http://www.msnbc.com/news/768925.asp
Malaria is spread to humans through the Anopheles mosquito. A new study in the journal Science expects global warming would extend the range of the mosquito and the disease.
From coral reefs to rainforests, diseases are spreading among marine and land animals including humans and global warming appears to be a major factor, researchers reported Thursday in the journal Science. The study, said to be the first to analyze disease epidemics across entire plant and animal
systems, bolsters climate models that have factored in the possibility of a
warmer Earth creating a sicker planet.
WHAT IS MOST surprising
is the fact
that climate sensitive outbreaks
are happening with so many different types of
pathogens viruses, bacteria,
fungi, and parasites as well as in such a wide
range of hosts including
corals, oysters, terrestrial plants, birds and humans,
lead author Drew Harvell,
a Cornell University biologist, said in a statement.
The researchers said they felt that common traits are likely linked to
global warming. Climate
change is disrupting natural ecosystems in a way that
is making life better for
infectious diseases, stated Andrew Dobson, a
Princeton University epidemiologist.
The accumulation of evidence has us
extremely worried. We share
diseases with some of these species. The risk for
humans is going up.
Human influences
Humans might be magnifying
warming by adding to the greenhouse gases naturally
present in the atmosphere.
Fuel use is the chief cause of rising carbon dioxide
levels. On the other hand,
humans create temporary, localized cooling effects
through the use of aerosols,
such as smoke and sulfates from industry, which
reflect sunlight away from
Earth.
The study tracked both causes and carriers of diseases that develop
more rapidly with slight
rises in temperature. It found that as temperatures
increase, carriers are likely
to spread into new areas where they could
devastate species that have
not been previously exposed.
In the statement accompanying the study, the scientists cited these
examples of disease outbreaks
tied to climate change:
Expanding range of
disease carriers due to temperature. Honeycreepers, forest
songbirds that evolved only
in Hawaii, are being decimated by malaria from
mosquitoes that have been
able to range higher in elevation due to warmer
temperatures. Today there
are no native birds below 4,500 feet, said Dobson.
Expanding range of
carriers due to moisture. Rift Valley Fever, a deadly viral
illness spread by mosquitoes,
is strongly linked to heavy rains, which trigger
mosquito explosions. There
is clear evidence that Rift Valley Fever outbreaks
are linked to El Niño
years and we expect an increase in the frequency of El
Niños with climate
change, stated coauthor Richard Ostfeld, a researcher at the
Institute of Ecosystem Studies
in Millbrook, N.Y.
Increased susceptibility
to disease. Coral reefs have become susceptible to
disease once they are stressed
by warmer sea temperatures. The researchers
isolated one fungus threatening
Caribbean sea fans and found that it grows
fastest at exactly the temperature
at which many of the corals in the Florida
Keys start to bleach, a
stress-created condition that turns coral white and can
eventually lead to die-offs.
Expanding range of
carriers in winter. Warmer winter temperatures can also
affect ranges of diseases
and carriers. A winter warming trend in the mid-1990s
allowed a parasite to spread
north to Maines oysters, the researchers noted.
MORE STUDIES URGED
The researchers urged other experts to consider that diseases in their
specialty might share a
common link in global warming.
This isnt just a question of coral bleaching for a few marine
ecologists, nor just a question
of malaria for a few health officials the
number of similar increases
in disease incidence is astonishing, said Ostfeld.
We dont want to be alarmist,
but we are alarmed.
The authors said they expect others to question their findings, in part
because
the issue of climate change
and diseases has had very little monitoring and few
long-term studies.
An immediate critic was Sherwood Idso, head of the Center for the Study
of Carbon Dioxide and Global
Change. He said the Science paper was based largely
on speculation and presented
no concrete examples that these things will happen
in the real world.
The authors urged the scientific community to tackle the issue head on
with more research and gathering
of statistics.
We need to pay better attention to this issue in an increasingly
unnatural world, stated
Dobson.
MSNBC.coms Miguel Llanos and The Associated Press contributed to this
report.
Arthur Magazine 