Malaysia was put on high alert, as 600 new cases of hand-foot-mouth disease were reported in the state of Sarawak on Borneo Island.
Deputy head of disaster relief George Chan Hong Nam said that 601 new cases have been reported in the last three days, bringing this year's total to more than 1,500 cases.
"The people should not take this lightly, as the consequences can be serious," Chan was quoted as saying by the Star daily.
Authorities last week ordered 488 kindergartens to be closed in an effort to contain the disease, which has already caused three deaths in the state.
However, Chan said that many parents continued to ignore the government's warnings to keep children from playing in large groups.
He urged parents and school authorities to remain vigilant against the disease, adding that the government would continue to conduct aggressive clean-up activities in the state to try to curb the spread of the disease.
Hand, foot and mouth disease (HFMD) is a viral infection common in children and results in fever, mouth sores and a blistering rash, usually on the hands and feet. It is unrelated to foot-and-mouth disease, which is a disease of cattle, sheep and swine.
Children are most susceptible to HFMD, but adults can also be affected.