Report: Plant Workers Affected by Brain Tissue

US - Mayo and Minnesota state researchers have published a paper on illness caused by pig-brain tissue in some workers at pig processing plants.
calendar icon 1 December 2009
clock icon 3 minute read

A scientific paper addressing a unique occupational autoimmune illness contracted by people working in an Austin, Minnesota, slaughterhouse has been published in The Lancet Neurology.

According to Post-Bulletin, some people working in the pig-brain harvesting area of Quality Pork Processors in Austin became ill, as did people doing the same job at two other US plants.

Mayo Clinic neurologist, Dr Dan Lachance, said: "It is highly likely that the (human) body's immune system reacted to several different components from the brain tissue and produced this disorder."

Researchers from Mayo and the Minnesota Department of Health published the paper. They believe a forced-air process of harvesting pig brains led to illness at Quality Pork Processors, Indiana Packers Corp. in Delphi, Indiana and Hormel Foods Corp. in Fremont, Nebraska.

Affected workers' immune systems attacked the airborne pig-brain tissue as a foreign invader. However, their immune systems also attacked their bodies' nervous systems because human and pig tissue are similar, said Dr Lachance, a co-author of the paper. The chance of developing symptoms increased in proportion to how close someone worked to the brain-harvest area, he said.

He added: "We tried to identify the position where they spent most of their time most of the preceding months, and then calculated the distance from that post to where the brain extraction occurred.

The calculation was inexact because workers sometimes traded places to fill in for each other.

Post-Bulletin reports that all three plants stopped the brain-harvest technique once illnesses were linked. Symptoms appeared as soon as four weeks after exposure to airborne brain tissue, the researchers report, and ranged from mild to life-altering. The health of all affected workers improved but most still have symptoms, according to Dr Lachance. Three from the Indiana plant were hospitalised, as were three or four from Austin, he said.

"Common presenting symptoms were pain (largely attributable to nerve root irritation), tingling, difficulty walking, and sense of fatigue and weakness," according to the article in The Lancet.


Lachance D.H., V.A. Lennon, S.J. Pittock, J.A. Tracy, K.N. Krecke, K.K. Amrami, E.M. Poeschla, R. Orenstein, B.W. Scheithauer, J.J. Sejvar, S. Holzbauer, A.S. DeVries and P.J.B. Dyck. 2009. An outbreak of neurological autoimmunity with polyradiculoneuropathy in workers exposed to aerosolised porcine neural tissue: a descriptive study. The Lancet Neurology, Early Online Publication, 30 November 2009 doi:10.1016/S1474-4422(09)70296-0

Further Reading

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