Parasite Rex: A World Everyone Loves to Hate
...ifferent strategy for survival. Take the tapeworm for example. Even though it is a simple creature, it has nasty effects on the large intestine on its host. Locking on to the walls with a crown of hooks, it feeds off the host, growing to incredible lengths. Humans are not the only suitable host for these parasites. Others can include cats, dogs, rabbits, and a slew of other mammals that ingest the tapeworm by either eating another animal that is already infected, or it could be carried on the animal itself, like a dog that has fleas. Different kinds of parasites have different effects on different parts of the body. Blood flukes for example can get in through the skin. It can take hours for the fluke to actually get inside of a capillary and find its way into the bloodstream. Once there, it may travel around the entire bloodstream three times before finally ending up in the liver. The liver is a prime location for it since all of the blood in the body has to pass through the liver at one point or another. The fluke then works on reproducing by laying eggs in individual blood cells. The eggs hatch, causing the red blood cells explodes. Most of the eggs are passed through the digestive system and escape the host, looking for yet another host to infect. Most of these parasites can be detected by white blood cells in the bloodstream, but very little can be done without the help of the immune system. The immune system in the human body is an amazing tool. Using different kinds of cells and receptors, it can horde off thousands of different types of bacteria, or in this case, parasites. When a parasite enters the body, the immune system can usually detect it right away. Using B and T cells, the immune system tries to eradicate the sickness by destroying the infected cell. The T cells can take three different forms, as he killer, the inflammatory type, or they can help produce B cells. Single celled parasites are harder for the immune system to find than more complex parasites. The parasitic animals are quite obvious to the immune system, and can usually be attack immediately after being detected in the body. Some parasites are not necessarily harder to find, but harder to destroy. Again, the tapeworm is a great example. The tapeworm usually has to have an intermediate host in order to survive in the final host. This is usually another mammal such as a pig, but humans can also be intermediate hosts. When the tapeworm enters the body, the immune system starts to find the T cells o help get rid of it. But by the time the immune system is ready to attack, the tapeworm has already formed into its cyst, where it could stay for years waiting for its final host. The immune system surrounds the outside of the cyst with T cells, but the parasite releases chemicals to stop the T cells from doing their job. Basically, the tapeworm can control one of the strongest systems in the body. Control is one thing that parasites need to survive. They have to be able to manipulate their hosts into doing what is needed for their own survival. In order to understand how these parasites work, we need to understand where they came from, and how they evolved. Biological control was a huge part of farming in the mid to late twentieth century. A good example of this is the mealybug in Africa decimating the cassava crop. Because most of the population in the area (around 200,000 people) depended on the crop for mere survival, something had to be done. That particular species of mealybug was not native to that area, so the key was to find where they came from, and find their natural predators. What scientists found was the paper wasp. This species of wasp would only lay its eggs in large healthy mealybugs, thus killing off the host and creating more of the parasite. When the wasp was introduced into the area, ninety-five percent of the mealybug population was wiped out. One may think that the genocide of one species just to create another would be wrong. Here in lies the solution, not the problem. Since the wasp would use only that t...