BANGKOK, Oct. 21 (Xinhuanet) -- Some 30 tigers infected with bird flu virus were culled on Wednesday at a private zoo in eastern Thailand to curb further spread of the epidemic, local press reported on Thursday.

    The 30 tigers have fallen sick of the H5N1 avian influenza virus at the Sri Racha Zoo, where the other 30 tigers died of the disease earlier this week.

    "We are not going to treat them, since we consider them to be the source of the disease," the Disease Control Department director-general Thawat Suntharacharn was quoted by newspaper The Nation as saying.

    The 30 sick tigers were given injection of potassium chloride to stop their hearts.

    They would be later either cremated or buried in deep-dug pit.

    Altogether 60 tigers at the private zoo have been culled or died of the disease since Oct. 14, when the first tiger died of infection.

    The authorities are now closely monitoring animals at the zoo, which raises more than 400 tigers and several crocodiles, ostrichsand other animals. Animals falling sick of the disease will be allculled.

    It's suspected that the tigers were infected by being fed with chicken carcass, and related investigation is being conducted.

    Some 56 people taking care of the animals have also gone through medical check and were proved free of the virus.

    Having hit by two rounds of bird flu outbreaks, the government has placed fighting the disease as the country's top priority and set Oct. 31 as the deadline to eradicate bird flu from the kingdom.

    The poultry epidemic has caused great economic loss including at least 30 million birds culled in first outbreak and more than 100 million US dollars has been spent for compensation.

    The epidemic also claimed lives of 11 Thais during the two outbreaks and the kingdom has been fully alerted over a "probable human-to-human transmission" case. Enditem