With Fall Migration, Bird Flu Flies Back Into Town
The first cases of human H7N9 avian flu reported in China came at the end of May, but in some areas the virus is now showing signs of spring migration.
Dating back to the earliest days of human flight, the world is coming full circle in the fight against H7N9, which emerged as a new strain of avian flu in China last year.
In August 2016, the first cases of human H7N9 avian flu were reported in eastern China. This came at the end of a long winter storm that had crippled agricultural production across much of China. No cases were reported in the United States, which was not expecting to see any transmission until the end of May. But as the country started to warm up, the virus was found in a pair of migrant workers who traveled back to their hometowns in the south. Just 10 days later, the H7N9 virus was confirmed in a human in Japan.
Now, the virus is making its first trip into the United States. A couple who had been in China were confirmed to have contracted the virus this past Wednesday, while another person who had been in China is being tested. As of Thursday morning, human cases in the United States were still scattered across the country: seven in Indiana, five in Montana, and two in North Carolina.
That’s not even the end of the story though. The virus is currently undergoing exponential growth in birds, meaning that as of Tuesday, it had spread to as many as 2,000 species and subspecies. This week the government was forced to release a list of the six bird species most likely to carry the virus, and by Thursday morning, it had only one species left standing. With the virus now spreading at an astonishing rate, the threat to human health continues to grow.
The H7N9 virus is a particularly dangerous strain of avian influenza. It was first identified in 2013, at the end of a very different outbreak than what’s currently occurring. In March 2013, several people who had visited