Hello again. I thought I should throw in a quick lesson on parasites before I get to the good stuff.
Bear in mind that I am not a teacher, but I probably do know more about parasites than the average person would even want to know, so here goes.
The definition of a parasite is: An organism that lives in or on and takes its nourishment from another organism. A parasite cannot live independently. There are thousands of different parasites, and fungi and bacteria can fall within that definition as well. The two main types are protozoan parasites (which are tiny and microscopic) and helminths (which are worms.) There are also carriers, called vectors, but I’m not getting into that right now.
What is important to know about parasites for what I am doing at work is that there are 3 main things most parasites do. They eat, they reproduce, and they secrete. One or more of those three things is what is harmful to the host. They might eat cells that are vital to the host, like the human brain parasite Naegleria fowleri. Or, the reproduction might be what hurts the host, because the parasite creates cysts to hold the cute little babies in, which cause all kinds of problems. And then there are the secretions. This is parasite poop. It is the waste that is usually toxic to the host, and there are so many examples of parasites that secrete harmful substances that I am not even going to start listing them out.
I am, however, going to introduce you to a little parasite you may already be quite well-acquainted with, although you may not know it. It’s Toxoplasma gondii. This little guy lives in raw meat and cat feces, and makes its way inside a person. It does a whole bunch of nasty stuff in there, but the most interesting part is that it seems that the secretions of this parasite may cause schizophrenia.
To sum it up, this is a parasite that is microscopic, is pretty common, and once it gets into a human body, it poops something that changes the chemical makeup of a person’s brain. It can make them "crazy." And that is just one example.
There are already many kinds of parasites that can invade an animal or insect and changes their behavior. There is a parasitic worm that will make a cricket jump into water and drown itself, so the worm can break out and lay eggs in the water. There is another that will convince an ant to hang from a leaf suicidally to attract a bird to eat it. Having a living organism that can invade a human’s body and then manipulate the behavior of the human is a pretty mind-blowing idea to begin with. If only we could control which behaviors are modified by the parasite and in what way. That is the idea behind the work at the lab.