A new kind of bird flu that has killed 43 people in China shows potential in the lab for sparking a global outbreak, according to a study by UW-Madison researcher Yoshihiro Kawaoka.
“We don’t know how many more changes are needed for this virus to cause a pandemic,” said Kawaoka, a flu expert whose findings were published Wednesday in the journal Nature.
Kawaoka studied two samples of the H7N9 flu virus from patients in China, where the strain has infected at least 133 people since March and killed 43, according to the World Health Organization.
The research found that H7N9 can infect monkeys and ferrets, and replicate in both kinds of animals. In monkeys, the virus infected cells in the upper and lower respiratory tracts — a cause for concern because most human flu viruses infect only the upper airway.
“This virus has the potential to cause severe disease,” Kawaoka said.
In addition, one of the H7N9 samples was spread through the air among ferrets, whose response to the flu is thought to mimic that of humans. Most bird flu viruses — including the H5N1 bird flu that has worried health officials for years — don’t do that.
For that reason, Kawaoka said, the H7N9 virus appears to pose more of a pandemic threat than the H5N1 virus.
Another complicating factor with H7N9 is that it doesn’t kill poultry, making it hard to track transmission among birds, Kawaoka said. But his study produced some good news: The H7N9 strains were somewhat sensitive to drugs used for seasonal flu.
Kawaoka’s study of the H7N9 virus, which isn’t known to have infected people outside of China, is one of several developments in his flu research.
He continues to wait for the federal government’s approval to resume studies on an altered H5N1 virus he created, which spreads among ferrets in the lab.
International concern about the potential for the virus — and a similar one created by another scientist in the Netherlands — to escape from the lab or be used for bioterrorism led to a moratorium on the research in January 2012.
Kawaoka did the altered H5N1 work at UW-Madison’s Institute for Influenza Virus Research at University Research Park. The lab is classified as Biosafety Level 3-Agriculture, the highest biosafety level at the university and half a notch below the top level anywhere of BSL4.
Kawaoka is leading a new study, funded by an $18.1 million grant from the National Institutes of Health, to analyze how animals respond to the flu, the Ebola virus and West Nile virus. He will do some of the flu and Ebola work at his Madison lab. The research could lead to the development of new drugs.
An experimental flu vaccine developed by FluGen, a Madison company co-founded by Kawaoka, could enter clinical trials next year. The vaccine, Redee Flu, is designed to protect against more strains of flu than existing vaccines.