June 13 (Reuters) - Further spread of bird flu among U.S. dairy herds presents additional opportunities for human infections, federal officials said on Thursday while urging farms to take enhanced biosecurity measures to contain the virus.
Bird flu has been reported in 94 dairy herds across 12 states since late March, according to the U.S. Department of Agriculture.
The spread among dairy farms is likely occurring from animal movement, shared personnel, and vehicles and equipment that travel between farms, Kammy Johnson, a veterinary epidemiologist with the USDA told reporters on a briefing call.
Biosecurity practices like cleaning equipment and limiting movement of sick animals are important to containing the spread of the virus, Johnson said.
Additional spread of the virus could increase the risk to public health, which is currently low, said Nirav Shah, principal deputy director for the U.S. Centers for Disease Control and Prevention, on the call.
"The more infections there are among cows, the more risk there is for infections to occur among humans," Shah said.
The CDC has monitored more than 500 people and tested at least 45 during the current outbreak, Shah said. Three dairy farm workers have tested positive since the virus began circulating on dairy farms.
(Reporting by Leah Douglas in Washington and Julie Steenhuysen in Chicago; Editing by Bill Berkrot)
