Bird flu hits Texas dairy cows, hens, human as ducks migrate (updated)

Cal-Maine Foods

03/04/2024 18:34

(Adds comments from USDA, Mexican authorities, a Texas
veterinarian and the White House in paragraphs 8-15)
    By Tom Polansek
       CHICAGO, April 3 (Reuters) - Migratory waterfowl are to
blame for widening avian-flu outbreaks in Texas cows and
poultry, and wild birds carrying the virus should be heading
north soon, state Agriculture Commissioner Sid Miller said.
    The U.S. government since last week has reported cases of
the disease in seven dairy herds in Texas and one person who had
contact with cows, making it the state most affected by the
country's first-ever outbreaks in cattle. Texas is the biggest
U.S. cattle producer.
    The cases in dairy cattle and the second human case in two
years in the United States renewed concerns about the virus,
which has been infecting poultry flocks and a growing number of
other species globally since 2022. 
    A positive test at a Texas egg farm led egg producer
Cal-Maine  CALM.O  to cull 1.6 million laying hens, the company
said on Tuesday. Texas had never before suffered such a major
outbreak at a commercial poultry facility, Miller said.
    "This is spread by waterfowl," he said in an interview.  
"We're ready for the ducks to head north to their nesting
grounds."  
    The U.S. Department of Agriculture (USDA) first reported on
March 25 that a cow and milk from two dairies in Texas tested
positive for bird flu, along with milk from two dairies in
Kansas. The agency later confirmed cases in additional dairy
herds in Texas, New Mexico, Michigan and Idaho. 
    The strain of the virus found in the subsequent states is
very similar to the strain confirmed in the initial cases in
Texas and Kansas that appear to have been introduced by wild
birds, the USDA said. 
    Experts said feces or other materials from infected wild
birds could have contaminated feed or water supplies ingested by
cows at dairies, though that has not been confirmed.
    USDA said it could not rule out transmission of the disease
between cattle. In Michigan, the dairy herd that tested positive
had recently received cows from Texas, according to the agency.
    Following the outbreaks, Mexico, a major market for U.S.
beef and dairy products, said it is increasing surveillance and
reinforcing inspections of U.S. livestock imports.
    Bird flu has primarily affected older cows at infected
dairies, and "only a small portion of each herd is presenting
with clinical signs," the USDA said in an email. The agency
added that it has not received reports of beef cattle showing
clinical signs of sickness or samples from beef cattle to test
for bird flu.
    "Why dairy cattle and not beef cattle? Everyone is
scratching their head," said Michael Kleinhenz, a veterinarian
and clinical associate professor of dairy cattle health at Texas
A&M University.
    "Here in the Texas panhandle, we have dairies next to
feedlots, and cows in close proximity on range, and we're only
seeing it on dairies."
    
    'DEAD BIRDS AROUND DAIRIES'
    The U.S. Centers for Disease Control and Prevention
considers the risk of bird flu for humans to be low. The Texas
patient's only symptom was eye inflammation, according to the
state's health department.
    President Joe Biden has been briefed on the bird flu
situation, White House spokeswoman Karine Jean-Pierre told
reporters at a news briefing on Wednesday.
    Richard Webby, a virologist at St. Jude Children's Research
Hospital in Memphis, said testing for flu in cattle is not
routine and that it was important to establish the connection
between the sickness in cows, and ducks and cats on the farms.
    "Some smart people made the link and actually tested them
for flu," said Webby, director of the World Health Organization
Collaborating Center for Studies on the Ecology of Influenza in
Animals and Birds.
    The Texas outbreak may have started about a month ago, when
a mysterious illness affected about 40% of the state's dairy
herds, Miller said. He said he now suspects it was bird flu,
though officials did not know it at the time and cannot confirm
it because the animals recovered.
    "We were testing for every cattle disease we could think of
and then somebody said, 'What are all these dead birds doing
around the dairies?'" Miller said. 

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FACTBOX-Bird flu spreads to mammals, raising concerns of human
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 (Reporting by Tom Polansek; Additional reporting by Julie
Steenhuysen and Steve Holland; Editing by Aurora Ellis and Bill
Berkrot)
 ((Thomas.Polansek@thomsonreuters.com))