The Virus Within, the Virus Without

Rotavirus, courtesy Wikipedia

by blogSpotter
Since various exotic diseases (HIV, Epstein-Barr, Hantavirus) became popular topics of the early 1980's, I've been interested in viruses, especially retroviruses. What makes the retrovirus interesting? It can copy its genetic material into a host cell, and make the imported material a permanent part of the host animal's genome. Scientists believe that as much as 8% of human genetic material is from ‘endogenous’ retroviruses, but can only guess what purpose any of it serves. The topic of retroviruses can lead to fanciful speculations (including my own, see last paragraph); several science fiction works cast a retrovirus as a villain’s modus operandi: Resident Evil, Doom and Stargate Atlantis to name three.

What adds to the story is that viruses are species-specific. A tobacco virus will eschew a pig, and a pig virus will shun a tobacco plant. The pig virus may take the great leap to something similar to a pig -- another mammal for instance. Is the virus making an intelligent selection? It certainly is expressing a chemical affinity, with seemingly intelligent results. Viruses also travel in ways almost as specific as a person booking a flight on orbitz.com. Methods of transmission include:

Mosquito
Ticks/Fleas
Skin contact
Breath droplets

There is speculation that a virus can alter the behavior of its host animal. Thus a mosquito could almost serve as a virus's private jet. Ticks and fleas themselves are species-specific, such that viruses on them (and in them) can make targeted landings. Obviously, skin contact is as direct as you can get -- a human who 'gets around' (Typhoid Mary let's say) could be a super-effective transmitter. Also worth noting, the least consequential viruses are normally those easiest to get -- breath droplets that give you the common cold for instance. The more 'intimate' connections seem to yield more astounding results -- permanent genome change or fatal disease. My own speculation is that genetic variety is sometimes enhanced by these mysterious viral agents, and the human body may 'open the door' for deliberate admission. Much like a company hiring a new employee, the immune system presumes it's chosen its new 'talent' wisely. This would assume that some viruses have a constructive purpose – who knows?

With biotic agents such as bacteria, you can’t judge them as universally harmful or helpful.. Some bacteria are flesh-eating deadliness at its worst. Other bacteria are actually good for you – bacteria that you get from yogurt benefit your digestion. Who is to say that the only good virus is a dead one? Maybe they perform in ways subtle and obscure – too minute for human observation. One thing to note – the virus makes it possible for genetic information to be exchanged outside of sexual reproduction. A truly permissive immune system might even admit genetic material from another species. Thus, a kiss is not just a kiss. A kiss may be very consequential – a genetic RNA infusion could result. You might or might not have physical symptoms. The world is a much more promiscuous, interesting place than we ever imagined. And these invisible cellular interlopers make it more so.

© 2006 blogSpotter.