Bird flu is here to stay. The H5N1 avian influenza is proliferating among U.S. cows and there are now two strains circulating among mammals and birds.
Though there are only 68 confirmed cases in people—largely dairy workers—public-health officials think bird flu is likely more widespread. Last week, a Centers for Disease Control and Prevention report documented three asymptomatic cases in veterinarians who took care of cattle they didn’t know had H5N1.
What’s clear is that people working on farms are sporadically contracting the virus. What hasn’t yet happened—and scientists believe has yet to happen in the history of the virus—is sustained human-to-human transmission.
