The official Xinhua news agency reports that a virus, known as Enterovirus 71, has been responsible for the disease outbreak in the Anhui province city of Fuyang.
Xinhua said the first cases emerged in early March, leading to accusations by the Chinese press of a cover-up by local authorities.
The Shanghai Daily reports that critics say the delay contributed to panic and wasted time that could have been used toward treating the disease.
While Enterovirus infections occur worldwide, the World Health Organization said it was especially concerned about the Chinese outbreak because of the unusually high number of fatalities.
Enterovirus 71, or EV71, can cause a disease that usually starts with a slight fever followed by blisters and ulcers in the mouth and on the hands and feet.
It may cause high fever, meningitis, encephalitis, pulmonary edema and paralysis in a small number of children. Health officials say paralysis is more common in children under two years and meningitis is more common in children between 2 and 5 years of age.
EV71 was first identified in 1974, and there is still not an effective vaccine to prevent the disease, or any available antiviral treatments to help those infected. The virus is spread through contact with infected blisters or feces.
Photo: China Ministry of Health