Health Officials Warily Watch Chinese Bird Flu Outbreak

New strain emerges

Federal health officials are already working on seed strains of China's new bird flu so they can make vaccines quickly should they be necessary.

The move is in response to a new strain of bird flu that has emerged in China in the last two months. It has already killed six of the 16 people who've gotten it, a 37% mortality rate that keeps public health officials up at night. All the known victims got sick between February 19 and March 31, said Thomas Frieden, director of the Centers for Disease Control and Prevention. The strain, named H7N9, appears to be transmitted from poultry.

This week Chinese officials began slaughtering more than 20,000 birds in a Shanghai poultry market to help stop the spread of the strain, which has been found in four provinces along China's eastern seaboard. The United States has not issued any travel advisories for China, but for a decade has advised Americans traveling to China to avoid contact with birds and other animals.