Featured Research

from universities, journals, and other organizations

Bird Diversity Lessens Human Exposure To West Nile Virus

Date:
October 8, 2008
Source:
Washington University in St. Louis
Summary:
This one's for the birds. A study by biologists shows that the more diverse a bird population is in an area, the less chance humans have of exposure to West Nile Virus.

When the red, red robin comes bob, bob bobbin' along, think West Nile Virus (WNV). Robins are anthrophilic - they love being around humans - and it's relatively easy for mosquitoes to take their blood meals from them because robins feed so much on the ground, making them a very common reservoir species for transferring WNV to humans.
Credit: Image courtesy of Washington University in St. Louis

This one's for the birds. A study by biologists at Washington University in St. Louis shows that the more diverse a bird population is in an area, the less chance humans have of exposure to West Nile Virus (WNV). Now, let's hear it for the birds.

Related Articles


"The bottom line is that where there are more bird species in your backyard, you have much lower risk of contracting West Nile fever," said Brian Allan, doctoral candidate in biology in Arts & Sciences at Washington University in St. Louis. "The mechanisms are similar to those described for the ecology of Lyme disease. Most birds are poor reservoirs for West Nile Virus, and so mosquito bites taken on them are 'wasted' from the perspective of the virus. Where many bird species exist, very few mosquitoes get infected, and so we humans are at low risk. A few bird species are highly competent reservoirs, and these tend to occur in urbanized and suburbanized areas where bird diversity suffers."

The most common "reservoir" species that urbanites and suburbanites and even rural dwellers in heavily farmed landscapes see are crows, grackles, house finches, blue jays, sparrows and American robins, with the robin being the most prolific carrier of WNV. Robins are anthrophilic — they love being around humans — and it's relatively easy for mosquitoes to take their blood meals from them because robins feed so much on the ground.

Allan, his advisor Jonathan M. Chase, Ph.D., associate professor of biology, and 14 collaborators from numerous institutions will publish their findings in a forthcoming issue of Oecologia.

While diversity of bird species is important in this scenario, that factor alone doesn't tell the whole story.

"It's not just about the number, but their relative proportions," Allan said. "It's a combination of richness - the number of species — and evenness — their relative proportions. In urban and suburban areas you see lower species richness and lower community evenness. For instance, you might have five species present, but in 100 animals 90 are just one species. That's why species number is only half the equation."

Allan and numerous graduate students began the research five years ago as they just entered graduate school and the topic of West Nile Virus was just beginning to receive lots of attention and the ecology of the organism hadn't been studied much. They identified a variety of field sites, both urban and rural, with their base of operations at Washington University's Tyson Research Center, a facility 22 miles west of St. Louis comprised of 2,000 acres of woods, glades and prairie.

They performed bird surveys at the sites, put up a variety of mosquito traps and studied different mosquito species and their ability to transmit the virus. Using kits provided by the Center for Disease Control, they tested the mosquitoes and found three positive pools.

"The infection rates are actually remarkably low, with maybe one in 1,000 carrying WNV," Allan said.

They expanded their study to include mosquito infection data from the St. Louis City and St. Louis County Health departments. They saw the same patterns. The greater bird diversity, the lesser incidence of WNV; the lesser diversity, the greater likelihood of WNV.

To broaden their finding even more, Allan and his colleagues used national data sets on human cases of WNV and a tool called the Shannon Diversity Index to estimate the diversity of bird populations across the U.S. These data are conducted nationwide by amateur bird watchers for the United States Geological Survey's Breeding Bird Surveys.

"We're seeing locally and nationally that bird diversity is a buffer against the occurrence of West Nile Virus in humans," Allan said. "That's a win-win situation for both conservation and public health."


Story Source:

The above story is based on materials provided by Washington University in St. Louis. Note: Materials may be edited for content and length.


Cite This Page:

Washington University in St. Louis. "Bird Diversity Lessens Human Exposure To West Nile Virus." ScienceDaily. ScienceDaily, 8 October 2008. <www.sciencedaily.com/releases/2008/10/081006180811.htm>.
Washington University in St. Louis. (2008, October 8). Bird Diversity Lessens Human Exposure To West Nile Virus. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2008/10/081006180811.htm
Washington University in St. Louis. "Bird Diversity Lessens Human Exposure To West Nile Virus." ScienceDaily. www.sciencedaily.com/releases/2008/10/081006180811.htm (accessed October 23, 2014).

Share This



More Plants & Animals News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Working Mother DIY: Pumpkin Pom-Pom

Working Mother DIY: Pumpkin Pom-Pom

Working Mother (Oct. 22, 2014) How to make a pumpkin pom-pom. Video provided by Working Mother
Powered by NewsLook.com
Goofy Dinosaur Blends Barney and Jar Jar Binks

Goofy Dinosaur Blends Barney and Jar Jar Binks

AP (Oct. 22, 2014) A collection of dinosaur bones reveal a creature that is far more weird and goofy-looking than scientists originally thought when they found just the arm bones nearly 50 years ago, according to a new report in the journal Nature. (Oct. 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins