Bovine tuberculosis, transmittable to humans, found in southeast North Dakota beef herd
BISMARCK — State veterinarians are investigating a beef cattle herd in southeast North Dakota after a first-of-its-kind strain of bovine tuberculosis in the United States was identified in seven of the animals.
Late last year, State Veterinarian Susan Keller said two older beef cows from the herd tested positive for the disease after lesions were found on them at slaughter plants in South Dakota and Minnesota.
The testing was confirmed by the National Veterinary Services Laboratory in Ames, Iowa.
Keller said the quarantined herd was later tested by state and federal veterinarians and five additional cows were confirmed to be affected. She said additional testing is ongoing, as well as tracing the history of the cattle herd.
The herd was on a small family cattle operation in Sargent County.
Keller said because tuberculosis can be transmitted from animals to humans and humans to animals, the family went to their physician.
Although there was no report of a transmission, Keller said the people probably most at risk are the veterinarians examining the animals.
Humans are at risk of contracting the disease from animals through mucus droplets in the air. Most cases of transmission to humans, however, occur through people consuming unpasteurized milk or dairy products.
Like the human version, bovine tuberculosis primarily affects the airways and lungs of the animals and can be deadly.
Keller said the family and veterinarians are puzzled as to how the cattle contracted tuberculosis, especially a strain not previously identified in the U.S. The strain is most similar to cases associated with cattle in Mexico.
She said possible risk factors were not found in the Sargent County operation as there were no other cattle from Mexico found in the area, the cattle had been purchased privately and not from a large-scale sales barn and there were no employees from Mexico involved in the family business.
Keller said perhaps it's a factor that's too often overlooked that humans can spread tuberculosis to cattle or other animals.
There were no other cattle herds in the Sargent County area that had direct contact with the herd, Keller said.
She added that animals which test negative may move to slaughter, but other movements are not allowed. Cattle with the disease are put down. Meat from animals that pass inspection is safe to consume, she said.
There is a nationwide bovine tuberculosis eradication program, a cooperative state-federal effort. But because of the federal government shutdown, Keller said federal funding and field staff "are currently limited in their ability to assist."