BANGKOK, May 19 (Xinhua) -- Thailand has recorded more than 20,000 cases of dengue fever in nearly five months of the year, half of the infected being children, according to the Public Health Ministry.

The ministry's permanent-secretary Dr Sukhum Kanchanapimai said on Sunday that statistics showed that 20,733 people have been infected with dengue fever from Jan. 1 to May 13, and 25 of them had died across the country.

"Fifty-two percent of the dengue fever patients are children, we hope all the parents, teachers pay more attention to children, as they are the most vulnerable group for the disease." said Sukhum.

Temperature, accumulated rainfall, and sunshine play an important role in the transmission cycles of dengue fever, Sukhum said, adding that the rainy season has come to Thailand and it happens to be new semester of schools right now.

He asked all parents and teachers to be wary of the mosquito-borne disease and look at ways to prevent mosquitoes breeding in and around their homes.

Breeding grounds for the Asian tiger mosquito (Aedes albopictus), which transmits the disease in Thailand, exist in both rural and urban areas.

The mosquito-borne infection caused a sudden high fever for 2-5 days along with severe headaches and pain of eye sockets and joint or muscle, loss of appetite, vomiting, coughing without running nose, skin rash, and bleeding from gum.

It also could lead to a shock episode, failure of the blood circulatory system, kidney and liver failure, and even death.