Global Warming: Dengue - Research Paper Example

?Global Warming: Dengue Introduction: The recent decades have witnessed an outbreak of a range of infectious diseases in various parts of the globe. Examples include: the Haiti Cholera outbreak in 2010 following the earthquake in January in the same year; Salmonella Enteritidis on account of contaminated Salmonella and eggs in the United States in August 2010; Multistate E. Coli outbreak associated with beef and prepackaged cookie dough during june 2009, in several states across the U.S.; increased incidences of H1N1 flu in the U.S. during April 2009 (CDC, 2011) ; and the outbreak of Dengue across Asia spread throughout various geographic locations such as Argentina, Paraguay, Dominican Republic, and various other subtropical regions in south east Asia (msnbc, 2007). Approximately 50 million people worldwide were affected by the Dengue fever leading to 19,000 deaths in the year 2002 according to statistics made available by W.H.O. Experts, researchers and scientists have attributed this phenomenon to global warming claiming that it has led to a substantial rise in the amount of water including sea water as well as fresh water bodies - which are predominantly considered as breeding grounds for mosquitoes. Furthermore, some scientists also believe that the sudden change in temperatures and shift in seasons could also be attributable to the rise in incidences of such outbreak of vector-borne diseases such as dengue and malaria (msnbc, 2007). Various factors are and could be held accountable for such an occurrence. This includes the sudden increase in urban population, increased incidence of international tourism, as well as exchange of goods and products across several countries, as a result of globalization. (NRDC, 2011). Impact of global environmental changes on outbreak of infectious diseases: The natural environment plays a key role in the globalization phenomenon, as it leads to an increased exchange of goods and services, as well as travelling between various geographic locations across the world. Furthermore natural phenomena such as earthquakes, tsunamis, hurricanes or accidents such as oil spills etc lead to depletion of natural resources causing severe imbalance, and leading to various air and water borne diseases. According to studies conducted over the years it was estimated that global warming is likely to cause increase in sea levels, leading to disruption of the eco-systems; cause further expansion of deserts and lead to increased storms and violent weather. Furthermore all the disruptions in the ecological system leads to a further disruption of the business activities such as transport of plants and animals. For instance, there is a shift of various species of birds and animals to different locations and a simultaneous change in the food chain, resulting in a destruction of various species. Diseases are increasingly going global. For instance the migration of the A2 strain of potato virus from central Mexico to the potato fields in the U.S.; leading to a large scale devastation of crops and translating into millions of dollars worth of losses (Winslow, 1995 in Clegg et al., 1996). Global warming poses a significant threat with regard to the spread of various infectious diseases because of its various repercussions such as increase in temperatures, leading to increased humidity in tropical and sub-tropical areas which are a prime breeding ground for mosquitoes, which in turn are the primary sources of water-borne diseases such as dengue fever and malaria. Figure: Climate change and the dengue fever vector Source: Christophers (1960, Pp. 49) As mentioned in the previous section of this paper, global mobility has further increased the chances of outbreak of infectious diseases worldwide. For instance, the Asian tiger mosquitoes are now biting the Americans, while termites from Taiwan are destroying American homes. According to Coates (2006) the breeding of this breed of temperate zone mosquito in the U.S. was first recorded in the year 1984 in Houston, Texas which spread to other parts of the country. Although the typical breeding sites of this breed of mosquitoes is coconut shells and bamboo stumps, basically anything that can hold water. This further reinstates the fact that increased globalization may lead to transfer of various species / breeds of such deadly insects across the globe thus, leading to an outbreak of infectious diseases on any part of the globe. Apart from globalization and the overall changes in the climate, various researchers believe that the outbreak of infectious diseases is a part of conspiracy on the part of nations to indulge in biological warfare. For instance, during the Korean War, accusations were made against the United States government, by North Korea, Soviet Union and China, regarding the deliberate use of biological weapons of destruction by the Americans. Although the U.S. categorically denied the charges, the incident brought to the fore, the possibility of such an occurrence and the ability of countries to transfer such deadly bacteria with an intention to cause an outbreak thus, leading to large scale damage to public life and health (Bollet, 2004). It has been documented through various researches that a minor rise in temperature could lead to widespread changes in the ecological system thus, triggering a series of changes in the natural environment. For instance, an increase of merely 3 degree Celsius is likely to cause significant changes in the natural habitats such as a total collapse of the Amazon rainforest or the Great Lakes wetland systems; undermining of the agricultural system which feeds almost a billion people; the expansion of deserts in Africa leading to displacement of millions of people and exposing them to hunger and making them more vulnerable to infectious diseases (World Bank, 2007). The changes in temperature and global climate could largely be attributed to human intervention / activities. For instance the large scale destruction of rain forests in Latin America as well as in the Pacific island forests resulted in reduction of population in those areas. In fact, there is documented evidence which suggests that an entire village in the region, threatened to commit suicide unless the seized lands were returned to them. The opening up of forests for various human activities, has led to the development and introduction of various diseases which have made their way to the forests by various means. According to various scientists, deadly diseases such as AIDS, dengue fever, as well as the Ebola virus are a result of interference of human activity with nature, such as the continuous deforestation which has resulted in disruption of rain forests and led to an imbalance in the natural environment. For instance, Deforestation is known to accelerate Co2 emissions and disrupt the natural balance in the forests resulting in a series of uncontrollable natural disasters (Schaeffer, 2003). Brief Background / Overview: There has been a constant and significant change in the global climate over the past couple of years. The earth, as observed by various scientists and researchers is known to have warmed up over the past 250 – 300 years. It has been claimed that the current temperatures bear a striking resemblance to those experienced during the medieval ages, especially during the 12th century which is known to be the hottest period so far. However most of the dominant years were relatively colder in comparison, as marked by the Ice Age (Lamb, 1995). The fluctuations in the earth’s temperature have been a fairly common phenomenon, since it is known to have occurred several times during the past 10,000 years. However, the sudden rise in the global temperature in the recent years, are largely on account of human activities which is known to have brought about significant variations in the earth’s natural climate over the years, and across the globe. For instance, a steady decline in the earth’s temperature was observed between the period from 1940 and 1970. This was attributed to the industrial pollutants as a result of industrialization, which was in turn, known to have resulted in global cooling Rasool, Schneider, 1971; Calder, 1974). However, the ensuing warming of the earth’s temperature globally, is attributed to the rise in carbon dioxide released in the atmosphere on account of increased human activities such as burning of fuels for livelihood, or transportation; as well as on account of emission of other equally hazardous green house gases (Houghton et al., 1995). Subsequent studies conducted over the years suggest that such a trend, i.e. that of increase in green house gas emissions and the resultant warming up of the planet, are likely to increase in the coming years (Lindzen, 1997; Soon, et al., 1999; Calder, 1974). Although various observations and suggestions have been made regarding the outbreak of infectious diseases ranging from climate change to conspiracy theories suggesting deliberate spread of deadly viruses as a part of biological warfare, the evidence regarding this being a result of global warming is over whelming. The fact that the dengue fever has recently resurfaced following drastic changes in the earth’s climate over the years, and across the globe, further substantiates the fact that global warming is indeed one of the major reasons for the spread of the dengue virus. Climate Change and the Re-emergence of the Dengue Fever The recent re-emergence of various infectious diseases has led to heated debates among the scientific community regarding the possible causes for such an outbreak. According to scientists and researchers, there is a strong relationship between climate and human health, and the disruption of the natural environment is likely to be the main cause behind the outbreak of such diseases as the dengue fever or malaria, thus leading to a deterioration of human health conditions (CNN, 1998). It is on account of this reason, that the issue of climate change, and the resultant impact on the geographic disruption of certain disease vectors have been of particular interest for the researchers over the years (McMichael et al., 1996). Furthermore, there have been specific studies which have proposed that the expected changes in the climate are likely to result in expansion of certain geographic ranges which are incidentally convenient breeding grounds for various mosquito-borne diseases such as malaria, yellow fever, as well as dengue (Jackson, 1995; Jetten and Focks, 1997; Shope, 1991). However, despite such evidence the exact relationship the climate change and disease vector ecology remains highly unclear. It has also been suggested by various researchers that apart from the apparent impact of climate change, various other factors such as the socio-economic conditions of a particular geographic region; the availability of health care facilities; as well as sanitation conditions etc, are also likely to play a key role in the spread of such infectious diseases. It has been claimed that mosquitoes carrying deadly bacteria such as malaria, dengue, or yellow fever have existed for a considerable period of time in the U.S., however the public awareness regarding the same and especially about the knowledge about control of spread of such diseases is highly doubtful (Gubler, 1998; Reiter, 1998). According to the World Health Organization, there are approximately 50 million cases of dengue fever reported each year, which totals to about 2.5 billion people in over 100 countries. This suggests that roughly 40 per cent of the world’s total population is at risk of attracting such a deadly disease (WHO, 2009). It has also been observed that the cases of people suffering from the dengue fever has risen drastically over the years, for instance in Argentina, despite the fact that the mosquito known to carry the dengue virus, i.e. the Aedes aegypti, was successfully eradicated (Aviles, 1999). Various studies conducted over the years with regard to the dengue fever, have successfully established the relationship between rise in global temperatures and its resultant impact on the vector-borne disease. It has been clearly established that the mosquitoes which carry the deadly virus are known to inhabit the tropical regions, where the climate is particularly hot and humid with abundant rainfall, i.e. a climate which is regarded as ideal for their breeding. The warming of the earth’s temperature even by as little as 1°Celcius would result in an increased reproduction of the infectious agent and cause the virus to multiply and increase their survival rates significantly (Aviles, 1999). Furthermore, it is also claimed that the change in climate is likely to bring about changes in the geographic distribution of this disease, which may result in it being spread to areas located at higher altitudes (Hellmann et al., 2008). As observed from the above discussions, the dengue fever has reached epidemic proportions, owing to climate change, and hence it is of utmost significance for researchers as well as those from the scientific community to initiate studies aiming to establish a strong link between the two, and ultimately devise means to prevent it from spreading further. The variations in the climate, for the purpose of this study entails, the change in temperature i.e. rise or fall; increase in humidity as well as precipitation; and other similar conditions which are known to be favorable for breeding of mosquitoes carrying the dengue virus. The key symptoms of the dengue fever include sudden high fever; severe joint pain; body rashes; as well as headaches. Other symptoms which are occasionally observed include: hemorrhagic fever alternatively referred to as the DHF; and irrepressible gastrointestinal bleeding which may often result in the death of the patient (Tapia-Conyer et al., 2009). It is known to be caused by four viral serotypes (i.e. DEN-1, DEN-2, DEN-3 and DEN-4) and exposure to any of them may result in a 50 per cent increase in the probability of attracting any of the three serotypes (Tapia-Conver, 2009). So far, no effective treatment has been developed to counter or control the virus, and hence the eradication of the disease poses a significant challenge to the researchers and scientists alike. Conclusion: There has been a sudden increase in global temperatures, especially during the current century. Scientists have claimed that that the earth is warming up and is likely to further heat up by 1 to 3.5 °C from the current temperature, by the year 2100 (Githeko et al., 2000). Climate change of such magnificent proportions is likely to further trigger the incidences of dengue fever and lead it to spread over larger geographic locations. The rise in global temperatures will make the human population highly vulnerable to the dengue virus which is known to thrive in such warm and humid climatic conditions. The dengue fever is known to be one of the most critical vector-borne diseases globally. Various countries are suffering from this epidemic, and the virus causing this disease has led to a major outbreak in various parts of the globe For instance countries in South East Asia, and especially those in the tropical regions. It has been successfully established through a range of studies, that the outbreak has been caused on account of drastic increase in global temperatures, which has led to the increase in mosquito population carrying the dengue virus. In the absence of a cure, countries worldwide are highly vulnerable to such a deadly disease and hence prevention is the only way to curb or restrict the further spread of the same. This includes active measures to prevent global warming, restrict or reduce the emission of greenhouse gases, and prevent deforestation among many others. This will help in maintaining the current temperatures, and discourage the growth of the dengue virus. It needs the combined effort of all the nations, to help prevent global warming and ultimately the spread of such deadly diseases in the future. References: Aviles, G., Rangeon, G., Vorndam, V., Briones, A., Baroni, P., Enria, D., and Sabattini, M.S. (1999). Dengue reemergence in Argentina. Emerging Infectious Diseases Journal. 5, Pp. 575-578. Bollet, A. J., (2004). Plagues & poxes: the impact of human history on epidemic disease, Demos medical Publishing, Pp. 11 Calder, N., (1974). The weather machine, New York: Viking Christophers, S. R., (1960). Aedes Aegypti: Yellow Fever Mosquito, ISBN 04638-6, Cambridge University Press, New York, Pp. 399, Figure 49-I Clegg, S., Hardy, C., Nord, W. R., (1996). 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Recent outbreaks and incidents [Online] Available at: http://www.bt.cdc.gov/recentincidents.asp [Accessed: June 18, 2011] CNN (1998). Global warming may harm human health [Online] Available at: http://articles.cnn.com/1998-11-16/tech/9811_16_climate.health.enn_1_dengue-fever-malaria-cases-warming?_s=PM:TECH [Accessed: June 17th, 2011] Msnbc (2009). Severe dengue fever outbreak hits Asia: Experts call for better prevention efforts, question link to global warming [Online] Available at: http://www.msnbc.msn.com/id/21492929/ns/health-infectious_diseases/t/severe-dengue-fever-outbreak-hits-asia/ [Accessed: June 18, 2011] NRDC (2011). Fever Pitch: Mosquito-Borne Dengue fever threat spreading in the Americas [Online] Available at: http://www.nrdc.org/health/dengue/ [Accessed: June 18, 2011] WHO (2009). Dengue and dengue haemorrhagic fever: Factsheet [Online] Available at: http://www.who.int/mediacentre/factsheets/fs117/en/ [Accessed: June 18, 2011] Read More