Following announcements in May concerning the detection of cattle herds infected with bovine tuberculosis (TB), the Michigan Department of Agriculture & Rural Development (MDARD) has issued a situational update regarding the herds in Presque Isle and Emmet counties in Michigan.
MDARD said routine bovine TB surveillance testing found the initial infected cattle herd was identified in Presque Isle County, and as a result of movement investigations, it quickly located a second bovine TB-infected animal that had been sold from the Presque Isle County herd to a herd in Emmet County.
Investigations into these herds utilized whole-genome sequencing, a specific test that can identify the DNA of TB bacteria, MDARD said, noting that these DNA test results supported evidence that the bovine TB found in both herds was similar to bovine TB in infected deer found in Presque Isle County in 2014 and 2015. It also verified a direct link between the type of bovine TB found in both Emmet and Presque County herds, confirming that the Emmet County animal was infected while in the Presque Isle County herd.
All of the remaining animals from the herd in Presque Isle County have been removed, MDARD said, adding that the only animal infected found in the Emmet County herd was the one moved from the Presque Isle County herd. The infected animal was removed from the Emmet County herd, which is under quarantine and will continue to undergo testing to confirm that the remainder of the herd is negative for bovine TB.
“Because the Presque Isle County herd was assembled recently from herds that are no longer in business, it is not possible to determine the specific time and location when the bovine TB-infected deer made contact with the cattle,” Michigan assistant state veterinarian Nancy Barr said, adding that MDARD “will work with cattle producers in the vicinity of the affected herd and the previous source herds to test their cattle.”
Through its surveillance program, the Michigan Department of Natural Resources (DNR) typically finds one to two bovine TB-infected deer every year in Presque Isle County, according to MDARD.
“Presque Isle falls within the DNR’s Deer Management Unit 487, a multi-county (unit) created to address bovine tuberculosis in the Northern Lower Peninsula Region. Since bovine TB can become more prevalent with higher deer densities, we encourage hunters to get out in the woods this fall and keep hunting. Increased harvest can help us fight bovine TB, and deer head submission by successful hunters is critical to detect any changes in the occurrence of the disease,” DNR state wildlife veterinarian Kelly Straka said.
TB testing will be conducted in cattle herds in portions of Presque Isle, Cheboygan and Emmet counties in response to the findings from these herds. Herd owners who are required to test in these counties will receive a letter from MDARD with instructions on test scheduling.
“Bovine TB is a serious disease to humans and animals, and finding bovine TB in cattle in an area that has been designated TB free is concerning,” Barr said. “Preventing the spread of bovine TB from infected free-ranging white-tailed deer to cattle herds is a top priority. Cattle owners in these areas must actively work to protect their herds daily.
“Cattle producers can protect their herds by ensuring stored feeds cannot be accessed by deer, feeding and watering sites are located in areas away from deer activity, fruit and nut trees are removed from in and around cattle areas and by using disease control permits from the DNR to remove deer that use their farm as their food source and are a disease threat to the cattle,” she added.