Featured Research

from universities, journals, and other organizations

Sensitivity To Seasonal Changes Affects Disease-causing Bugs' Success

Date:
August 9, 2004
Source:
University Of Michigan
Summary:
As concerns about global warming and erratic climate fluctuations grow, scientists wonder how human disease patterns will be affected. They're especially concerned about diseases such as cholera, which seem to be strongly influenced by environmental changes.

ANN ARBOR, Mich. -- As concerns about global warming and erratic climate fluctuations grow, scientists wonder how human disease patterns will be affected. They're especially concerned about diseases such as cholera, which seem to be strongly influenced by environmental changes.

An analysis by University of Michigan graduate student Katia Koelle, to be presented Aug. 5 at the annual meeting of the Ecological Society of America in Portland, Ore., offers new insights into the relationship. Koelle used game theory to study interactions between strains of disease-causing organisms with different sensitivities to seasonal climate fluctuations. Her work helps explain why a mutant strain of cholera has replaced the original strain in Bangladesh, and the same approach might be used to predict the outcome of competition between other disease strains.

Cholera, an intestinal infection with symptoms that may include diarrhea, vomiting and leg cramps, is a serious health problem in many parts of the world. Scientists who study climate change predict that temperatures will increase worldwide and climate will become more variable in some regions, so understanding connections between human health and climate variability is more important than ever, Koelle said.

In her study, Koelle classified disease-causing organisms as seasonal generalists or seasonal specialists. Seasonal specialists can function only within narrow temperature and rainfall ranges. Seasonal generalists may not be quite as effective as specialists in the best of conditions, but they're able to function over a wider range of environmental conditions.

Koelle showed that when climate conditions are far from optimal, pathogens are under evolutionary pressure to become more generalist than specialist. Factoring in such evolutionary changes may yield more accurate long-range predictions of disease trends than just looking at the immediate ecological effects of climate change, she said.

Koelle also analyzed cholera dynamics using disease incidence data collected between 1966 and 2002 by a surveillance program of the International Center for Diarrhoeal Disease Research in Bangladesh. One strain, known as the Classical strain, has been in the area "for as long as anyone knows," Koelle said. A mutant strain, El Tor, appeared in the 1970s and has virtually replaced the Classical strain.

"I wanted to know what's different about the El Tor strain that allowed it to survive and replace the Classical strain," Koelle said. "Why is it more fit, in the evolutionary sense, than the strain that's been around for hundreds or thousands of years?" Her analysis showed that El Tor, which is more of a generalist, may have an advantage over Classical in dealing with the hot, wet summers that have been occurring in Bangladesh.

With collaborators in a working group from the National Center for Ecological Analysis and Synthesis (NCEAS), Koelle also is looking into what makes previously harmless strains of bacteria start infecting humans and causing disease, and the researchers are especially interested in the role environmental changes may play in the process.

"With escalating climate change and habitat destruction, we need to consider how these changes may affect the evolution of pathogen life history strategies, and the ultimate effects on human health," Koelle said.

Koelle did the research under the direction of Mercedes Pascual, associate professor of ecology and evolutionary biology, with funding from the University of Michigan and a grant to Pascual from a joint program on Climate Variability and Human Health funded by governmental agencies including the National Oceanic and Atmospheric Administration.


Story Source:

The above story is based on materials provided by University Of Michigan. Note: Materials may be edited for content and length.


Cite This Page:

University Of Michigan. "Sensitivity To Seasonal Changes Affects Disease-causing Bugs' Success." ScienceDaily. ScienceDaily, 9 August 2004. <www.sciencedaily.com/releases/2004/08/040805085016.htm>.
University Of Michigan. (2004, August 9). Sensitivity To Seasonal Changes Affects Disease-causing Bugs' Success. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2004/08/040805085016.htm
University Of Michigan. "Sensitivity To Seasonal Changes Affects Disease-causing Bugs' Success." ScienceDaily. www.sciencedaily.com/releases/2004/08/040805085016.htm (accessed August 1, 2014).

Share This




More Earth & Climate News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com
Big Waves In Arctic Ocean Threaten Polar Ice

Big Waves In Arctic Ocean Threaten Polar Ice

Newsy (July 30, 2014) Big waves in parts of the Arctic Ocean are unprecedented, mainly because they used to be covered in ice. Video provided by Newsy
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) 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:
from the past week

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