San Antonio scientists are working to create a new vaccine for bird flu. Researchers have been at it for years, but the arrival of the disease in Texas is adding a new urgency. Three herds of cattle, including one in Texas, have tested positive for avian flu. The virus has been transmitted to one human patient, and that case is here in Texas. Researchers say the public health risk of the virus is low, though people who work directly with cattle may want to be cautious. Dairy products are pasteurized, which kills the virus.