Health bureaus around the country must step up monitoring for hand, foot and mouth disease following a "relatively large" outbreak in the central city of Fuyang, the Health Ministry said in notices on its Web site.
The ministry warned that cases were more numerous this year than in recent years, and the peak for transmission would likely come in June and July.
The outbreak is another concern for China's communist government as it gears up to welcome hundreds of thousands of foreigners for this summer's Beijing Olympics. It's also an uncomfortable reminder of the SARS pneumonia outbreak in 2003, which Beijing tried to cover up but then adopted drastic measures to control.
Saturday's warning was prompted by a jump in cases in Fuyang of Enterovirus 71, or EV-71, a type of hand, foot and mouth disease.
Up to Thursday night, 3,321 cases of EV-71 were reported in Fuyang, a fast-growing city in largely rural Anhui province. Besides the 22 deaths, 978 people remain hospitalized, 58 of them in serious or critical condition, the ministry said in a separate statement.
The state-run Xinhua News Agency also reported that preliminary tests showed an 18-month-old boy who died Friday in southeastern Guangdong province was infected with EV-71, and a second suspected death was under investigation. Cases of hand, foot and mouth outbreaks, but not necessarily EV-71, have been reported in at least two other provinces.
"Health bureaus at all levels must recognize the importance and urgency of preventing the spread of infectious diseases," the ministry said in its nationwide order.
Enterovirus 71 is one of several viruses that cause hand, foot and mouth disease, which is characterized by fever, mouth sores and a rash with blisters. It is spread by direct contact with nose and throat discharges, saliva, fluid from blisters, or the stool of infected persons.
The illness mainly strikes children young than 10 and is not related to foot and mouth disease, which infects cattle, sheep and swine.
The nationwide order said preventing the spread of infectious diseases was necessary "to guarantee the smooth staging of the Beijing Olympics and Paralympics and to practically preserve social stability."