Parasites and Parachutes: The role of Toxoplasma Gondi

If you have not seen the short clip named ‘grinding the crack’ then you should. No it’s not porn, it’s a 3 minute video of a guy named Jeb Corliss descending a Swedish mountain via wingsuit.

Here is the clip if you haven’t seen it before:

Amazing clip, but there may be more at play here than thrill seeking. I am going to jump subject for a bit but I will come back to the video in a bit I promise.

Parasites are animals that find another animal (its host) and instead of killing it outright and consuming it like your average predator, it thrives inside the animal taking away just enough of the hosts energy (normally via blood) to sustain itself without killing the host. Some parasites will have numerous host animals in their life span as the animal they are inside gets eaten by another animal and the parasite infects the animal that consumed their previous host.

Parasites sometimes need to go though numerous animals before they are able to reproduce, this is called completing their life cycle.

What’s remarkable is that these parasites can actually change the behaviour and appearance of their host to increase the likely hood of them getting chomped by another animal so they can complete their life cycle; here are a couple examples of this.

Parasites are known to turn shrimp from transparent to coloured so that they are more likely to be spotted and therefore eaten by fish.

Ants climb to the top of blades of grass by controlling their brains so they get eaten by cows grazing on the grass.

These are just two examples of the type of control parasites can exert on their host animals, so how does this link in with a crazy guy flying down the side of a mountain?

Well there is a  parasite called Toxoplasma Gondi that cycles between infecting rats and cats. When the parasite is in rats, it  affects certain parts of their brains and manages to distort their natural fear responses. The actual mechanisms of how they do this are unclear but it is known that they increase the rats testosterone levels which can make them more brazen, it may even cause the rat to be sexually aroused by the smell of cats urine! Whatever the mechanism, the rats have no fear of cats and will even run directly towards them.

The result is this behaviour is the poor rat ending up as lunch and the parasite accomplishes its mission of infecting a cat and completing its life cycle.


Thug life.

Here is a diagram of the parasites life cycle if you are interested.

toxo pic

So can this parasite infect human beings? , the answer is yes it can and yes it does. A study by Global Health estimates that 22.5 % of Americans have toxoplasma infections and infection rates in some parts of the world can be as high as 95 %.

The primary source of infection is from eating undercooked meat, and although global infection rates are high it is normally symptomless and inactive in a human host. This is because our immune system promptly kicks the shit out of it shortly after the initial infection and the parasite goes into hiding.

However if the individual has a weak immune system the parasite can become active.

We know that the parasite removes the instinctual fear in rats, but what is unnerving is that it may also alter and influence certain natural neurological process is humans and ultimately our natural fear instincts as well. On a fundamental level our brains are very similar to rats and scientists claim that this parasite could affect us in a very similar manner.

It could perhaps explain how someone is capable of launching themselves of a cliff like some kind of giant bat at 122 mph!

However, some people might just be dumb like this crazy bastard.

Fuck that for a laugh.

This extreme risk taking behaviour could be related to an active infection of toxoplasma Gondi removing our fear instinct and what is more startling is that it also might also be related to suicide rates in humans.

Studies have indicated that people with an active toxoplasma infection could by 54% more likely to attempt suicide.

It is certainly biologically plausible that a parasite messing with your body’s natural fear of death at a time of immense difficulty and trauma in a person’s life could play a role in a person’s decision to commit suicide. The parasite is also known to cause potential complications in pregnant woman.

The good news is that a toxoplasma infection is easily treatable with antibiotics and although around a third of the global population is infected (infection rates vary drastically with location, only 7% of Brits carry the parasite compared to a much larger 67% of Brazilians) and in the vast majority of cases it is not active and symptomless.

For more information on toxoplasmosis symptoms and treatment click here.