A Murderer In Your Head

Small, the unit of measurement of time was the time elapsed until the circus back to a clearing next to my house. When that happened, they spent two things disappearing dogs and cats in the neighborhood (a source of fresh meat and cheap) and something pushed me to infiltrate the cat cages. Remained terrified and fascinated all he could to those cats than 200 kilos, and more than once I was tempted to put my hand through the bars. Without knowing it, could have been the puppet of a silent murderer.

It has long been known that a parasite (Toxoplasma gondii), causes an anomalous behavior in mice. When cat urine is spread in a corner, healthy mice elude pass near the site. However, those infected with T. gondii lose their innate fear and even seem attracted by the smell. The reason is simple, the parasite can only reproduce in the digestive system of cats, so it has evolved to control the will of its host, so bringing it to their next stop, the mouth of the cat. Then reproduces sexually and releases millions of eggs in feces.

What is worrying is that this parasite also infects humans. Toxoplasmosis, which well-known this infection is usually asymptomatic. It is present in 10% of the U.S. population and over 50% of that of France. However, the parasites tend to be very selective with their hosts, and humans are not part of the diet of cats, what then becomes infected?

In the complicated fabric of nature are not usually given stitch without thread, whether behavioral or biological structures exist is because at one time was helpful. Our body hair is a vestige of the dense coat that entertained us. Likewise, toxoplasmosis may be the legacy of a time when we fled from the lions in prairie? Africa. The parasite we get a ticket to travel through the intestines into pieces of the big cats What is the "modus operandi" of the murderer?

According to some studies, is housed in the form of cysts in the brain, especially in the amygdala, a structure related to anxiety and fear. From there, T.gondii interferes with the secretion of dopamine, the molecule that induces the sensation of pleasure. It is possible that the parasite "reward" his guest with a release of dopamine during activities that endanger their lives, especially with cats.

So far there is nothing to worry about, it would suffice to keep away from tigers and lions fairly easy. However, in a road safety study conducted in Czechoslovakia for a year and a half, it was found that the probability of an accident was six times higher for drivers infected with the parasite T. gondii Is the cause of many suicides and risk behaviors in humans?

If so, the butler did not hide murderer behind a double wall or expect in a corner of the house. Be hidden in the damp cave your skull, surrounded by neurons and feeling the invisible threads of your will, just as you would a spider in its web. Rather than a Chandler detective novels, the best fit T.gondii in Poe horror tale.

But in nature there are no criminal intent. Simply echo could be dusty ancestral force, the same man who hypnotized the African savanna as they approached the lions ... or twelve year old boy who wanted to pet the tiger of Bengal.