The Centers for Disease Control and Prevention announced late Thursday that a person in Colorado has tested positive for an H5 bird flu virus — the first such recorded infection in the United States. The CDC did not reveal the neuraminidase subtype of the virus — the N portion of an influenza A virus’ name. The country is currently experiencing an unprecedented outbreak of H5N1 bird flu in both wild birds and in commercial poultry flocks. The man, described by Colorado health officials as being younger than 40 years old, experienced only fatigue; he is now in isolation and being...