Reducing Biodiversity Increases Risk that Diseases will Jump from Animals to People


Deer mouse, one of the species studied. Photo: Wikipedia, Public domain.
Bio-what? *cough* *cough*
It's obvious that biodiversity is a good thing, but we're still discovering new ways that it helps us. Indeed, a new study gives more evidence that reduced biodiversity can increase the chances that certain diseases will jump from animals to humans. "In the last few years, scientists have increasingly noticed that, when biodiversity dips, rates of Lyme disease, West Nile virus, SARS and other infectious diseases rise. Called zoonotic diseases, these illnesses also spread from animals to people." Read on for more details.Discovery News writes:

For most zoonotic diseases, there is usually a small number of host species that act as a reservoir for the infection. Mice and chipmunks, for example, are the main reservoirs of Lyme disease, even though the ticks that carry Lyme-causing bacteria will bite pretty much any warm-blooded vertebrates they encounter -- including raccoons, foxes and squirrels, which don't carry the disease.

When there are lots of species around, chances are greater that ticks will bite animals that don't carry Lyme disease, making them less likely to be infectious themselves when they later bite people. As diversity drops, on the other hand, mice and chipmunks are the types of species that tend to be left behind, allowing the disease to proliferate.

It's called the "dilution effect", and we should take it seriously. It's not as if we didn't already have enough reasons to protect biodiversity, but with the recent swine flu media coverage, maybe now is a good time to point out that there's one more important benefit.

Via Discovery News
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