TROPICAL DISEASES

Mosquitoes, ticks, rats and bats are the usual suspects when it comes to spreading disease, and warming climates will make it easier for them to adapt to new ranges.

Illnesses that were once isolated within tropical environments could become much more widespread, showing up in North America and Europe as regions become warmer.

West Nile virus, spread via mosquito, has spread into the United States and is moving north to Canada, infecting more than 21,000 people so far. Dengue fever, a potentially lethal infection also spread also by mosquitoes, was once limited to elevations of 1,000 feet, but has been discovered recently as high as the Andes Mountains in Colombia. Cases of Lyme Disease are also appearing in the United States, with a predicted spread into Eastern Canada. Mosquitoes that carry malaria are moving into new regions, including Australia, Europe and North America, where natural immunity is very low. Malaria kills 2 million people a year and infects 300 to 500 million.

The recent outbreak of a fungal infection on Vancouver Island bears the worrisome mark of climate change. Cryptococcus gattii is a microscopic pathogen usually found in warm, tropical, and subtropical regions. Infection usually results from the inhalation of fungal spores, affecting the lungs, nervous system and more rarely the brain. Africa, India, South America and Australia are typical hosts, so its appearance on Canada's West coast and the Pacific Northwest is worrying scientists.¹

^{Source: "Dangerous Fungus thrives on west coast." Globe and Mail," February 10, 2007.}
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Cryptococcus gattii has infected 165 people and killed 8 since its discovery in 2001. It has also stricken household pets, horses and marine animals. The infection is not contagious, and most people exposed never develop any symptoms. However, there is no known vaccine. Right now, scientists and physicians are hoping that with more exposure a natural immunity will develop.² Slightly comforting.

^{1 Source: http://www.cher.ubc.ca/cryptococcus/new/default.htm}

^{2 Source: "Dangerous Fungus thrives on west coast." Globe and Mail," February 10, 2007.}