Etiology of malaria
Malaria is an infectious disease, which can cause flu-like symptoms. The virus is transmitted via parasite carried by mosquitoes. Malaria continues to be an issue in tropical and subtropical areas and remains one of the world’s leading death-causing infections. Malaria is single celled organism. There are four different classes of malaria parasites (1) Plasmodium vivax is universal and widely distributed in subtropical and temperate area and it can also relapse. (2) Plasmodium Falciparum causes the most serious and lethal disease. They are mainly found in tropical regions. (3) Plasmodium malariae can only be found in subtropical areas. (4) Plasmodium Ovale is the least familiar malaria group, which is normally found in Africa, and can also relapse (WHO, 2009).
There are approximately 500 million cases of malaria and 1 million deaths from malaria each year (Maslove et al., 2009). However, recent research shows that the incidence of malaria has dramatically reduced in some parts of Africa by increasing exploitation of anti-mosquito measures (Maslove et al., 2009). Apart from the human toll, malaria causes considerable economic devastation in high-rate areas, reducing Gross Domestic Product (GDP) of a country with high level of disease to 1.3% (WHO, 2009). In the long-term, these cumulative annual losses would result in significant variation in GDP among countries with malaria and countries without malaria (WHO, 2009). The healthcare cost on malaria involves both personal and public spending on prevention and therapy. In some countries with high incidence rate, and prevalence of the disease, public health expenditures accounts for about 39 percent, 50 percent of inpatient hospital admissions and about 60 percent of outpatient visits (WHO, 2009). Malaria excessively affects low-income families that cannot afford treatment and have no access to healthcare, thus trapping those families and their communities in a downward curve of poverty (Maslove et al., 2009).
Impact of DDT
- Mechanisms action of DDT
Dicholor-Diphenyl-Trichlorethane (DDT) has a chemical formula C1H9C15. It is not natural product. It was synthesized in 1874 and since 1945, it has been commercially offered by concentration of chloral with chlorobenzene (Tomatis, February 1, 2002). It is an insecticide that has a low solubility in water and relatively high solubility in fats (Tomatis, February 1, 2002). When DDT is dissolved in the plasma membrane of an organism, it finds its way into and causes the cell to leak. Two things slip through these leaks sodium ions and potassium ions. After DDT gets into the plasma membrane, nerve impulses (signals) no longer fires when they are supposed to, thus, an organism dies by neither seizure nor paralysis when poisoned with DDT (DDT: Introduction)
- Alternatives to DDT
In countries where malaria is prevalent, the organochlorine pesticides are applied in houses to prevent and eradicate mosquitoes from spreading the diseases (Yang, May 4, 2009). This is done notwithstanding the lack of data on the impact of people health exposed to DDT Researchers after reviewing almost 500 epidemiological studies all agreed that increased efforts should be made to decrease the exposure to DDT, and create an alternative method to DDT that could eventually be used for controlling malaria (Yang, May 4, 2009). Some non-chemical methods of malaria control include emptying sources of standing water, and diagnosis cases of malaria cases and swiftly treating those cases (Yang, May 4, 2009).
- Toxicity of DDT
DDT is most famous for its effect on birds, some research studies has shown that certain species, DDT causes the thinning of the eggshells. Some species affected by DDT include; osprey, eagles, pelicans and hawks (Szaflarski et al, 2006). In the past, DDT was used to control mice, rats and bats. Bats are very sensitive to DDT. Very low doses of DDT can affect them severally. A lot of current research deals with DDT’s effects on larger mammals (Szaflarski et al, 2006).
- Toxicity DDT in Human Beings
A study was conducted on the effects of DDT in men, with high occupational exposure to DDT the result of the study revealed a raise on the risk of birth deficiency. The men sampled were malaria control workers employed for at least a year (Salazar-Garcia et al, 2004). Most of the children born to these fathers had congenital malformations, specifically the nervous system, followed by spontaneous abortions, and birth defects (Salazar-Garcia et al, 2004).
In another study conducted on women who were exposed to DDT early in life (before the age of 14) and particularly during the peak periods of usage of DDT in the United States, the result revealed fivefold increased risk of breast cancer(Cohn et al., 2007). Women who were not exposed to DDT early in life showed no increased risk (Cohn et al., 2007). Neurotoxic effects of DDT on insects may conversely disrupt neuronal activity in humans too. These neurotoxic effects have been studied in infants, Sagiv et al, (2008), while conducting a research on the effects of parental exposure to DDT and infant behavior, found out that low level of DDT in umbilical cord serum at birth were linked with reduced concentration during the first year of their lives. Further, Garabrant et al, (1992) researched the association of pancreatic cancer and the exposure to DDT among chemical manufacturing plant workers. The researchers reported that there was a relationship between DDT exposure and pancreatic cancer among plant worker who were exposed. Finally, prolonged exposure to DDT increases the risk of pancreatic cancer substantially.
The use of DDT should be banned in all circumstances. It is essential that any public health measures are void of substantial health risks. The use of DDT has been associated with substantial health risks including neuro-developmental delays in infants and children, endocrine-mediated dysfunction, and cancer risk (Cox, 2007; Turyk et al, 2009). The concept of nonmaleficence also applies to wildlife and the environment at large (Eskenazi, et al 2009; Cohn et al, 2007; Roger & Chen, 2005). Under the environmental stewardship model, DDT should never be utilized because it is a ‘persistent organic pollutant’ POPs (Moeller, p.23 2005), it bio-accumulates in the environment, poses a threat to wildlife, and breaks down into metabolites which are also highly persistent in the environment (ATSDR, 2002). Consequently, mosquitoes may be resistant to the effects of DDT through genetic mutation and enzyme up-regulation (Maslove, et al, 2009). This means that the use of DDT exposes humans and the environment to definite risks, but indefinite health benefits.
A better recommendation would be to use safer chemical alternatives such as malathion and deltamethrin, which are good, substitutes to DDT because they exhibit far lesser toxicological risks (Sadasivaiah, et al, 2007). Other alternative strategies for malaria prevention include the use of bed nets insecticide-treatments, indoor residual spraying (IRS), and source reduction through larval control (CDC, 2008). Further, access to a better health system would provide a reliable diagnosis for optimal treatment. However, in most malaria prevalent countries, access to treatment and diagnostic service are limited. With increased international efforts to decrease the rate of malaria on DDT, prompted World Health Organization (WHO), and United Nations to launch integrated vector management (IVM) technique for controlling malaria. This technique would provide sustainable, efficient and cost-effective substitute for DDT use. The goal of IVM is to reduce DDT application by 30 percent over the current usage (UN, 2009).
Most countries have banned DDT except for spraying indoors in developing regions where prevalence of malaria is high. However, IRS in homes is used in those countries given the reappearance of malaria in recent decades. There is growing concerns about the adverse human health effects of DDT. Research evidence indicates that exposure to DDD with its breakdown product DDE at levels considerably reduced rate of incident than in communities using IRS could be related with diabetes, spontaneous abortions, breast cancer, reduced semen quality, and impaired child neuron development. The IVM project has showed a reduction of about 60 percent decline in the occurrence of malaria and over 80 percent decline seen in most serious type of malaria, which is triggered by plasmodium falciparum (Sadasivaiah et al., 2007). Thus, this achievement has regenerated hopes that an end to DDT dependents is achievable. IVM accomplishes such reduction in strategies, by using insecticide-related bed nets, and draining.
The Centers for Disease Control and Prevention (CDC, 2008), states that the only insecticides permitted for bed nets use are Pyrethroids that are less toxic to human than other pesticides. From a public health standpoint, IVM should be equivalent to DDT in terms of malaria control. However, the potential problem for IVM is the inability to maintain interest of communities of IVM strategies (CDC, 2008). Moreover, properly executed IRS strategies would also entail sustained effort as well as an expensive to maintained infrastructure. It is believed that the result of these projects would enable developing countries to decrease their reliance on DDT, thus avoiding its potentially hazardous consequence on people health and the environment, while reducing the occurrence of malaria (CDC, 2008).
Finally, a total ban of DDT can only be accomplished at a cost that developing countries that depend on the use of insecticide for public health purposes, would not be to afford it without considerable and long-term financial aid from developed countries (Turusov, Rakitsky, and Tomatis, 2002). I believe that effective pesticides with no negative substance of DDT and its metabolites should be required with the aim of eliminating DDT completely (Turusov, Rakitsky, and Tomatis, 2002).