Wildlife group lists diseases that global warming may spur

Oct 8, 2008 (CIDRAP News) – The Wildlife Conservation Society (WCS) has included avian influenza, Ebola fever, Rift Valley fever, and plague on a list of 12 diseases and pathogens that it believes may spread to new regions as a result of climate change.

The report, titled "The Deadly Dozen: Wildlife Diseases in the Age of Climate Change," gives examples of diseases that may increase their ranges in response to changing temperatures and precipitation patterns, threatening wildlife and human health and causing economic damage.

The report's release yesterday at a meeting in Barcelona nearly coincided with a World Health Organization (WHO) announcement today that a group of experts has agreed on an agenda for research on the health effects of climate change.

More than melting ice caps
In releasing the WCS report, Steven E. Sanderson, president of the group, said in a statement, "The term 'climate change' conjures images of melting ice caps and rising sea levels that threaten coastal cities and nations, but just as important is how increasing temperatures and fluctuating precipitation levels will change the distribution of dangerous pathogens."

The best defense against the problem is to monitor wildlife to detect how the diseases are moving, so that health professionals can prepare to mitigate their impact, the group said.

The WCS cautioned that its list does not include all pathogens that may be spurred by climate change—and that future studies could cross some of them off the list. The group made the following observations about specific diseases (the full report was not available online):

  • Avian influenza: Currently the poultry business largely drives the geographic movement of H5N1 avian flu, "but changes in climate such as severe winter storms and droughts can disrupt normal movements of wild birds and can bring both wild and domestic bird populations into greater contact at remaining water sources."
  • Ebola hemorrhagic fever: There is evidence that outbreaks of the deadly Ebola fever and its cousin, Marburg fever, are related to unusual variations in seasonal rainfall patterns. "As climate change disrupts and exaggerates seasonal patterns, we may expect to see outbreaks of these deadly diseases occurring in new locations and with more frequency."
  • Plague: Changes in temperature and rainfall are expected to change the distribution of rodent populations, which would affect the range of rodent-borne diseases such as plague. The disease is caused by Yersinia pestis, which is spread by rodents and their fleas.
  • Rift Valley fever, a viral hemorrhagic fever. The disease causes abortions and high death rates in livestock in Africa and the Middle East and can be fatal in humans. Climate change raises concern about the disease because it is spread by mosquitoes.

Other diseases and pathogens on the WCS list are babesiosis, cholera, intestinal and external parasites, Lyme disease, the harmful algal blooms called red tides, trypanosomiasis, tuberculosis, and yellow fever. The list does not include some other mosquito-borne diseases that have often been mentioned as candidates to increase their ranges in a warming world, such as dengue fever, malaria, and chikungunya fever.

WHO lists five research priorities
The WHO announced its research agenda on the health effects of climate change at the end of a 3-day meeting of experts in Madrid.

"Our 193 member states asked WHO to help them strengthen the evidence base for policy action," WHO Director-General Margaret Chan said in a statement. "This plan provides the framework for doing just that. It sets out guidance to governments, research institutions and donors looking to fill crucial knowledge gaps."

Although climate change has been increasingly seen as a threat in the past decade, its effects on health have received little research attention, the WHO said. For example, studies on the effects of air pollution outnumber those on the health effects of climate change by almost 8 to 1.

In a news teleconference today, Tony McMichael of Australian National University, chairman of the Madrid meeting, said "one quite basic problem" is that most of the relevant research in the past decade has been done in rich countries, whereas global warming's worst effects on health are likely to occur in poor countries.

The agency said those attending the meeting identified five priority research areas:

  • Interactions of climate change with other health determinants and trends, such as economic development, globalization, urbanization, and inequities in health risks
  • Long-term changes such as increasing drought, declining freshwater supplies, and population displacement
  • The comparative effectiveness of short-term interventions to deal with climate change–related health threats such as heat waves and floods
  • The health impact of efforts to prevent or mitigate climate change, such as the potentially negative effect of biofuels development on food security
  • Strengthening public health systems to address the health effects of climate change

The aim of the plan is to speed up and focus climate change and health research to strengthen the evidence base for discussion at the United Nations conference on climate change in December 2009, the WHO said. World leaders at that meeting will try to forge a new agreement to succeed the Kyoto Protocol, which laid out steps and objectives for preventing and mitigating climate change.

The research agenda builds on a comprehensive review of what is already known about the health effects of climate change, the WHO said. The Madrid meeting included representatives of donor organizations and other UN agencies.

See also:

Oct 7 WCS news release
http://www.eurekalert.org/pub_releases/2008-10/wcs-dr100608.php

Oct 8 WHO news release
http://www.who.int/mediacentre/news/releases/2008/pr36/en/index.html

WHO information on climate change and health
http://www.who.int/globalchange/en/

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