May 20, 2013 – TAIPEI, Taiwan – The only H7N9 patient so far in Taiwan was carrying two strains of the same virus, with one being drug resistant and the other not, making it tricky to treat to him, doctors said. Huang Li-min, a doctor from National Taiwan University Hospital (NTUH), explained that it was possible the avian flu virus was not drug resistant when the patient was first infected, but mutated later to become resistant to Tamiflu. With Tamiflu failing, NTUH later switched to another intravenous drug, Huang said. Because of the presence of the two strains simultaneously, it was difficult for doctors to determine how much the virus’ drug resistance had undermined the therapy Chou Chi-hao, deputy director-general of the Centers for Disease Control (CDC), said it is natural for viruses to mutate, saying the H1N1 flu strain mutated after infecting human beings.

http://theextinctionprotocol.wordpress.com/2013/05/20/evolving-deadly-h7n9-virus-develops-drug-resistance-to-tamiflu/