Featured Research

from universities, journals, and other organizations

Global Warming Would Foster Spread Of Dengue Fever Into Some Temperate Regions

Date:
March 10, 1998
Source:
NIH-National Institute Of Environmental Health Sciences
Summary:
Scientists using computers to simulate the general circulation of the earth's climate have predicted that rising global temperatures will increase the range of a mosquito that transmits the dengue fever virus. Dengue fever is now considered the most serious viral infection transmitted in man by insects, whether measured in terms of the number of human infections or the number of deaths.

Scientists using computers to simulate the general circulation of the earth's climate have predicted that rising global temperatures will increase the range of a mosquito that transmits the dengue fever virus. Dengue fever is now considered the most serious viral infection transmitted in man by insects, whether measured in terms of the number of human infections or the number of deaths.

Most of the new areas of mosquito encroachment were predicted to be temperate regions that currently border on endemic zones. These fringe areas represent places where humans and the primary carrier, the mosquito Aedes aegypti, often co-exist, but where lower temperatures now limit disease transmission. Lead author Jonathan Patz, MD, MPH, from the Johns Hopkins School of Public Health said, "Since inhabitants of these border regions would lack immunity from past exposures, dengue fever transmission among these new populations could be extensive." Unlike the yellow fever virus, carried by the same mosquito, the dengue virus is not vulnerable to any vaccine or drug.

The only serious outbreak of dengue fever in the continental United States occurred in Philadelphia in 1780, when the ship-borne introduction of the virus apparently coincided with an unusually hot summer.

The researchers used three different general circulation models to predict the patterns of global climate change; all three showed that dengue's epidemic potential increases with a relatively small temperature rise. The higher a virus's epidemic potential, the fewer mosquitoes are necessary to maintain or spread dengue in a vulnerable population.

The geographic range of Ae. aegypti is limited by freezing temperatures that kill overwintering larvae and eggs, so that dengue virus transmission is limited to tropical and subtropical regions. Global warming would not only increase the range of the mosquito but would also reduce the size of Ae. aegypti's larva and, ultimately, adult size. Since smaller adults must feed more frequently to develop their eggs, warmer temperatures would boost the incidence of double feeding and increase the chance of transmission.

In addition, the time the virus must spend incubating inside the mosquito is shortened at higher temperatures. For example, the incubation period of the dengue type-2 virus lasts 12 days at 30 C, but only seven days at 32-35 C. Shortening the incubation period by five days can mean a potential three-fold higher transmission rate of disease.

An estimated 2.5 billion people are currently at risk from dengue infection, and since the late 1970s dengue has reemerged in the Americas, with 280,000 reported cases reported in Latin America in 1995 alone. Outbreaks in urban areas infested with Ae. Aegypti, can be explosive, involving up to 70-80% of a population.

While the accuracy of long-term climate forecasting by computers will continue to be questioned, the global warming scenarios predicted by the various different computer models are increasingly coming to resemble one another.

Climatologists are projecting that global climate will change at an unprecedented rate over the next century. Dr. Patz said, "Our study makes no claim that climate factors are the most important determinants of dengue fever.

However, our computer models illustrate that climate change may have a substantial global impact on the spread of dengue fever."

The study was funded in part by the Climate Policy and Assessment Division of the U.S. Environmental Protection Agency, the National Institute of Public Health and Environment (RIVM) (the Netherlands), and the Center for Medical, Agricultural, and Veterinary Entomology of the U.S. Department of Agriculture.

The research was published in the March issue of Environmental Health Perspectives, the monthly journal of the National Institute of Environmental Health Sciences.


Story Source:

The above story is based on materials provided by NIH-National Institute Of Environmental Health Sciences. Note: Materials may be edited for content and length.


Cite This Page:

NIH-National Institute Of Environmental Health Sciences. "Global Warming Would Foster Spread Of Dengue Fever Into Some Temperate Regions." ScienceDaily. ScienceDaily, 10 March 1998. <www.sciencedaily.com/releases/1998/03/980310081157.htm>.
NIH-National Institute Of Environmental Health Sciences. (1998, March 10). Global Warming Would Foster Spread Of Dengue Fever Into Some Temperate Regions. ScienceDaily. Retrieved October 2, 2014 from www.sciencedaily.com/releases/1998/03/980310081157.htm
NIH-National Institute Of Environmental Health Sciences. "Global Warming Would Foster Spread Of Dengue Fever Into Some Temperate Regions." ScienceDaily. www.sciencedaily.com/releases/1998/03/980310081157.htm (accessed October 2, 2014).

Share This



More Health & Medicine News

Thursday, October 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Pregnancy Spacing Could Have Big Impact On Autism Risks

Pregnancy Spacing Could Have Big Impact On Autism Risks

Newsy (Oct. 1, 2014) A new study says children born less than one year and more than five years after a sibling can have an increased risk for autism. Video provided by Newsy
Powered by NewsLook.com
Robotic Hair Restoration

Robotic Hair Restoration

Ivanhoe (Oct. 1, 2014) A new robotic procedure is changing the way we transplant hair. The ARTAS robot leaves no linear scarring and provides more natural results. Video provided by Ivanhoe
Powered by NewsLook.com
Insertable Cardiac Monitor

Insertable Cardiac Monitor

Ivanhoe (Oct. 1, 2014) A heart monitor the size of a paperclip that can save your life. The “Reveal Linq” allows a doctor to monitor patients with A-Fib on a continuous basis for up to 3 years! Video provided by Ivanhoe
Powered by NewsLook.com
Attacking Superbugs

Attacking Superbugs

Ivanhoe (Oct. 1, 2014) Two weapons hospitals can use to attack superbugs. Scientists in Ireland created a new gel resistant to superbugs, and a robot that can disinfect a room in minutes. Video provided by Ivanhoe
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


Health & Medicine

Mind & Brain

Living & Well

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