At the beginning of summer, health authorities in several states announced warnings against amoeba in freshwater lakes that cause a severe brain infection. A recent study highlights a parasite called Toxoplasma gondii, or T. gondii, and its association with neuropsychiatric and behavioral conditions.
Scientists from Imperial College London's London Centre for Neglected Tropical Disease Research published their study in the cell journal Trends in Parasitology. Evidence suggests that T. gondii may be an underestimated threat to the world.
T. gondii is a protozoan parasite that invades a host's tissues and cells. The single-celled organism was previously associated with congenital toxoplasmosis, which affects people with a weak immune system. However, the researchers present piling evidence that the parasite is related to an even broader range of neuropsychiatric disorders.
According to the Centers for Disease Control and Prevention, the known host of the parasite are cats who expel T.gondii in their feces. Humans can get infected from exposure to the feline waste, contaminated food or water, or consuming infected wild game.
Parasite Associated with Various Neurological Conditions
The authors wrote that studies in the 1950s revealed that T. gondii could be the cause of schizophrenia. Recent evidence has also connected the parasite to illnesses such as Alzheimer's disease, bipolar disorder, epilepsy, and obsessive-compulsive disorder.
They estimate that the parasite causes nearly 150,000 to 300,000 cases of schizophrenia and between 500,000 and 2.9 million non-fatal suicide attempts. T. gondii can also be transferred via the placenta between a mother and fetus, frequently resulting in miscarriages. If the baby is born, it will struggle with developmental problems and abnormalities, called congenital toxoplasmosis.
The parasite has also been linked to addictive and obsessive behaviors as it affects serotonin and dopamine levels. As T. gondii affects dopamine levels, the reward system is affected, which plays a significant role in addiction.
Serotonin is the hormone that regulates mood, behavior, appetite, and other functions. Low serotonin levels are commonly associated with depression.
In one of the studies, the team compiled data from patients from sub-Saharan Africa with active convulsive epilepsy who tested positive for T. gondii infection. Those with epilepsy also tested the highest for T. gondii compared to other infectious parasites.
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Treating T. gondii
The researchers believe that treatment and prevention of the infectious parasite need to expand beyond acute diseases and congenital transmission. Another study from Princeton describes a drug that may treat malaria and toxoplasmosis.
Although drug treatments have been continuously developed for decades, especially for malaria, it's been a losing battle. Parasites have been shown to evolve and resist drug treatments over time.
Early trials of the drug JAG21 removed 100 percent of active T. gondii parasites. Robert Prud'homme shared that they hope to develop the drug into nanoparticles delivered via nasal spray. If successful, the drug would be the first effective treatment against T. gondii infections as there are currently no existing vaccines for felines nor humans.
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