Texas veterinarian helped solve the mystery of bird flu in cows

TThe first calls Dr. Barb Petersen received in early March were from dairy owners concerned about the deaths of crows, pigeons and other birds on their Texas farms. Then came the news that barn cats – half of them on a farm – died suddenly.

Within days, the Amarillo veterinarian heard about sick cows with unusual symptoms: high fever, reluctance to eat and much less milk. Tests for typical diseases were negative.

Petersen, who monitors more than 40,000 cattle on a dozen farms in the Texas Panhandle, collected samples from cats and cows and sent them to Dr. Drew Magstadt, a college friend who now works at Iowa State University’s veterinary diagnostic laboratory. .

The samples tested positive for an avian flu virus never before seen in cattle. It was the first proof that bird flu, known as H5N1 type A, could infect cows. As of Wednesday, 36 U.S. herds had confirmed infectionsaccording to the US Department of Agriculture.

“It was just a surprise,” Petersen recalled. “It was just a little bit of disbelief.”

At the same time, on almost every farm with sick animals, Petersen said he also saw sick people.

“We were actively checking for humans,” Petersen said. “I had people who never missed work, missed work.”

So far, two people in the US have been confirmed to be infected with H5N1, most recently a Texas dairy worker linked to the cattle outbreak, according to the U.S. Centers for Disease Control and Prevention. About two dozen people have been tested and about 100 people have been monitored since the virus appeared in cows, Dr. Demetre Daskalakis, a CDC respiratory disease official, told reporters Wednesday.

Daskalakis said the CDC has not seen unusual flu trends in areas with infected cows, but some experts wonder whether anecdotal reports of sick workers mean more than one person caught the virus from the animals.

Petersen said some workers had symptoms consistent with the flu: fever and body aches, stuffy noses or congestion. Some had conjunctivitis, the eye inflammation detected in the Texas dairy farmer diagnosed with bird flu.

Dr. Gregory Gray, an infectious disease epidemiologist at the University of Texas Medical Branch in Galveston, has been collecting samples from livestock and people on two Texas farms. On farms with confirmed livestock infections, there have also been reports of mild illness among workers, he said.

His research was difficult. Many workers are reluctant to get tested. This may be because they have limited access to healthcare or are afraid of disclosing private health information.

Without confirmation, no one knows whether the sick workers were infected with the bird flu virus or something unrelated, Gray said.

“They appear to be linked in time and space, so one would say it is biologically plausible,” Gray said.

Some of the workers who fell ill sought treatment and received oseltamivir, an antiviral medication sold under the brand name Tamiflu, Petersen said.

Some farmworkers who were exposed to infected animals or people received the drug, CDC spokesman Jason McDonald said. State health authorities are responsible for evaluating and providing treatment in accordance with federal guidelines.

Texas health officials provided Tamiflu to the person known to be infected with H5N1 and family members, as well as two people on a second dairy farm who tested negative but were exposed to infected animals, said Chris Van Deusen, a spokesman for the Department. of State of Texas. Health services. He said he was not sure if the antiviral had been offered to others.

Farmers have been hesitant to allow health officials on their land, said Dr. Kay Russo, a Colorado veterinarian who consulted with Petersen about the outbreak.

“This particular disease is seen as a scarlet letter,” Russo said. “There’s this stigma attached to it now.”

Russo called for broader testing on livestock, people and milk.

“We don’t know what we don’t measure,” she said. “Unfortunately, the horse came out of the barn and bolted much faster than we could mobilize.”

Gray fears that a recent federal order Requiring testing of all lactating dairy cows moving between states could make cooperation even more difficult. All laboratories that perform tests must report positive results to the Department of Agriculture. But many farmers may simply decide not to test, hoping to survive the outbreak, he said.

The reluctance of workers and farmers to allow testing is “enormously difficult” to understand how the virus spreads, the current size of the outbreak and how quickly it could grow, Gray said.

“It’s a negative, very negative effect,” he said.

Petersen said he understands the concerns of workers and farmers. She praised the farmers who were willing to let her collect the first samples that confirmed the outbreak and reflected on what the results could mean.

“You immediately think of the cows, the people who care for them and the families who own these farms,” she said. “You’re thinking about the big picture, the long term. Your mind starts going all this way of worry.”