Most of us can agree that we’re not quite ourselves when we’re sick. But in some cases, the microscopic invader making us sick does a whole lot more than simply make us feel “under the weather.” Some sneaky microbes can actually hijack our brains and manipulate our behavior. One of these mind-bending microbes is known as Toxoplasma gondii.

Today we’re going to dive into all the details surrounding this pesky parasite, exactly how it exerts its brain-manipulating effects, and most importantly – how you can protect yourself. Let’s dive in.

What Is Toxoplasma Gondii?

Toxoplasma gondii is a single-celled protozoan parasite that’s known to inhabit and infect most warm-blooded animals – humans included. This tiny intruder can survive for extended periods of time and lie dormant in its host’s body for years. Oftentimes Toxoplasma gondii simply co-exists within its host body, never causing noticeable symptoms or issues.

In fact, this little parasite is so prevalent, it’s estimated that in the United States and the United Kingdom anywhere from 16% to 40% of the population is infected. While in regions like Central and South America and continental Europe, infection rates are estimated to range anywhere from 50% to 80%.¹

While Toxoplasma gondii infection is often entirely asymptomatic, occasionally infection with this microscopic invader can take a sinister turn – causing an infection known as toxoplasmosis. But before we dive into the devastating effects of a serious case of toxoplasmosis, let’s explore exactly how this parasite is contracted and transmitted. 

Toxoplasma Gondii Transmission

The life cycle of these parasites is rather complex and involves two different kinds of hosts – definitive and intermediate. 

Definitive hosts are animals in which Toxoplasma gondii reproduces and forms eggs.

Intermediate hosts are animals in which the parasite reproduces by repeatedly cloning itself – after which these replicated cells cluster inside cysts.² 

While felines – both wild and domestic – are the only known definitive hosts for Toxoplasma gondii, this parasite can survive and replicate within the body of nearly any warm-blooded animal that serves as its intermediate host. Because Toxoplasma gondii can survive in so many species, there are numerous ways you can potentially come into contact with this sneaky parasite, including:³ 

• Accidentally ingesting Toxoplasma gondii through contact with cat feces that contains the parasite. Potential ways this could happen include:
  • Cleaning out an infected cat’s litter box 
  • Ingesting or touching an object that has come into contact with infected cat feces
  • Unknowingly consuming contaminated soil via unwashed fruits, vegetables, or hands

• Eating contaminated meat or shellfish that has not been thoroughly cooked (particularly lamb, pork, and/or venison).
• Having contact with contaminated meat or utensils that have been used to process contaminated meat. Toxoplasma gondii can be contracted both orally and absorbed through intact skin. 
• Drinking toxoplasma gondii contaminated water.

• Congenitally – or mother-to-child transmission.
• Receiving an organ transplant or blood transfusion from an infected individual (this is incredibly rare though).

With such insidious mechanisms of transmission, you’re probably curious about exactly what kind of symptoms this cunning microbe can cause.

Toxoplasma Gondii Symptoms

The symptoms of a Toxoplasma gondii infection can range from non-existent to extreme. Milder symptoms of an infection with this parasite typically include flu-like symptoms but can quickly take a turn for the worse and include:⁴ 

• Body aches
• Swollen lymph nodes
• Headache
• Fever
• Fatigue
• Headaches
• Confusion
• Poor coordination
• Seizures
• Lung infections and complications
• Severe inflammation of your retina (ocular toxoplasmosis) causing blurred vision

Toxoplasmosis can be particularly troublesome in babies who become infected during pregnancy. The earlier in pregnancy the infection occurs, the more serious the consequences may be. Babies born with a Toxoplasma gondii infection are at increased risk of:⁴ 

• Seizures
• An enlarged spleen and/or liver
• Jaundice – yellowing of the skin and whites of the eyes
• Severe eye infections
• Hearing loss
• Mental disability

But one of the lesser-known, and more sinister, side effects of a Toxoplasma gondii infection, is how this parasite affects your brain. 

Can Toxoplasma Gondii Manipulate Behavior?

Toxoplasma gondii has been dubbed a ”mind-altering parasite” due to its potent ability to manipulate its host's behavior. While scientists still have more questions than answers when it comes to Toxoplasma gondii’s mind-bending abilities, it’s speculated that this parasite has evolved in a way to essentially trick its host into transporting the virus back to its only definitive host – cats.

You see, researchers have found that Toxoplasma gondii has a very specific effect on the brains of certain animals like mice and hyenas. The parasite essentially hijacks their brains, making these animals that are usually cautious and wary of the felines that prey on them, suddenly lose their fear.⁵ In fact, studies have found that the parasite triggers an attraction to these predatory felines – giving them a boldness and lack of fear not seen in non-infected animals.⁶

So, if Toxoplasma gondii employs such remarkable and menacing manipulation tactics on mice and hyenas, what kind of effects does it have on our brains?

Effects of Toxoplasma Gondii Infection on the Brain

While Toxoplasma gondii infection doesn’t seem to make cats irresistible to humans, it does have some serious and scary implications for our brains and mental health. Normally, a healthy immune system has no problem fighting off this parasite. However, for those with a compromised or weakened immune system, Toxoplasma gondii entering the brain can have serious consequences that go something like this:^7,8,9

1. The parasite gains access to your brain: Once the parasite is ingested, it adeptly camouflages itself using a “Trojan horse” tactic to trick your body into allowing it to pass through your blood-brain barrier.
2. Brain cells are invaded: After it gains access to your brain, it weasels its way into a variety of brain cells including your neurons, astrocytes, and microglia.
3. Protective cysts are formed: To protect themselves from detection by your immune system, the Toxoplasma gondii parasites form a bubble-like compartment, or cyst, where they hide out within your brain cells and begin replicating.
4. Inflammation spikes: In response to this invasion, your immune cells begin secreting pro-inflammatory cytokines, causing neuroinflammation – or inflammation of your brain. In serious cases, this can lead to toxoplasma encephalitis – or acute and severe inflammation of the brain. 
5. Neurotransmission is disrupted: In addition to climbing inflammation levels, this sneaky parasite can also begin manipulating neurotransmitter signal transduction, receptors, ion channels, and other critical components of brain function – altering how your brain communicates amongst itself and the rest of your body.

So how exactly do these physiological changes translate and affect your behavior?

Toxoplasma Gondii Brain Control: Is It Real?

These cellular changes within your brain can have serious consequences when it comes to behavior and mental health. An underlying Toxoplasma gondii infection has been linked to:^10,11,12,13

• Psychiatric conditions – particularly schizophrenia
• Increased risk of suicide and thoughts of self-harm
• Obsessive-compulsive disorder
• Decreased cognitive function – including decreased processing speed, memory, and executive functioning
• Increased progression of neurodegenerative diseases like Alzheimer’s

This is just the tip of the iceberg when it comes to fully understanding Toxoplasma gondii’s effects on the human brain. And there’s mounting evidence that Toxoplasma gondii’s brain control abilities may be a significant underlying factor in numerous mental health conditions.

So how exactly can we treat and eradicate this mind-bending parasite?

Toxoplasma Gondii Treatment

Most of the time, toxoplasmosis recovery doesn’t require any treatment. But in more severe cases, you may be treated with a combination of antiparasitic drugs including:¹⁴

• Pyrimethamine
• Sulfadiazine
• Folinic acid

But because this sneaky parasite is so prevalent, the best way to protect yourself is by being proactive.

How Can I Protect Myself Against Toxoplasma Gondii

The best way to protect yourself from this pernicious parasite is to take a two-pronged approach. Focusing on prevention while simultaneously keeping your immune system in tip-top shape is without a doubt your best bet – so here’s what I recommend:

Avoid Infection:

• Wear gloves when cleaning your cat's litter box and always properly dispose of any cat waste.
• Thoroughly wash your hands with soap and water after handling any soil or sand. 
• Always clean your hands before eating, drinking, or touching your face.
• Clean all produce before cooking or eating.
• Properly wash all kitchen utensils.
• Invest in a high-quality water filtration system.
• Ensure any meat or animal products are cooked thoroughly and avoid feeding pets raw or undercooked meat. 

Taking precautions to avoid the contraction of this parasite can go a long way in keeping you safe.

Boost Your Immune System:

Your immune system is always your best weapon against invading microbes. Keep your immune system running at full capacity by:

• Eating a well-rounded anti-inflammatory diet
• Getting plenty of high-quality sleep
• Being mindful of your toxic burden
• Finding ways to minimize and release stress
• Prioritizing gut health

For a detailed guide on exactly how you can supercharge your immune system, I strongly encourage you to head over and check out my article Powerful Ways to Support Your Immune System.

So How Worried Should I Be When It Comes to Toxoplasma Gondii?

Toxoplasma gondii can have some serious and eerie complications if left unchecked. And while Toxoplasma gondii’s brain-altering tactics are certainly not to be taken lightly, the truth is, you have a ton of power over your health and well-being. Simply practicing some basic precautions and taking steps to prioritize your health are the most powerful ways to defend yourself against this creepy parasite.

Your body is well-designed to protect you against invading microbes like Toxoplasma gondii. So, ensuring your body has the support and resources it needs to safeguard you is often the only protection you need. That’s why I’m dedicated to bringing you knowledge and tools to simplify healthy living – so you can make your health a priority without feeling overwhelmed.

If you enjoyed this article and are looking for more ways to prioritize your well-being, head over and check out my blog. It’s full of hundreds of articles to help you optimize your health. And if you want to take it to the next level, you can sign up for my weekly newsletter by entering your name and email address in the form below.

Now it’s time to hear from you. Were you surprised to learn about Toxoplasma gondii’s mind-manipulation tactics? What steps are you taking to bolster your immune system to defend against harmful microbes like Toxoplasma gondii? Leave your questions and thoughts in the comments below!

References:

1. Toxoplasma gondii: transmission, diagnosis and prevention – ScienceDirect
2. Toxoplasmosis in Cats | Cornell University College of Veterinary Medicine
3. CDC – Toxoplasmosis – General Information – Frequently Asked Questions (FAQs)
4. Toxoplasmosis – Symptoms and causes – Mayo Clinic
5. Toxoplasma gondii infections are associated with costly boldness toward felids in a wild host | Nature Communications
6. Toxoplasma gondii: A Microbe That Turns Mice Into Zombies · Frontiers for Young Minds (frontiersin.org)
7. The Neurotropic Parasite Toxoplasma Gondii Increases Dopamine Metabolism (plos.org)
8. Effects of Toxoplasma gondii Infection on the Brain (nih.gov)
9. Toxoplasma: making a Trojan horse run | Journal of Cell Science | The Company of Biologists
10. Toxoplasma on the Brain: Understanding Host-Pathogen Interactions in Chronic CNS Infection (hindawi.com)
11. Toxoplasma gondii seropositivity increases risk for mild cognitive impairment (healio.com)
12. Toxoplasma gondii Infection Potentiates Cognitive Impairments of Alzheimer's Disease in the BALB/c Mice (bioone.org)
13. The Association between Suicide Attempts and Toxoplasma gondii Infection (nih.gov)
14. CDC – Toxoplasmosis – Treatment