Re: Am I the only person...

"The rise of AIDS, SARS, and now bird flu are all indirectly related to disinfectants and global mass immunizations. When you reduce the population of innocuous viral agents, it makes "room" for the nastier ones to flourish. Just like Antibiotics set you up for secondary infections and ongoing health problems.

I remember sitting in lecture 19 years ago and thinking "wow, if you apply fitness to infectious agents, we're going to see a some really lethal viruses crop up in this lifetime" and now here it is..."

I have to disagree...it's not as if before the advent of immunization there were no deadly diseases, nor after are there more. Really lethal viruses have appeared throughout history, and will continue to do so. The rise of AIDS, SARS, and bird flu have more to do with:

1. Transportation - in this day and age, flying across the globe is easier than ever before. You never know what diseases are hitching a ride, allowing rapid establishment of a pandemic. For example, someone in Hong Kong acquires SARS, but shows no serious symptoms yet is infectious. They catch a plane to the US, infecting several passengers in the process. Upon arrival, these passengers each go their separate ways - you now have a pandemic. Diseases are no longer confined to their origins as in the past (think smallpox and its introduction to North America).

2. Better medical treatment. People with deadly, infectious diseases are living longer, increasing their ability to spread it. Not to mention, the population of susceptible individuals is increasing (elderly, AIDS patients, other immuno-compromised individuals). Natural selection is a thing of the past (for humans).

3. Overcrowding/Population Density/Contact. Metropolises/Cities give viruses the high population they need to flourish. There is a critical threshold in population if a virus is to be successful.

Antibiotics increasing chances for secondary infections operates by a different mechanism - reducing the population of the natural gut flora that normally inhibit establishment by more pathogenic spp. (through secretion of inhibitors, preventing attachment, reducing nutrient availability, etc.). There is no "natural viral flora" that inhibit establishment by more virulent viruses. The only possible mechanism I can think of in which immunization increases likelihood of increased virulence is inhibiting the "culling of the weak," as bad as that sounds. Of course this is all just based on what I know, which may very well be wrong - I welcome debate. Tweet