This 2005 electron microscope image shows an avian influenza A H5N1 virion. On Wednesday, Michigan health officials said a farmworker has been diagnosed with bird flu, the second human case connected to an outbreak in U.S. dairy cows. Cynthia Goldsmith, Jackie Katz/CDC/AP hide caption toggle caption Cynthia Goldsmith, Jackie Katz/CDC/AP This 2005 electron microscope image…