Ever seen those movies where one person manages to take over the mind of another and turns them in to a puppet? The victims becoming mindless and obedient drones? Sometimes it's done through the injection of chemicals in to the body, other times a nasty bug is introduced to the victim. But is this possible in reality? Let's take a look at some cases.
The first is about Toxoplasma gondii which is a parasite commonly found in cats. The parasite's 'larval' stage exists outside any living creature which is then eaten by rats, mice or any other animal inclined to do so.
Once inside the host, the parasite begins to create cysts' throughout the body and brain. The parasite then waits for the host to be devoured by a cat so that it can make it's way to it's primary host.
So where's the mind control? Well in lab experiments that were conducted on rats, some interesting differences were noted. Normally rats that smell cat urine are immediately afraid and leave the area, not daring to be eaten by the predator. It turns out that rats infected by T Gondii did not exhibit this reaction and in some cases actually sought out areas with cat urine. Such action serves no benefit to the rat and is equivalent to a person walking in front of a moving bus. But it does serve the purpose of the parasite...
This parasite can also travel to humans by for example eating unwashed vegetables or improperly cooked meat.
The Ampulex Compressa is an interesting wasp. It's behaviour is like that of any other wasp except when it comes to laying eggs. The female wasp will find an unwilling victim, it's favourite, a cockroach.
It's first sting to the cockroach's midsection causes its front legs to give way, effectively grounding it on the spot. The second sting is a more precise shot to the head that is actually carefully guided by the wasp in to the brain of the cockroach. Apparently the sting on the wasp is very sensitive and it carefully navigates its way through to the brain and finds a very specific part that controls the escape reflex. A special venom is injected that neutralizes the escape reflex.
The cockroach effectively becomes a zombie at this point. The Wasp then leads the roach by it's antenna back to wasps burrow. The cockroach obediently follows and stays inside the wasp's home, while the wasp is busy sealing the burrow up. Then the wasp lays an egg on the underside of the cockroach with no resistance whatsoever. The egg eventually hatches and the larva chews a hole in the side of the cockroach and crawls in to its new home.
For 8 days an all you can eat buffet follows as the larva chooses from various fresh internal organs and eventually makes a cocoon within its gracious host. Eventually the wasp emerges from its cocoon and bursts out of the cockroach body, ready to tackle the world.
The larva emerges out of the cockroach in a scene reminiscent of the movie 'Alien'.
The Sacculina barnacle uses crabs as its platform for reproduction. The female of the species will crawl over a selected crab until it finds a weakness its its outer shell, normally at the joints. At this point the barnacle disposes of its own protective shell, becoming a gelatinous blob and makes its way inside the crab.
Once inside the Sacculina begins to grow long tendrils that eventually form a bump on the underside of the crab. The female also creates a hole in the back of the crab so that a male Sacculina can enter from there.
During the female's infestation, the crab loses its ability to reproduce. Eventually breeding begins inside the crab, and it plays hosts to millions of Sacculina eggs and larva. The crab cares for these as if they were it's own and loses any interest in reproducing itself. In the event that the crab is male, the female Sacculina alters the brain to female behaviour so that the crab takes on a more caring and effeminate role.
This process once again has no benefit to the crab, and is further breeding more Sacculina that will go on to infect more crabs in the future.
Mind control in limited forms has been happening in nature for ages. Besides these there are quite a few other examples of parasites altering the behaviour of their hosts.
Apparently a large portion of people (approx 3 billion) are infected with T-Gondii and scientists now believe that this may be linked to Scizophrenia in humans.
Science Fiction or Science Fact? Could a really complex parasite evolve that could become our puppet masters? It's in the realm of possibility.
An infested brain exhibit from the Japanese Parasitology Museum