Bacteria have led to the death of hundreds of millions of house finches since they jumped species and started an epidemic in the 1990s. Mycoplasma gallisepticum infected poultry before it adapted to the house finch Carpodacus mexicanus population. The bacteria are responsible for the red, swollen, crusty eyes of a sick house finch, which leaves it unable to survive.
When thousands of wild house finches started dropping dead from a mysterious eye infection in the Washington, DC, area in the winter of 1994, scientists were puzzled. The birds had red, swollen, crusty eyes that left them unable to see or forage for food, until they eventually died from starvation or predation. Researchers soon identified the cause — a bacterium called Mycoplasma gallisepticum, a common cause of respiratory infections in turkeys and chickens that was previously known to infect only poultry.
By the time biologist Geoff Hill spotted his first sick bird in Auburn, Alabama, in 1995, the disease had spread through the eastern part of the continent, as far north as Quebec and as far south as Florida. "This was a devastating pandemic," Hill said. Since its discovery, the epidemic has spread as far west as California, and is estimated to have wiped out hundreds of millions of birds. But scientists are still far from understanding how Mycoplasma gallisepticum gained the ability to spread to house finches — which diverged from chickens and turkeys some 80-90 million years ago — or what turned it into such a sweeping killer.
The House Finch (Carpodacus mexicanus) is a bird in the finch family Fringillidae, which is found in North America. Originally only a resident of Mexico and the southwestern United States, they were introduced to eastern North America in the 1940s. Their breeding habitat is urban and suburban areas in eastern North America as well as various semi-open areas in the west from southern Canada to northern Florida and the Mexican state of Oaxaca.
Sources:
msnbc.com, February 11, 2012
http://www.msnbc.msn.com/id/46343744/ns/technology_and_science-science/
physorg.com, February 9, 2012
http://www.physorg.com/news/2012-02-deadly-bird-parasite-evolves-except…
Wikipedia
http://en.wikipedia.org/wiki/House_Finch
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