What is H7N9?
Since 2013, H7N9 virus infection has been found in birds and people in China. While the H7N9 virus continues to spread in poultry with sporadic human infections, no ongoing person-to-person spread of this virus has been found at this time. Here are some common questions and answers about H7N9 virus.
"H7N9" is a subtype of influenza A viruses that is sometimes found in birds, but that does not usually infect humans. Like all influenza A viruses, there are many different strains of H7N9 virus. Many H7 virus have circulated in poultry for centuries. Beginning at the end of March 2013, China reported the first known cases of zoonotic infections with a new strain of H7N9 virus that was very different from previously known H7N9 viruses. The virus was found to be circulating in poultry in the area. Since 2013, H7N9 viruses have continued to cause infections of poultry in China, with associated annual increases in the number of human infections with H7N9 viruses during the fall, winter, and spring months. China is currently experiencing its 5th epidemic of human infections with H7N9 virus during 2016-2017. Most human cases of H7N9 virus infection have been reported from eastern China (south to north), but cases also have been reported from northwestern China. Human cases of H7N9 virus infection acquired in China also have been identified in Taiwan, Malaysia and Canada.