Toxoplasma gondii is a parasite that causes rats to become less afraid of cats. It also might change the behavior of humans, making women more outgoing and warmhearted, while men get jealous and suspicious. Toxoplasma gondii is shed in cat feces, which get eaten by rats. Infected rats become fearless to cats and then get caught easily, thus completing the parasite's cycle through its different hosts. If a parasite can make you feel friendly, what other unusual benefits might they have?

Currently people have a negative view of parasites, an aversion which is understandable. Most parasites cause harm to their host instead of helping them. Scientists have discovered parasites can evolve fairly quickly to become helpful to humans instead of deadly and harmful. By selecting and breeding the friendly parasites and discarding the harmful ones, certain parasites can become very beneficial to humans. For example, these parasites can be bred to help to build up the human immune system. Parasites can help develop antibodies for their host. These antibodies can protect its host against viruses or even poisonous deadly bites by snakes like the black mamba.

These “friendly” parasites can be used for all kinds of other purposes, other than boosting the immune system. A genetically modified tapeworm could help its host lose weight, leeches could keep your blood flow healthy, and internal skin parasites might smooth out your skin.

With these friendly parasites in mind I imagine a society in which it is a standard to carry different species of parasites around. The people in this society will think more positively about parasites because they use them to physically and mentally improve their lifestyle. Unlike household pets a parasite doesn’t need much attention. They only need to be placed in their host and after that they can take care of themselves. In a while the parasite becomes a part of its user and together they can both live a healthy life.

With these parasites a new market will emerge in which companies breed all kinds of different parasites that will improve the life of the consumer. These parasites will be bred for cosmetics, healthcare or even as exclusive pets.But to let this happen someone must make the first step. Are people ready to let parasites enter their bodies?

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  • Absolutely Amazing. I've never heard of such friendly parasites. I wonder how could this be possible. Mostly we consider parasites to show negative association. Toxoplasma in this case can make miracles, isn't it? I really loved the article so much that I am going to discuss this topic in my class. Thanks for sharing such a nice information.

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  • Interesting piece, however I am surprised you don't mention allergies. Some people speculate that the steep rise in allergies in rich countries is due to people becoming totally free of parasites. There are new experimental allergy treatments being developed involving people getting infected by intestinal parasites under strict supervision by doctors. No one knows how parasites such as these magically lower inflammation of all sorts, though drug companies are trying to extract this property and patent it as medicine.

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