No cases of human-to-human transmission of the H7N9 Bird Flu that broke out of China have been reported – Until this week.

A 32-year-old woman most likely became infected when she was looking after her father at his bedside in the hospital in March, according to a study published in the British Medical Journal.  She had no known exposure to live poultry, and yet samples of the virus taken from the father and daughter proved almost genetically identical.  Both patients eventually died.

“Our findings reinforced that the novel virus possesses the potential for pandemic spread,” the study's authors wrote.  But they point out that transmission in this particular case “was limited and non-sustainable,” as Forty-three people who had been in close contact with the man and his daughter all came up negative for H7N9 infection.

H7N9 was first identified in eastern China, with the first known human case of the virus reported in March.  So far, 134 cases have been reported, resulting in 43 deaths.