Posts or Comments 24 June 2024

Environment &Surveillance Bill Brieger | 06 Dec 2009 07:29 am

Climate change conference – implications for malaria

Copenhagen is ready for the United Nations Climate Change Conference, which opens tomorrow for two weeks. Live webcasts and archived versions will enable people with adequate bandwidth to feel part of the deliberations. At present the main consequences of climate change that are attracting global attention include –

  • More droughts and more flooding
  • Less ice and snow
  • More extreme weather incidents
  • Rising sea level

drylands-sm.JPGThese physical changes will have major social, political, economic and health consequences.  Implications for malaria specifically, require some interpretation. This is where reports of the Intergovernmental Panel on Climate Change may help.

Projected trends in climate-change-related exposures of importance to human health will have mixed effects on malaria; in some places the geographical range will contract, elsewhere the geographical range will expand and the transmission season may be changed.

The IPCC Report also acknowledges “the difficulty of generalizing health outcomes from one setting to another, when many diseases (such as malaria) have important local transmission dynamics that cannot easily be represented in simple relationships.” Examples of individual country assessments follow:

  • Australia may see potential change in the geographical range of dengue and malaria
  • Bolivia expects intensification of malaria and leishmaniasis transmission. Indigenous
    populations may be most affected by increases in infectious diseases
  • Bhutan might experience spread of vector-borne diseases into higher elevations
  • India projects that Malaria could to move to higher latitudes and altitudes

The IPCC report sees that drought would have a limiting effect on malaria.

In the long term, the incidence of mosquito-borne diseases such as malaria decreases because the mosquito vector lacks the necessary humidity and water for breeding. The northern limit of Plasmodium falciparum malaria in Africa is the Sahel, where rainfall is an important limiting factor in disease transmission. Malaria has decreased in association with long-term decreases in annual rainfall in Senegal and Niger.

We certainly do not hope that drought provides a ‘solution’ for malaria elimination in endemic countries.  What these climate proceedings should remind us of is the need for strong surveillance systems that can detect and respond to trends.

Countries therefore, need to be ready to adapt their malaria control efforts not only to the positive results of universal coverage but also to the negative spread and shifts in malaria transmission that could come from climate change.

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