Stardate 20011005.1049 (On Screen): Chemotherapy for treatment of disease is one of the most miraculous inventions of modern medical science -- and one of the most fragile, for it runs right into the theory of Evolution. There is genetic variation in the disease pathogens and mutation takes place constantly. When a single victim of a disease may have upwards of a billion pathogens inside, and when they reproduce every half hour, and when you have millions of victims, there's plenty of opportunity for newer, more resistant strains to develop. The drugs simply become part of the environment, one more aspect of selection. The pathogens who are susceptible to the drug will preferentially die, the ones resistant will preferentially survive, and soon resistant forms of the disease will spread and become common. Thus development of drugs for treatment of diseases has to be thought of as a holding action. As soon as you've found one, you need to start looking for the next one, because the one you've found will eventually become useless.
As many as one sixth of the people in the US who are infected with HIV have a version which is resistant to the drugs currently used to treat the disease, and of course that will continue to become more common. All the existing drugs work by trying to interfere with the reverse transcription by which HIV, an RNA virus, adds its genetic information to the DNA in the chromosome of the cell it infects (using an enzyme called Reverse Transcriptase). A research team has now found a new target which could potentially be attacked with drugs, the protein which the virus uses to exit a cell so as to try to infect another one. It's an interesting approach and I hope it works, but it isn't going to be a cure, and even if it does work it won't work forever.
The right treatment for HIV is still prevention. Though I have enormous respect for him and don't wish him ill, I sometimes find myself wishing that Magic Johnson didn't look so damned healthy. He's unconsciously a walking poster child for the idea that HIV isn't really very serious. (discuss)
