Seven deer on a central Minnesota farm were infected with chronic wasting disease, state animal health officials said Wednesday.
Chronic wasting, a brain disease that's fatal to the animals, was first discovered in the deer herd on the farm near Merrifield, Minn., in 2016. The Minnesota Board of Animal Health monitored the herd but allowed the farm to continue operating.
That view changed earlier this year after a wild doe found about a half-mile from the Merrifield farm tested positive for chronic wasting, increasing concern that the disease had spread. It was the first time state officials had found chronic wasting, also known as CWD, in a wild deer outside southeastern Minnesota.
State officials pushed for the infected central Minnesota herd to be destroyed , although Minnesota law does not require it. Instead, the U.S. Department of Agriculture negotiated an agreement with the farm's owner to pay an undisclosed amount through the USDA's indemnity program. The herd was destroyed.
On Wednesday the animal health board released the results of testing on that herd by the USDA's National Veterinary Services Laboratory. Of 102 deer removed from the farm, results showed chronic wasting in seven deer. In 82 animals, the disease was not detected; another 13 were either too decomposed to test, or the testing was unsuccessful, the board added.
"The results give us a clearer picture of the disease prevalence on the farm as we continue our efforts to contain and eliminate any remaining infectious CWD prions in the enclosed property," Dr. Linda Glaser, the animal health board's assistant director, said in a statement.
Officials noted that chronic wasting is a "difficult disease because it is transmitted by abnormally shaped proteins called prions, which are very resistant to traditional disinfection treatments like heat and chemicals."
The land will remain fenced and monitored for at least five years to reduce the risk of the disease being spread off the site, the agency added.