I just finished writing the second of a two-part series on prion disease for my Montana Woman magazine monthly Lipstick Logic health and lifestyle column. The prion topic is important, and few people really understand this fatal disease and potential for contagion.
Over two-hundred people died after consuming prion-infected beef during the epidemic in the 1990s. Today, 1 in 2000 British people show evidence they carry mad cow prions but have not yet developed symptoms.
The cause of the mad cow epidemic in Great Britain was from animal food contamination. Rendering plants accepted prion-infected cattle and sheep carcasses and processed protein slurry carrying the deadly prions was made into animal feed. By the time the source was identified, it was too late. People died and millions of cows had to be destroyed.
Feeding cattle animal protein was banned and is still banned in the U.S. The few cows detected positive for prions today are thought to be from mutations and not spread from other animals. Just as the many types of prion diseases in humans, some are inherited mutations. Sometimes in the past, prion disease was caused by infection from contaminated surgical instruments, tissue grafts, corneal transplants and human-based growth hormone. Surgeons and pathologists have died from accidental contamination. Funeral homes have special safety regulations for body handling. Cremation to destroy the prions is encouraged.
The disease first made news in the 1920s when members of the Fore tribe in New Guinea were found to have kuru from ritual cannibalism. They called it “laughing death” because of the terrible neurologic symptoms victims experienced before finally lapsing into coma and dying. Parts of the contagious corpse were sometimes eaten by tribal members and spread the disease.
The Centers for Disease Control and Prevention (CDC) considers prion infection in wildlife an emerging disease. Epidemic spread in wildlife is occurring. Currently 25 states have identified infected wild game animals including deer, elk, antelope, moose and reindeer. Captive bison have also been infected. It is also in Canada, Norway and in imported elk in South Korea. Hunters and anyone who eats game meat should know about the disease and use caution.
Today, 1 in 2000 British people show evidence they carry mad cow prions but have not yet developed symptoms. This estimate is based on tissue biopsies appendectomies from people without neurologic symptoms. No one know what this means. Are they carriers who will someday develop prion disease? Can they transmit it to others? Is it in their blood? On the blood donor questionnaire there is a list of over 40 European countries where possible exposure to CJD may have occurred.
At this time, no human has been identified with prion disease from eating infected wild game, but a recent Canadian study confirmed primates (Rhesus monkeys) died from eating CWD infected venison. With a close genetic relationship to humans, CWD prions crossing the species barrier from deer to the monkeys suggest it could happen in humans like it did with mad cow infected beef. What can we do to prevent potential human prion disease from big game?
In the past two years, the Department of Fish, Wildlife and Parks detected 26 cases of CWD in Montana along the northeast Canadian border and in numerous counties extending from North Dakota into an area south of Billings. Surveillance of hunter kills, and planned hunts where infected deer are found are carried out to cull potentially infected animals to slow the spread.
Of concern is ease of transmission and the epidemic spread among wildlife. The Montana FW&P website details the process to test animals for hunters for a small fee.
Prions are difficult to destroy. To avoid the disease, you must avoid contact and consumption. Cooking the meat well-done does not kill infectivity. Incineration is recommended for contaminated items and cremation for all prion-infected human and animal remains.
Recently, studies showed hypochlorous acid (Briotech) can kill prions on surfaces. Before Briotech, lye solutions were effective in destroying prions but usual hospital sterilization techniques failed, leaving surgical instruments contaminated and able to spread disease.
In a press release from the University of Washington: “Briotech (BRIO HOCL PrP Formula) has been laboratory tested and proven to be the world’s first safe method to eliminate all detectable seeding activity of misfolded infectious proteins and is safe for skin and mucosal contact.”
For more information contact:
FWP Wildlife Health Lab at (406) 994-6357 (for testing information)
The next blog will be on disease symptoms and diagnosis.
Thanks for stopping by.
Betty Kuffel, MD