By KEVIN WALKER
Michigan Correspondent
 
LANSING, Mich. — State officials scheduled a public meeting for last week after another farm was shown to have an animal infected with bovine tuberculosis (TB).

This is the second time in a 12-month period that a farm has come up infected with TB in this area, so the development is significant, according to James Averill, a veterinarian with the Michigan Depart-ment of Agriculture (MDA) and bovine TB eradication program coordinator.

“The concern is we are closer to stepping back in status in that part of the state,” Averill said. “Fall is our busy time of year doing a lot of testing. There is a concern.”

Averill also said the MDA disagreed with the USDA about the finding. It asked that it be called an “exposure” to TB, since the animal infected was a leased bull that was on the farm, but wasn’t a regular part of the herd. USDA is sticking with the “infected” designation, however.

The public meeting is standard for every new finding of bovine TB, Averill said. The 12-month cutoff date is April 1, 2011. If state officials find two more instances of bovine TB on other farms in what’s known as subzone 1 of that zone before that date, it could result in a downgrading of that area’s federal TB status. That would trigger new, more stringent rules regarding how cattle are handled.

Subzone 1 is part of the area known as the modified accredited advanced zone (MAAZ). It includes Antrim, Charlevoix, Cheboygan, Crawford, Emmet and Otsego counties. The MAAZ covers most of the Lower Peninsula (L.P.), except the counties in the northeastern part of the L.P. where TB is considered to be endemic.

That area is called the modified accredited zone (MAZ). It includes Alcona, Alpena, Montmorency, Oscoda and Presque Isle counties. It also includes parts of Iosco and Ogemaw counties. Subzone 1 of the MAAZ was a part of that zone until Jan. 4, when it was upgraded to its present status.

The entire Upper Peninsula (U.P.) has TB-free status.

This zonal system goes back to 1917 when the federal government established a nationwide bovine TB eradication program that designated status levels for each state, based on the prevalence of the disease in that state. There are several TB status levels that can apply to a whole state, or part of a state. There can also be subzones.

The closer a state or area gets to being TB-free, the less restrictive the rules are for testing, handling and movement of cattle. Michigan achieved TB-free status in 1979; however, in 1994, that all changed when a whitetail deer was diagnosed with TB. A surveillance plan to assess the extent of the disease in the state was developed.

Based on preliminary results of the surveillance, the USDA revoked the state’s TB-free status in 2000, declaring the entire state to be modified accredited. New restrictions on animal handling and movement were put into place.

In April 2004, the state was granted a split-state status and thus was born the current face of bovine TB in Michigan. In 2005 the U.P. was granted TB-free status. In 2009, state officials asked the USDA to allow the state to expand the MAAZ to include several more counties, including Emmet.

The ultimate goal is to return the entire state to TB-free status.