Researchers in Shanghai have discovered that the H7N9 virus in some patients is showing signs of resistance to treatment methods, Agence France-Press reported. These are the first documented bird flu cases that have shown resistance to common treatment methods. Out of 14 patients being monitored at a Shanghai clinic, three had a form of the virus that was drug resistant. One of three with the drug resistant virus developed resistance after they were medicated with Tamiflu, a common antiviral drug. On Monday, health authorities reported that two weeks had gone by without new documented cases of the H7N9 virus appearing.