Microbial Attractions

Sterility is not considered healthy anymore. Medicine is shifting from an antibiotic towards a probiotic approach and the idea of hygiene is becoming an organization of contamination rather, as opposed to disinfection. Last year, it was determined that the placenta is not sterile after all. The growing fetus was earlier believed to thrive in an absolutely clean bubble; instead, it seems to be confronted with germs through the filter of its mother’s biological system and building its future immune system from the very start of cell division.

There are trillions of viruses, bacteria, fungi and parasites thriving in each of us right now. Around two pounds of our body weight consists of what are popularly called bugs. Many of the microbiotic organisms are ancient. The most feared are viruses like Ebola or HIV, bacteria like streptoccocus, and parasites like rabies. But next to the few fast and furious, scary exceptions, most of the common organisms are rather easy to deal with for our immune system—even when they are pathogenic. New research suggests that many of them are actually keeping us healthy; they seem to be “training” our immune system.

The term “microbiome” was coined in the 1990’s, but research is still in the beginnings of sorting out the good from the bad. As this community of organisms is so manifold and complex, one speaks about a sea, a forest, a new natural world to be discovered within us. The main idea so far is, that the more diversity—not just in the environment we live in, but also in the environment that lives within us—the better.

One rather simple clinical treatment that has turned into a substantial new industry is fecal transplants from healthy to sick people. Not just has it shown to heal the colon from an overgrowth of clostridium difficile, a bacteria that often can not be cured by antibiotics anymore, but in the way it helped obese people miraculously lose weight. And as it turns out the gut is fundamentally intertwined with our brain and it influences our psychological sanity.

Current research points to how certain bacterial cultures cause anxiety, depression, and even Alzheimers, while others might be able to help alleviate these ailments. But the impact on our state of mind seems to be even more shockingly direct if we take toxoplasmosis as an example: a neuro-active parasite that influences one of the most existential feelings, sexual attraction.

We, alongside mice and other mammals, are only intermediary hosts—cats are its main target. In this unconscious ménage a trois the parasite wants the mouse to be attracted to the cat, so it travels up to the region of the mouse’s brain where sexual arousal occurs, and there it lets that mouse react to the scent of the pheromones of the cat. This again makes the mouse dizzy and lets it approach the cat instead of fleeing, so that the cat can much more easily catch it and ingest it.

Once inside that cat, the parasite has reached its goal, it can reproduce. Humans are part of its scheme in more abstract ways. Those who carry it are more attracted to scents that originate from cat pheromones. This scent can be found in many perfumes—allegedly Chanel No. 5 for instance. Overall, about thirty percent of the global population are infected—quite a target group! Apparently, this segment of humanity is also more prone to be involved in car accidents, and female carriers are known to acquire more designer clothes.

We tend to see sexuality as one of the main markers of our individuality, but not only does our own biological system react to sexual attractions in ways that we can’t control, there are also parasites that can neurologically influence, or possibly even direct our behaviour. It’s a provocative and difficult topic and it challenges the fundamental understanding of what it means to be human.

We are in constant exchange with our germs. We shake hands, kiss, have sex, travel, use toilets, go to parties, churches… Why do we do that? Touching the same wall, drinking from the same cup. Now there is research about how religion, as a social event, might be entangled in that complicated communal sharing of microbial organisms. When we come together, what do we really exchange? Might it be that our need for social interaction is also influenced by the secret powers of microbes?!