Parasite Associated with Frailty in Older Adults, Study Finds

A parasite known as Toxoplasma gondii (T. gondii), primarily spread by cats, is associated with signs of frailty in older adults, according to a study published in the Journal of Gerontology: Medical Science. The research, conducted by an international team of scientists from institutions including the University of Colorado Boulder, suggests that the parasite, already linked to risky behavior and mental illness, could contribute to exhaustion, muscle loss, and other signs of frailty in older individuals.

Approximately 11% to 15% of people in the U.S. have been infected with T. gondii, and the rates tend to be higher in older individuals, reaching over 65% in some countries. Once infected, individuals can unknowingly harbor the parasite for life.

The study involved analyzing the blood of 601 Spanish and Portuguese adults over 65 and measuring frailty markers, such as unintentional weight loss and tiredness. While the researchers did not find a direct association between T. gondii infection and frailty, they did discover that individuals with higher concentrations of antibodies to the parasite were more likely to be frail. This higher concentration could indicate a more virulent or widespread infection, multiple infections, or recent reactivation of a latent infection.

T. gondii is typically spread through contact with contaminated cat feces or by consuming undercooked pork, lamb, or other infected meats. While the parasite often remains dormant for decades, mounting research suggests it could have various impacts, including behavioral changes and an increased risk of certain mental disorders.

Although the study does not prove that T. gondii causes frailty, it identifies a compelling association that warrants further research. The researchers hope their findings will inspire further investigation into the relationship between the parasite and frailty, possibly leading to new ways to mitigate the harm it can cause.