Scientists Concerned About Effects Of Global Warming On Infectious Diseases
Pastor Dale Morgan
Scientists Concerned About Effects Of Global Warming On Infectious Diseases*
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.
by Staff Writers
Toronto. Canada (SPX) May 23, 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."