The United States Department of Agriculture – Wildlife Services (USDA-WS) is evaluating the ability to deliver an oral bovine tuberculosis (TB) vaccine to wild deer by deploying vaccine delivery units through Michigan.
The vaccine trial began in late February and will continue into next month at 12 to 15 selected sites in part of Alpena.
The units, consisting of alfalfa and molasses cubes containing an edible sphere with the liquid vaccine, are being placed systematically in crop fields where deer are frequently spotted, according to the Michigan Department of Natural Resources (DNR).
The vaccines contain encapsulated liquid bacillus Calmette Guerin (BCG), a weakened strain of Mycobacterium bovis.
According to the DNR, BCG has been used for over 100 years to protect children from TB and is one of the most widely used vaccines in people around the world.
These vaccine delivery units remain in place for up to two days, during which the sites are monitored, followed by the retrieval of any vaccines not consumed by the deer.
TB trial results
Several weeks after the units are placed, the USDA-WS will harvest deer from the trial area under permits issued by the DNR.
Samples will then be submitted for analyses by the State of Michigan and USDA.
The DNR stated that it will not allow vaccination of deer beyond the scope of this trial until broader-scale testing of deer for the vaccine becomes practical.
There are no physical markers identifying deer that have ingested the vaccine, according to the DNR.
Work conducted with penned deer prior to the trial has shown that BCG was not found in deer muscle tissue at any time it was tested, including 12 months after oral vaccination.
In these studies, BCG was only detected in lymphoid tissue and intestinal organs.
It is unknown exactly how long a deer would be protected, but a single vaccination would not last a deer’s lifetime.
Protection in deer has been shown to last four months, however, it hasn’t been tested past that point.
The DNR confirmed that vaccination sites are not near homes or yards and that unconsumed vaccine delivery units will be recovered.