Bird flu infections have been confirmed in a dairy worker in California and a poultry worker in Washington, raising the U.S. total to 46 people, said the Centers for Disease Control on Wednesday. Meanwhile, the USDA said tests indicated that migratory waterfowl were the source of H5N1 avian flu infections in two pigs on a backyard farm in central Oregon.
With the new human cases, 21 farmworkers in California and 11 in Washington have contracted bird flu from infected animals. Colorado has the third-highest total, 10 people.
The Oregon hogs were the first U.S. discovery of bird flu in swine. “Genomic sequencing of samples from migratory birds in the area showed very similar sequences, which increases the probability that the pigs and poultry on this farm became infected after coming into contact with infected migratory birds, not dairy cattle or other livestock,” said the Animal and Plant Health Inspection Service.
In addition, the USDA agency said that by the end of the month, it will begin testing samples of milk drawn from bulk coolers to better identify regions with H5N1 infections in dairy herds. Colorado’s system of mandatory tests each week “has been highly successful,” it said.
The agency also said it had approved two additional field safety trials of vaccine candidates for H5N1 in cattle. Two other field trials were approved previously.