Thai officials have sent an epidemiology team to Chiang Mai to carry out an investigation into the death of a New Zealand woman and the poisoning of her two travel companions.
It was reported Wellington woman Sarah Carter, 23, died in Thailand on February 6 after eating a seaweed dish at a food market in the northern city of Chiang Mai.
However, health officials are doubtful it was this dish that was responsible.
The director of epidemiology at the Thai Health Ministry's Centre for Disease Control, Pasakorn Akarasewi, said he had not seen infections from seaweed before.
Dr Akarasewi said the women's symptoms were similar to many diarrhoeal diseases prevalent in Thailand and usually caused by poor hygiene practices.
At this stage, Carter's death was thought to be from myocarditis inflammation of the heart from viral, bacterial or fungal infections.
The team of doctors was reporting back to him and he hoped to have a report ready this week.