CASPER, Wyo. — Brucellosis has been found in a second Park County cattle herd, Wyoming livestock health officials said Wednesday, just days after an earlier outbreak of the disease had been determined to be contained.
The newly detected infection is not related to the earlier case disclosed in late October, State Veterinarian Jim Logan said in a media release late Wednesday afternoon. But once again, he said it appears the cattle were exposed to brucellosis in free-ranging elk.
Historically, the discovery of brucellosis in a second cattle herd would cause the state's cattle industry to lose its federal “brucellosis-free” status, but Logan said that probably won't be the case now.
Officials with the USDA's Animal and Plant Health Inspection Service have been working on a new policy that provides some flexibility in how outbreaks are handled, and as a result, “Wyoming is not in jeopardy of losing its free status as long as the state is appropriately handling the cases that arise,” he said.
Brucellosis can cause spontaneous abortions, infertility, decreased milk production and weight loss in cattle, elk, bison and other mammals. It persists in herds of wild elk and bison around Yellowstone National Park and has periodically passed to cattle in Montana, Idaho and Wyoming.
Loss of a state's “brucellosis-free” status can trigger costly restrictions on marketing of all cattle from that state.
According to the media release, 12 heifers in Park County were tested for brucellosis this fall when they were sold, a requirement under the state's brucellosis rules in that part of the state. Two of the 12 were found to have been exposed to the disease.
One of the animals was destroyed on Nov. 10, and samples from the heifer were tested to determine whether it was actually infected. The infection was confirmed on Nov. 24.
The remaining 11 animals from the group of 12 were tested, along with 250 herd mates, the release said. Eight of those animals were found to have been exposed to the disease.
While a blood test from a live animal can detect exposure to brucellosis, the only way to confirm actual infection of an animal is to destroy it.
As a result of the test results, federal officials have designated the herd as an “affected herd.” The Wyoming Livestock Board has quarantined the herd and another “adjacent” herd, and testing is scheduled to continue on Monday on the affected herd and adjacent herds.
“Epidemiologic interviews are under way to determine the extent of this outbreak,” the release said.
Late last week, Logan said officials were preparing to lift a quarantine of nearly a dozen cattle herds in northern Wyoming following the earlier case detected in Park County, also believed to have been caused by contact with infected elk.
The state tested more than 3,500 cattle in the county after four cows of one 300-head herd were found to have the disease in October. The herd and 11 others nearby were quarantined while tests were done to see if the disease had spread. Officials determined it had not.
In that earlier case, the one herd with the infected cows will remain under quarantine for about a year and undergo more testing to make sure the disease is no longer present. The four infected cows have been slaughtered.
If more cases are found within the herd, that entire herd may have to be slaughtered.
In Wednesday's media release, Logan said the USDA is preparing to issue a new “interim rule” regarding brucellosis, a result of a year and a half of discussion among federal officials and state veterinarians in Wyoming, Idaho and Montana. He said he met late last week with USDA regional officials to discuss the implications of the two Park County cases and was given assurance that Wyoming's brucellosis-free status is not yet in jeopardy.