Technicians wearing protective suits begin to kill poultry at Huhuai poultry wholesale market last week in Shanghai, China, where the new H7N9 bird flu virus was first detected in pigeons.
Eight people have already died and 20 others have been infected with H7N9, all of them in eastern China, according to ABC News.
Nancy Cox, head of the U.S. Centers for Disease Control and Prevention's influenza division, told ABC News that her agency is working on a vaccine that uses the virus's genetic code rather than the virus itself—a first for the CDC.
"Nobody knows, and at this point nobody can know, because influenza viruses are inherently so unpredictable. They mutate continually. Their eight major gene segments snap apart, like Poppit beads, and reconnect with segments from other flu viruses," he wrote.
Photograph from Reuters
Among fears of bird flu, a woman wears a face mask inside a subway station in Shanghai.
Even so, Cox said she expects to see limited person-to-person transmission.
Photograph by Carlos Barria, Reuters
A Chinese boy gets flu treatment at a hospital in Hefei, China.
So far there haven't been any cases of the virus jumping from person to person.
Photograph from AFP/Getty Images
Passing the Time
Vendors play chess beside birds at a poultry market in Wuhan, Hubei Province, on Sunday. The market closed live poultry trading on Monday amid concerns about bird flu.
Traces of the H7N9 virus have been found in pigeons, chickens, and quail, all available at live markets in Shanghai and other Chinese cities, and officials have ordered mass cullings and market closures, according to Quammen.