A mass intestinal virus infection in Fuyang City in east China's Anhui Province has hit 2,477 children and killed 20 others, a provincial government spokesman said on Thursday.

Among the infected, 738 had been cured. The death toll had been steady at 20 for four days. Another 702, including 36 seriously ill, were still in hospital and under observation. The outpatients numbered 1,017, the spokesman said.

Hospitals in Fuyang started to take in children with fever, blisters, mouth ulcers and rashes on their hands and feet in early March. Some were diagnosed with brain, heart and lung damage.

All were aged below six, of whom the majority being under two.

In a bid to stop the virus spreading to more children, all kindergartens in Fuyang City began the May Day holidays two days early.

There are about 400,000 children below the age of five in Fuyang.

Enterovirus 71 can cause hand, foot and mouth disease that usually starts with a slight fever followed by blisters and ulcers in the mouth and rashes on hands and feet.

It may also cause high fever, meningitis, encephalitis, pulmonary edema and paralysis in a small number of children.

Infection could lead to high mortalities rates in serious cases and no vaccine was available.