Three more people in China were reported infected with a lesser known strain of bird flu, H7N9, bringing the total number of avian influenza cases to 21 since late March, Xinhua news agency reported on Monday.
So far, all the cases of H7N9 avian influenza, which have already claimed six lives, have been registered among people from provinces in east China and the Shanghai Municipality.
Authorities in Shanghai, which has 10 registered cases of H7N9 with four deaths, placed about 200 people who had contacts with the infected under medical examination. The authorities also ordered the slaughter of 98,000 poultry and incinerated them.
Last week, the Chinese Center for Disease Control and Prevention said there had been no cases of human-to-human transmission of H7N9.
According to the agency, China approved a new drug on Saturday believed to be effective in treating the H7N9 avian flu virus.