The outbreak of a mysterious illness that has affected 11 Quality Pork Processors employees over the last year is so rare, it is attracting the attention of neurological disorder experts and national and international foundations.

According to health experts, they haven't seen an outbreak of chronic inflammatory demyelinating polyneuropathy before, a disorder in which the body's immune system attacks the protective coating around the peripheral nerves. It normally affects fewer than two in 100,000 people, but 11 of the 80 to 100 people who work in the hog head processing area of the plant have been affected since December 2006.

State epidemiologist Ruth Lynfield said she's not aware of any outbreaks of CIDP in the past, making finding out what is causing it in one group of QPP workers all the more difficult to ascertain.

"That's why we are collaborating with a lot of partners," Lynfield said. Those partners include the Centers for Disease Control in Atlanta.

CIDP is a chronic disorder, meaning it is persistent and lasting. The most notable outbreak of CIDP's acute counterpart, Guillain-Barre Syndrome, occured in 1976, when 500 of the 40 million people who had been vaccinated against swine flu developed GBS. Twenty-five of those individuals died.

According to QPP president and CEO Kelly Wadding, the company does not administer swine flu vaccinations to its employees.

The state health department continues to look for the cause of CIDP in the 11 employees, but says the investigation will take some time.

"We are starting to interview workers who do not have illness just to evaluate for exposure," Lynfield said. "We also have sent out through our public health network queries to see if other people are seeing an increase in this kind of neurological illness."

According to Wadding, the 11 employees all worked in the hog head processing area, but doing different duties within that area. An average worker will process between 95 and 100 heads per shift.

Of the 11 workers, two were hospitalized and all are in varying stages of recovery. The health department said there have been no fatalities associated with this outbreak.