CHICAGO, June 5 (Reuters) - A U.S. outbreak of bird flu in dairy cows expanded to a tenth state as Iowa reported its first infection in a herd on Wednesday.
The United States has confirmed cases in more than 80 herds nationwide since late March and three dairy workers have tested positive.
Iowa, which is projected to be the tenth biggest milk-producing state this year, is the first new state to find an infected dairy herd since the U.S. confirmed an outbreak in Colorado on April 26.
The U.S. Department of Agriculture in late April began requiring lactating cows to test negative before being shipped across state lines. It later said the order likely helped prevent the spread of the virus to new states.
Iowa's agriculture department said it would take additional steps to protect its dairy cows and poultry flocks. Avian flu has circulated in wild birds and poultry for years and more recently infected several species of mammals.
"Poultry producers and dairy farmers should immediately take steps to harden their biosecurity defenses, limit unnecessary visitors, and report symptomatic birds or cattle to the department," said Mike Naig, Iowa's agriculture secretary.
USDA previously confirmed that poultry farms in at least five states had been infected with the same distinct H5N1 virus genotype detected in dairy cattle.
Iowa said genomic sequencing of the bird flu virus detected at a commercial farm with egg-laying chickens last week was consistent with the variant in infected dairies in other states. Officials are sequencing the DNA of the virus detected recently in a turkey flock in Iowa and in the infected dairy herd.
(Reporting by Tom Polansek and Leah Douglas Editing by Chris Reese and Lisa Shumaker)
