Influenza has been spreading in Nakhon Ratchasima, Chaiyaphum, Buri Ram and Surin provinces, said Dr Theerawat Walaisathien, director of Disease Prevention Control in Nakhon Ratchasima.
A total of 1,919 people had been diagnosed with the disease from jan 1 to June 6, comprising 1,278 in Nakhon Ratchasima including seven who died. There were 170 cases in Chaiyaphum, 335 in Buri Ram and 136 in Surin.
In the same period last year in the four provinces, there were 987 cases and no deaths.
Dr Theerawat said the influenza virus had been reproducing faster this year, resulting in an expanded spread. Another cause was weather fluctuations early in the year, he added.
People at risk are young children, the elderly and people with chronic diseases. The Ministry of Public Health has distributed influenza vaccine to all hospitals and vaccinations for high-risk groups should be completed in July, said Dr Theerawat.