Genes-R-Us — Viruses: The original ‘Pirates of the Caribbean’
Posted: Wednesday, December 21, 2011 5:03 pm
Last week my husband and I went on a cruise to the Western Caribbean. By the second day, our ship captain announced over the intercom system that “we” had confirmed cases of gastrointestinal illness (GI) onboard the ship. Those affected and their roommates were to stay in their room until released by cruise line medical staff (yeah, right.) and everyone else was to wash their hands — repeatedly.
Although there are many different viruses that cause gastroenteritis, half of the 14 cruise ships that reported GI illnesses to the US Center of Disease Control in 2010 were confirmed as due to the norovirus or the Norwalk-like virus.
As I am naturally immune to the norovirus, according to my direct-to-consumer genetic testing results, I felt reasonably protected from the ship’s outbreak of GI illness. (I have a broken gene that is unable to make the exact protein that the norovirus latches onto to accomplish its dirty work.) I also knew that my husband was not naturally immune.
How many times have you been told, “It’s a virus, there is no point in giving you antibiotics; you need to let the virus run its course?”
Unfortunately that is as true as it is frustrating. Antibiotics are not going to work on something that is not alive.
And viruses are not really alive like bacteria. Bacteria are single cell organisms that pretty much do the same things that we do on a macro scale: They eat, they reproduce and they excrete waste. The genomes of bacteria are much smaller than ours.
Viruses, though not alive, are not exactly dead either. In order to be classified as a life form a virus would have to be able to reproduce on its own — and it can’t. They are not really a parasite either. A virus is only a piece of genetic material and some kind of coating. Viruses can be a single or double strand of DNA. They can also be RNA, which is DNA taken a step further into the protein manufacturing process.
A virus incorporates its genetic material into the genome of the host cell by directly entering the host cell or by injecting its genetic material without actually entering the host cell. In either case, the virus hijacks the fancy reproductive machinery of the invaded cell to churn out additional copies of it.
As your immune system detects these viral “pirates,” you typically start to feel nasty. And the norovirus is particularly vile and horribly contagious. Ask anyone who has had it.
But this is not the end of the cruise story…
On the first leg of the plane ride my husband and I were unable to sit together. Sitting next to me instead was a young man with a rattling chest cough, flushed face and no hanky to sneeze or cough into. I was in the cattle car section (i.e. small seats) and the plane was full. Either an adenovirus or influenza virus was likely the culprit “pirate” in his case — not the norovirus.
About two and a half days into the cruise I knew I was coming down with some kind of upper respiratory challenge. By the fourth day, I felt like the young man sitting next to me in the plane must have felt. I was thus afforded many hours of reading time in my cabin, saved money on excursions that did not happen and perhaps consumed less delicious food than I would have otherwise.
But this is not the end of the cruise story either.
About six hours after we arrived home last night, my husband awoke feeling lousy and nauseated. All symptoms considered (of which I will spare you the details) he appears to have a GI-type virus. Maybe it is not the norovirus, for his sake; although that would be good for me.
But the very thing that makes the virus a foe can also make the virus a friend. For some diseases scientists know what genes are defective, mutated or simply turned off.
In gene therapy the defective piece of DNA is replaced by a properly functioning piece of DNA.
Since viruses have perfected the process of inserting their genome into their host cell’s genome, scientists have used viruses as one method of patching into the genome a functional gene. In the early years of gene therapy, some unfortunate choices for the virus vector killed this amazing area of research for more than 15 years.
At this point I doubt reading about the promise of gene therapy using viral vectors will improve my husband’s sense of well being. But I do hope by the time you read this column he feels much better and still loves cruising as much as I do.
And that would be a nice end to this cruise story.
Nancy Miller Latimer has worked in scientific research and development for 27 years. She blogs at neuronalbeauty.blogspot.com. Published in The Messenger 12.21.11