BANGKOK, Oct. 27 (Xinhuanet) -- Thai authorities on Thursday ruled out the possibility of bird flu infection of three people from the French Indian Ocean island of Reunion in a Thai zoo.

    Thai Prime Minister Thaksin Shinawatra told media that the type of case had never happened in Thailand and investigation was going on. He urged the public not to believe it.

    Thawat Suntrajarn, director general of the Disease Control Department, said the three may have a normal case of flu, because the lab had detected influenza virus.

    "It must be a type 5 virus to be a bird flu infection," he said.

    Charal Trinvuthipong, assistant to the agriculture minister, said earlier it was impossible the three could have been infected just because they went to the zoo.

    He explained people could contract the virulent H5N1 virus only when they had close contact with infected birds and touched their saliva or mucus, or slaughtered them.

    However, French Health Minister Xavier Bertrand said three people in Reunion were in contact with birds while visiting a zoo in Thailand. Initial tests were positive and the samples had been sent to Paris for further tests, he said.

    Thailand reported the 13th human death from bird flu last week. It has 19 confirmed cases of the virus in humans but no cases of human-to-human transmission have been confirmed so far. Enditem