Toxoplasma gondii is a tiny parasite that infects about a quarter of the world’s population, hacks their immune systems and most disturbingly has the ability to alter their mental states, with research hinting the parasite might have subtle behavioral influences. Now I know what you’re thinking: This is some hokey sci-fi bull-shit. But I ain’t kidding, it’s for reals!
But don’t panic just yet. This thing isn’t exactly a brain slug from Star Trek 2, and the majority of human infections (it spreads into humans through contact with infected animal feces or undercooked meat) are asymptomatic. But that doesn’t mean it’s benign to humans either as due to the parasites ability to exert slight control infected individuals are more likely to attempt suicide than your average Joe and T. gondii infection may also increase brain cancer risk. That’s right: HOLY FUCK!
Luckily for us humies the parasite (which can live in any warm blooded host) favors cats and rodents and prefers to end up in the gut of a cat, where it can breed like crazy. To do this the parasite takes control of the minds of rodent hosts, makes the reek of cat urine sexually appealing to them rather than terrifying and nudges the rodent in the direction of some neighboring cats so it gets chowed down with T. gondii who is riding shot gun into the poor moggies belly.
Research by a Swedish team led by Antonio Barragan of Karolinska University Hospital Huddinge in Sweden found that an infection by T. gondii makes a certain type of immune cell go batshit crazy. These cells, called dendritic cells, are spiny little free-floaters that move throughout the body’s tissues. When a dendritic cell meets a foreign invader, it engulfs and processes it, carrying the pieces to lymph nodes, which then launch a full immune attack. In short, the dendrites infected by T. gondii carry it around the body at an accelerated pace and effectively allow it to high-jack our immune system.
Barragan’s team infected both human and mice dendritic cells with T. gondii and realised that this caused increased levels of GABA, a neurotransmitter that is important for brain cell function and also makes dendritic cells move. Infected cells making more of GABA moved in more random directions and so faster than uninfected dendritic cells.
Treating some of their infected live mice with compounds that inhibit the release of GABA the researcher found that in treated mice, parasite levels were 2.8 times lower than untreated mice four days post-infection.
Either way. That’s one bad ass parasite. Makes you think though don’t it….