Two cattle herds in Iosco County have tested positive for bovine tuberculosis (TB), according to the Michigan Department of Agriculture and Rural Development, or MDARD.
Bovine tuberculosis is a disease caused by the Mycobacterium bovis bacteria, and it can impact all mammals, including humans.
The disease is typically found in the free-ranging white-tailed deer population in northeastern lower Michigan counties like Alcona, Alpena, Montmorency, and Oscoda, while other areas are usually free of the illness, according to state data.
"These latest detections of bovine TB underscore why this disease is so challenging to address and the critical need to thoroughly investigate animal movements and maintain active surveillance in order to manage this disease,” said State Veterinarian Nora Wineland in a news release.
Michigan State University Extension Educator Phil Durst, who specializes in cattle health and production, said that while humans have a small chance of getting bovine TB, those who are around deer more often are at a higher risk.
“The risk to humans is very low,” he said. “However, we’re coming into deer hunting season, so anybody who works with deer can be at risk if they harvest an animal that has been infected.”
MDARD stated that they are working to manage the disease through herd testing, animal identification, wildlife biosecurity programs, and encouraging deer hunting in the northeastern lower Michigan area.
Durst said that the general public can help the management effort as well by withholding from feeding deer that they see.
“We sometimes take pity on deer and think that they need to be fed,” he said. “Those things maintain the population at a higher level than should be maintained, and it presents a greater risk of transmission of the disease.”
Iosco County has previously had issues with bovine TB as recently as May 2026. MDARD reports that investigations are currently underway to find other possible cases related to the recent positive tests.
"MDARD remains committed to working together with agency partners, producers, and stakeholders to ensure the strength of Michigan’s cattle industry as well as to protect animal and public health,” Wineland said.
