Dr Kusak Kukiattikul from Phuket's public health said on Tuesday that the number of patients were the highest on June 8, adding that both Thai and foreigners had developed symptoms, such as nausea, vomiting, diarrhoea and fever.
Phuket Provincial Public Health Office is going all out to contain the spread of the diseases that has infected 6,382 people from June 5 to 12.
About 70% of the patients have been infected with norovirus, which causes inflammation of the digestive system and spreads quickly, Dr Kusak said.
However, he said the number of patients with diarrhoea had declined, adding that students who developed symptoms earlier had recovered.
“We suspect that the digestive disease spread from water resources and ice, so we collected samples from six factories and tap water in Phuket for inspection,” he said. The results are expected within a week.
He said the Phuket Provincial Public Health Office has instructed venue operators to ensure cleanliness in their areas and purify the water with chlorine before use.
Schools have been instructed to strictly undergo sanitation, while hospitals have been instructed to prepare medical equipment and supplies to support patients, he said.
He added that the office has cooperated with related agencies on creating awareness among foreign tourists on the issue in a bid to gain their confidence.