Toxoplasma
Toxoplasma gondii () is a species of parasitic alveolate that causes toxoplasmosis. Found worldwide, T. gondii is capable of infecting virtually all warm-blooded animals, but members of the cat family (Felidae) are the only known definitive hosts in which the parasite may undergo sexual reproduction.
In rodents, T. gondii alters behavior in ways that increase the rodents' chances of being preyed upon by felids. Support for this "manipulation hypothesis" stems from studies showing that T. gondii-infected rats have a decreased aversion to cat urine while infection in mice lowers general anxiety, increases explorative behaviors and increases a loss of aversion to predators in general. Because cats are one of the only hosts within which T. gondii can sexually reproduce, such behavioral manipulations are thought to be evolutionary adaptations that increase the parasite's reproductive success since rodents that do not avoid cat habitations will more likely become cat prey. The primary mechanisms of T. gondii–induced behavioral changes in rodents occur through epigenetic remodeling in neurons that govern the relevant behaviors.
In humans infection is generally asymptomatic, but particularly in infants and those with weakened immunity, T. gondii may lead to a serious case of toxoplasmosis. T. gondii can initially cause mild, flu-like symptoms in the first few weeks following exposure, but otherwise, healthy human adults are asymptomatic. This asymptomatic state of infection is referred to as a latent infection, and it has been associated with numerous subtle behavioral, psychiatric, and personality alterations in humans. Behavioral changes observed between infected and non-infected humans include a decreased aversion to cat urine (but with divergent trajectories by gender) and an increased risk of schizophrenia and suicidal ideation. Preliminary evidence has suggested that T. gondii infection may induce some of the same alterations in the human brain as those observed in rodents. Many of these associations have been debated and one study conducted in 2016 has found them to be weak.
T. gondii is one of the most common parasites in developed countries; serological studies estimate that up to 50% of the global population has been exposed to, and may be chronically infected with, T. gondii; although infection rates differ significantly from country to country. Estimates have shown the highest IgG seroprevalence to be in Ethiopia, at 64.2%, as of 2018.
Similar Artists