A common parasitic disease could change a person's mind on politics

This infection, usually from foodborne illness, could alter the way you think politically.
Brittney Grimes
Cells of a parasitic disease.
Cells of a parasitic disease.


A common parasitic infection called Toxoplasmosis might influence a person’s thinking habits geared towards politics. The new study was published in Evolutionary Psychology.

Common, sometimes dangerous parasitic disease

Toxoplasmosis is a parasitic disease that is “considered a leading cause of death attributed to foodborne illness in the United States,” according to the Center for Disease Control and Prevention (CDC). The infection is from a parasite called the Toxoplasma gondii. Toxoplasma can infect humans and other warm-blooded animals, including rodents and birds. It remains persistent in the central nervous system. This parasite enters the body through contaminated food or water or transmission, such as “cleaning the litter box of an infected cat.” It is one of the most widespread parasitic diseases.

Although the infection can be asymptomatic in humans, it can be dangerous for pregnant women or people with weak immune systems.

Increased risk for certain disorders

Toxoplasma gondii can often go unnoticed, but the parasitic disease does heighten the risk of certain other diseases and disorders. It can also create personality and behavioral changes, according to the new study. Jaroslav Flegr, author of the study and professor at Charles University in Prague, noted that the disease activates the immune system and increases certain proinflammatory cytokines, like IL-6.

In other words, the parasitic disease creates inflammation, which has been found to influence and impact behavioral processes, including political preference. It is the stress component that causes people to seek a certain political belief.

“In the last ten years, we have been studying it [toxoplasmosis] in the context of the stress-coping hypothesis. This hypothesis posits that infected humans suffer from mild chronic stress and that the observed changes in their behavior and personality are a response to this stress," Flegr said. “Stressed people switch to a faster life history strategy, which may affect their policy preferences. In a recent study, we sought, and found, support for this hypothesis.”

Flegr and his research team noticed that some personality traits associated with the parasitic infection could coincide with changing political beliefs. Mentioned, for example, people infected with the disease could “demonstrate lower conscientiousness, generosity, and novelty-seeking.” The infection is also known for being linked to anxiety disorders.

Details of the study

To test the association between Toxoplasma and political values, the research team distributed a questionnaire online to participants who were tested for the parasitic disease and could report their status. The test consisted of 2,315 people from the Czech Republic — 1,848 women and 467 men. As for people in the study infected with Toxoplasma, 90 men and 518 women reported having the disease.

Most Popular

The individuals were asked questions related to their physical and mental health, including any prescription drug use, doctor visits or if they experienced anxiety, depression, phobias or mania. They were also asked if they’ve been previously diagnosed with a mental health disorder, selecting from a list of 25 disorders.

For the political portion, they were asked about political beliefs and values, which included 34 questions about tribalism, economic equity, cultural liberalism and anti-authoritarianism and if they agreed or disagreed with the inquiry.


Overall, the results showed that, for women, being infected with Toxoplasma was associated with worse mental and physical health, and for men, it was associated with worse physical health.

To support the researchers’ idea that this infection can affect political standpoint, they looked at the individuals with Toxoplasmosis and their political beliefs and values. The study concluded that “toxoplasmosis was associated with higher tribalism, a construct defined by loyalty to one’s tribe and an “us versus them” mentality. Toxoplasmosis was also associated with lower cultural liberalism and lower anti-authoritarianism.”

However, results were different when divided by gender, suggesting men were more positively associated with economic equity, which the team did not expect, since “men with Toxoplasmosis have previously been found to show higher risk-taking behavior and higher entrepreneurship activity,” a sort of paradox.

Two key points

Flegr said the results of his study have a couple of key factors, the first being how this common parasitic disease could affect political outcomes. “Toxoplasma is a very widespread parasite, and therefore its prevalence can influence not only the political climate in different countries and different social strata of the population, but also real-world politics and, consequently, history.”

The second factor of his study is the idea that Toxoplasma could affect the health and well-being of those infected. “Toxoplasma gondii, which is the source of long-term infection in 30% of the human population in both developed and developing countries, is likely to be a significant source of stress that affects not only the behavior and personality of infected people but also their physical and mental health and well-being.”

It is truly remarkable, and unbelievable, to know that a parasitic infection can change a person’s thought process, and even impact the choice for a possible future political leader.

message circleSHOW COMMENT (1)chevron