Scientists concerned about effects of global warming on infectious diseases

May 22, 2007

As the Earth’s temperatures continue to rise, we can expect a signficant change in infectious disease patterns around the globe. Just exactly what those changes will be remains unclear, but scientists agree they will not be for the good.

"Environmental changes have always been associated with the appearance of new diseases or the arrival of old diseases in new places. With more changes, we can expect more surprises," says Stephen Morse of Columbia University, speaking May 22, 2007, at the 107th General Meeting of the American Society for Microbiology in Toronto.

In its April 2007 report on the impacts of climate change, the Intergovernmental Panel on Climate Change (IPCC) warned that rising temperatures may result in "the altered spatial distribution of some infectious disease vectors," and will have "mixed effects, such as the decrease or increase of the range and transmission potential of malaria in Africa."

"Diseases carried by insects and ticks are likely to be affected by environmental changes because these creatures are themselves very sensitive to vegetation type, temperature, humidity etc. However, the direction of change – whether the diseases will increase or decrease – is much more difficult to predict, because disease transmission involves many factors, some of which will increase and some decrease with environmental change. A combination of historical disease records and present-day ground-based surveillance, remotely sensed (satellite) and other data, and good predictive models is needed to describe the past, explain the present and predict the future of vector-borne infectious diseases," says David Rogers of Oxford University, also speaking at the meeting.

One impact of rising global temperatures, though, can be fairly accurately predicted, says Morse. In the mountains of endemic areas, malaria is not transmitted above a certain altitude because temperatures are too cold to support mosquitoes. As temperatures rise, this malaria line will rise as well.

"One of the first indicators of rising global temperatures could be malaria climbing mountains," says Morse.

Another change could be the flu season. Influenza is a year-round event in the tropics. If the tropical airmass around the Earth's equator expands, as new areas lose their seasons they may also begin to see influenza year-round.

And extreme weather events will also lead to more disease, unless we are prepared. As the frequency, intensity, and duration of extreme weather events change, water supplies become more at risk, according Joan Rose of Michigan State University.

"Hurricanes, typhoons, tornados and just high intensity storms have exacerbated an aging drinking and wastewater infrastructure, enhanced the mixing of untreated sewage and water supplies, re-suspended pathogens from sediments and displaced large populations to temporary shelters. We are at greater risk than ever before of infectious disease associated with increasing extreme weather events," says Rose.

There will also be indirect effects of climate change on infectious disease as well. For instance, says Morse, the effect of global warming on agriculture could lead to significant changes in disease transmission and distribution.

"If agriculture in a particular area begins to fail due drought, more people will move into cities," says Morse. High population densities, especially in developing countries, are associated with an increased transmission of a variety of diseases including HIV, tuberculosis, respiratory diseases (such as influenza) and sexually transmitted diseases.

"I’m worried about climate change and agree that something needs to be done," says Morse. "Otherwise, we can hope our luck will hold out."

Source: American Society for Microbiology

Explore further: 600 Ebola cases in hard-hit countries in past week

add to favorites email to friend print save as pdf

Related Stories

NASA issues 'remastered' view of Jupiter's moon Europa

47 minutes ago

(Phys.org) —Scientists have produced a new version of what is perhaps NASA's best view of Jupiter's ice-covered moon, Europa. The mosaic of color images was obtained in the late 1990s by NASA's Galileo ...

Dish restores Turner channels to lineup

1 hour ago

Turner Broadcasting channels such as Cartoon Network and CNN are back on the Dish network after being dropped from the satellite TV provider's lineup during contract talks.

LiquidPiston unveils quiet X Mini engine prototype

6 hours ago

LiquidPiston has a new X Mini engine which is a small 70 cubic centimeter gasoline powered "prototype. This is a quiet, four-stroke engine with near-zero vibration. The company said it can bring improvements ...

Recommended for you

At one month, US Ebola monitors finding no cases

1 hour ago

The U.S. program that requires weeks of monitoring for travelers from African countries with Ebola reaches the one-month mark Thursday. And so far, no cases of the disease have turned up.

EU calls for 5,000 doctors to fight Ebola

1 hour ago

The European Commission called for 5,000 doctors to be sent from EU states to combat west Africa's Ebola epidemic, a European source with knowledge of the matter said on Wednesday.

Guinea, hit by Ebola, reports only one cholera case

1 hour ago

The health workers rode on canoes and rickety boats to deliver cholera vaccines to remote islands in Guinea. Months later, the country has recorded only one confirmed cholera case this year, down from thousands.

Sierra Leone official: Ebola worst could be over

1 hour ago

The Ebola outbreak in Sierra Leone, which has been surging in recent days, may have reached its peak and be on the verge of slowing down, Sierra Leone's information minister said Wednesday.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.