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Desert Diary

Arthropods/Blood Sisters


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Disease transmission has always had nasty surprises lurking about. We've long known that West Nile virus is spread by female mosquitoes who pick up the virus by feeding on infected birds. If such a mosquito then feeds on a human, transmission to the human may occur, causing infection. A recent addition to our knowledge as to how the disease spreads is ominous: the host upon which the mosquitoes feed doesn't itself have to be infected. Instead, if an infected mosquito feeds on an uninfected host at the same time as an uninfected mosquito, the second mosquito may pick up the virus and thenceforth be able to pass it on. It's suggested that this may be one reason that the West Nile virus has spread so rapidly in North America since its introduction.

West Nile virus is a serious concern in the Chihuahuan Desert, where most human populations tend to cluster around sources of water—the very habitats necessary for mosquito reproduction. If you're attacked, hope that the little vampires are well mannered enough to wait their turns.

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Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.