Does fungus cause Alzheimer's?

Alzheimer's disease
Diagram of the brain of a person with Alzheimer's Disease. Credit: Wikipedia/public domain.
Traces of fungus have been discovered in the brains of Alzheimer's sufferers, researchers said Thursday, relaunching the question: might the disease be caused by an infectious microbe?

There is no conclusive evidence, but if the answer turns out to be "yes", it means Alzheimer's Disease (AD) may be targeted with antifungal treatment, a Spanish team reported in the journal Scientific Reports.

"The possibility that AD is a fungal disease, or that fungal infection is a risk factor for the disease, opens new perspectives for effective therapy for these patients," they wrote.

The five-member team had found cells and other material from "several fungal species" in the brain tissue and blood vessels of all 11 deceased Alzheimer's patients analysed, but not in ten Alzheimer's-free controls.

The findings are published just a month after scientists warned in the sister journal Nature of a risk of accidental surgical transmission of Alzheimer's "seeds" from one person to another.

Alzheimer's Disease is the most common form of dementia, which the World Health Organisation (WHO) says affects nearly 50 million people worldwide—some 7.7 million new cases per year.

Old age is the major risk factor, and there is no therapy to stop or reverse Alzheimer's symptoms, which include memory loss and disorientation, as well as anxiety and aggressive behaviour.

Some researchers have suggested AD may be an infectious disease or, at least, that infection with certain microbes may boost Alzheimer's risk.

Genetic material from viruses and bacteria had previously been found in the brains of Alzheimer's patients, and viruses which cause herpes and pneumonia have been suggested as potential AD "agents", according to the study authors.


The main suspect in AD to date has been brain "plaques" caused by a build-up of sticky proteins, but trials with drugs targeting these have yielded disappointing results.

The new study adds another possible cause to the list of hypotheses.

Traces of several fungal species were found, said the team, which "might explain the diversity observed in the evolution and severity of clinical symptoms in each AD patient."

A fungal cause would fit well with the characteristics of AD, the researchers added, including the slow progression of the disease and inflammation, which is an immune response to infectious agents such as fungi.

The researchers did point out, however, that fungal infection may be the result, not the cause, of AD.

Alzheimer's sufferers may have a weaker immune response, or changes in diet or hygiene, that could leave them more exposed.

"It is evident that clinical trials will be necessary to establish a causal effect of fungal infection of AD," wrote the team.

"There are at present a number of highly effective antifungal compounds with little toxicity. A combined effort from the pharmaceutical industry and clinicians is needed to design clinical trials to test the possibility that AD is caused by fungal infection."

Outside experts agreed that further study must be done to confirm or disprove the fungus theory.

As they stand, the findings are "very speculative", French neurodegenerative disease expert Sylvain Lehmann told AFP.

"We cannot conclude from this work that such (fungal) infections cause or increase the risk of the disease," added Laura Phipps of Alzheimer's Research UK.

Last month, a study said people injected with hormones extracted from cadaver brains in a long-abandoned medical procedure may have received "seeds" of Alzheimer's—raising the spectre of it being a transmissible disease.

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Journal information: Scientific Reports , Nature

© 2015 AFP

Citation: Does fungus cause Alzheimer's? (2015, October 15) retrieved 20 May 2019 from
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Oct 15, 2015
Looked closely at Alzheimers circa 2010 as part of post grad studies in Food Science at Curtin University, as part of modern dietary issues & contributory factors, there is the odd mechanism that pathogens of various types including fungi can get directly from outside the body into the brain & past the blood brain barrier... vis a vis

In respect of one particular fungi which came up a few times re some bacterial symbiosis


Point is, the level of infection, according to peer reviewed journals, suggest level of infection and especially so during gardening, can be ameliorated by diet management re higher levels of metal mineral complexes, anti-inflammatory naturally occurring eg Willow bark & significant reduction in free fructose ie Without plant fibre moderators & veg/fruit anthocyanins

Oct 15, 2015
Plant this in your theory book: Senile dementia of the Alzheimer type is caused by FEAR.

Oct 16, 2015
LaPortaMA urged
Plant this in your theory book: Senile dementia of the Alzheimer type is caused by FEAR
What book, those devoted to Scientific Method or napkin notes or fairy stories or prayer requests at local evangelical laying on of hands ?

When you say plant, is this organic, put a seed there & it magically grows to influence without foundation ?

Tell us about your idea of theory is it formed with foundation - of any sort, of this paradigm ?

Until that time LaPORTaMA you have a notion, a mere unformed untested idea :-(

What particular version of Alzheimers, prefrontal, amygdalic, brain stem, what ?

What is the acronym "FEAR" refer to ?

Futile, Reactionary, Entertaining, Reductionism
Facile, Retrograde, Effusive, Retard

Or if you mean fear as in being afraid; what type, fear of what, how moderated, how generated etc ?

Details man, "Details matter, because the truth so often hides so well in the details !"

Nov 12, 2015
It could also be that fungal infection is an opportunistic byproduct of a weakening of the vascular system by a different pathogen.

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