Last night I scared the bejesus out of myself reading about the Spanish flu epidemic of 1917, hantavirus, and the Ebola virus. Then I started to wonder. We can kill bacteria. If you come down with a nasty case of bubonic plague, it's at least possible that your doctor could knock it out with an antibiotic. How come we can't kill viruses once they've gotten inside a person? Is anyone working on figuring out how?
Randi, via the Internet
There’d better be, considering the money we pour into antiviral research. But beating viruses isn’t easy. They’re so little — only 1/20th to 1/100th the size of an average bacterium — that most can’t be detected with an ordinary light microscope; you need the electron variety. Worse, a virus is not, strictly speaking, a living organism, and it’s pretty tough to kill what ain’t alive.
You think computer viruses are insidious? They’ve got nothing on the organic kind. Unlike bacteria, viruses aren’t cells. They’re basically just encapsulated DNA or RNA code. They can’t reproduce on their own, so they can’t be grown in the lab (not without special tricks anyway), which makes them hell to detect. The world’s smallest parasites, they do their thing by insinuating themselves into living cells and using the host cell’s amino acids and other chemical building blocks to reproduce. Some viruses insert their DNA into the host’s DNA, so that the viral DNA reproduces whenever the cell does. To destroy the virus you have to destroy the host cells and maybe the host, which sorta defeats the purpose.
In short, virologists have their work cut out for them. Despite decades of research, most viruses have no cure. Antibiotics are useless — prescribing them for a viral infection only helps breed drug-resistant strains of bacteria. The most effective approach is still vaccination, which creates antibodies that intercept the virus before it invades a cell. Antibodies can’t penetrate cell membranes, though, so once a virus gets past that point, too bad for you.
Apart from vaccination, antiviral drug researchers focus on interfering with virus replication — something that’s easier said than done. Effective antiviral drugs are available for only a handful of diseases, and typically the virus is merely suppressed rather than wiped out. For example, using a cocktail of drugs (reverse transcriptase inhibitors and a protease inhibitor), doctors have been able to reduce HIV in the blood to undetectable levels, but the recipients must stay on the drugs for life. Then again, using a combination of alpha interferon and ribavirin, doctors have produced seemingly permanent remission of hepatitis C, so clearly there’s hope. For now, though, prevention, be it vaccination or safe sex, is still your best bet.
In a current Volkswagen commercial, a customer in a car repair shop sees a spare tire in the trunk of a VW and says he thought full-size spare tires were extinct. The repair guy says, “That’s what they said about the colacanth.” Later the repair guy goes on, “Prehistoric fish. They thought it disappeared over ten thousand years ago, then somebody caught one off the coast of Madagascar — colacanth?” — as if to say, “You know about this, right?” I didn’t. What’s more, I didn’t find anything when I looked it up. What gives?
You weren’t spelling it right, silly — it’s coelacanth. Don’t feel bad — the scriptwriter for the commercial obviously didn’t have much of a clue either. Experts originally thought the coelacanth became extinct 65 million years ago, not ten thousand. Either way, reports of the critter’s demise were greatly exaggerated. In 1938 a specimen was caught off the African coast. For nearly 60 years thereafter the several hundred coelacanths near the Comoro Islands, north of Madagascar, were believed to be the last of their kind.
Wrong again. In 1997 a scientist and his wife were walking through an Indonesian fish market when the wife spotted a fishmonger having a special on fresh coelacanth. (Well, one fresh coelacanth.) The couple barely managed to snap a photo before the thing was sold. A year later another specimen was pulled from Indonesian waters. Scientists are now trying to figure out how the coelacanth could have migrated thousands of miles from Madagascar. The rest of us are trying to figure out how scientists could have overlooked a five-foot-long fish. Keep an eye on that tuna melt; the next sighting could be yours. For more, see www.dinofish.com.
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