Mutated H1N1 virus found in Japan

A five-year-old patient in Japan has been found to have a genetic mutation of the H1N1 influenza A virus that proved to be resistant to the well-known anti-influenza drug Rapiacta.

The Japanese National Institute of Infectious Diseases, based in Tokyo, said it is most likely the first case in Japan of a person contracting the resistant flu while being treated with the intravenous drip medicine introduced in January 2010, according to

According to a report posted on the institute’s website, a genetic mutation was found in a virus from the child. The child had been treated with Rapiacta and had already tested positive for influenza type A. The boy was found last month.

"This is only one case and there is no need to worry," Takato Odagiri, head of the Influenza Virus Research Center at the institute, said, according to "We need to carefully watch how frequently such a virus resistant to Rapiacta appears.""

The institute said that the virus in the child was also shown to be resistant to Tamiflu, another well-known influenza drug. The virus was not, however, resistant to either of the anti-influenza drugs Relenza and Inavir, reports. The patient had been hospitalized, but has since been released.