This post is part I of a two part series on the question of PD transmission.
OK now don’t panic! The purpose of this post is not to scare anyone. Parkinson’s is not a virus that spreads from person to person. At least we haven’t observed anything like that in the hundreds of years that medicine has known about the disease. That said, with a 20 plus year incubation period it’s possible that some low level of transmission could be missed. But it is very unlikely.
So why the question? Why ask if Parkinson’s is contagious?
Well, because one of the current, favored hypotheses (that means “theory” in scientific language) for how Parkinson’s starts and spreads within the body is that PD is highly similar to an infection.
The idea is that something enters the body, possibly through the gut or the nose, and sets off a chain reaction that spreads from cell to cell, finally working its way to the brain where it destroys the dopaminergic neurons, among others. That “something” may be a virus, a pesticide, metal dust, or any number of environmental toxins. We just don’t know yet. Genetics plays a role in determining how easily and quickly that process happens.
The fact that this process appears to spread from cell to cell implies a contagion. Additionally, one of the proteins implicated in Parkinson’s disease, α-synuclein, appears to have many similarities to a prion.
What is a prion? A prion is a contagious, pathogenic protein. It is responsible for “Mad Cow” disease, and there are a number of related diseases that affect humans, including certain tribes in Papua New Guinea who contract the disease by eating the brains of their dead family members.
What appears to happen is that the prion protein is just a normal protein with a normal function within the body. But something changes the form of one of them, which then changes the form of another, and so on and so on, until these mass of “misfolded” proteins, or aggregations of those proteins, are doing damage and causing disease.
Prion diseases can be transmitted by eating infected animals, or injecting or implanting material derived from infected animals. Once in the body these prion proteins induce the abnormal folding of normal proteins, creating a chain reaction. The incubation time of human prion diseases can sometimes be more than 20 years.
While certain aspects of PD etiology are similar to that of prion diseases, it is still unclear whether this pathological protein is sufficient to cause PD in humans. Even if that were to be the case, that pathological protein would likely not be spread by saliva or by sex. Again, those that postulate an entry point into the body suggest either the gut or the nose, possibly via a virus or triggered by some environmental toxin which is either ingested or inhaled through the nose.
Evidence for the prion-like behavior of Parkinson’s disease includes:
- α-synuclein aggregates are toxic in living cells.
- Pathological human α-synuclein can be inoculated into the brains of animals, initiating a PD-like disease in those animals.
- Animals can even be infected by injecting the protein into their muscle tissue. This infection then appears to travel up the sciatic nerve on its way to the brain.
- Transplantation of fetal cells in PD subjects became “infected” 14 years after grafting.
- Origins of PD pathology appear to be in the gut or nasal area, then followed by migration to the brain.
- Some of the vaccines being created to stop PD progression aim to prevent the chain reaction and aggregation mentioned above. Success of these vaccines depends on the validity of the pathogenic protein hypothesis for PD.
There is also evidence arguing against a pathological protein model for PD etiology. Either way, there is still much to discover about the role of α-synuclein in Parkinson’s pathogenesis. We are determined to find the optimal combinations of safe, natural substances most likely to stop PD progression. Currently it includes natural substances known to block α-synuclein misfolding and aggregation. We will be sharing these combinations as they are published with our mailing list.
No doubt you will hear more in the future about prions and PD. Assuming this turns out to be true, please keep in mind that any casual transmission is very unlikely. So if there were any fears about transmission to friends, family and coworkers of PD sufferers, this post has hopefully allayed them. However, there is still a potential danger of PD transmission through blood or organ donation. This will be the subject of part II of this series, which will be posted shortly.
Researcher at Stop Parkinson's
Dr. Steve is a biochemist, specializing in medical bioinformatics and nutrition. Dr. Steve directs a biomedical consulting laboratory, focusing primarily on biomedical investing and health policy.
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When can we find out substances to block synuclean? Is mannitol one of them?
Hi Louise, the first recommendations should be sent out by email this week or next. They will include one substance (for now) that reduces alpha-syn toxicity.
very interesting read,looking forward to part 2
Thanks Ros! What did you think of part 2?
I believe that Parkinson’s disease may be contagious, because in my family, my mother and my father had this disease
I live in Roumania (Europa)
Regarding this point: “However, there is still a potential danger of PD transmission through blood or organ donation,” — IF it turns out that PD is a prion disease that is transmissible through blood, then that would have implications for potable reuse of recycled municipal wastewater since blood can get into sewers and since prions might be able to find their way through the advanced wastewater treatment processes. Lots of big “ifs” there, but … this is yet another reason for municipalities that don’t really absolutely have to resort to potable reuse of sewer water should hold off until more is known about prion diseases and until wastewater treatment technologies are improved.
My grand mother is suffering from parkinson disease….will it spread to the family members who are takimg care of her….by what means does it spread…is it by contamination or by genes???
I know this is an old post but still looking for a reply. The post said that there is potential danger of PD thru blood or organ donation. Does it include other body fluids? Can the disease be passed thru unprotected sex? Just curious.
Hi Carrie, there’s currently no evidence for casual person to person transmission, and it seems extremely unlikely. Even with the long incubation time for PD we should have seen some association by now, given how common these situations are.
Hello Doctor Steve, My name is Nurse Andrew from nigeria. I am currently nursing a PD patient, The post said that there is potential danger of PD through blood. My question is, will the disease spread to me as the care giver
Hi Andrew, I can’t imagine that a nurse would be in danger. Unless you get a transfusion with the patient’s blood… and even then there is a low likelihood.
I was wondering if someone could catch Parkinson’s from sleeping on a previous long term used mattress of someone who has Parkinson’s disease? Also, if they clean the bathroom of someone who has it or uses their utensils.
I also wonder this with Prions in general. Can they be transmitted by a mattress or living in the same household?
If someone with PD bleeds onto commonly used surface in a household, For example: Bathroom, bathtub, mattress couch, floor. would that contaminate those surfaces with PD or prions that could then be transmissible?
Other people in a household can experience cuts and injuries and since we all use common and shared surfaces frequently in a household, If someone’s cut or open wound came in contact with a surface where a person with PD’s blood particles where left behind, would that be a potential way of transmission? You mentioned blood to blood contact and surgical equipment. So I am trying to understand.
Thanks, AJ
Could eating venison cause PD?