The heat is on Disease Will Spread As Globe Warms So often, the timing of truths is stranger than fiction. In the midst of one of Maryland's snowiest Januarys and on the heels of one of the state's worst blizzards of this century, comes a study from the School of Public Health reporting that the Earth is actually getting warmer. And at a potentially alarming rate. In findings published in the Jan. 17 issue of the Journal of the American Medical Association, lead author Jonathan Patz reported that the average global temperature is expected to rise 2 degrees Celsius (35.6 degrees Fahrenheit) during the next 100 years. The slight increase, the report said, could contribute to a worldwide surge in infectious diseases, especially those transmitted by insects and water. The report also notes that a simultaneous rise in ocean waters by 6 inches to 3 feet also may increase the prevalence of infectious diseases. Since the late 1890s, the average global temperature has risen .5 degrees Celsius. The predicted increase is a fivefold faster rate of increase, which Patz, a research associate in the Department of Molecular Biology and Immunology, said results from an increase in carbon dioxide. Climate changes are likely to have the greatest effect on the spread of malaria and dengue, the report notes. Currently, about 2 billion people worldwide are at risk for contracting the mosquito-borne malaria. Patz said the rise in temperature would put an additional 620 million people at risk by the year 2050, which he added would cause 1 million additional malaria-related deaths annually. Dengue is another infectious tropical disease transmitted by mosquitos. It is characterized by severe pain in the joints and back, accompanied by fever and skin rashes. The major mosquito carrier of dengue cannot survive freezing temperatures, and the malaria parasite cannot develop at temperatures below 16 degrees Celsius, or 60.8 degrees Fahrenheit. Global warming, the report says, would increase the mosquitos' geographic range, allowing them to carry diseases to places previously protected by colder temperatures. At a news conference last week, Patz and his colleagues from Harvard University and George Washington University said, "Climate is not the only factor driving these diseases." They said that at-risk populations could reduce their chances of exposure by taking measures such as putting screens on windows and limiting the amount of standing water in populated areas. The report notes that other diseases that may increase with global warming include river bindness, prevalent in West Africa; sleeping sickness, commonly diagnosed in sub-Saharan Africa; and St. Louis encephalitis, indigenous to the United States among other locales. "These long-term ecological and climatological changes portend serious and widespread public health threats," Patz said.
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