The discovery that two Indiana pork-plant workers apparently developed symptoms of the same mystery illness that struck meatpackers in Austin, Minn., may be a significant break in a case that has baffled disease investigators for a month.

Like the workers in Minnesota, those at the Indiana plant were stationed near a powerful air-compression system used to blow brains out of pig heads during processing, said health officials. The process, which is no longer being used at either plant, exposes workers to floating particles of blood and brain that investigators theorize could have made them sick.

The fatigue, numbness and tingling in arms and legs reported by workers at both plants are hallmarks of the inflammatory neurological condition, which investigators have yet to name.

"It makes the possibility of exposure to the swine brain tissue more compelling," said Ruth Lynfield, Minnesota state epidemiologist.

The Austin and Indiana plants are two of only three in the nation known to have used the high-compression air system to remove brains.

The third, in Fremont, Neb., is owned by Hormel Foods and is also part of the investigation. But so far no cases have been discovered there, Lynfield said. All three stopped using the compressed-air process after the illnesses came to light.

Investigators will be able to compare all three plants "and then find out what the differences are," she said. "It is significant."

Too early for a link

Dr. Jennifer McQuiston, an investigator for the U.S. Centers for Disease Control and Prevention (CDC), cautioned that it's too early to be sure the cases in Minnesota and Indiana are connected. "They're in the process of tracking down this information," she said. "We're trying to learn all we can."

The Indiana workers were identified after investigators began inspecting packing plants across the country after the Minnesota cases came to light. The CDC has looked into slaughtering practices in 25 large pork-processing plants in 13 states. Officials from United Food and Commercial Workers (UFCW), the union that represents workers at Quality Pork Processors (QPP) in Austin, said they polled local packing house unions across the country about processing practices.

Dr. James Howell, who is heading the investigation for the Indiana State Department of Health, said the two cases there were first identified by a doctor in early January. More may be identified as the investigation moves forward, officials said. Howell said the Indiana plant has been using the air-compression system for about 10 years. The Austin plant began using it in late 2006.

Backing off initial diagnosis

So far 12 workers at the QPP plant in Austin have been identified as having the same collection of symptoms. Initially, health officials said the symptoms fit an extremely rare disease called CIDP (chronic inflammatory demyelinating polyneuropathy). But after further testing they backed off of that diagnosis, and now say the illness is a new syndrome.

Elizabeth Hart, a spokeswoman for the Indiana health department, declined to release any details of the investigation, including the condition of the patients or the name of the processing plant.

Logical deduction

But UFCW officials said Thursday that they know of only one plant in Indiana that uses the air-compression system: Indiana Packers Corp. in Delphi.

The union represents workers at a nearby Tyson pork plant, but not at Indiana Packers, said Jackie Nowell, health and safety director for the union.

Officials of Indiana Packers, which is owned by the Japanese conglomerate Mitsubishi, didn't return phone calls Thursday. However, the Indianapolis Star has reported that a company official said the Delphi plant was not involved.

"We know that Indiana Packers was using the same [processing] method," Nowell said. "In our opinion, logically, the plant is Indiana Packers." • 612-673-7394 • 612-673-7384