SEOUL, Nov. 30 (Xinhua) -- South Korean health authorities on Monday reported its first case of a patient infected with the A/H1N1 flu strain resistant to the anti-viral drug Tamiflu.

    According to the Ministry for Health, Welfare and Family Affairs, they found a virus enzyme that could inactivate Tamiflu in samples from a five-year-old boy last month.

    The boy, however, did not develop the same kind of tolerance to the Relenza drug also used to treat flu patients, the authorities said.

    The ministry said it marked the first time that such a development was detected in the country, which calls for authorities to take additional measures.

    The World Health Organization said that there have been 75 cases of people developing tolerance for Tamiflu since the outbreak was first reported in North America in April.

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