Climate Change And Vectors

Climate Fever and Malaria

Robert Green Ingersoll once said, “In nature there are neither rewards nor punishments; there are only consequences.” At the turn of the 20th century, it is becoming increasingly evident that global warming has serious implications on all aspects of human life, including infectious diseases such as malaria. Infectious diseases are global entities whose prevalence depends directly upon the interaction between the population and a region’s climate. Therefore, global warming may result in a considerable shift of the spectrum of these disease-inducing vectors, specifically, Mosquitoes. Climate plays an important role in the geographical distribution and seasonal abundance of Mosquitoes. In North America, where 1500 cases of malaria occur each year, a change in temperature, precipitation, humidity or wind pattern can directly influence these vector species reproduction, development and longevity. This research paper will introduce the basic concepts of global warming, its implications on malaria vectors thus human health in North America, and suggest possible preventatives and solutions we can utilize.

What is malaria? Often associated with poverty, Malaria is the world’s most important and common vector-borne disease. About 2400 million people are at risk of contracting the disease and malaria is currently in 92 countries and of those 2400 million, 1500 cases occur in North America. The water-related disease is caused by protozoan parasites of the genus Plasmodium and only four types of the parasite can infect humans. Malaria parasites are transmitted by female mosquitoes and multiply in the red blood cells of human beings thus causing many symptoms such as anemia, high fevers, chills, nausea, coma and in extreme cases, even death. Because Mosquitoes are arthropods meaning that their cold-blooded and that their internal temperature is greatly affected by temperature, climate change can directly effect the size of the vector population. Malaria existed in parts of North America since the 1900s. Although it was not native to the country, infected British soldiers introduced the disease during the colonial times. In 1950, America attempted to control malaria with DDT and in 1957, the US gave $790 million to the Global Eradication of Malaria Program. Since then, the occurrence of malaria in North America has been greatly reduced however recent climate changes may prove otherwise.

The change in prevalence of malaria vectors cannot be so neatly explained by the simple rising of the Earth’s temperature. Instead, the impact depends on a complex interaction between a growing population, food scarcity, poverty and local environmental decline due to climatic change. First and foremost, as the world’s population increases, many natural resources imperative to the prevention of malaria decreases. For example, water is a basic necessity for human beings. Yet currently, 1.1 billion people do not have access to adequate supplies of safe water and 2.4 billion people do not have access to adequate sanitation. Even though in the developed country of North America, water contamination and scarcity is not as problematic and severe as that of developing countries, North America nevertheless experiences water shortages with a growing population and contamination from pesticides and oil spills. Because malaria is a water-related disease meaning that insect vectors such as mosquitoes rely on the water for a habitat, where there is contaminated water, the likelihood of it being a habitat for mosquitoes increases. Furthermore, as the global temperature rises, the progression of the mosquito larval in its aquatic stages is accelerated because optimal larval development is at 28 degrees Celsius and optimal adult development is between 28 degrees and 32 degrees Celsius. At places where temperatures are below 16 degrees Celsius or above 33 degrees Celsius, malaria transmission can rarely occur. Clearly, transmission does not occur in climates where mosquitoes cannot survive. Rates of transmission also depend on the number of times the infected mosquito bites the host and the duration of the mosquito lifespan, both of which are influenced by temperature. Therefore global warming provides conditions that are most conducive to mosquito propagation and survival.

Second, food scarcity and increased demands for food have indirect global warming risks. According to the State Hunger and Poverty Data, currently in the United States, there are 11.4 million people who have food insecurities meaning that they have trouble obtaining food, and 3.8 million people who have food insecurities and are hungry. In the world, there are currently 800 million people who are malnourished. As the world’s population increases, food consumption is expected to double over the next few decades. Problems associated with intensifying production on land already in use are becoming increasingly evident. Expanding the amount of cultivable land is an