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Infection from this popular parasite could change a person’s political beliefs

Infection from this popular parasite could change a person's political beliefs

[Legitscience] – A new study shows that an infection from this popular parasite called Toxoplasma could change a person’s political beliefs.


According to a recent study in the journal Evolutionary Psychology, a person’s political opinions and values can alter as a result of the illness, most likely as a result of an inflammatory reaction.

One of the most common parasitic diseases in the world, Toxoplasmosis is brought on by the parasite Toxoplasma gondii. Cleaning an infected cat’s litter box or eating tainted, raw meat are only two examples of how infections can develop.

In humans, the illness frequently goes undetected. However, it can still be deadly for expectant mothers or those with weakened immunity.

Data indicates they raise a person’s chance of developing some illnesses and disorders. This is despite the fact that Toxoplasma infections frequently go undetected.

According to study author Jaroslav Flegr and his co-authors, an infection also appears to cause behavioral and psychological changes.

This is most likely because the illness stimulates the immune system and raises IL-6 and other pro-inflammatory cytokines. According to the scientists, it has been discovered that inflammation affects both emotional and behavioral activities.

“Our laboratory has been researching the impact of latent toxoplasmosis on human (and rodent) behavior and personality since 1992.” This is according to Flegr, a professor at Charles University in Prague.

“We have been researching it within the framework of the stress-coping concept for the past ten years. According to this hypothesis, infected people experience minor chronic stress. This is responsible for the observed alterations in their behavior and personalities.”

“Stressed individuals adopt a quicker life history, which may have an impact on their preferences for policy. We looked for (and discovered) support for this logic in a recent study.”

An infection from this popular parasite Toxoplasma could change a person’s political beliefs

Flegr and colleagues note that some toxoplasmosis-related personality features may be related to shifts in political beliefs.

Men and women who have the illness, for instance, have lower levels of conscientiousness, altruism, and novelty-seeking. Anxiety disorders and parasite infection have both been connected.

The researchers disseminated an online survey to gather information about the relationship between political values and toxoplasma infection.

Only participants who acknowledged having a toxoplasmosis test and were thus able to report their status were included in the analytic sample.

As a result, a sample of 2,315 Czech citizens was assembled, consisting of 467 men and 1,848 women.

Participants were questioned about their physical and mental health. This includes if they used prescription medications and how often they visited their doctors. It also includes whether they had any phobias, mania, depression, or anxiety.

On a list of 25 mental health illnesses, they also indicated whether they had received a diagnosis. Additionally, they completed a survey about political ideas and values. This evaluated four factors: economic equity, cultural liberalism, tribalism, and anti-authoritarianism.

The outcome of the study

The findings showed that 518 women and 90 males had toxoplasma infections. Toxoplasma infection was linked to poorer mental and physical well-being in women and to poorer physical well-being in males.

The link between toxoplasmosis status and political views was the next area of investigation for the researchers.

In the total sample, toxoplasmosis was linked to greater levels of tribalism. This is characterized by devotion to one’s tribe and a sense of “us versus them.”

Additionally, lower levels of cultural liberalism and anti-authoritarianism were linked to toxoplasmosis. The researchers discovered significant gender differences when they independently examined this for men and women.

Toxoplasmosis status is no longer linked to tribalism among men solely. According to the authors, the smaller proportion of male participants may be the cause of this lack of a meaningful effect.


Toxoplasmosis was positively correlated with economic equity, or the notion of a just and equal society, but only among men.

Since men with toxoplasmosis have earlier been discovered to display more risk-taking behavior and higher entrepreneurial engagement, this finding was unexpected.

To learn more about these gender discrepancies, more study will be required.

“The most ‘sexy’ conclusion from our research, is that biological issues. This includes parasite illnesses, which also influence our political opinions,” according to Flegr,

“Toxoplasma is a fairly common parasite, hence its predominance (which varies greatly between and within nations) can affect not only the political environment in various countries and the different social strata of the people, but also actual politics and, as a result, history.”

“The study’s ‘less-sexy’ message is that Toxoplasma gondii. This causes long-term infection in 30% of people worldwide in both developed and developing nations.”

“This is probably a major cause of stress that has an impact on infected individuals’ behavior and personalities. This is in addition to their physical and mental health and well-being.”

“Therefore, much more work needs to be done to develop a Toxoplasma vaccine as well as a cure for latent toxoplasmosis that lasts a lifetime.”

The researchers claimed that their findings mostly concur with earlier research demonstrating that residents of places where parasites are a problem exhibit higher levels of conservatism and authoritarianism.

The parasite-stress theory, which contends that these attitudes serve to limit contact with strangers in order to avoid disease infection, may help to explain this.

This logic might not hold up, though, because the current individuals are from a tiny area with little parasite burden.

Instead, the authors contend that a toxoplasmosis-related inflammatory response may result in modest yet persistent stress, which alters personality and, in turn, affects political opinions.

According to Flegr, “Our understanding of how toxoplasmosis affects our political opinions and values is still speculative.”

“The latent toxoplasmosis is a considerably more potent health-related factor than is generally believed, if our stress management hypothesis is right.”

“Additionally, we are unsure of the extent to which the observed events are widespread and the strength of their influence on people’s actual conduct, such as if it influences voters’ behavior during elections.”

Limitations of the study

The sample size for the study had a substantially lower proportion of men than women, which was a limitation. This is probably because testing for toxoplasmosis during pregnancy makes it more likely for women to be aware of their status.


“I am an evolutionary biologist, the author of the theories of frozen evolution, frozen plasticity, and turbidostatic and chemostatic selection,” Flegr said.

“At first, I mainly studied toxoplasmosis as a pastime in terms of its behavioral impacts. That a little parasite may influence our personality, sexual preferences, or political convictions strikes us as absurd.”

“Because of this, the efforts of our team were recognized with the Ig Nobel Prize in 2014 and featured in the 2021 episode “Family Cat” of the American animated television program Family Guy.”

“However, in the course of mapping the impacts of toxoplasmosis and looking for the mechanism underlying these effects, we unearthed some extremely unsettling facts concerning the influence of latent toxoplasmosis on human health, even though most doctors still view it as clinically irrelevant.”

“Our highly cited 2014 research shows that toxoplasma infections raise the risk of a wide range of serious illnesses and conditions, such as ischemic heart disease, certain malignancies, and epilepsy.”

In fact, according to Flegr, “differences in toxoplasmosis prevalence between nations account for 23% of the diversity in the overall burden of illness in Europe.”

“At the same time, Toxoplasma can only procreate sexually in cats, making it simple to eradicate through the use of effective veterinary vaccines.”

“The narrative of latent toxoplasmosis research may one day serve as a compelling example of why funding fundamental research yields the highest returns.”

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