Human Activity Affecting Spread of Disease

Global climate change is supposed to cause significant changes in the Earth’s rainfall patterns.  According to Geotimes, a well respected scientific journal, “the wet places are going to get wetter, and the places that are dry are going to get drier,” Northern lands, such as Canada and Norway, will become more Mediterranean in terms of climate, with hot, dry summers and cool, wet winters.  Meanwhile, regions now considered Mediterranean will see less overall rainfall. What is causing these precipitation changes?  According to Geotimes, these precipitation changes stem from the combination of increased liquid water available as the two major ice sheets in Antarctica and Greenland melt, followed by evaporation that puts more moisture into the atmosphere. With more water in the atmosphere, rainfall increases worldwide.

More rainfall and warmer temperatures may at first seem harmless, but there are many dangers associated with this climate shift.  I will discuss some of the dire consequences that ultimately occur as a result of global warming, more specifically warmer climate leading to changing rainfall patterns.

First and perhaps most frightening aspect of a warmer climate is the spread of disease.  Warmer temperatures allow mosquitoes that transmit diseases such as malaria and dengue fever to extend their ranges and increase both their biting rate and their ability to infect humans. There have been increasing instances of mosquito related outbreaks in highland communities where temperatures have risen during the past century. In studies published over the last five years, models and observations have shown that precipitation and temperature strongly influence the spread of diseases such as “Malaria, Dengue fever, Filariasis, Giardia, Cryptosporidiosis, West Nile virus, Avian Flu, and Giardia. Hantavirus pulmonary syndrome and Bubonic plague.”  (Geotimes, Sever)  These diseases sound far away and exotic, but they are a reality to many people all over the world.  We have no idea what it is like to have to worry about these horrible diseases, and if we keep going the way we are going, it is just a matter of time before these diseases reach us.  The only thing that keeps these diseases from reaching us is our cold winter season.  The cold weather makes it impossible for these tropical diseases to thrive.  With rising temperatures, milder winters and earlier springs, these diseases are able to thrive much better.  We are currently in the middle of “flu season.”  Could you imagine if we had a “malaria season” or a “dengue fever season?”  Most people in our country have absolutely no idea how terrible these diseases actually are.  During the first months of 2007, over 16,000 cases were reported in Paraguay alone.  The scariest news, however, is yet to come.

In 2003, world-renowned virologist Robert Webster published an article titled "The world is teetering on the edge of a pandemic that could kill a large fraction of the human population" in American Scientist. He called for adequate resources to fight what he sees as a major world threat to possibly billions of lives. On September 29, 2005, David Nabarro, the newly-appointed Senior eUnited Nations System Coordinator for Avian and Human Influenza, warned the world that an outbreak of avian influenza could kill anywhere between 5 million and 150 million people. Experts have identified key events such as infecting new species and spreading to new areas, marking the progression of an avian flu virus towards becoming pandemic.  Scarier still, many of those key events have occurred more rapidly than expected.  However, steps are being taken to protect ourselves from the impending pandemic.  On September 14, 2005, President George W. Bush announced the International Partnership on Avian and Pandemic Influenza in his remarks to the High-Level Plenary Meeting of the United Nations General Assembly.  According to President Bush, the core principles of this partnership are as follows.

“The International Partnership on Avian and Pandemic Influenza is committed to protecting human and animal health as well as mitigating the global socioeconomic and security consequences of an influenza pandemic. The idea is to work with all concerned states to limit the spread of H5N1 avian flu and any other highly pathogenic influenza strain by taking all necessary steps to prevent, prepare for, and respond to the growing threat.”

It is important that we take we take proper precautions to limit the fossil fuels we burn and how much energy we are using a daily basis. If we do not do these things then the future does not look promising for the human race. People will start to loose their lives from these diseases where they have never before been a problem and there will begin to be many more cases in places that hit far to close to home.

Bibliography

http://www.geotimes.org/may07/article.html?id=feature_avianflu.html.

http://www.geotimes.org/may07/article.html?id=feature_plague.htm

Hales, S N de wet, J. Maindonald and A. Woodward

2003: Modeling the Transmission of Vector Born Disease: Dengue

Hoop M, Foley J., (2003) Worldwide Fluctuation is Dengue fever cases related to Climate Variability. Climate rec. 25: 85-94

Patz, J.A., et al., effects of environmental change on emerging parasitic diseases, Int. J parasitol, 30 (12-13) p. 395-405 (2000)