H7N9 Avian Flu

About H7N9 Avian Flu

H7N9 avian influenza emerged in eastern China in March 2013. Unlike H5N1, H7N9 causes little or no illness in birds, making it harder to detect through visual surveillance. The virus infected about 1,568 people with a case fatality rate of approximately 39 percent. Most cases were linked to exposure to live poultry markets. H7N9 raised particular concern because it had acquired mutations associated with mammalian adaptation. Some isolates showed resistance to the antiviral oseltamivir. Seasonal H7N9 waves occurred annually from 2013 to 2017, primarily in winter and spring. China developed an H7N9 vaccine candidate virus. The closure of live poultry markets in major cities significantly reduced cases. By 2018, H7N9 cases had declined dramatically following poultry vaccination campaigns in China. The virus continues to circulate at low levels. H7N9 is considered a high threat for pandemic potential due to its high mortality rate and ability to infect humans without causing severe disease in birds.