Doctors say food poisoning is suspected after 147 children experienced abdominal pain, vomiting and diarrhoea at a public school in Yasothon on Wednesday.
Some of the young pupils from Thetsaban 3 Hathanwakham School exhibited more severe symptoms, requiring admission to Yasothon Hospital in Muang district of the northeastern province.
The Muang Yasothon municipal office said that 38 young students were admitted to the hospital for stomachache, vomiting and diarrhoea and were under close watch by medical personnel there.
Yasothon governor Charnchai Srisrivichai visited the school on Thursday, with officials saying the immediate priority was preventive measures to contain the spread of the outbreak.
As well, an epidemiology team has begun conducting a thorough investigation of personnel involved to find the cause of the incident.
The children affected ranged from kindergarteners to grade 3. Investigators are examining raw materials, samples from food handlers, drinking water and the school environment at large.
Samples from the patients have been sent for laboratory testing and authorities are waiting for official confirmation of results.
Thetsaban 3 Hathanwakhom School announced it would close on Thursday and Friday to ensure the highest level of disease control and safety for students and staff. The school is now undergoing a thorough cleaning and disinfection process to prevent a recurrence.
Municipal officials said the investigation would be conducted in a transparent and fair manner. If causes related to food production are found, action will be taken in strict accordance with relevant regulations and laws.
Mr Charnchai also visited the young patients at Yasothon Hospital to offer encouragement to the children and reassure their parents.
Dr Thamsilp Kanmalai, the hospital director, and paediatrician Dr Kiriya Chitnapakarn said the children were safe, but needed to be kept for observation because of high fever and dehydration from vomiting and diarrhoea.
Initial assessments suggest the cause is most likely food poisoning, they said. Nonetheless, a diagnosis of any possible co-infections would await detailed epidemiological investigation.
