The Adaptive Parasite
Viruses are molecular sharks, a motive without a mind. They have sorted themselves into tribes, and they infect everything that lives. . . . Unknown viruses are coming out of the equatorial wildernesses of the earth and discovering the human race. . . . You might call AIDS the revenge of the rainforest. (Preston 160-61)
After reading Richard Preston's ominous and threatening portrayal of viruses in his article "Crisis In The Hot Zone," one may be alarmed enough to invest in surgical scrubs and a space suit to wear as a permanent precaution against these evidently vengeful creatures. In truth, there are lethal viruses that exist for which there is currently no vaccine or cure, and there are various emerging viruses that are infectious to humans. However, despite this unfortunate and frightening reality, Richard Preston and other creative writers may be presenting a misleading depiction of a virus' actual niche within the global ecosystem, modes of infection, and relationship with humans. Science fiction novels and movies like "Outbreak" encourage the public to view viruses as microscopic monsters that exist to ultimately put an end to the human population, but viruses are not motivated by either logic or instinct to kill. In fact, viruses are not motivated at all. They have merely evolved to survive by utilizing the raw materials that the ecosystem provides. Viral pathogens have developed, through the selective process of evolution, to exist as parasites, and the inevitable ecological interaction between organisms, the ignorance and negligence of human behavior, and the cultural habits and customs of humanity has enabled a multitude of viruses to emerge and thrive within our population.
Viruses are simple, microscopic organisms; however, they are no exception to the evolutionary function of natural selection. The process of evolution results when organisms reproduce more individuals than the environment can support, genetic variation naturally and inevitably occurs, the organisms that are the most successful within their habitat survive, and those that are deficient and weak are eliminated. The survivors of this ecological pressure are able to flourish, reproduce, and pass their favorable genes onto subsequent generations. Many biologists believe that viruses evolved after the appearance of the first cells and favor the hypothesis that they "originated from fragments of cellular nucleic acids, [DNA or RNA], that could move from one cell to another" within an organism (Campbell, Mitchell, and Reece 330). This theory asserts that a portion of DNA or RNA initially became separated from the remainder of the cell's genome, and the newly formed virus then migrated into another cell. Isolated fragments of DNA or RNA would be biologically inert; therefore, viruses have been "engineered by the forces of evolution" to maximize their survival as mobile, parasitic organisms (Preston 159). Viruses, as mere...