,462 ducks, according to the Chinese Ministry of Agriculture. The remaining birds were all slaughtered..
In Shaanxi, the H7N9 virus killed 810 layers out of a flock of 1,000 birds.
Last year, the number of bird flu cases in China spiked as the annual outbreak was much worse than normal. It also saw the virus split into two distinct strains that are so different, they no longer respond to the same vaccines, according a Reuters report from late last year. H7N9 is becoming increasingly pathogenic, meaning it possesses the capacity to kill infected birds.
According to the South China Morning Post, Yoshihiro Kawaoka of the University of Wisconsin and a colleagues tested a version of the new H7N9 strain taken from a person who died from their infection last spring. They found that the virus replicated efficiently in mice, ferrets and non-human primates, and that it caused even more severe disease in mice and ferrets than a low pathogenic version of the same virus that does not cause illness in birds.
But perhaps the most disturbing aspect of the virus is its ability to spread easily from cage to cage. When placed in cages adjacent to healthy ferrets, the virus will spread easily from infected animals and health animals, suggesting the virus can be transmitted by respiratory droplets such as those produced by coughing and sneezing.
As one expert pointed out, "the work is very concerning in terms of the implications for what H7N9 might do in the days ahead in terms of human infection," said Michael Osterholm, an infectious disease expert from the University of Minnesota.
Since 2013, the H7N9 bird flu virus has sickened at least 1,562 people in China and killed at least 612. Some 40 percent of people hospitalized with the virus die.
And the number dying during each epidemic has increased dramatically in recent months.
In the first four epidemics, the virus showed few changes. But last flu season, there were some 764 cases - nearly half of the 1,562 total.
Which is why a new risk assessment tool from the U.S. Centers for Disease Control and Prevention ranks H7N9 as the leading animal flu strain with the potential of causing a human pandemic.