Beijing - An outbreak of intestinal virus in eastern China has claimed the lives of at least 21 children and the number of reported cases has risen to nearly 2,500, the official Xinhua News Agency said Friday.

Xinhua said all those suffering from Enterovirus 71 were under age 6 and most were under age 2. The outbreak was first reported in March in Fuyang, a city in the eastern province of Anhui.

The report gave no details on the latest death from the virus, which causes fever, mouth sores and a rash with blisters.

Xinhua quoted Gao Kaiyan, director of the Anhui provincial health department, as saying the total number of infected children stood at 2,477.

It said about 700 children are hospitalized, 36 of them in serious condition, and just over 1,000 are being treated as outpatients. Some 740 youngsters have recovered, Xinhua said.

Some of the children have been diagnosed with brain, heart and lung damage, the report said.

The number of cases has steadily increased, the Anhui Health Bureau's Web site said earlier this week. An official investigation into the cause of the outbreak is under way, along with a prevention and control effort to contain infected areas, the bureau said.

The World Health Organization said Thursday that experts predict the virus will continue to spread in coming months, with a peak in June or July.

The WHO said there is no specific anti-viral therapy, adding that "in certain situations, it may be advisable to close child-care facilities and schools to reduce the intensity of transmission."

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.