Worm your way into health...

I have just seen a documentary about parasites. The first reaction I get when I think about parasites is one of disgust. They did show some pretty disgusting parasites (most of them worms. Like guinea and screw worms) that cause all sorts of misery. It underlines everyone's prejudice that all parasites are bad.

Not totally founded as it turns out. Apparently, parasites like worms can sometimes help in keeping our bodies in balance. In fact intestinal worms are so effective in calming and balancing our immune systems that they are sometimes prescribed for people with hay fever and certain bowel diseases. This treatment means ingesting worm eggs deliberately (eeeeeuw!) . It is even suggested that because we are mostly worm free in the western world we have such high occurrences of asthma and other allergies. The worms need us to exist and it may turn out that we need worms in equal measure to stay healthy too.

It was also suggested that parasites can change normal behaviour. Not only in animals but also in humans.

They gave a few examples where this happens but this one sticks out. A stickleback which is infected with a tapeworm is not frightened by its predators anymore. They showed that very effectively by putting an infected and a healthy stickleback in a tank and then putting a fake herron lookylikey above it. The healthy stickleback fled like its life depended on it but the infected stickleback did not even move and just stared the herron out. In nature the herron eats the infected stickleback, the tapeworm releases its eggs in its guts and the herron poo lands in the water to make the circle complete. The tapeworm thus benefits from altering the behaviour.

They also touched upon the fact that one in three of us is infected by taxoplasmosis parasite which lodges in our brain. The Taxoplasmosis protozoa alters the behaviour in rats in a very similar way to the tape worm altering the behaviour of the stickleback. Rats are carriers but taxoplasma parasites need another host to complete the cycle. Cats are notorious for being active hosts and because they make the rat less fearless, they more easily become prey for a cat to complete the cycle. We get infected by our cats in obvious ways (eeeuw eeeeuw!!!) and this has also been linked to reckless behaviour. People with taxoplasmosis infections have slower reactions and also show a lessened sense of danger.

Now I am a cat owner and again I have found another reason NOT to drive a car. Which in fact proves that I have not been infected because if I had, I would probably have less fear of driving. This is my version of the story and I am sticking to it.

So in conclusion some parasites ARE useful.. Even though they are thoroughly disgusting....