Tuesday, February 5, 2013

The Treatment of Malaria in the Third World



The Treatment of Malaria in the Third World

Introduction
The history of malaria dates back to before the history of humanity. This is because it is an ancient disease which evolved before the evolution of humans. The disease, which is widespread as well as potentially fatal is infectious and has affected humanity for most of human history. Human malaria is argued to have its origin in Africa and coevolving along with non-human primates and its host, mosquitoes. The initial evidence of the parasites responsible for the disease was revealed in preserved mosquitoes from the Palaeogene era which are estimated to be 30 million years old. Human beings may have for the first time infected with Plasmodium falciparum from primates, particularly gorillas. According to Packard (2007) approximately 100 centuries ago, the disease began having a major effect on the survival of humans which corresponded with the beginning of agricultural practices, (Neolithic revolution), a result was natural selection for thalassaemias, sickle-cell disorder, ovalocytosis, elliptocytosis, glucose-6-phosphate dehydrogenase deficiency and loss of the Duffy antigen and Gerbich antigen on the erythrocytes due to fact that the disorders of the blood present a selective benefit against infection of malaria (Shah 2010).  
According to Snow et al (2005), malaria is a disease caused by a parasite and is responsible for the demise of at least one million individuals per year, 90 percent of the deaths occurring sub-Saharan Africa. Deaths from malaria in the third world mostly affect children under the age of five. Regardless of the efforts to prevent and treat malaria in the third world, the burden of the disease is still significantly high. The treatment and prevention of malaria has been studied in medicine and science for centuries, and following the identification of the parasite causing the disease, focus has been on its biology. The studies are still on given that there is still no effective vaccine for the disease has been produced. While some efforts have been put in the third world with the help of the international community, the disease continues to be elusive given that some older anti-malarial medications lose their effectiveness because of the parasite developing resistance to the drugs. 
The causes of malaria
Parasites that cause malaria in humans are from the genus Plasmodium, phylum Apicomplexa. In humans there are five species of Plasmodium which infect and are transmitted by human beings: P. falciparum, P. ovale, P. malariae, P. vivax and P. knowlesi. The severe cases of malaria are mostly caused by P. falciparum. The type of malaria caused by P. ovale, P. vivax and P. malariae, is normally of milder form and are not as fatal as those caused by P. falciparum. Among the people infected by the parasite, P. falciparum is the mainly the common species recognized (~75 percent), then P. vivax (~20 percent). P. falciparum is also responsible for most deaths from malaria (Owusu-Ofori, Parry and Bates 2010). Proportionally of P. vivax is more widespread in countries outside of Africa. Documented cases of infections with various species of Plasmodium originating from higher apes have been identified; nevertheless with the exemption of P. knowlesi, which is a zoonotic species, prevalent in Southeast Asia, causing the disease in macaques. However, it can cause serious infections in human beings (Mueller, Zimmerman and Reeder, 2007).  
The disease is common in tropical areas due to the fact that these regions receive significant amount of rainfall, constantly with high humidity as well as high temperatures, together with stagnant waters. These are the breeding grounds for mosquito larvae where they readily mature, providing them with such an environment conducive for their continued breeding (Owusu-Ofori, Parry and Bates 2010).  
The classic hosts for the parasite that causes the disease are the Anopheles female mosquitoes. The mosquitoes play the role of the transmission vectors to human beings and other vertebrates as the secondary hosts. The parasite is ingested by young Anopheles female mosquitoes once they feed on infected vertebrate carriers. The salivary glands of the mosquitoes that have been infected with the parasite carry Plasmodium sporozoites. According to Mueller, Zimmerman and Reeder (2007) the mosquito is infected once it consumes a blood meal from a vertebrate which is infected. Following ingestion, the gametocytes of the parasite are taken up in blood where they are again differentiate into female or male gametes and then combine in the gut of the mosquito. An ookinete is produced which the lining of the gut producing an oocyst in the wall of the gut. On rupturing of the oocyst, sporozoites are released that move through the body of the mosquito to the salivary glands. It is from the salivary glands that they are capable of infecting a human host. When the mosquito is feeding on the blood of a human host, the sporozoites along side the saliva of the mosquito are injected into the skin (Snow et al 2005).  


The treatment of malaria
The treatment of the disease is normally on the basis of the seriousness of the disease. The experience and assessment of the physician determines whether a person is given medications, injections or admitted in the hospital for more specialized treatment. For uncomplicated or mild malaria, treatment can involve oral drugs. The most effective treatment for malaria caused by P. falciparum is the administration of artemisinins together with other anti-malarials (referred to as artemisinin-combination therapy). This treatment procedure is carried out in reducing the risk of artemisinin resistance. The other ant-malarials use in the combination includes amodiaquine, mefloquine, lumefantrine, or sulfadoxine/pyrimethamine. There is another recommended combination which is piperaquine and dihydroartemisinin (Sarkar et al. 2009).
Severe cases of malaria necessitate the parenteral administration of anti-malarial medications. Up to the mid 2000, the most commonly used strategy for treating severe cases of malaria was quinine. However, treatment using artesunate has been revealed to be more effective compared to quinine in both adults and children. Treatment of such cases if malaria also necessitates supportive strategies which are effectively carried out in critical care units, such as managing high fevers (hyperpyrexia) as well as the successive seizures which may come as a result, supervision for hypoglycemia, respiratory depression, and hypokalemia. Those infected with P. ovale, P. vivax, or P. malariae are normally given treatment on an out-patient basis. Infection with P. vivax requires treatment both of blood stages (using ACT or Chloroquine) and primaquine to clear liver forms (Sarkar et al. 2009).  


Prevention of malaria
Hartjes (2011) argues that transmission of malaria basically happens between dusk and dawn. There are various methods which are use in preventing the transmission of the disease and all of them basically involve prevention of the parasite being injected into the body by a mosquito.  Some of the methods which are used in the prevention of malaria include mosquito eradication, medications, and the prevention of bites. Staines and Krishna (2012) posits that the presence of the disease in a region necessitates a blend of high mosquito population density, high human population density, and high rates of transmission from mosquitoes to humans as well as from humans to mosquitoes. In case any of these elements is decreased significantly, there will be eventual disappearance of the parasite from the region. This was the case in Europe, North America, Europe and most regions in the Middle East. Nevertheless, unless there is complete elimination of the parasite from the entire world, re-establishment could occur in case of reversion of conditions to a blend which supports the reproduction of the parasite. Due to the increase migration and travelling, there are various cases of imported malaria in many countries (Pates and Curtis 2005).  
However, researchers and medical experts have argued that in the long run, prevention of the disease might end up being more cost-effective in the third world compared to its treatment. Nevertheless, the capital costs necessary for prevention are still too much for the poor in the third world countries. There is still a wide gap between the cost of control (that is maintaining low endemicity) and eradication projects between nations (Carmichael, 2010). For instance in China, where the government in the year 2010 pronounced a strategy for pursuing eradication of the disease in the provinces in the country, the necessary cost is a minor percentage of public spending on health. On the other hand, the same kind of project in a country like Tanzania would require an approximated one-fifth of the public spending on health (Hartjes 2011). 

Staines and Krishna (2012) suggest that some of the specific methods of preventing malaria include vector control, indoor residual spraying, mosquito nets, and medications. Vector control involves eradication of the diseases by eliminating mosquitoes. Efforts such as drainage of wetland breeding grounds as well as effective sanitation play a major role in vector control. Use of pesticide DDT as well as other methods of eliminating mosquitoes was successful in prevention of the disease in some countries like Egypt and Brazil. Another method of vector control resulting from the use of genetic technology is genetic manipulation of malaria mosquitoes. This is the introduction of foreign DNA into the genome of the mosquito to make it more resistance or increase its lifespan. Indoor residual spraying (IRS) involves the spraying insecticides on the walls of the house from the inside. This kills mosquitoes resting on the walls after feeding. DDT is one of the common pesticides. Sleeping under treated mosquito nets keep the mosquitoes away from humans. Thus, they cannot not feed and infect them with the parasite. Drugs such as Chloroquine are used, but due to resistance others such as, mefloquine (Lariam), doxycycline, or the mixture of proguanil hydrochloride (Malarone) and atovaquone are used in preventing infection (Carmichael, 2010).  

Conclusion
Malaria is a potentially fatal disease which is caused by a parasite transmitted by female anopheles mosquitoes. Malaria has a very long history probably preceding human evolution. The disease is common and one of the main causes of death in the third world, especially the sub-Saharan Africa. The diseases cause more deaths in these regions that in other parts of the world particularly in children below the age of five. Malaria can be prevented with effective means although the cost of prevention is high for these regions. Treatment is also possible although some of the drugs have become resistance. Therefore, there are calls for the international community to put more efforts in helping in the fight against malaria in the third world, being one of the reasons behind the failure to eradiate poverty.













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