U.S. health officials are closely monitoring the recent surge in avian influenza from birds to cattle — and earlier this month to a dairy farmer in Texas.
The Centers for Disease Control and Prevention Stresses that the present public health risk is low – the virus isn’t known to spread amongst humans or through the food supply, is never transmitted through contact with infected animals and where human infections have occurred, they are sometimes mild and manageable.
But the jump to cattle by the H5N1 strain of influenza, which is widespread amongst wild birds and an everyday threat to domestic poultry, was unexpected and a worrying development since the more the virus spreads, the greater the possibility it is going to mutate. The COVID-19 pandemic was a transparent example of the danger of “spillover” when pathogens pass from animals to humans.
Humans have frequent contact with cattle, creating the chance for more contact. Experts suspect that transmission is feasible amongst animals in a herd or through contaminated milking equipment.
California, the country's top milk producer, is working on the main points of a testing program that each one arriving animals must comply with a brand new federal requirementbased on the California Department of Food and Agriculture.
Concerned dairy farmers are taking biosecurity measures to assist protect their herds, at the same time as testing of the state's animals stays voluntary.
Some farmers are covering their water supplies with tarps to discourage migratory birds and are requiring hygiene measures equivalent to disinfecting tools and boots for people traveling from ranch to ranch, equivalent to hoof trimmers. based on Anja RaudabaughCEO of Western United Dairies in Turlock.
However, there isn’t a state or federal requirement to frequently test cows or milk. Clinical signs of flu occur in just a fraction of cases, leading some experts to fret that the virus could also be hiding in untested animals.
Bird flu was once only a bird problem. But it has now been detected in 33 dairy herds in eight states. It doesn't kill the cows, but it surely causes a dramatic drop in milk production.
While California stays off the list of infected states, “it's a very dynamic situation that can change from day to day,” he said Dr. Terry W. LehenbauerDirector of the Veterinary Medicine Teaching and Research Center on the UC Davis School of Veterinary Medicine in Tulare.
“Wild birds have introduced avian influenza into cattle in the Midwest; it could also happen in California,” According to Dr. Michael Payne, Director of the California Dairy Quality Assurance Program.
There are two key clues that the outbreak is larger and commenced sooner than experts thought.
A clue was present in the milk supply. This week, the U.S. Food and Drug Administration discovered fragments of the inactivated H5N1 bird flu virus in milk purchased in stores across the country. Because milk is pasteurized, it’s protected – but that is evidence that infected cows aren’t being counted.
The other was detected within the genome. A brand new genetic evaluation shows that the virus jumped from birds to dairy cows in mid-December – probably as an isolated case. This is going on sooner than previously thought and suggests it has turn into more widespread. According to evolutionary biologist Michael Worobey of the University of Arizona.
According to the U.S. Department of Agriculture, that is the worst bird flu outbreak in U.S. history. The virus has also been detected in other mammals, equivalent to elephant seals and sea lions in South America, where it is rather deadly.
Pigs routinely tested for flu are still negative. This is reassuring because pigs have each bird and human cell receptors that act as “mixing vessels” for flu viruses.
The latest federal regulation requiring all lactating cows to be tested before moving to other states will aid disease investigation. Labs and veterinarians that find the virus or antibodies to it must report it to the USDA.
California ships numerous dairy cows out and in of the state, Lehenbauer said. Most cows coming to California are heifers that don't yet produce milk. The cattle leaving the state are typically steers headed to feedlots for beef production.
To prevent infection of the state's 1.72 million animals, California requires that cattle coming from a state where there are infected herds be inspected and given a clean bill of health. Cattle aren’t allowed entry in the event that they come from a suspicious herd.
“Our heightened approach at our border crossings and quarantining cattle from affected areas have really helped prevent further spread of this virus.” Raudabaugh said.
And regulations which are too restrictive could disrupt the critical supply chain that supplies the country's milk, Lehenbauer said.
“Given our current situation, I think the procedures and policies we have in place are appropriate and appropriate. … We don’t want to unduly restrict our animal production systems,” Lehenbauer said. “I am very confident that our milk and dairy product supply is very safe and healthy.”
However, this approach has drawn criticism from some experts who consider the shortage of testing on healthy animals is short-sighted.
“This is not good, guys,” said Dr. Eric Topol, director of the Scripps Research Translational Institution in San Diego. on twitter. “I am not (yet) concerned about transmission of H5N1 to humans, but … the lack of testing of asymptomatic cattle” and other issues “impacts confidence.”
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