As swine flu continues to wreck havoc in the life of Mexico City residents and threatens to escalate to a global pandemic, the question of whether climate change might have a role in spread of disease seems appropriate. The short answer is “YES,” climate is likely to have a significant effect on the proliferation and geographic distribution of diseases.
Many of the world’s most notorious and persistent diseases, for example, are directly related to the lack of clean water and proper sanitation. The UN, in its 3rd World Water Assessment Report, attributes nearly three million deaths annually to such maladies. As temperatures rise, vector-borne diseases like malaria and dengue fever are expected to expand their range into regions that previously had been inhospitable to them. Likewise, where climate change causes precipitation to increase, water-borne pathogens including bacteria, parasites and algal blooms will flourish. The result will be a significant geographical shift in the range and proliferation of various diseases.
In the case of swine flu and other diseases originating in animals, changing climates could disrupt normal geographic movements and distributions of animals harboring such diseases. These disruptions could bring the pathogens into closer contact with other animals and pathogens, as well as humans, and could result in alternate transmission routes and, possibly, alternate mutations.
Last October (2008), the Wildlife Conservation Society (a US organization based at the Bronx Zoo that operates in 60 nations to save wildlife and habitats worldwide), issued its “deadly dozen” list of diseases that could spread into new regions and become more virulent as a result of climate change. Among others, the list included avian flu, one of the three genetic components of the Mexico swine influenza. The complete “deadly dozen” list includes [in alphabetical order]:
- Avian influenza
- Intestinal and External Parasites
- Lyme Disease
- Red Tides
- Rift Valley Fever
- Sleeping Sickness (trypanosomiasis)
- Yellow Fever