May 15, 2008

sobering thought

Making a host unwell has certain benefits for the microbe. The symptoms of an illness often help to spread the disease. Vomiting, sneezing, and diarrhea are excellent methods of getting out of one host and into position for another. The most effective strategy of all is to enlist the help of a mobile third party. Infectious organisms love mosquitoes because the mosquito's sting delivers them directly to a bloodstream where they can get straight to work before the victim's defense mechanisms can figure out what's hit them. This is why so many grade-A diseases-malaria, yellow fever, dengue fever, encephalitis, and a hundred or so other less celebrated but often rapacious maladies-begin with a mosquito bite. It is a fortunate fluke for us that HIV, the AIDS agent, isn't among them-at least not yet. Any HIV the mosquito sucks up on its travels is dissolved by the mosquito's own metabolism. When the day comes that the virus mutates its way around this, we may be in real trouble.


Bummer.

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