A new study published in the journal Scientific Reports shows that the parasite Toxoplasma gondii, which is normally transmitted from cats to humans, triggers changes in the brain that can worsen neurological diseases such as Alzheimer's, Parkinson's and epilepsy.
"This study is a paradigm shift," says one of the 32 co-authors of the paper, neuroscientist Dennis Steinler. "Now we have to insert infectious diseases into the equation of neurodegenerative diseases, epilepsy and neural cancers."
The research, involving 16 different institutions from the United States, United Kingdom, Australia and Canada, identifies important vulnerabilities in the human brain that would allow the parasite to alter the course of a neurological disease with the potential to worsen it.
T. gondii cyst in the brain of a mouse. Image: Wikimedia
In addition to the spread of cats to humans, the parasite T. gondii can be contracted by congenital transmission from mother to child or by eating undercooked foods. In the United States, one in ten people would be infected. In the world, at least two billion people would have toxoplasmosis.
The findings could serve as a guide to design new drugs and treatments with which to repair and prevent neurological damage caused by T. gondii parasite. "From drugs to changes in diet and lifestyle," explains Steinler, "to delay the onset and progression of the disease in the brain." However, more research is needed to evaluate in detail the impact of the parasite on the human brain.
Most people with robust immune systems do not show signs of infection when they become infected with toxoplasmosis. It is known, however, that the parasite can cause miscarriages, organ damage and eye disorders. Other studies have associated T. gondii infections with migraine, convulsive disorders, intermittent explosive disorder, traffic accidents, schizophrenia and increased suicide rates, but most are based on correlation, and do not are conclusive.
Division of T. gondii parasites. Image: Wikimedia
There have also been epidemiological studies that previously linked to toxoplasmosis with neurological diseases such as alzheimer's and parkinson, but scientists could not explain what the parasite did to exacerbate those disorders, or how we could mitigate their effects.
The new study sheds light on the first of the two unknowns in demonstrating that T. gondii influences the course of neurological diseases when it expresses its genes in the infected brain. Those genes could limit the ability of the host to prevent infection and increase its susceptibility to other diseases already present in the body.
For the study, researchers collected data dating back to 1981 of 246 people infected with T. gondii parasite and examined the effect of infection on cultured neural stem cells, which allowed them to see how they altered proteins and modified genetic expressions .
The results do not imply that all persons infected with T. gondii are at risk for neurological diseases: that depends on genetic and proteomic factors. Each person reacts to the parasite differently, and it is now the task of scientists to determine who is at risk.
The measures that are usually recommended to prevent toxoplasmosis, especially pregnant women, are general hygiene and avoid raw meat, unpasteurized milk and contact with cat feces.
[Scientific Reports]
Well written and informative. Thank you for posting this. Steem On! :)
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