Malaria and its effects on public health and economy in eastern africa
Malaria is a mosquito-borne infectious disease that has plagued the world for centuries. It is caused by a parasite that is transmitted to humans by bites from infected, female Anopheles mosquito. Cases of malaria have dated back to 2700 BC, as symptoms of the disease were recorded in Chinese medical writings (CDC History of Malaria 2004). However, no one knew that the cause of these symptoms was from malaria. For centuries, the Europeans characterized malarial symptoms as "quartan" and "benign tertian," which were fever-like symptoms experienced by the infected malarial patient (Gallup & Sachs 2001). It was not until 1880 that malaria was actually identified. French army surgeon, Charles Louis Alphonse Laveran, was the first to notice the parasites in one of his patient's blood (CDC History of Malaria 2004). Then in 1897, four species of malaria parasites that infect humans were discovered. These species are: Plasmodium malariae, Plasmodium vivax, Plasmodium falciparum, and Plasmodium ovale (Gallup & Sachs 2001). Despite advancements in malarial research and knowledge, malaria is still prevalent today and one of the most severe public health concerns worldwide. By looking at the impact of invasive Anopheles mosquitoes and malaria in eastern Africa and their effects on public health and economies, the magnitude of problems this invasive species and disease cause may be revisited, thus improving awareness and the chances of eradicating malaria.
Malaria symptoms can occur anywhere between nine and forty days. Initial symptoms of malaria include: fever, chills, profuse sweating, nausea, vomiting, and headaches. As the disease progresses, infected individuals can have confusion, coma, neurologic focal signs, severe anemia, respiratory difficulties, and possibly death (Gallup & Sachs 2001). Each year, there are approximately 350-500 million cases and one million deaths caused by malaria. Ninety percent of these deaths occur in Sub-Saharan Africa (CDC Malaria Facts 2007). This is because the majority of infections in Africa are caused by Plasmodium falciparum, the most fatal of the four human malaria parasites. Currently, there are several ways to prevent and control malaria. Prophylactic drugs can be taken a week before an individual enters a malaria-endemic area, and people can use an indoor residual spray, which is an insecticide spray that kills malaria-infected Anopheles mosquitoes. Mosquito nets, bedclothes, and vaccinations are also available to prevent individuals from being infected with malaria. Despite tools available to prevent malaria, many people are still infected with malaria every day. Luckily if an individual does get malaria, there are several anitmalarial drugs available such as: chloroquine, sulfadoxine-pyrimethamine, mefloquine, quinine, and doxycycline (CDC Malaria Prevention 2004). These drugs are normally administered in pill, suppository, and intravenous infusion forms.
Although society has come a long way in regards to malarial research, prevention, and treatment, the disease continues to evolve and prosper. In order to effectively understand how malaria has evolved and affected society over the past decades, it is important to understand the malaria life cycle. The life cycle consists of two hosts: humans and Anopheles mosquitoes. A malaria-infected female Anopheles mosquito feeds on humans and inoculates sporozoites into its human host's blood stream. The sporozoites then travel to the liver and invade the liver's cells. Over the next five to sixteen days, the sporozoites mature into schizonts, which eventually rupture and release merozoites (CDC Life Cycle of Malaria 2006). Some of the parasites remain dormant in the liver, which subsequently leads to relapses weeks or months later. After the initial replication occurs, some of the merozoite-infected parasites leave the host's liver and undergo asexual replication in the red blood cells of the infected human. This multiplication can last anywhere from one to three days and can result in thousands of parasite-infected cells in the host's bloodstream (CDC Life Cycle of Malaria 2006). Some merozoite-infected cells do not reproduce asexually. Instead, some of the cells develop into sexual forms of the parasite. The cells either become male or female gametocytes. Once a mosquito bites an infected human, it subsequently ingests the gametocytes. The infected blood cells of the human burst and release gametocytes, which develop into mature gametes (CDC Epidemiology 2004). Male and female gametes then fuse to form diploid zygotes, which eventually become actively moving ookinetes that burrow into the mosquito midgut and form oocysts (CDC Life Cycle of Malaria 2006). Growth and division of the oocysts produces thousands of sporozoites. After eight to fifteen days the oocysts bursts, releasing sporozoites into the body cavity and salivary glands of the mosquito (CDC Life Cycle of Malaria 2006). At this point, the infected mosquito infects a human, and the vicious cycle repeats.
Despite having a plethora of information pertaining to the pathology of the life cycle of malaria, man and malaria continue to evolve concurrently. With that being said, malaria has impacted the public health of eastern Africa in several ways. Such public health factors include: environmental, social, behavioral, and occupational. Environmental climatic factors such as temperature, topography, and rainfall demonstrate a positive correlation to the evolution and incidence of malaria. This is because malaria is a climate sensitive vector-borne disease, which ultimately affects the geographic distribution of malaria incidents. Temperature does not influence malaria precedence as much as rainfall does; however, it does affect the longevity of the mosquito, length of the sporogonic cycle, and overall mosquito activity (Obsomer et al. 2007). According to the Center for Disease Control (2004), a female Anapholes has to live anywhere between nine to twenty-one days, at 20- 25°C and 60% humidity, to complete its growth cycle (Mushinzimana et al. 2006). Warmer temperatures shorten the duration of the extrinsic cycle and increases chances of transmission. If temperatures are too warm or too cold, the extrinsic cycle cannot be completed, thus eliminating the chance for malaria to be spread. A study conducted by Jones and Briffa (1992) analyzed the temperatures between 35°N and 40°S latitude and 20°W and 55°E. The study used temperature databases dating back to 1895 and found that 1995 was the warmest year recorded globally (Mouchet et al. 1998). The correlation between higher temperatures and malaria incidences explain why the transmission of malaria is more prevalent in warmer areas such as eastern Africa.
Topography has also influenced the evolution of malaria (Obsomer et al. 2007). This is because topographic features affect the availability and suitability for anopheline larvae (Zhou et al. 2004). Topographic elements such as foothills, farmlands, and pastures play a major role in the incidence of anopheline larval habitats because these areas generally have stagnant water bodies, which are ideal breeding grounds for Anopheles mosquitoes. A study by Protopopoff et al. (2007), confirms this by providing research that shows 93% of Anopheles activity occurs in valley bottoms. By knowing ideal habitats for Anopheles mosquitoes, eastern Africans can be cognizant of this and potentially reduce the risk of being infected with malaria.
As well as temperature and topography playing a role in the increase of Anopheles mosquito population and incidence of malaria, rainfall arguably plays the most important role in the livelihood of Anopheles mosquitoes. Rainfall can create collections of water, which serve as breeding sites for Anopheles mosquitoes. The amount and pattern of rainfall are both important and affect the larval development of the mosquitoes (Chavez et al. 2008). Studies have also shown that Anopheles mosquitoes prefer light rainfall that occurs approximately every one to two weeks (Obsomer et al. 2007). Light rainfall brings more particulate food onto the surface of Anopheles mosquitoes' aquatic habitat and keeps growth conditions optimal year-around (Martens et al. 1995). However if there are heavy rains, larval habitats will most likely be flushed away, and adult mosquitoes may not be able to leave their habitats because the rain is too powerful.
As previously stated, it is known that certain climatic factors aid in optimal mosquito reproduction. However, proper environmental management techniques such as installation of permeable concrete, soil amendments, implementation of water treatment facilities, and cistern installs could alleviate some of the issues. Unfortunately, poorer countries in eastern Africa usually do not have such luxuries. They have primitive irrigation systems that do not have waste treatment facilities. As a result, Anopheles mosquitoes thrive in these areas, thus causing malaria to be even more prevalent. Furthermore, since there is a lack of planning and limited resources the likelihood of having environmental management techniques is unlikely. Therefore, the control of malaria will be even more difficult.
Although there is undoubtedly a correlation between malaria and environmental factors, social and behavioral human factors have also played a significant role. Population from 1955 to 1995 has increased from 125 million to over 450 million people (Mouchet et al. 1998). With society increasing at such an exponential rate, there are more opportunities for people to be infected by Anopheles mosquitoes. As populations increase, people may move to other areas which could potentially cause once malaria-free areas to become highly endemic. This scenario has occurred in Ethoiopia. Individuals from this endemic region moved to a malaria-free area, and as a result, there was a significant increase in malaria cases (Mouchet et al. 1998). Furthermore, many have argued that malaria and poverty are intimately related (Gallup & Sachs 2001). This is because poorer, rural populations are generally not able to afford housing and bed nets, which protect against malaria, and often lack the education which enables them to recognize, treat, or prevent this disease.
Moreover, the population influx has not only increased the chances of people getting malaria, but the increase in population has also resulted in urbanization and the expansion of new agricultural practices. With the influx of people, there is a higher demand for urbanization of land for food and shelter. Forests have been cleared, and new agricultural and irrigation practices have been developed. Dams, irrigation channels, and rice fields have created breeding fields for Anopheles mosquitoes. According to distinguished anthropologists Frank B. Livingston, as humans developed increasingly larger agricultural societies, humans encroached on the mosquitoes' habitats (Rich et al. 2009). Livingston further asserts that because of this encroachment, there is a higher risk of transfer for new malarial pathogens (Rich et al. 2009).
Not surprisingly, with the increase of populations, comes the need for more jobs. Certain occupations can also be linked to higher infections of malaria. Agricultural workers are also more at risk of getting infected with malaria while harvesting various crops. Farming is one of the most common professions in eastern Africa. Because of the increase in deforestation, farmers are more likely to be subjected to Anopheles mosquitoes. Cattle farmers and gold miners are also at greater risk because Anopheles mosquitoes may look for alternative sources of blood meals and subsequently increase human exposure (Mouchet et al. 1998).
In addition to aforementioned public health factors, the suppression of vector control is the most significant cause of the evolution of malaria. In 1987, a serious malaria epidemic occurred in Madagascar (Mouchet et al. 1998). This epidemic affected all age groups and was deadly due to the lack of available medication. In order to prevent this from happening again, Madagascar's government ensured that there were ample doses of chloroquine and DDT indoor spray (Mouchet et al. 1998). However, the levels of chloroquine and DDT indoor spray did not last for long. In 1993, availability of chlorequine and DDT indoor spray were reduced drastically, and the number of malaria incidents began to rise (Mouchet et al. 1998). A similar scenario also occurred in Swaziland and Zimbabwe. In 1955, malaria incidents in Swaziland were almost eradicated. However, there were numerous accounts of health care irregularity which subsequently caused an epidemic during 1985-1986 (Mouchet et al. 1998). Zimbabwe also had an effective malaria program. However, small outbreaks were prevalent because people were not conducting insecticide treatments (Mouchet et al. 1998).
With the influx of malaria cases due to several public health factors, malaria has also been a significant economic burden in poverty stricken places such as eastern Africa. There are a multitude of ways malaria is connected to the economy, ranging from economical ruin of families, communities, and nations. Studies have shown that there is a correlation between low income levels and malaria. In fact, of the 44 countries with severe malaria, thirty-five are located in Africa. Of the forty-four countries with the highest rates of malaria, all but three are ranked among the lowest incomes per capita, while the thirty three richest countries are malaria free (Gallup & Sachs 2001). These statistics clearly show a correlation between poor countries and the incidents of malaria. Although it is difficult to say whether malaria is a cause or consequence for low incomes levels, it is a factor either way.
Malaria affects individual families significantly, especially in eastern Africa. If the breadwinner of a family dies or becomes extremely ill from malaria, severe financial burdens arise. Rates of malaria are also higher during crop collecting. In eastern Africa, many work agriculturally related jobs. If they get malaria, crops cannot get cleared, thus affecting the family. One study compared the amount of land cleared by families who are and are not affected by malaria. The study found that families affected by malaria cleared 60% less land than families that do not have malaria (Mushinzimana et al. 2006). Children in families also suffer from malaria. Children can either miss school by having the disease or are forced to stay home to do the work of their other family members who are unable.
In addition to individual families being affected, malaria also causes economic problems for communities. According to the World Health Organization, three out of every ten hospital beds in countries affected by malaria are occupied by malaria patients (1998). Therefore, the economic burden falls on communities. With so many victims, communities have fewer workers and usually have to pay for medical equipment and medical staff. Additionally, lack of knowledge and education is another serious social cost that is connected to malaria. In fact, roughly 35-60% of children who live in endemic countries are impacted in some way by this disease (Mushinzimana et al. 2006). If children are not educated, preventive management is not taught, and the problem continues to be prevalent.
Malaria not only affects families and communities, but it also affects nations. Studies have shown that countries with high rates of malaria have slower economic growth rates. Economic growth per capita between 1965 and 1990 has been a dismal 0.4% per year in poorer eastern African countries, while average growth for other countries is 2.3% (Gallup & Sachs 2001). Similar to the relationship between malaria and poorer countries, it is not known if the disease causes poverty or vice versa. Regardless, they correlate in some way. To further explain the magnitude of this problem, the direct and indirect costs of malaria in Sub-Saharan Africa exceeded two billion dollars in 1997 (WHO 1998). If developing countries in eastern Africa continue to have a lack of education and programs in place, this will be a never ending, vicious cycle.
In conclusion, there are various ways that malaria has affected the public health and economies in eastern Africa. Climatic factors in this region provide ideal breeding grounds for Anopheles mosquitoes. Furthermore with population increase, there is a higher risk of more people getting malaria because of more chances of exposure. The more people are exposed to malaria, the bigger the economic impact has on families, communities, and nations. Until there is a free vaccine, eastern Africa inhabitants will continue to be greatly affected. In the interim, in order to alleviate problems caused by malaria, people must be educated. Awareness and knowledge of malaria is the most important asset developing countries can have in order to prevent more malaria cases. The more aware people are, the better off the world, especially eastern Africa, will be. According to some sources, steps to decrease the effects of malaria are apparent, as the number of malaria related deaths in eastern Africa have decreased from 240,000 to 180,000 between 1960 and 2000 (CDC Malaria Facts 2007). These statistics are promising, but there are still too many preventable deaths occurring. By understanding malaria and how public health and economies are affected by this vector-borne disease, hopefully awareness is increased and this problem will be resolved.
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