The Cause and Symptoms of Malaria - Research Paper Example

An Analysis on Malaria History of Malaria Malaria in a disease that is caused by four parasitic Protozoans species belonging to the genus Plasmodium. The disease is classified as vector-borne due to its transmission in vertebrates through bites from infected mosquitoes. The name Malaria was coined from the Medieval Italian ‘mala aria’ which translates to bad air. The name is due to the then belief that the disease was caused by bad smelling air. Researchers believe the disease has existed since the prehistoric times, infecting early primates. However, the first recorded symptoms of the disease were in 2700 BC in China written down in early Chinese medical texts. The disease was first effectively managed from the early 17th Century following the understanding of Quinine by Jesuit Priests through their interaction with indigenous tribes of the New World. The cause of the disease remained unknown until 1880. That year Charles Louis Alphonse Laveran, a French army surgeon, became the first person to propose that the disease was caused by organisms he had observed in malaria-infected blood. Further discoveries over the course of the Century yielded that the disease were caused by Plasmodium species and was spread by mosquitoes. During that period, other antimalarial treatments were discovered. From the 1960s onwards, there were global eradication efforts conducted mainly through outdoor and indoor spraying of insecticides by DDT and other insecticides to control mosquitoes and other pests. However, this had detrimental effects on the environment primarily on the climate and on local fauna and increased resistance from insecticides by mosquitoes. In 2014, the World Health Organization (WHO) estimated that 1.2 billion people are at high risk of malaria. They also estimated that from 198 million malaria cases worldwide, the disease caused an estimated 584,000 deaths with Ninety percent of the deaths occurring in Africa (World Health Organization, 2014). Description of malaria Malaria in humans is caused by four Protozoan species: Plasmodium vivax, Plasmodium malariae, Plasmodium ovale and Plasmodium falciparum. Of the four species, the most common forms are P. vivax and P. falciparum with P. falciparum being the most deadly. P. falciparum contributes to 75% of reported cases and deaths and P. vivax around 20%. P. knowlesi causes malaria in primates. An infected female Anopheles mosquito is the primary host for the disease. On fertilization, female mosquitoes feed on blood to support egg development. By feeding on an infected person, the secondary host, the female mosquito is infected by the Plasmodium, which develops and reproduces. When the infected mosquito bites an uninfected person, the parasite is passed to the person through the mosquito’s saliva. The disease can also be transmitted by blood transfusion, but this is less likely due to the intense screening that blood undergoes prior to transfusions. Systems involved The process of malaria infection occurs over two stages. The first phase, exo- erythrocytic phase, is characterized by the malaria parasites rapidly multiplying in the liver. The second phase, erythrocytic phase, is characterized by the malaria parasites infecting the red blood cells of the infected person. When the mosquito vector bites an uninfected person, infective cells known as sporozoites enter the bloodstream and take root in the liver. Here, the sporozoite infects the liver cells (hepatocytes) and multiply into merozoites asexually without any symptoms. Hepatocytes perform the liver functions of detoxification, bile production, protein storage and synthesis, and aid in digestion. The sporozoite effectively seizes control of the host liver cells and exploits the resources of the cell to multiply into thousands of merozoites per liver cell. The spread of sporozoite impairs on healthy liver function and eventually leads to immature cell death of the host liver cell (Kaushansky et al., 2013). After a period of 8-30 days, the parasite escapes the liver and enters the bloodstream camouflaging itself as the host liver cell. The parasite rapidly infects and multiplies within red blood cells. Normal red blood cells are deformable and stable in order to perform its oxygen-carrying function through the body’s capillary network. Infected red blood cells, however, undergo structural changes (Cooke, Mohandas, and Coppel, 2001). The cells become more rigid and unable to deform. The red blood cells also become more adhesive and stick to capillary walls. This stickiness and rigidity impair blood circulation. While infecting the host liver cells, the parasite is relatively invisible to the immune system. However, when infected red blood cells rupture, they release malaria parasites triggering an immune response by the body. The parasite then avoids detection by changing critical identification surface proteins (Artavanis‐Tsakonas, Tongren, and Riley, 2003). The parasite then reverts to its normal self when it infects a new red blood cell and starts to multiply. Signs, Symptoms, and Causes The signs and symptoms of the disease are caused by the spread and infection of the parasite in the different cells of the body. The symptoms occur after 8-30 days after initial infection. Paroxysm is a classic malaria symptom. It is characterized by a cyclical occurrence of shivering and fever for a number of days caused by the asexual multiplication cycles inside red blood cells. Other symptoms such as fatigue, vomiting, joint pain, jaundice, and headaches are also a result of the bursting and reinfection of red blood cells. Cerebral malaria leads to neurological symptoms such as retinal damage, convulsions, seizures, and comas. Complications Severe malaria results in a number of complications. In pregnant women, malaria crosses the blood placenta barrier causing placental malaria. This disease results in stillbirths, low birth weight or the abortion of fetuses. When malaria crosses the blood-brain barrier, it causes cerebral malaria. This disease may cause severe brain damage, migraines, coma or death of an infected patient. Due to the destruction of red blood cells and liver cells, malaria may also result in anemia and liver failure or enlarged livers respectively. Red blood cells transfer oxygen within the body and their destruction during the infection leads to respiratory discomfort and pulmonary conditions. Malaria treatment and side effects There is no effective malaria vaccine. However, there exist many types of antimalarial medications. They include Quinine and related chemical agents, Artemisinin and derivatives, Chloroquine, Proguanil, Sulfonamides and Mefloquine among others. The exact type of antimalarial chemical agent depends on the spread of resistance, type of malaria or the reason for the treatment. Uncomplicated malaria is treated with oral antimalarial medication while severe malaria is treated intravenously. P. falciparum has attained resistance for quinine and is thus treated by a combination of artemisinin and other antimalarial agents (Sidhu, Verdier-Pinard, and Fidock, 2002). Side effects from the different antimalarial include may include nausea, vomiting, diarrhea, abdominal pain and dizziness, cramps, and itching among other effects. Conclusion In conclusion, the future of malaria treatment remains promising due to the intensive research conducted in providing a malaria vaccine. The polymorphic nature and diversity of the parasite makes it difficult to develop a sustainable vaccine. However, potential vaccines with promising results are being developed that target the parasite at the pre-erythrocytic (infection) stage (RTS et al., 2012). In the meantime, more is required to be done in prevention of the disease. Prevention can be through mosquito control measures such as draining stagnant waters and spraying insecticides outdoors. These measures destroy mosquito breeding grounds. Also use of insecticide-treated mosquito nets and insect repellent are an effective deterrent from mosquito bites at night. Only time and a concerted global effort by governments and researchers in malaria education, prevention and research will effectively reduce deaths that result from malaria. It should be the goal of every global citizen to make malaria, like many deadly diseases before it a think of the past. Reference Artavanis‐Tsakonas, K., Tongren, J. E., & Riley, E. M. (2003). The war between the malaria parasite and the immune system: immunity, immunoregulation and immunopathology. Clinical & Experimental Immunology, 133 (2), 145-152. Cooke, B. M., Mohandas, N., & Coppel, R. L. (2001). The malaria-infected red blood cell: structural and functional changes. Advances in parasitology, 50, 1-86. Kaushansky, A., Metzger, P. G., Douglass, A. N., Mikolajczak, S. A., Lakshmanan, V., Kain, H. S., & Kappe, S. H. (2013). Malaria parasite liver stages render host hepatocytes susceptible to mitochondria-initiated apoptosis, Cell death & disease, 4(8), e762. doi: 10.1038/cddis.2013.286. Rts, S. C. T. P., Agnandji, S. T., Lell, B., Fernandes, J. F., Abossolo, B. P., Methogo, B. G., ... & Laserson, K. F. (2012). A phase 3 trial of RTS, S/AS01 malaria vaccine in African infants. The New England journal of medicine, 367(24), 2284-95. doi:10.1056/NEJMoa1208394 Sidhu, A. B. S., Verdier-Pinard, D., & Fidock, D. A. (2002). Chloroquine resistance in Plasmodium falciparum malaria parasites conferred by pfcrt mutations. Science, 298(5591), 210-213. doi:10.1126/science.1074045 World Health Organization. (2014). World Malaria Report 2014. Read More