Global Warming Linked to Spread of Infectious Diseases

>From Grist Magazine <www.grist.org> 2/23/05

GLOBAL WARMING -- IT'S INFECTIOUS
Environmental change linked to spread of infectious diseases

If the catastrophic flooding, drought, and weather-related calamities
associated with global warming don't kill you, exotic infectious
diseases might step up to do the job, a new report released by the
U.N. suggests. It found that changes to the environment -- such as
deforestation, urban growth, mining, and pollution of coastal waters
-- may be aiding the spread of infectious diseases, including
ailments never before seen in humans. The report also suggests that
global warming could be a major aggravating factor because rising
temperatures and altered habitats could allow more diseases and their
carriers to flourish. Climate change may also increase the number of
environmental refugees moving to new areas and taking germs with
them. The researchers noted a rise in the occurrence of dengue
fever, found in only nine countries in the 1970s, but now present in
more than 100. Other ailments scientists have linked to the
environment include tuberculosis, bubonic plague, and cholera.

straight to the source: The Independent, Michael McCarthy, 22 Feb 2005
<http://grist.org/cgi-bin/forward.pl?forward_id=4391>

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The Independent (UK)

New diseases arise as environments destroyed, says UN

By Michael McCarthy, Environment Editor

22 February 2005

Changes to the environment that are sweeping the planet are bringing about a
rise in infectious diseases, the United Nations Environment Programme (Unep)
has warned.

Loss of forests; the building of roads and dams; urban growth; the clearing
of natural habitats for agriculture; mining; and pollution of coastal waters
are promoting conditions under which new and old pathogens can thrive,
according to research published today in Unep's Global Environment Outlook
Year Book for 2004/2005.

Ailments previously unknown in human beings are appearing, such as the Nipah
virus, which until recently was found normally in Asian fruit bats,
according to the report.

Nipah's emergence in the late 1990s as an often fatal disease in humans has
been linked to a combination of forest fires in Sumatra and the clearance of
natural forests in Malaysia for palm plantations. In searching for fruit,
bats were forced into closer contact with domestic pigs, giving the virus
its chance to spread to humans.

Climate change in particular may aggravate the threats of infectious
diseases in three ways, the report suggests. First, by increasing the
temperatures under which many diseases and their carriers flourish.

Second, by further stressing and altering habitats. For example, the
geographic range and seasonality of two of the world's most serious
mosquito-borne infections, malaria and dengue fever, are very sensitive to
changes in climate. Also, Neissseria meningitidis, a common cause of
meningitis, can be spread many miles in the dusty conditions that occur
following prolonged drought in the Sahel.

Third, climate change may increase the number of environmental refugees who
are forced to migrate to other communities, or even countries. This in turn
will also favour the spread of diseases from one location to
another.Overall, it seems that intact habitats and landscapes tend to keep
infectious agents in check.

The issue of environmental degradation and a rise of many new and old
infectious diseases is a complex, sometimes subtle one that is causing
increasing concern among scientists and disease specialists.

Many scientists are now convinced that ecological disruption, dramatic
environmental change, and poor handling of human and animal wastes are
playing an important part in the spread of diseases such as malaria,
bilharzia, Japanese encephalitis, and dengue haemorrhagic fever.

The report is based on research by some of the leading specialists. They
include Tony McMichael of the Australian National University, Bernard
Goldstein of the University of Pittsburgh and Jonathan Patz of the
University of Wisconsin.

© 2004 Independent Digital (UK) Ltd