A single spillover, from a bird to a cow, led to the infections, a review of genetic data has found.A single spillover, from a bird to a cow, led to the infections, a review of genetic data has found.Read Moreyour-feed-science, Avian Influenza, Disease Rates, Cattle, Agriculture and Farming, Dairy Products, Viruses, Milk, Livestock Diseases, Agriculture Department, Food and Drug Administration, Texas, North Carolina, KansasNYT > Health