By the BBC's Jonathan Kent
A 14-year-old boy in Thailand is being tested for suspected bird flu, according to the health ministry.
Thousands of birds have already been infected with avian flu
Tests on a 12-year-old girl also suspected of having contracted the potentially deadly virus proved negative on Friday.
This is the first time the Thai authorities have confirmed suspected cases since a region-wide outbreak earlier this year.
That outbreak claimed the lives of eight Thais and 16 people in Vietnam.
Both of the children tested on Friday come from the north-eastern province of Nong Khai, near Thailand's border with Laos.
Health officials said the boy's case was probably bird flu. But the head of disease control, Doctor Charal Trinvuthiphong, said bird flu had been ruled out in the second case.
Since the epidemic across the region earlier this year, doctors have been on alert for cases where people are found to be suffering from high fever and are known to have been in contact with poultry.
Up to 10 people have reportedly been taken to hospital this month in Thailand after showing symptoms of the virus. All have tested negative.
In the last three weeks, the virus has been detected in poultry in 15 of Thailand's 76 provinces, and 160,000 birds are reported to have been culled so far this month.
This week, China removed from observation the last of those suspected of having the disease after an outbreak in poultry in the central province of Anhui.
Bird flu has also re-emerged in Vietnam and Indonesia, where the authorities are considering vaccinating livestock in an attempt to stamp it out.