By Tom Polansek and Leah Douglas
CHICAGO (Reuters) – Colorado has started requiring dairies to test milk supplies for bird flu every week, the state veterinarian told Reuters on Tuesday, as a federal team arrived to help investigate an outbreak. growing in cows that has spread to chickens and people.
The state’s new mandate aims to identify additional farms that may be infected and spread the disease to other dairy farms or poultry flocks, after the largest cluster of human cases to date in the United States occurred on a Colorado farm this month.
Avian flu infections linked to dairy cows have wiped out 3.1 million laying hens in Colorado in recent weeks, and poultry workers have also tested positive.
Colorado has confirmed infections in 47 dairy herds since the outbreak in U.S. cows began in late March, with about 60% of cases detected last month, according to U.S. data. Nationally, 13 states have reported infections in about 168 herds since the spring.
In Colorado, the loss of millions of chickens triggered a requirement for licensed dairies with lactating cows to test their bulk milk supply weekly, state veterinarian Maggie Baldwin said in an interview. About 70% of the state’s laying hens have been eliminated, according to US data.
“We have actually said that what we are doing now is not effective and that we need to change strategy,” Baldwin said.
Since late April, the U.S. Department of Agriculture has required testing for lactating cows shipped across state lines. The agency later launched a voluntary program to test bulk milk supply.
A USDA epidemiological “strike team” arrived in Colorado this week to assess how the virus might be spreading among dairies there, Baldwin said. Workers or vehicles can carry the virus from farms.
If mandatory testing reveals additional infections, Colorado could take additional steps to contain the virus, Baldwin said.
Six Colorado farmworkers tested positive for bird flu in July after slaughtering chickens at an infected egg farm, the U.S. Centers for Disease Control and Prevention said.
More than 150 workers were exposed to the infected birds and 69 developed symptoms and were tested, according to the Colorado Department of Public Health and Environment.
Colorado’s public health department reported a presumptive positive human case at a different Colorado poultry farm on Friday. About 350 people were involved in slaughtering chickens at that farm, where 23 workers developed symptoms and were tested, the department told Reuters. The CDC has not confirmed the presumptive positive case.
Testing remains ongoing, the Colorado health department said Tuesday.
(Reporting by Tom Polansek in Chicago and Leah Douglas in Washington; Editing by Bill Berkrot)
