U.S. researchers and scientists confirmed April 16 that 18 pork plant workers in Minnesota, at least five in Indiana and one in Nebraska have contracted a newly identified neurological condition while reportedly removing brains from slaughtered pigs.

Experts said the illness is a new disorder that produces a number of signs from inflammation of the spinal cord to mild weakness, fatigue, numbness and tingling in the arms and legs.

“As far as we are aware, it is a brand new disorder,” says Daniel Lachance, MD, of the Mayo Clinic in Rochester, who presented his findings at the American Academy of Neurology meeting in Chicago.

Lachance says all 18 Minnesota patients he has been closely following have evidence of nerve involvement, typically affecting the legs.

Research indicates this damage extends to the nerves at the root level near the spinal cord, and at the extremities of their motor nerves, where the nerves connect with muscle.

The first cases of the condition were reported in late November in some workers at Quality Pork Processors in Austin, MN. These workers were using compressed air to blow pork brains out of the skull cavity.

This process apparently produces some sort of inflammatory response, says Lachance.

No infectious agent has been found, and researchers don’t believe this condition can be passed from worker to worker.

The U.S. Centers for Disease Control have surveyed 25 of the largest pork processing in the United States, and have found only these three plants in three states where the process is used and the problem has occurred.

All three plants have suspended the process as a precaution.

Most patients have mild conditions, which are being treated with drugs. But none of the affected workers has completely recovered.