A parasite is a living organism that lives by exploiting another organism. Parasitism is a form of one-sided symbiosis where the parasite benefits and the host is harmed. While it used to be thought that parasites were very simple creatures generally with little impact on their ecosystems; however, biologists now understand that parasites can be very sophisticated, precisely created to take advantage of their hosts and that parasites can have significant effects on their environment and on their host's life. Common parasites in humans include Toxoplasmosis and the Malarial parasite. Worms are also common parasites, with up to 7,000 species of parasitic worms described. These species include the roundworms, hookworms and whipworms. Most parasitic worms are nematodes that are invisible to the naked eye.
Unlike many bacterias and viruses, parasites can have extremely long lifespans. Tapeworms, for example, can live up to 10 years, or more, in a host. Some forms of protozoan parasites called trypanosomes will persist in the heart muscle, skin and liver for a person's entire life, these cause the fatal illness Chagas' disease and are common in South America. Charles Darwin may have suffered from Chagas' disease.
Young earth creationists see parasites, along with diseases, as coming about as a result of Adam's sin against God and are one of the problems that arose on Earth because of the beginning of sin. For example, viruses are categorized as obligate intracellular parasites, and are ‘infectious particles’ rather than organisms. Creation scientist Dr. Jerry Bergman asserts that God did not make pathogenic viruses and that it is a result of a post fall world. Bergman says that "pathogenesis is evidence of something gone wrong, a mutation or the accidental movement of genes, and not evidence of a system deliberately designed to cause human disease and suffering. In addition, creation scientists point out that the elimination of some parasites cannot be explained vis a vis the theory of evolution. For example, David Catchpoole wrote:
|“|| Carnivorous fish such as the Oriental sweetlip and the coral rock cod normally feed voraciously upon shrimps and smaller fish. But these photographs show them placidly allowing cleaner wrasse and cleaner shrimp to crawl around tongue, gill chamber and vicious-looking teeth—and the cleaners don’t seem to be at all reticent to enter the 'jaws of death'. And when the wrasse and shrimp have finished picking off parasites, the large fish let the cleaners go again without eating them.
The 'cleaning symbiosis' benefits both species, but evolutionary mutation/selection can’t explain how it arose. Nobel laureate Albert Szent-Györgi summed up the evolutionary puzzle presented by such symbiotic relationships (he was actually referring to a much simpler relationship between a young herring gull and its parent): ‘All this had to be developed simultaneously [like the cleaner entering the big fish’s mouth at the same time the big fish suspends his 'normal' (post-Fall) habit of eating small fish], which as a mutation has the probability of zero. I am unable to approach this problem without supposing an innate drive in matter to perfect itself.'
- Zimmer, Carl, Parasite Rex, Simon & Schuster 2001, ISBN 0743213718 Excerpt
- Taylor, Paul S. and Van Bebber, Mark Is the age of the Earth a “trivial” doctrinal point?, 1998 (ChristianAnswers.net).
- Armitage, Mark H., Trematode Parasites: What Is Their Genesis? CRS Quarterly, 36(3):184-194 March 2000.
- Bergman, Jerry, Did God make pathogenic viruses?, Journal of Creation 13(1):115–125, April 1999
- Parker, Gary, Nature's Challenge to Evolutionary Theory, 2007 (Institute for Creation Research)
- Catchpoole, David, Off the menu …, Creation 28(2):56, March 2006.
- "Only now are scientists thinking seriously about how parasites may be as important to ecosystems as lions and leopards.", Zimmer, 2001, p xxi-xxii.
- Zimmer, 2001
- Armitage, 2000
- Bergman, 1999
- Parker, 2007.
- Catchpoole, 2006