The World Health Organisation (WHO) has warned that a virus that has killed 24 young children and infected more than 5,000 could continue to spread regardless of efforts to contain it.
The Enterovirus 71 (EV-71) causes a severe strain of hand, foot and mouth disease, and experts say it usually reaches its peak outbreak rate in June and July - they are concerned that the infection rate could soar as the weather becomes warmer.
On a daily basis hundreds more cases are emerging despite China's health authorities increased efforts to contain the spread of the virus which has now emerged in Henan, Hubei, Shaanxi, Zhejiang, Jiangxi and Guangdong provinces, as well as Hong Kong and Macao.
Twelve children remain in a critical condition and more than 600 are still in hospital, some with brain damage and heart and lung problems.
The centre of the outbreak is in Fuyang, in the eastern province of Anhui, where 22 of the deaths occurred; nurseries and schools have been closed and workers have sprayed disinfectant around houses in the affected areas.
A nationwide alert launched on the weekend has called for greater efforts to control the spread of all infectious diseases including hepatitis A and measles, as well as EV-71, particularly with the upcoming Beijing Olympics and Paralympics.
The WHO says the virus does not currently present a threat to the Olympics or any other events.
Nevertheless EV-71 can be fatal with serious forms of the illness causing complications including meningitis and heart problems.
It is usually a common illness among infants and children and not usually fatal; it causes is fever, sores in the mouth and a rash with blisters and there is no vaccine or cure for it.
All of those affected so far have been under six years of age with most under two.
Two more children died on the weekend in Guangdong province, 1,000 miles south of Anhui and the WHO says in those cases the virus had probably come from different sources rather than spread, as had small outbreaks reported in Shaanxi and Hubei.
These latest deaths had been difficult to diagnose, as the children had died from respiratory complications and did not show the normal symptoms, causing a delay in diagnosis.
The WHO says it is important for the health ministry to alert the public about such outbreaks early on; the Chinese media have accused the authorities of a cover-up reminiscent of the SARS outbreak.
The health ministry has now warned that anyone covering-up or delaying disclosure of outbreaks faces punishment and requires hospitals to report the disease within 24 hours.
Local health departments have also been told to publicize emergency information and the epidemic situation.
Authorities say special equipment is being installed in children's wards and at a local level checks on food and water safety are being increased to stop the disease from spreading.
The WHO acknowledges that since a rapid response from the government the "extraordinarily high" fatality rate of 11% in March was now down to about 0.2%.
The virus EV-71 first appeared in the 1960s but in the last decade several large outbreaks have occurred across Asia.