It is the H3N8 dog flu. While fears of a flu pandemic among humans have shifted from the deadly H5N1 avian flu to the relatively mild H1N1 swine flu, the H3N8 canine flu has been a quiet undercurrent in the U.S. It initially looked quite lethal, and caused panic. Now it is clear that it has killed relatively few victims—and many of those have underlying conditions. Dr. Cynda Crawford of the University of Florida veterinary school estimates that by itself, it kills 5-8 percent of the dogs that catch it. Last week, the United States Department of Agriculture announced that it had approved the first vaccine for it.