The Department of Disease Control has sent a medical team to Suan Phung district in Ratchaburi province after reports emerged of 14 Singaporeans infected by mosquito-borne Chikungunya disease.
Dr Suwannachai Wattanayingcharoenchai, the department's chief, said the team would start fogging mosquitoes in targeted areas this week.
In addition, local officials would provide mosquito nets to communities as well as launching a major clean-up to eradicate water-clogged spots, known as breeding grounds for mosquitoes.
The move came after the department last weekend declared the district as high-risk after 14 of Singaporeans -- teachers and students -- tested positive for Chikungunya disease.
The Singaporeans had visited a community in the district and subsequently developed fever, headache, body pain and vomiting.
They were rushed to a hospital, treated, and returned home.
However, the department will follow up the case by contacting the Singaporean authority.
"We have learnt the Singaporean group is in good health right now. The medical team is now working in areas prone to outbreaks to closely watch the case. It is important to destroy the source of mosquito breeding because it can save people from getting sick," Dr Suwannachai said.
He said an initial inspection found communities in this district had a higher amount of mosquito larvae than was standard in the community, schools and hospitals in Suan Phung district.
According to the department, there have been 3,592 cases of Chikunganya, with zero deaths, reported this year.
Most patients are aged 25-34 years, followed by those aged 15-24 and 35-44 years respectively.
The disease can affect all ages with symptoms of skin rash and itches. If a child is infected, the symptoms will not be severe. For adults, pain in the joints will occur but could disappear in a few weeks, according to Dr Suwannachai.
In some cases, however, the pain can last a year. There is no antidote, but treatment is prescribed to deal with each symptom until the body builds up immunity.