The woman, whose name has not been publicly released, worked in a deli and nowhere near live birds, which has left investigators with more questions than answers as to how she developed the disease. After symptoms began to emerge, the woman underwent tests that came back positive for H6N1. However, some of her close friends and family members who came down with similar symptoms not long after tested negative for the virus.

Details of the woman's story were published in a recent release of the journal Lancet Respiratory Medicine. Researchers from the Taiwan Centers for Disease Control explain how the abnormalities of the event illustrate the "unpredictability of influenza viruses in human populations."