Introduction: We investigated the frequency of H274Y-positive swine-origin 2009 A (H1N1) influenza virus outbreak in Thailand during May-August 2009.
Methodology: This study sought to find Oseltamivir resistance mutation H274Y by using pyrosequencing.
Results: From 8,710 real-time RT-PCR swine-origin 2009 A(H1N1) influenza virus-positive specimens, 100 randomly selected samples identified one such virus with H274Y mutation using pyrosequencing.
Conclusions: The patient probably acquired oseltamivir resistance from natural variation, since he had never received that form of treatment before and recovered from influenza-like symptoms without using anti-influenza drugs.