Global Warming and Vector Born Disease

Global Warming and Vector Born Disease
Vector-Borne Disease
Vector-borne diseases are transmitted by vectors like fleas, ticks and mosquitoes. One such a vector-disease is malaria. It is an important health condition because of its significant health burden and global distribution. This mosquito-borne disease is caused protozoan of the Plasmodium (falciparum, ovale, vivax, and malariae) (Fernando, 2010). Malaria account for a large number of deaths annually, particularly in tropical regions. Malaria is influenced by precipitation patterns and temperature extremes. Global warming can lead to increase in severe events and modified weather patterns that can impact malaria outbreak (Fernando, 2010). Mosquitoes involved in malaria transmission are climate change sensitive. Climate change influences vector survival, reproduction, activity, development, abundance and distribution.
Factors That Contribute To Global Warming
Evidence for global warming included increases in average global temperature near the earth’s surface and ocean temperature. Average global temperature increased by 0.74 degree Fahrenheit over the period 1906 to 2005 (Haldar, 2011). High temperatures have shifted climate patterns. Emission of greenhouse gases by anthropogenic activities has made the planet earth warmer. Greenhouse emissions contribute to a global mean surface warming through the greenhouse effect. They trap heat in the atmosphere and prevent it from escaping into space. Common greenhouse gases include water vapor, carbon dioxide, nitrous oxide, methane, and ozone (Haldar, 2011). While these gases exist naturally, human activity has increased their concentration in the atmosphere. Combustion of fossil fuels, deforestation and livestock farming are responsible for increasing emissions. These greenhouse gases have made some regions warmer than others, increased precipitation and other climate patterns.
Changes in the energy output of the sun have caused the climate change. Solar viability plays a role in climate change resulting in global warming. Solar irradiation from the sun is also contributing to warming. Solar irradiation is rising global temperature. Solar flares and sunspots alter the energy radiating (Lean, 2010).
Combustion of fossil fuels contributes to emission of greenhouse gases. Emissions from power plants and cars are driving temperature rise. Combustion of fossil fuel is releasing more emissions into air. Today, there are billion of vehicles on road and flying aircraft that add gases into air.
Overpopulation and farming are also contributing to global warming. With increasing population, there is increasing demand for more food to feed the masses. As a result, formerly forested lands have been cleared to expand farming activities and crop production, to built houses and factories. Additionally, farm animals are notorious producers of methane gas. The use of fertilizers to make crop thrive well produce varied greenhouse gases (Haldar, 2011). The use of firewood and charcoal adds greenhouse emissions to the atmosphere. All these factors make it hard for heat to escape into space.
Global Warming and Incidence of Malaria
Three elements are important for infectious diseases: pathogen (an agent), vector (a host) and transmission environment (Fernando, 2010). Appropriate weather and climate conditions are required for the reproduction, survival and distribution of pathogens, hosts and vectors. Long term global warming favors the expansion of infectious diseases to many regions of the world. Moreover, extreme weather conditions help to create viable opportunities for vector disease outbreaks at new places.
Malaria is a health outcome that is sensitive to climate change. Elementary modeling indicates that increase in global average temperature enhances the rates of transmission of mosquito-borne diseases, as well as expand geographical distribution (Zhou, Minakawa, Githeko, & Yan, 2005). The increase in malaria incidence is recognized as potential effect of global warming. The relationship between climate change and malaria is a complex one as evidenced by knowledge gap in the linkage mechanism. Nevertheless, climate change is believed to provide viable conditions for the transmission of malaria in regions that has been eliminated, traditionally malaria-endemic area and areas that are not malaria endemic (Fernando, 2010). In Sub-Sahara Africa, the distribution and intensity of malaria transmission is influenced by climate change. Climate change has had significant effects in the highland regions of east Africa where the population is at higher risk.
A rise in humidity, precipitation and temperature causes the proliferation of mosquitoes that carry malaria, leading to an increase in incidence of malaria transmission in regions that have not reported malaria cases before. Warmer temperatures in low altitudes change pathogen’s the growth cycle in the host allowing it to grow faster, thus increasing transmission. Relative humidity influences the transmission of malaria through affecting the survival and activity of mosquitoes.
Global warming may influence the El Nino cycle which is implicated in increased risks of mosquito-borne diseases. Heavy precipitation in dry climates provides viable breeding grounds for infectious mosquitoes. Altering precipitation patterns and increasing temperature are influencing the abundance and distribution of mosquitoes that transmit malaria (Fernando, 2010). Humans are central to malaria mosquito transmission cycle. Increasing surface temperature causes the range patterns of vector to change. More importantly, warmer conditions tend to shorten the incubation periods of microbes in mosquitoes.
Conclusion
There is no doubt that climate change impacts the survival, development, reproduction, distribution and abundance of vector-borne diseases like malaria. An increase in humidity, precipitation and temperature provide viable opportunities for the proliferation of pathogens. Warmer climate shortens the incubation period of malaria-causing pathogens, thus increasing the transmission of malaria.

Reference
Fernando, S. (2010). Climate Change and Malaria – A Complex Relationship. UN Chronicle, 47(2):12-15
Haldar, I. (2011). Global warming: the causes and consequences. New Delhi: Mind Melodies, 2011.
Lean, J. (2010). Cycles and trends in solar irradiance and climate. Wiley Interdisciplinary Reviews: Climate Change, 1,111-122.
Zhou, G., Minakawa, N. Githeko, A. K. Yan,G.(2005). Climate variability and malaria epidemics in the highlands of East Africa. Trends in Parasitology, 21; 54-6