El Nino And Disease - Essay Example

El Nino And Disease Introduction The El Niño phenomenon scientifically referred to as ENSO – El Niño Southern Oscillation – pertains to a climatic event, which originates from the Pacific Ocean. It is of critical importance and global concern because it often results in a wide array of consequences; regarding weather patterns and climatic conditions. Furtherance is its direct link, with certain human health issues and illnesses. Of core, importance is that, through the effects and influences of El Niño and La Niña, human health individually and as a public is affected fundamentally. On a global scale, there is often an increase of the human effect with regard to natural disasters, increasing substantially whenever El Niño occurs. ENSO has been scientifically proven to enhance the probability of wide-scale epidemics such as malaria and cholera. The latter was evident in the state of Bangladesh, with malaria becoming more prevalent in parts of South America and South Asia. The strongest of factual evidence provided, displaying this co-relational link, is through time-series analysis inclusive of data from varied events. In addition, is the presence of evidence, abate weakly supported, of rodent-borne and mosquito-borne illnesses increasing during such an event (Caviedes, 2001). However, both Cholera and malaria lead to their effects on human health, necessitating the enhanced focus on disaster preparedness and endemic control. This is best achieved through strategic targeting of resources, to be used, based on necessity and risk-levels present. El Niño: A Regional Phenomenon Although largely a regional phenomenon, as Fagan (1999) portrays, the effects are global in nature, as shown through various analyses. Warm ocean water temperatures, occurring anomalously, do develop from the South American west coast and influence climatic conditions across the vast Pacific Ocean. The El Niño-Southern Oscillation (ENSO) refers to different variations, in terms of the surface ocean temperatures along the tropical eastern Pacific Ocean. Air surface pressure is also affected within the Pacific Ocean’s tropical eastern region with the two variations being coupled (successive in nature). First, is the warm oceanic phase (El Niño), which goes hand in hand with high air surface pressure, within the western Pacific region. Next follows the cold phase (La Niña), which occurs with low oceanic air pressure. The above scenario portrays two extremes of climatic patterns, with the oscillations causing such conditions as droughts on the one hand, and floods on the other. This is the primary reason, why cholera and malaria are the most endemic of diseases significantly influenced by this phenomenon. Regionally, the wider Pacific Ocean is affected, in terms of water temperatures (both above and below the surface); in addition to developing nations, especially those bordering the water mass. These states, majorly dependent upon the fishing industry, and the agricultural sector are thus influenced in more than one way (Fagan, 1999). Not only is their economic basis majorly affected, so too are the prevailing health statistics. The warming period is usually noticed around the Christmas period, which coincides with the boom in the tourist attraction and holidaymaking. This is another reason for worry, as has been witnessed during various occasions where tsunamis occur. The most severe of these can easily be focused on the Japanese event, which brought about the huge loss of life, as well as major destruction of property. At given times shockwaves can be felt in far away regions as India and the East coast of Africa. El Niño: The Phenomenon As Enfield and Mayer (1997) allude, through prolonged warming of the sea surface temperatures within the Pacific Ocean often at irregular levels, the El Niño effect occurs. Roughly 2-7 years intervals elapse before a serious case of the event occurs lasting for a period of 9 months to 2 years. Critically, signs of this event usually are: - the rise of warm air near Peru, thereby causing rain in the northern Peruvian deserts; the fall in air pressure, over the Tahiti region, as well as the rest of the eastern and central Pacific Ocean area, and the weakening of trade winds within the South Pacific region. Adding to that is the presence of a rise in surface pressure, especially over the Australian, Indonesian, and the Indian Ocean regions. This is usually because of warm water spreading to the eastern Pacific from the Indian Ocean and the West Pacific. This naturally results in rain clouds being transferred to the usually dry eastern Pacific area vis-à-vis the cause of extensive droughts within the western Pacific region. The warm rush of water is mainly poor in nutrient content, as opposed to the cold, nutrient rich Humboldt Current, which is usually replaced. If such conditions last long, extensive ocean warming often occurs, in addition to the reduction of eastern trade winds. This has the effect of limiting the flow of the nutrient-rich cold water, affecting the local and regional fishing industry. Essentially, climate data survey indicates a tendency of the event occurring in the Equatorial Pacific region, of being linked to a warm North Atlantic tropical climate during the following summer and spring seasons (Enfield & Mayer, 1997). Effects and Influences of the ENSO Phenomenon During the warming phase, the El Niño warm-pool feeds existing thunderstorms above, thus creating increased rainfall rates across both the eastern and east-central Pacific Ocean region. In addition to this areas, are several segments of South America's west coast. Thus, during the April-October season, very warm and wet months are experienced, especially along the Ecuadorian and Peruvian coastlines. As Caviedes (2001) portrays, this results in enhanced flooding in cases where such events are extreme. Northern Argentina, as well as southern Brazil, is also affected, in terms of wetter-than-normal conditions. Conversely, parts of Colombia, Central America, and the larger Amazon Basin to experience hotter and drier weather patterns. Regarding the North American region, the winters present, when this phenomenon is taking place, are usually drier and warmer than average. This is especially in the northern Midwest, and Mideast, as well as the Northwest United States. This results in reduced snowfalls, with the southwest U.S., and northwest Mexico experiencing wetter winters. Conversely, southeast U.S. and northeast Mexico to experience wetter and cooler-than-average winters. A positive effect would be the fact that it is credited with the suppressing of hurricanes. Tropical cyclones are also affected, due to El Niño’s effect on the subtropical ridge position close to the Equator. Therefore, areas west of the Korean and Japanese peninsula experience fewer impacts during neutral and El Niño years. Elsewhere, varied reactions are felt, from wetter than normal long rains in the East African region (Tanzania, the White Nile basin, and Kenya) vis-à-vis drier-than-normal conditions in the south-central African region, in states such as Botswana, Zimbabwe, Zambia and Mozambique. Additionally are the effects felt in parts of Northern Australia and Southeast Asia (Caviedes, 2001). There is also a tendency of bushfires occurring, often leading to decreased air quality from the extreme haze. Droughts and famines are hence found within a given geographical region, at the same time as flooding because of these variations of weather patterns. El Niño: Social and Health Impacts The extreme weather conditions present, whenever the ENSO phenomenon occurs, do correlate with prevailing changes in terms of epidemic disease incidences. As an example, during the event’s cycle, there is a direct link with increased risks of mosquito-transmitted diseases such as - Rift Valley fever, dengue, and malaria. Consequently, as Collins et al. (2010) allude, enhanced cycles of malaria within Brazil, Venezuela, Colombia, and India, has now been directly linked with El Niño. In Australia, the MVE (Australian encephalitis), also occurs increasingly after the flooding and heavy rainfall. During the 1997-98 El Niño season, a severe outbreak of the Rift Valley fever, ravaged through northeastern Kenya and the southern part of Somali. It is the combination of such effects, which can, and has on different occasions, been linked to civil conflicts and strive. From data by The Earth Institute (Colombia University), dated from 1950 to 2004, portrays a significant role-play of El Niño, to be at 21% of existing civil conflicts. Specific disease outbreaks, inclusive of some of the worst pandemics of the past century, have been linked to the weather patterns aforementioned. Through the tracking of such climatic changes, officials can hence be able to not only anticipate but also plan for surges of such sicknesses. When the phenomenon causes ripples throughout the global climatic area, the shifts do result in disease carriers interacting in new ways. This interaction does create environments for the creation of novel pathogens in addition to the increased likelihood of outbreaks. Through increased sea temperature, the global rainfall patterns are altered, affecting even bird migration patterns (Collins et al., 2010). The change in migration brings about a different pattern of interactions. Because bird species are the vectors for varying influenza viruses, there is often an emergence of new flu strains. This is whenever various populations reunite after splitting for a few years, because of the ENSO phenomenon. Mutation brings about new strains, which are difficult to treat with existing vaccines and medicines, thereby causing untold suffering and death. These infections are mainly transmitted through aerosols, fluids, and feces; thus in the event of floods, there is an exponential increase in transmission rates. The separation of carriers enables the mutation of the virus differently, within the two-separated group of vectors. Their eventual mingling, after a while, provides the chances of varying carriers being infected by more than a single strain/ variety. The further interaction may result in hybrids being formed, with the resulting re-assortment being most devastating during radical changes in weather patterns. The end-result in a pandemic, due to the lack of proper immunity, as well as vaccination measures, is usually disastrous. An example would be the 1918 global flu pandemic that killed over 50 million individuals (Fagan, 1999). Cholera is also influenced in terms of prevalence, scale, and impacts. However, it should be noted that these pandemics emerge from cyclical changes, as opposed to the ENSO phenomenon. Regarding endemic infections, it is more prevalent after the onset of a La Niña season, given a period of 3-6 months. Cholera is best enhanced due to the capacity of it being the variability-sensitive ailment. It thrives more in brackish water sources, essentially linked to the ENSO event, spreading through shellfish and contaminated water. The two ailments are also most prevalent in congested/ densely populated areas of the affected regions (Enfield & Mayer, 1997). Conclusion While the ENSO phenomenon may be linked directly to the increase in endemic occurrences, it should be noted that the presence of a rising global average temperature does also directly influence such conditions. The migratory patterns of birds, which often converge after some time frame, do result in mutations of influenza; hybrids which are difficult to treat as a result of the lack of proper immunity and vaccines. Migratory patterns also affect different parts of affected regions, especially from one island to another. Thus, there is also the factor of inter-state travel, as well as population density transfer, which also influences overall infection transfer rates. References Caviedes, C. N. (2001). El Niño in History: Storming Through the Ages. Gainesville: University of Florida Press. Collins, M., Ganachaud, A., Guilyardi, E., Jochum, M., Power, S., Timmermann, A., Vecchi, G. & Wittenberg, A. (2010). The impact of global warming on the tropical Pacific Ocean and El Niño. Nature Geographical Science, 3(6): 391–97. Enfield, D. B. & Mayer, D. A. (1997). Tropical Atlantic sea surface temperature variability and its relation to El Niño–Southern Oscillation. Journal of Geophysical Research 102(C1): 929–945. Fagan, B. M. (1999). Floods, Famines, and Emperors: El Niño and the Fate of Civilizations. New York: Basic Books. Read More