evidence: Federal officials are preparing for the possibility of additional human cases of bird flu, testing components to create a vaccine after a Texas dairy worker was infected with the highly virulent virus, even as they stress the United States remains far from needing to activate a full-blown emergency response [...] The heightened attention on bird flu comes after the virulent H5N1 strain was recently identified in U.S. dairy cattle for the first time. Federal and state officials announced Monday that a dairy worker in Texas is being treated for bird flu, marking the second-ever human case of this bird flu strain in the United States. The patient — who experienced eye inflammation as the only symptom — was exposed to cattle presumed to be infected with the virus. Disease trackers are monitoring for additional cases, particularly whether the virus can jump from human to human, which has happened infrequently and would be cause for more alarm. [...] Since bird flu outbreaks have become widespread globally in recent years, the CDC and the Agriculture Department have enhanced surveillance — closely monitoring anyone who has been exposed to infected birds or poultry infected with H5N1 for 10 days. More than 8,000 people have been monitored in all the 50 states, D.C., New York City, Puerto Rico, Virgin Islands and the Northern Marianas. Until this week, the only positive case was in Colorado in 2022.