Cat Parasite Linked to Age-Related Frailty
The widely recognized single-cell parasite Toxoplasma gondii, which induces hazardous behavior in its hosts to enhance its transmission and can lead to severe mental and physical health issues, is now linked to the acceleration of age-related frailty. This microscopic organism that prospers in felines (via rats and birds) is now associated with hastening the onset of age-related weakness.
Approximately 11-15% of individuals in the United States have been exposed to T. gondii at some point in their lives, whether they were aware of it or not. This parasite has the capability to reside within a human host for an extended duration, possibly even a lifetime. However, a well-functioning immune system in a healthy individual should result in minimal, if any, noticeable symptoms.
A First-Time Discovery by Researchers
As per data from the Centers for Disease Control and Prevention, over 40 million Americans harbor the parasite widely recognized as toxoplasmosis. However, even when it remains inactive and mostly symptomless, scientists suspect that it could be a contributing factor in the acceleration of age-related frailty. This influence is not attributed to the infection itself but rather to the response of the body’s immune system to this tiny intruder. For the first time, researchers from the University of Colorado Boulder, University of Maryland School of Medicine, and the University of A Coruña in Spain have established a connection between this parasite and frailty in older adults.
“We often consider T. gondii infection to be relatively symptom-free, but this study underscores that, for certain individuals, it could lead to significant health repercussions in the future,” stated Christopher Lowry, a professor in the Department of Integrative Physiology at CU Boulder and co-author of the study.
A Complex Geriatric Condition
Frailty represents a geriatric condition characterized by a combination of physical and cognitive decline. It is a multifaceted state that can manifest as weight loss, exhaustion, reduced physical activity, slowness, weakness, an increased risk of falls and hospitalization, as well as lengthier recovery from illnesses. While it is not an inevitable outcome, approximately 10% of individuals aged 65 and above are diagnosed with frailty, a number that escalates to between a quarter and half of those aged 85 and older.
When investigating the prevalence of T. gondii infections among older adults with frailty, the researchers theorized that the mere acquisition of this parasite might potentially accelerate age-related physical and cognitive deterioration.
In a study of 601 older adults in Spain and Portugal with frailty symptoms, researchers found that 67% had evidence of previous T. gondii infection (seropositivity). Although a direct link to infection wasn’t confirmed, those with higher levels of parasite-specific antibodies (serointensity) were more likely to exhibit frailty traits. Co-author Blanca Laffon, a professor at the University of A Coruña, emphasized the paper’s significance as the first evidence of a connection between the intensity of the immune response to T. gondii infection and frailty in older adults.
Inflammation and Sarcopenia in Individuals with High Seropositivity and Frailty
Moreover, individuals with both high seropositivity and frailty displayed increased inflammation markers, indicating that the parasite’s immune response may exacerbate age-related inflammation, potentially contributing to sarcopenia, which is age-related muscle wasting.
T. gondii is typically contracted when handling cat litter, although it also utilizes birds and rodents as intermediate hosts. It primarily resides in cats, where it reproduces in their intestines, leading to the presence of its eggs in the litter box. (Eggs can also be found in contaminated water, unwashed vegetables, and undercooked meats.)
Research has shown that the parasite can induce unusual and risky behaviors in its hosts to enhance its transmission. For instance, infected rats and mice lose their fear of cats, making them easier prey, and infected chimpanzees even display an attraction to the urine scent of their feline predator, the leopard.
The Impact of T. gondii on Human Behavior and Mental Health
Research in humans has shown that T. gondii encourages risk-taking behavior, potentially boosting entrepreneurial tendencies and increasing the likelihood of car accidents. It is also linked to a higher occurrence of schizophrenia and mood disorders, largely because the parasite prefers to form cysts in the brain’s cortex, a vital region responsible for processing sensory information.
An unconventional study even hinted that the parasite might make infected individuals appear more sexually attractive, possibly to enhance its chances of close contact with other potential hosts.
The researchers hope this study will stimulate further exploration into the relationship between T. gondii and frailty, seeking ways to prevent the parasite from worsening age-related decline. They stress the importance of maintaining hygiene and understanding the risks associated with cleaning cat litter, especially for individuals with compromised immune systems and those aged 65 and older when the immune system undergoes more significant declines.
The paper underlined, “Our study, conducted in an older adult population from the Iberian region with a high prevalence of T. gondii seropositivity, is, to the best of our knowledge, the first to establish a link between serological markers of chronic T. gondii infection and frailty.”
Read the original article on: New Atlas
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