Japan has found a third case of Tamiflu-resistant swine flu in a man who had taken the drug to prevent infection, the Tokushima prefectural office said Tuesday.
Just six cases of Tamiflu-resistant swine flu have been reported worldwide.
In a statement, the prefectural health department said the man in his 30s was given Tamiflu after his colleague was infected with the virus this month.
The Tamiflu-resistant strain does not appear to have spread beyond the man, who has recovered, the prefectural health department said.
Preventive use of Tamiflu has occasionally given rise to resistant viruses, including those of seasonal flu.
Denmark, Hong Kong and Canada also have reported one case each of Tamiflu-resistant swine flu.