A surge in the number of hand, foot, and mouth disease (HFMD) cases among school-aged children in Malaysia's northern Borneo state of Sabah has forced the temporary closure of five schools, according to health authorities.

More than 4,300 HFMD cases were reported between January to April, with nearly 83 per cent involving children under the age of seven, the Sabah Health Department said in a recent statement.

Sabah Health Director Maria Suleiman, a health crisis expert, said the closures were a precautionary measure to allow for thorough cleaning and disinfection of affected premises to break the chain of infection, Xinhua news agency reported.

"All reported cases have been mild and treated as outpatients. There have been no ICU admissions or deaths," she said, adding that parents have been urged to keep symptomatic children at home and maintain good hygiene by regularly disinfecting commonly used items.

Hand-foot-and-mouth disease is a mild, contagious viral infection common in young children. Symptoms include sores in the mouth and a rash on the hands and feet. Hand-foot-and-mouth disease is most commonly caused by a coxsackievirus.

There's no specific treatment for hand-foot-and-mouth disease. Frequent hand-washing and avoiding close contact with people who have hand-foot-and-mouth disease may help lower your child's risk of infection.

Hand-foot-and-mouth disease often causes a rash of painful, blister-like lesions on the palms of the hands. Rashes appear differently depending on skin tone.

The usual period from initial infection to the time symptoms appear (incubation period) is 3 to 6 days. Children may get a fever and develop a sore throat. They sometimes lose their appetites and don't feel well.