Thailand has strengthened hygienic measures to prevent malaria spread, while high number of cases reported in the southern and border areas.
Malaria rates in seven southern provinces were high with more than 400 cases found in only one of them, daily newspaper Nation on Thursday quoted local public health officials as saying.
In Chumphon, one of the worst hit southern provinces, 465 cases were reported last month, a 140-percent jump of the 185 cases reported of the same period in last year.
In a bid to prevent further outbreak, the Public Health Ministry has also sent mobile working unit to clear mosquito and publicize related knowledge to people around the country, especially in border areas.
Thirty provinces have reported serious cases of malaria, with most of them located on the border, said Thawat Suntharacharn, director-general of the Disease Control Department of the ministry.
He noted that illegal workers from neighboring countries had been among the worst hit by the disease.
"Fearing arrests, employers hide them from health authorities, who could treat them by inoculating them with vaccines," said Thawat.
This in turn has inflated the number of victims this year. Employers are now being encouraged to have their workers checked and treated by medical authorities.