Well, that didn’t take long.  The H7N9 Bird Flu is already developing resistance to one of the most-popular anti-influenza drugs.  It’s an alarming development because the virus crossed over from birds to humans only a few weeks ago.

Back in the middle of April, researchers in China and in Tokyo were successfully stopping H7N9 from multiplying by using Tamiflu, as well as Relenza and two other commonly used drugs.

But now Doctors in Hong Kong and Shanghai report the H7N9 has grown resistant not just to Tamiflu, but also to an experimental anti-viral called Peramivir, which was developed as a last-gasp emergency treatment during the Swine Flu pandemic of 2009.

“The apparent ease with which antiviral resistance emerges in A/H7N9 viruses is concerning;  it needs to be closely monitored and considered in future pandemic response plans,” the researchers wrote in an article published online by the British medical journal The Lancet.

What’s more, in one of the three patients for whom Tamiflu did not work, it appears H7N9 mutated after the patient was infected.  That’s raising fears that the drug itself triggers the mutation that makes the bug stronger.

So far, all H7N9 patients are in China.