Gut worms may hinder the spread of prions to the brain
Study of an infectious brain condition that destroys nerve cells helps to explain why some individuals may be at more risk than others.
The study shows how the progression of prion diseases to the brain is slowed if animals have previously been infected with a gut worm.
Prion diseases – which include variant Creutzfeldt-Jakob disease (vCJD) in people and bovine spongiform encephalopathy (BSE) in cows – are infectious brain conditions that affect people and animals. Prion infections are caused by abnormally shaped proteins and can be passed on by eating contaminated meat.
Previous studies have shown that the body’s immune response to a gut worm infection can alter susceptibility to infection with other pathogens, such as Salmonella and norovirus. A team – led by Professor Neil Mabbott at the Roslin Institute – investigated whether gut worms might also influence the risk of contracting prions.
Delaying the onset of prion disease
The study showed that in animals that had previously been infected with a gut worm, the spread of the prions to the brain was reduced, delaying the onset of disease.
During a prion infection, prions accumulate in a specific region of the gut, called the Peyer’s patches. The team observed that previous infection with a gut worm reduced this accumulation, hindering the ability of the prions to then spread to the brain where they cause damage to nerve cells.
We observed that the early accumulation of prions within Peyer’s patches was reduced and survival times were significantly extended in individuals that had been infected by a gut worm.
Sheep, cows and deer in their natural environments are constantly exposed to gut worms. Our findings may help to explain why some animals are at more risk than others of developing prion disease.
Currently no cures are available to treat prion diseases. The researchers hope that by understanding how the worm infection was able to slow the spread of prions to the brain, they may be able to design novel treatments to block prion diseases.
The study, which has been funded by the UK Government’s Biotechnology and Biological Sciences Research Council and the Mexican National Council of Science and Technology, and is published in the journal Scientific Reports.
** The Roslin Institute receives strategic investment funding from the Biotechnology and Biological Sciences Research Council and it is part of the University of Edinburgh’s Royal (Dick) School of Veterinary Studies. **