Been Acting Different Recently? Blame Parasites In Your Brain

In a documentary that aired on the BBC last night, Journalist and Doctor Michael Mosley infected himself with parasites to gauge if they alter human behaviour in any way. The results were surprising.

Mosley ingested parasites such as tapeworms and leeches for the experiment in a bid to understand more about them and found out that they use a range of ways to manipulate their host.

Mosley also ingested a pill-sized camera, so he could observe the behaviour of the parasites in his stomach.

Mosley found that, despite claims to the contrary, ingesting a tapeworm actually made him put on weight. Victorian ads used to sell women tapeworm eggs for dieting purposes, but despite hosting three, Mosley said that they appeared to make him eat more and he had cravings for chocolate and beer.

Mosley also found out that plasmodium, the parasite that causes malaria, can cause a host's body odour to change, in order to attract mosquitoes; once a mosquito has drunk the blood of a host infected with malaria, the parasite infects the mosquito's brain, making it more likely to target humans. In this way, the parasite is able to easily spread. This kind of research could be valuable in order to engineer more effective repellent.

Another interesting parasite Mosley looked at was toxoplasma gondii, where the most famous studies revolve around cats and mice. Toxoplasma changes the mouse's behaviour and makes the smell of cat urine attractive, so the mouse is lured out, eaten, and the parasite can infect the cat.

People with toxoplasma also seem to behave recklessly, with up to twice as many getting into car accidents when infected and slowed-down reaction times, making us more vulnerable to predators, perhaps?

Parasites are currently being researched heavily for their ability to fine-tune the immune system, which could help in cures for afflictions like hayfever.

The research Mosley has done on the subject is fascinating, and gives a chilling insight into ways parasites can subtly alter our behaviour.