A chicken, which according to its owner is not infected with H7N9 bird flu, crows at a yard in central Beijing, April 13, 2013.
Credits: REUTERS/Jason Lee
Some strains of bird flu have developed resistance to the two drugs used to treat them, a new study has found.
An examination of the first person stricken with H7N9 influenza found about 35% of the viruses in the infection carried a mutation that made them resistent to the drugs Tamiflu and Relenza, while the other 65% were "sensitive" to those drugs.
Furthermore, the mutated strain of H7N9 proliferates when treated with those drugs, called NA inhibitors, spreading resistance even further.
Bird flu has already proven to be resistent to another class of drugs — M2 ion channel blockers — making the lack of suitable treatment "a grave cause for concern," researchers say in the article published in the journal of the American Society for Microbiology.
If the virus develops the ability to spread from person to person, "we could be in big trouble," said Dr. Robert Webster of St. Jude Children's Research Hospital in Memphis.
Since bird flu emerged in China earlier this year, 132 people have been infected and 43 have died.
The researchers were unable to say how widespread the resistent mutated virus is.