Malaria and Global Warming Jocelyn Maher & Mickey Rowe
What is Malaria? Malaria is an infectious disease caused by parasites. It is spread by the Anopheles mosquito. Malaria is an immediate concern because it is currently the #1 infectious killer in the world.
What is Malaria? (notes) Malaria is an infectious disease caused by protozoan parasites from the Plasmodium family that can be transmitted by the sting of the Anopheles mosquito or by a contaminated needle or transfusion. Falciparum malaria is the most deadly type. The symptoms of malaria include cycles of chills, fever, sweats, muscle aches and headache that recur every few days. There can also be vomiting, diarrhea, coughing, and yellowing (jaundice) of the skin and eyes. Persons with severe falciparum malaria can develop bleeding problems, shock, kidney and liver failure, central nervous system problems, coma, and die. The treatment of malaria is with oral or intravenous medications, including chloroquine, mefloquine (Larium), or atovaquone/proguanil (Malarone). Sources: Centers for Disease Control and Prevention
The Link to Warming Anopheles mosquito cannot survive in cold environments Prolonged floods and standing water make great breeding grounds for mosquitoes Strong rains are detrimental for anopheles mosquito High temperatures lead to increased health care expenses
The Link to Global Warming (notes) As the earth progressively warms, it provides more hospitable locations for the Anopheles mosquito to live. An example of this warming, and its effects on the mosquito population, is in the East African high-lands, where scientists, who have been monitoring temperature records in the highlands since 1970s discovered an overall warming trend of 0.5 C. A computer simulation then showed that this change in temperature lead to a 40% increase in the number of mosquitoes present in the East African high-lands, and doubling in parts of Uganda. In tropical, and possibly other milder locations, the projected increased temperatures in the summer months and heavier rainfalls paired with warmer winters make ideal breeding conditions for the Anopheles mosquito. Though, as Dr. Wallace once said, it is possible to have too much of a good thing, in the case of the Anopheles mosquito too much heavy rains can prevent the female, (the one who transmits the disease) from flying for mating or blood consumption. Such rain can also destroy breeding ponds and wash larvae away, thus resulting in decreased incidences of Malaria. The actual optimum time for mosquito breeding is just after heavy rains. And finally, because of the increase of Anopheles mosquito population, in certain areas of the globe, usually associated with warming temperatures, the cost of healthcare in these usually developing nations has also increased. The cause for this spike in cost is mainly due to the fact that under high temperatures there is a rapid spread of Malaria, usually resulting in the patients need for intense treatment. Sources: "Malaria; Malaria Spread Blamed on Global Warming." Africa News 27 Mar. 2006. LexisNexis. 17 Feb. 2009 <http://www.lexisnexis.com:80/us/lnacademic/search/homesubmitform.do>. Mckillop, Jim. "Malaria Threat Heading Our Way; Climate Change to Create Haven for Disease Carrying Mosquito." The Herald [Glasgow] 10 Feb. 2001: 7-7. LexisNexis. University of Washington, Seattle. 17 Feb. 2009 http://www.lexisnexis.com:80/us/lnacademic/search/homesubmitform.do Ana P., Luiz Bevilacqua, and Marat Raflkov. "Simulating Malaria Model for Different Treatment Intensities in a Variable Environment." Ecological Modeling 206 (2007): 322-30. Science Direct. University of Washington, Seattle. 17 Feb. 2009 <http://www.sciencedirect.com/science?_
What Do The Skeptics Say? Other contributors to Malaria include: Health policies Protection from mosquitoes Poor vaccinations Economics
What do the Skeptics Say? (notes) Some believe that in developing nations such as Zimbabwe, government money should be put towards better anti-malaria treatments instead of efforts to decrease carbon emissions. According to Bjorn Lomborg, a climate skeptic, with the Kyoto Protocol we can prevent 140,000 Malaria deaths. However, at one sixtieth of the cost, we can prevent 85 million deaths. For every one person we save through climate change policies, we could have saved 36,000 through better anti-malaria policies. However, a strong economy is needed in order to implement any sort of health system that will make any real change in the malaria outbreaks. More wealth can lead to better mosquito control, increased accessibility to better medicines, and agricultural development which could dry up the mosquito breeding ponds. Sources: Business Day [South Africa] 17 May 2005, sec. Opinion & Editorial: 11-11 The Skeptical Environmentalist's Guide to Global Warming by Bjorn Lomborg. Copyright (c) 2007 by Bjorn Lomborg. Reprinted with permission from the publisher Alfred A. Knopf, a division of Random House, Inc.
Projections for 2050
Projections for 2050 (notes) Yellow is where the mosquitoes carrying malaria currently live. Red is where these mosquitoes could expand too (suitable climate) taking malaria with them by 2050. Current distribution represents the maximum extent of the distribution of the falciparum Malaria parasite. This is due to where the Anopheles mosquito can survive in the current climate. For 2050 this area of suitable climate for the disease and the Anopheles mosquito has expanded. This scenario is based on the high scenario from the HadCM2 experiment. Source: Rongers. Randoloph. The Global Spread of Malaria in a Future, Warmer World. Science (2000: 1763-1766).
Solutions Assuming Global Warming continues as usual, we can still prevent Malaria through: Insecticide-Treated Bed Nets Indoor Residual Spraying Source Reduction (Larval Control)
Solutions (notes) Insecticide-treated bed nets (ITNs) are a form of personal protection that has repeatedly been shown to reduce severe disease and mortality due to malaria in endemic regions. In community-wide trials in several African settings, ITNs have been shown to reduce all-cause mortality by about 20%. Many malaria vectors are endophilic, resting inside houses after taking a blood meal. These mosquitoes are particularly susceptible to control through indoor residual spraying (IRS). As its name implies, IRS involves coating the walls and other surfaces of a house with a residual insecticide. For several months, the insecticide will kill mosquitoes and other insects that come in contact with these surfaces. IRS does not directly prevent people from being bitten by mosquitoes. Rather, it usually kills mosquitoes after they have fed, if they come to rest on the sprayed surface. IRS thus prevents transmission of infection to other persons. Source Reduction or Larval Control means killing the mosquito larva. Oils may be applied to the water surface, suffocating the larvae and pupae. Most oils in use today are rapidly biodegraded. Biological control agents include toxins from the bacterium Bacillus thuringiensis var. israelensis (Bti). These products can be applied in the same way as chemical insecticides. They are very specific, affecting only mosquitoes, black flies, and midges. Insect growth regulators such as methroprene. Methoprene is specific to mosquitoes and can be applied in the same way as chemical insecticides. Mosquito fish (Gambusia affinis) are effective in controlling mosquitoes in larger bodies of water. Source reduction is an ideal approach to mosquito control. Mosquito larvae are concentrated in defined areas, and source reduction eliminates mosquitoes before they reach the stage that is responsible for disease transmission. But with along with all of these solutions, we need to remember that Global Warming may also be contributing to the increase in this infectious disease, and it is in the global health community s best interest to prevent as much warming as possible in order to mitigate the spread of Malaria. However, as we stated earlier, some climate skeptics and health policy advocates stress that money spent on solving the Global Warming Crisis should instead be put towards bettering the health care for Malaria-struck areas. (Source: Center for Disease Control and Prevention)
Things to Ponder What in your opinion is more pressing? The need to solve (or at least mitigate) the effects of Global Warming The need to solve (or at least mitigate) the spread and incidences of Malaria