Kamphaeng Phet, Nakhon Sawan, Phichit and Uthai Thani, grouped as Public Health Region 3, have together reported 1,187 cases of dengue fever this year, two of them fatal, said Dr Siriporn Kunchana, the health inspector of the region.

"Compared to the other regions, these four provinces together have the highest prevalence of dengue fever," she said.

The Public Health Ministry will today ask health officials in the four provinces to meet and map out urgent measures to tackle the epidemic, Siriporn said. The meeting will be held in Nakhon Sawan.

The country as a whole has had close to 20,000 cases of dengue fever this year, 20 of them fatal, she added.

Currently, the best the local administrations and the provincial health offices can do is step up the spraying of houses and schools, which where found to be the most common places where patients were bitten by mosquitoes and contracted the disease, Siriporn said.

Residents of the four provinces were also called on to help by getting rid of possible breeding places for mosquitoes, such as water containers, said Dr Suriya Wongkhongkhathep, the health communicator for Public Health Region 3.