Caretaker Agriculture Minister Sudarat Keyuraphan inspects chickens and ducks on sale at a market in Bangkok’s Soi Yaowarat 14 yesterday in preparation for the Chinese Lent festival today.

The laboratory results on the 17-year-old man from Phichit, which came out yesterday, showed no signs of dengue, said caretaker Public Health Minister Pinij Charusombat.

The man died on July 24 and was confirmed days later as the first bird-flu mortality in Thailand this year.

The ministry followed up the case because it was high profile and to boost both public trust and prudence in standards of medical treatment, said Pinij.

I usually take between one and two weeks to confirm dengue in such a case, said Dr Paijit Warachit, director-general of the Department of Medical Sciences, which is responsible for testing patients with suspected bird-flu symptoms. The samples taken from the Phichit man at a molecular level did not reveal any signs of dengue, said the doctor, adding that the Polymerase chain reaction (PCR), a molecular biology technique, was used to test for the existence of dengue.

The ministry's move was apparently aimed at toning down the media speculation over whether there was any risk of the bird-flu virus mutating if the patient had died as a result of it in combination with dengue fever.

In response to media concerns, Paijit said the department had examined the H5N1 virus taken from this case to see whether there were any significant changes that could lead to the virus mutating.

The primary results showed the virus still was the same in terms of mutation.

"So, don't panic. The ministry has continued to monitor the virus," he said.

What was most important for the public to bear in mind was they should try their best in preventing themselves from catching the bird-flu virus, said the doctor.

"Do not touch the suspected source of bird flu without proper protection and alert either the livestock or health authorities immediately if poultry sicken or die suddenly," said Paijit.

As for two other patients being investigated in Uthai Thani - the province where the second bird-flu victim was reported at the weekend - a 73-year-old man was taken off the list as his lab results showed he had influenza and not bird flu, said Dr Thawat Suntrajarn, the head of the Disease Control Department.

The results for the other patient, a 17-year-old worker at a chicken slaughtering house in the province, were not ready said the doctor.