Characterizing H7N9
Live market chickens have been implicated in the H7N9 outbreak. WIKIMEDIA, THEGREENJ
What scientists are learning about the zoonotic flu virus that has infected more than 100 people in China since February
By Kate Yandell
On March 31, Chinese Center for Disease Control and Prevention announced that scientists had isolated a novel influenza A virus from four patients in eastern China, three of whom had died. As of yesterday (April 25), the confirmed cases in China has risen to 108 including 22 deaths, according to the World Health Organization’s official count, and an additional person in Taiwan who had traveled from China has been diagnosed with the virus, identified as H7N9.
Virologists and epidemiologists worldwide have sprung into action trying to understand and control the outbreak. Chinese researchers have posted the viral sequence in an open-access repository and are sending samples of the live virus to labs around the globe for study.
Encouragingly, H7N9, which has never before infected humans, is not thought to spread readily between people. There have been some clusters of disease among closely related people, but it is unclear whether they resulted from shared exposure to the disease in animals, or very limited human-to-human transmission. Furthermore, the death rate may not be as high as it seems, as milder cases are more likely to go unreported.
But that’s where the good news ends. The virus appears to be more virulent than past H7 avian flu viruses in past outbreaks, which have caused conjunctivitis but have only been blamed for one death. Furthermore, this virus appears to be spreading from its hosts to humans unusually readily.
“The virus does appear to be more infectious for humans than other avian viruses in the past, including H5N1,” said virologist Richard Webby, who heads the WHO Collaborating Center for Studies on the Ecology of Influenza in Animals and Birds at St. Jude Children’s Research Hospital in Memphis, in an email to The Scientist. “In my mind, this does create some urgency.”
Keep reading: Characterizing H7N9 | The Scientist Magazine®.
