July 18, 2025
Do you have a brain parasite?
Does someone you know have brain parasites?

It turns out that as many as 30% of adults and up to 80% of senior adults in the USA & Canada have protozoan parasites, Toxoplasma gondii … that have moved from their gut to their brains … and the there’s evidence that these T. gondii parasites are significantly affecting dopamine production & dopamine levels.

The increases in dopamine, along with T. gondii’s immunomodulatory effects on brain inflammation, have been shown to contribute to
~ Impulsivity,

~ Risk-taking, and

~ Sometimes even driving sexually aggressive behaviors reported in some infected individuals.

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Individual Context:
~ T. gondii parasitic infections aren’t just a public health and hygiene concern — there is evidence that they shape how we think, feel, and act — spreading, growing & increasing over the decades of the parasite-infested person’s life.

~ Up to 30% all Americans & Canadians and up to 80% of mature Americans & Canadians appear to be affected.

~ That rare-steak eater, or medium rare~hamburger eating individual ~ … or ~indoor cat-keeping pet owner~ …
grows more & more parasitic cysts over time … slowly, gradually becoming more impulsive … more emotionally reactive … less rational over time … due to more & more T. gondii PARASITES … growing & accumulating over the decades.

…
Why haven’t we heard about this before?

In a series of 5 research reports this past year, scientists are just now reporting on both the brain chemistry changes and neurological changes caused by protozoan parasite infections of Toxoplasma gondii … found in under-cooked meats … and cat feces.

Seriously:
Does someone you know eat rare or medium rare meats?
Do someone you know have a litterbox?

Have they become a bit irrational? … Impulsive?

Specifically, T. gondii directly increases dopamine production in infected neurons by expressing its own tyrosine hydroxylase, a key enzyme in dopamine synthesis.

Infections with T. gondii parasites that form cysts in the brain unfortunately have been shown to disrupt key circuits in emotion and decision-making …

The parasite cysts also raise risks of disorders like schizophrenia, depression, or even suicidal behavior.

…
Why now?
This past year’s research studies reveal that T. gondii parasites appear & grow as accumulating parasitic cysts in the brain, skeletal and cardiac muscle of the host … Troublingly, reporting that as many as 30% of all Americans & Canadians … and up to 80% of mature adults suffer from biochemical and neuroimmune changes from the accumulating parasite cysts.

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Additional T. Gondii Facts & Effects:
Toxoplasma cysts vary in size between 5 and 70 μm, are intracellular, and typically reside within neurons. Neurons are responsible for receiving and sending sensory and motor signals, allowing for information to be transmitted in our brains, and in our bodies.

Toxoplasma cysts are able to spread, persist, and grow over decades, by masking their presence from detection by our immune system … altering our normal neuron-astrocyte communication, bypassing our traditional immune mechanisms of recognition.

Why care?
Key Facts:
The implications reach beyond individual health, suggesting that widespread infections could even influence societal trends in aggression, risk-taking, and mental health disorders.

~ That medium rare-steak eating individual ~ … or ~indoor cat-keeping pet owner ~ … grows more & more parasitic cysts over time … slowly, gradually becoming more impulsive … more emotionally reactive … less rational over time … due to more & more PARASITES … growing over the decades.

…
“Behavioral Impact: Infected individuals may exhibit more aggression, impulsive decisions, and even heightened sexual risk behaviors.”

“Public Health Relevance: Up to 80% of older humans may carry T. gondii, underscoring the widespread potential for subtle behavioral influence.”

…
Parasitic infections aren’t just a public health and hygiene concern— the evidence shows that they can also shape how we think, feel, and act – by affecting our astrocytes in our central nervous system & brain.

“Astrocytes are the most abundant glial cell in the brain and assist with support and nourishment of neurons, promoting signaling, and taking-up nutrients from the blood to transfer to neurons [11]. In addition, astrocytes are vital for maintaining the blood brain barrier (BBB) and their dysfunction can lead to neurological disorders, including neurodegenerative diseases, stroke, and epilepsy [12].”

“Toxoplasma gondii (T. gondii), a prolific protozoan parasite, forms cysts within neurons of the central nervous system that maintain infection for the lifetime of the host. Astrocytes are fundamental to neuronal health by providing nutrients and structural support and help regulate neurotransmitters by continuous communication with neurons.”

Further, T. gondii cysts have profound effects on our astrocytes’ extracellular vesicles (EVs) that are critical to moving key biochemicals in our bodies, nervous systems & brains.

“Extracellular vesicles (EVs) function in intracellular communication and can contain proteins, lipids, DNA, miRNA, and other RNA subtypes. The cargo of EVs can be diverse and includes DNA, RNA, and protein. Micro RNAs (miRNAs) can alter gene expression by post-transcriptional silencing or via chromatin modifications to silence or activate genes.”

https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1012733

https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1012733

“EVs are produced by all cells and play an important role in neuronal-astrocyte interactions, including the regulation of glutamate receptors on astrocytes. Previous work has demonstrated that Toxoplasma infection reduces astrocytic expression of the primary glutamate transporter, GLT-1.”

” Here we tested if cyst infection of neurons alters the production and content of EVs. EVs were isolated from uninfected and infected primary murine cortical neurons and their size, concentration, and characterization were confirmed with nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), ELISA, western blot, liquid chromatography (LC)-mass spectrometry (MS)/MS, and microRNA sequencing. Analysis reveals that infection of neurons reduced neuronal production of EVs and altered their protein and miRNA content.”

“In addition to changes in host protein content, EVs from infected neurons contained the Toxoplasma proteins GRA1, GRA2, GRA7, MAG1 and MAG2. Following incubation of neuronal EVs with primary astrocytes, GRA7 protein could be observed within intracellular EVs and the nuclei of GRA7 + EV-containing cells. EVs from infected neurons altered gene expression of astrocytes resulting in an increase in pro-inflammatory transcriptional signatures, along with a downregulation of GLT-1 protein expression with similar transcriptional changes found in astrocytes in vivo.”

BIG DEAL RESULTS:
” These results demonstrate the ability of a parasitic infection in the brain to alter EV production and the fundamental communication between neurons and astrocytes.”

“Our study found that Toxoplasma cyst infection decreased EV production by neurons and altered EV host protein and miRNA content. “

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So … SOME of the last 30 years of USA & Canadian societal changes … and changes in some individuals’ increased impulsivity … and increased risk taking … may be due T. gondii parasites … from eating undercooked meat … and from cat-litter boxes …

https://neurosciencenews.com/brain-parasite-personality-29480/#:~:text=Summary:%20New%20research%20highlights%20how,potential%20for%20subtle%20behavioral%20influence.

Cheers …

Dr. Steven M. Fry


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