New Diseases Arise As Environments Destroyed -
UN
By Michael McCarthy - Environment Editor - The Independent
UK - 25 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.
©2005 Independent News & Media (UK) Ltd.
http://news.independent.co.uk/
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