BEIJING -- More than 140,000 people have been infected with hand, foot and mouth disease (HFMD) and six died from the disease in China this year, according to China's Center for Disease Control and Prevention (CDC).

As of April 20, a total of 141,978 cases had been reported, with six deaths and 581 in critical conditions. The disease incidence rate was lower than the same period of last year, the CDC said in a statement.

Zhang Jing, researcher with the CDC, said HFDM was a common infectious disease that usually affects infants and children younger than five years old.

During the peak season for HFMD, from April to June, the CDC said measures are needed to closely monitor and prevent transmission of the disease, especially at primary schools and kindergartens.

Qian Suyun, doctor at Beijing Children's Hospital, reminded parents and teachers to take children to hospital as soon as they show symptoms such as fever, vomiting, irritation, and limb weakness.

The disease can be transmitted through close contact with excreta and respiratory secretions, among other ways.