China officially confirmed the occurrence of humans infected with H7N9 late last month.
Since then, through Sunday, 102, people have been infected resulting in 20 deaths and 82 patients being treated in hospitals. Twelve people had been discharged from hospitals as of Saturday, leaving 70 still hospitalized, CNN reported.
Those affected are mostly in eastern China, with 33 cases and 11 deaths in Shanghai, 24 cases and three deaths in Jiangsu Province, 38 cases and five deaths in Zhejiang Province, and three cases and one death in Anhui Province. Beijing has reported one case and Henan Province has had three cases.
Officials are concerned the disease can pass from person to person, but there have been no signs of this happening, the official Xinhua news agency reported.
"Right now it is still an animal virus that rarely infects humans," said Dr. Michael O'Leary, the head of the WHO's office in Beijing.
The Chinese Center for Disease Control and Prevention said 40 percent of patients with H7N9 had not come into contact with poultry.
The government suspended the sale of wild birds Thursday to try to halt the spread of the virus.
Xinhua reported a large number of birds have been slaughtered.
O'Leary warned the mass killing of poultry was premature.