Malaria Parasites May Benefit from Climate Change
Kelleher, Maria, Alternatives Journal
The general warming associated with global climate change will favour increased incidence of malaria in many parts of the world and may bring malaria back to southern Canada, researchers say. While the risks that the disease will reestablish itself here are small, it is one more climate change problem requiring attention.
The 1996-97 Canada Country Study, carried out by Environment Canada to assess climate change impacts and adaptation options, predicted that malaria could return to Southern Ontario with climate change. The conclusion was supported in preliminary modelling projects by Pim Martens et al. at the University of Maastricht, Holland.
Malaria is transmitted from one human to another by the female anophelene mosquito. For malaria to establish itself and become endemic in an area, a number of factors need to come together. These include temperature, population density, a reservoir of humans with malaria parasites in their blood, and sufficient anophelene mosquitoes.
Until the 1930s and 40s, malaria was endemic in much of the US south, but was eventually wiped out by a variety of measures, including use of window and door screens combined with a DDT spraying programme that lowered mosquito population densities.
Malaria was also present in Southern Ontario during the construction of the Rideau Canal in the early 1800s, and was spread northwards by US troops during the Civil War later that century. In both cases, large numbers of humans with the malaria parasite in their blood created a sufficient reservoir for the disease to be spread by the anophelene mosquitoes, which were already present in Southern Ontario.
Today, a reported 1200 Canadians come down with "imported malaria" each year, after returning to Canada from malaria endemic areas. …