A parasite found in undercooked meat and contaminated water may be linked to rare brain cancers

• Toxoplasma gondii, a parasite commonly found in undercooked or raw meat, could be linked with certain brain cancers.
• A study by a team of American Cancer Society researchers found brain cysts caused by the parasite could cause glioma, a rare and deadly tumor.
• According to the study, 20% to 50% of the global population has been exposed to T. gondii, often spreading through contaminated water and food.
• Researchers say the study suggests people who are exposed to T. gondii are more likely to develop glioma.

Researchers at the American Cancer Society's department of population science found a link between Toxoplasma gondii, a parasite commonly found in raw or undercooked meat and contaminated water, and certain types of brain tumors.

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Researchers studied blood samples from 111 people in a US database and 646 in Norway. The results showed those with larger amounts of T. gondii antibodies appeared to have a higher risk of developing glioma, an aggressive form of brain cancer that makes up 80% of malignant tumors.

Approximately 20% to 50% of the global population is exposed to T. gondii, according to the study.

Nearly half of the world's population is exposed to T. gondii, but cases of deadly brain cysts are rare

A majority of people can fight off the common parasite, so they are often unaware of their exposure.

But occasionally, T. gondii causes its host to develop cysts in their brain, which can cause swelling. Researchers say it's the swelling that may lead to gliomas.

While there is a correlation between elevated rates of T. gondii antibodies and glioma, researchers say it is still important to acknowledge glioma is an extremely rare diagnosis, and they did not prove a direct link between the two.

According to the National Organization for Rare Disorders, 6.6 people for every 100,000 are diagnosed with glioma every year. The most common type of glioma is a glioblastoma, which former US Senator John McCain had. It carries a 5% chance of surviving five years post-diagnosis.