Earthsky Interviews
Private: Familiar suburban birds hit hard by West Nile virus
May 19, 2007 - Biodiversity
Here in the U.S., the virus, which is spread by mosquito bites, has infected almost 24 hundred people and killed 962, according to the “Centers for Disease Control and Prevention”:http://www.cdc.gov (CDC.) But the disease has been far deadlier for birds, the Associated Press “reported”:http://www.wilmingtonstar.com/apps/pbcs.dll/article?AID=/20070517/NEWS/705170373/-1/State. The death toll for crows and jays is in the hundreds of thousands.
According to a study published yesterday in the journal Nature, the West Nile virus has hit seven bird species especially hard – American crow, blue jay, tufted titmouse, American robin, house wren, chickadee and Eastern bluebird. The hard-hit of all of these has been the crow. The virus has killed about one-third of crows nationwide.
All seven of these species are associated with cities and suburban areas, which suggests that our human world is creating breeding places for mosquitoes, according to a “Reuters”:http://today.reuters.com/news/articlenews.aspx?type=scienceNews&storyID=2007-05-17T213859Z_01_N17350854_RTRUKOC_0_US-WESTNILE-BIRDS.xml&pageNumber=0&imageid=&cap=&sz=13&WTModLoc=NewsArt-C1-ArticlePage2 report.
The birds act as an early warning system for humans, said Wesley Hochachka, assistant director of bird population studies at Cornell Lab of Ornithology. “If you start seeing crows dying and dying in numbers, that means there could be a human outbreak,” said Hochachka.
About 80 percent of people infected with West Nile virus show no symptoms. But about one in 150 will develop severe illness, with symptoms including high fever, disorientation, coma, tremors, convulsions, vision loss and paralysis, according to the CDC.
On the Internet:
“Centers for Disease Control and Prevention maps and figures on human cases of West Nile virus”:http://www.cdc.gov/ncidod/dvbid/westnile/surv&control.htm