Parkinson's Movement
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Giardia - Parkinson's connection?

In my quest to discover the source of the "idiopathic" part of Parkinson's, even though I had no symptoms, I had a stool analysis done as a last ditch effort to find a PD cause and then could possibly prevent more progression.

Result was a shocker: giardia infestation.

I was stunned because I had no symptoms, and I don't fit the profile of risky behavior. I wash my hands constantly, am very careful about washing food and my dishes and flatware are sterilized in the dishwasher. I don't drink from rivers or streams and used to drink city water (now drink bottled because city water can also be a source). Also, I've had no symptoms, so I don't how long I was infected.

Of course I googled "giardia parkinson's" and found this:

"Giardia also produces neurotoxins—toxins that harm the nervous system. These toxins cause depression, sleep disorders, and an inability to concentrate, among other symptoms. Giardia is linked to autoimmune disease, particularly with neurological autoimmune processes such as multiple sclerosis, ALS (Lou Gehrig’s disease), and Parkinson’s disease."

And this, which is the process of causing leaky gut to give birth to autoimmunity:

"Pathogenesis of giardiasis is not completely understood and several hypotheses exist. Theories include direct damage to the brush border intestinal mucosa either by trophozoites or by host immune-response activation..

..Giardia disrupts tight junctions in human intestinal monolayers, which increases epithelial permeability [24] [25] and results in fat malabsorption. Weight loss and malabsorption of fat-soluble vitamins, lactose, and vitamin B12 are commonly seen in chronic giardiasis. Children can present with failure to thrive.

Giardia induces programmed cell death (apoptosis) in infected cells. [26] [27] This causes malabsorption of sodium, water, and glucose and reduced disaccharidase activity due to loss of absorptive surface area of the epithelium."

Have you had a stool analysis or endoscopy with giardia positive? I'd like to know if this could be a factor that the neuros haven't investigated.

I found another website that lists giardia infestation as a diagnostic marker of PD.

Egg or chicken first? Have they looked? Lynn

10 Replies

Hmmm. Very interesting. Will have to ask at hubby's next visit.


Giardia is everywhere.

It is the most common waterborne disease in the world. Though generally transmitted through water it can be transmitted through food and person to person contact as well.

Most people with giardia infection never develop signs or symptoms but still carry the parasite and unknowingly spread it to others through their stool.

Giardia transmission prevention rule #1 : wash hands after using the toilet.

Ever wonder why so many adults become lactose intolerant? Giardia might be the thief that took your beloved dairy away from you.

A strong immune system is your best friend. Unfortunately, many diseases (PD and PDP) and medications lower immunity and slow down gastrointestinal tracts allowing an opening for 'invaders' to take root.

Staying hydrated is one of the most important choices a patient can make to promote better health and well being. Very basically, water helps ease and quicken the passage of the dung out of the body.

FYI : Use chlorine bleach to disinfect your bathrooms - especially taps / faucets.

Close the lid of toilets prior to flushing as toilet plume (fecal matter within droplets) will contaminate the area.

Keep your toothbrushes, towels, and drinking cups in a cabinet well away from toilet plume exposure.

Carry on strong.


your answer was very informative, thank you. Do you think that it's necessary to be checked for this?


The simple answer : yes.

A more complete answer ...

If you have gastrointestinal challenges or immunodeficiencies – with PD or PDP – a stool test for parasites is a wise choice with or without symptoms.

It is an inexpensive non invasive test with rapid definitive results. Easy peasy.

If you have symptoms of possible giardia infection, aka giardiasis, then absolutely have your stool tested.

Most common symptoms : loose watery stools / diarrhea, abdominal bloating, and nausea that lasts more than a week. Remember ... giardiasis can be asymptomatic.

Otherwise, use probiotics on a regular basis, wash your hands, and always stay hydrated (with safe drinking water).

Hydration is the single most important factor in maintaining happy gastrointestinal health and over all well being.

FYI : It is standard protocol to run 3 separate samples collected over a period of days to be certain giardia is caught; but additional tests are unnecessary if the 1st sample test is positive.

Giardiasis is a zoonosis with cross-infectivity between animals and humans. If you have dogs or cats … it places you at a slightly higher risk … remember to wash your hands.


Thank you very much for answering my question. I will ask my doctor about testing me. I don't have any symptons, but I did have a cat and dog.


Won't hoit. Most health insurance will pay for the test, which is non invasive. I never would have known if I hadn't had the test. There were no signs.

Don't want any neurotoxins in my body.


Thanks. I have an appointment with a new GI doctor. Hope she is a human being. I will DEMAND this test. Last time I was tested for parasites I paid $200 and did not get a complete report.


Wow. Outrageous. For a common O&P? It is a simple matter of smearing stool onto a slide adding dye and looking under a microscope. Done did.

You must have had specific related tests added into the mix. Had you traveled into a high risk region? Wow. $200...

The simplest route go to your local pharmacist and ask for a stool kit. Use it at home. Fill out the forms provided and pop the sample into the post. Results sent to your GP (or doctor of choice) and to you. Easy peasy.


Were you tested for heavy metals and Lyme? If not, do it as soon as you can.

Some symptoms are similar to PD.


i'll have to get the test out and look again. Yes, we asked for a lot and got only "negative for parasites" . . . I was too ill at the time to complain.


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