Malaria Still a Global Health Problem - Term Paper Example

Diseases Malaria In spite of the advances in the understanding of how malaria is caused, spread, and effects the human body, Malaria still remains aserious public health problem, affecting nearly 2.4 billion or forty percent of the population of the world, emphasis on countries in the tropical and sub-tropical regions of the world that include Africa, Asia, Latin America, the Islands of the South, West and Central pacific Ocean, the Caribbean Islands and Turkey. (1). In the United States of America malaria ceased being an endemic disease in 1947, and cases of malaria are few, mostly resulting from traveling to regions of the world, where malaria is endemic and neglecting to take the required prevention measures. (2). The parasitic protozoa species of the plasmodium genus is responsible for malaria in humans making it the vector for transmission of malaria. The primary mode of transmission of the infection is through the bite of a female anopheles species of mosquito. Severe malaria that can lead to severe morbidity or even death is normally attributed to Plasmodium falciparum. Though malaria can also be transmitted during blood transfusion or between mother and child during pregnancy, these modes of transmission are found to occur rarely. (2). The plasmodia are present in the saliva of the infected anopheles mosquito and pass it on to the human host at the time of drawing blood from the human as its meal. The plasmodia target the red blood cells and enter them and use the hemoglobin and other proteins in the cells for nutrition. This results in RBC cystoloysis leading to the toxic metabolic byproducts entering the blood stream and producing the symptoms of malaria, which resemble flu and include chills, headache, myalgias, and malaise. Jaundice, anemia and kidney failure are the more severe results of malaria, which can progress to coma and death. The more severe consequences of malaria can be avoided through proper treatment. (2). Chloroquine phosphate remains the drug of choice in the treatment of malaria. (2). However the treatment of malaria is not easy because of resistance to chloroquine and evaluation of resistance by the infecting strain is essential to decide on the anti-malarial agent to be used. Where resistance is encountered use of other forms of quinine or a range of other anti-malarial drugs capable of arresting the infection would have to be considered for use. (3). Filariasis Filariasis occurs in both humans and animals. The nematode parasites of the order Filariidae or filariae are responsible for the infection. Only about 8 species of the hundreds of filarial parasites cause natural infections in humans. Depending on the where the adult worms locate themselves in the human body the filarial parasites are classified into three groups. The cutaneous group consists of Loa loa, Onchocerca volvolus, and Mansonella streptocerca; while the lymphatic group is made up of Wuchereria bancrofti, Brugia malayi, and Brugia timori; and the body cavity group comprises Mansonella perstans and Mansonella ozzardi. (4). The parasites that contribute to a significant proportion of the disease burden belong to the lymphatic and cutaneous groups, with particular emphasis on Wuchereria bancrofti and Brugia malayi, which live almost exclusively in the human body and cause lymphatic filariasis. (5). The mosquito is the vector responsible for the transmission of the infection and so the burden of the disease is felt mainly in the tropical and sub-tropical regions. The World Health Organization puts in excess of a billion of the world’s population at risk for lymphatic filariasis spread across eighty countries, with more than 120million already affected and forty million of these either incapacitated or disfigured due to the infection. Nearly a third of those infected are found in India, another third in Africa and the remaining distributed between South Asia, the Pacific and the Americas. (5). Currently filariasis is not prevalent in the U.S.A. Visitors from America to filariasis endemic areas may bring the disease, if the duration of stay is long and adequate mosquito protection is not taken. (4). Filariasis is on the increase and the cause of this increase has been laid at the growing number of mosquito breeding grounds created by rapid and unplanned growth of cities in the endemic areas. (5). The disease gets transmitted through mosquitoes biting infected individuals in their feeding process and picking up the microfilaria, which develop in the mosquito and gets passed on when the infected mosquito bites another individual. There is lack of clarity on how filariasis develops in the human body, but is generally believed that the infection occurs in early childhood, but manifests itself only in the adult stage due to the slow process of development of the disease. In lymphatic filariasis the filarial worms lodge themselves in the lymphatic system and cause inflammation in the lymphatic vessels. This leads to the overt manifestations of the disease in the form of enlargement of the entire arm or legs, genitals, vulva or breasts. As a result there is strong social stigma attached to the disease. In addition to these overt manifestations, the infection also causes damage to the kidneys and the lymphatic system. (5). Diethylcarbamazine (DEC) and albendazole are effective antifilarial agents for eliminating the infection from an individual. Current therapeutic practices consist of using a combination of the two therapeutic agents for a full year and are found to be 99% effective in eliminating the infection, which has led to the hope for eliminating lymphatic filariasis. In addition to eliminating the filarial infection it is also useful to take into consideration the high risk of superimposed fungal or bacterial infection and manage them based on presence of these infections in the individual. (5). Dengue Dengue is a viral infection that is transmitted by mosquitoes and causes illness that is similar to flu, with the potential risk of deadly complications called dengue hemorrhagic fever (DHF). Being a mosquito-borne infection the burden of the disease is carried by the countries in the tropical and sub-tropical regions of the world, with particular emphasis on the urban and semi-urban areas of these countries. Dengue is endemic to over 100 countries located in Africa, the Americas, the Eastern Mediterranean, South-east Asia and the Western Pacific. The threat posed by dengue is on the rise, as the incidence of dengue is reported to be on the rise. Nearly forty percent of the world’s population making up 2.5 billion people faces the risk of dengue infection. Estimates suggest that around the world nearly fifty million people are affected by dengue infections every year. (6). Dengue is not endemic in the U.S.A., but cross border infection from Mexico into Texas has seen the incidence in Texas rising. Estimates suggest that this incidence is around a hundred cases every year. (7). The dengue virus is made up of four distinct, yet closely related serotypes, DEN1-DEN4, which retains the infection cycle mainly using the Aedes aegypti mosquito. As with other mosquito-borne infections the infection gets transmitted through the mosquito carrying the infection from an infected individual to an infection free individual through its bites in its feeding process subsequent to an incubation period in the mosquito. (8). The manifestation of the infection varies according to the age of the individual infected. In infants and children the infection manifests as fever with rash. In older children and adults the infection manifests as a mild fever or with more severe signs of high fever, severe headache, pain behind the eyes, pain in the muscles and joints and rash. Though dengue is seldom fatal, it could lead to the deadly complication of DHF, which is characterized by high fever, usually accompanied by enlargement of the liver, and when in severe cases circulatory failure. Like many viral infections, there is no specific treatment regimen for dengue till date, and managing DHF consists of addressing the manifestations, with particular emphasis on maintenance of the circulatory volume in the patient. The emphasis in dengue lies in preventing or controlling the transmission of the infection, through vector control. (6). West Nile Virus The West Nile virus (WNV) belongs to the genus Flavivirus that can infect humans. It is again a mosquito-borne infection. The life cycle however involves the transmission of the virus from animals and birds to humans after a period of incubation through any of the Aedes, Culex, or Anopheles mosquitoes. Though it can be transmitted through any non-human mammal, wild birds appear to be the main culprit in the transmission of the infection. As a result, WNV infection is reported across the world in Africa, Asia, the Middle-East, and North America. (9). WNV infection in humans is classified into three namely WNV neuro -invasive disease (WNND) involving encephalitis, meningitis, or acute flaccid paralysis; West Nile Fever (WNF) consisting of symptomatic WNV disease with no impact on the nervous system; and unspecified clinical syndrome. In 2007, a total number of 3,639 cases of WNV were reported in the U.S.A, with 34% of them WNND, 65% of them WNF, and 1% of them unspecified clinical syndromes. (10). WNV infection lasts for about a week and the manifestations of mild infection include nausea, anorexia, malaise, myalgia, headache, backache, rash, eye pain and vomiting. Symptoms of a more severe infection include severe muscle weakness, flaccid paralysis, photophobia, seizure, alterations in mental status, breathing difficulty and rash on the neck, trunk, arms or legs. The involvement of the central nervous system with meningitis and encephalitis are signs of very severe infection. (9). There is no specific treatment regimen for WNV infection, as most patients even with involvement of the central nervous system recover without treatment of the infection and with only supportive therapy consisting of intravenous fluids and pain killers. Interferon therapy is under investigation to reduce the duration of the infection. (11). Comparison The common characteristic of these infections is that they are all mosquito-borne infections, even though the agents vary from protozoa in malaria, nematodes in filariasis, and virus in dengue and WNV. In the case of malaria, filariasis and dengue, the mosquito transmits the disease from human to human after a brief period of incubation in the mosquito, while in the case of WNV the transmission is from birds and animals to humans. Being mosquito-borne diseases the overall burden of the diseases is felt in the tropical and sub-tropical regions in the world, with minimal impact of the infections in the developed world, where effective mosquito prevention and control programs have been put in place. It is only in the case of dengue and WNV that a small portion of the burden of the disease is seen in the U.S.A. Manifestation of the infections vary, though some similarity in the initial symptoms is seen in the case of malaria, dengue and WNV. Effective treatment regimens are available for malaria and filariasis and lack of treatment can cause the infection to progress and create severe complications. In the case of dengue and WNV there is no specific treatment and the infection in most cases is self-limiting. However, supportive care for the symptoms is necessary involving maintenance of circulatory volume and pain killers. The best means of preventing and controlling these infections is by controlling the transmission vector of the mosquito. Works Cited 1. Diggins, C. Kristene. “Malaria Still a Global Health Problem”. Topics In Advanced Practice Nursing eJournal. 2.3 (2002). 25 Nov 2009. . 2. Fernandez, C. Miguel. “Malaria”. 2009. emedicine from WebMD. 25 Nov 2009. . 3. Rosenthal, J. Philip. “Protozoal & Helminthic Infections”. Current Medical Diagnosis and Treatment 2009. Forty-Eighth Edition. Ed. Stephen, J. McPhee & Maxine A. Papadakis. Berkshire, U.K: McGraw-Hill Lange, 2009. 1315-1356. 4. Wayangankar, Siddharth, Bronze, Stuart Michael & Jackson, L. Rhett. “Filariasis”. 2009. emedicine from WebMD. 25 Nov 2009. . 5. “Lymphatic Filariasis”. 2000. World Health Organization. 25 Nov 2009. . 6. “Dengue and dengue haemorrhagic fever”. 2009. World Health Organization. 25 Nov 2009. . 7. Shepherd, Moore Susan, Hinfey, B. Patrick & Shoff, H. William. “Dengue Fever”. 2009. emedicine from WebMD. 25 Nov 2009. . 8. Isnar, A. Gagop & Sentochnik, Deborah. “Dengue”. emedicine from WebMD. 25 Nov 2009. . 9. Salinas, D. Jess & Steiner, L. Monica. “West Nile Virus”. emedicine from WebMD. 25 Nov 2009. . 10. Limdsey, P., Lehman, J. A., Staples, J. E., Komar, N., Zielinski-Gutierezz, E., Hayes, E.B., Nasci, R. S. & Duffy, M. “West Nile Virus Activity -- United States, 2007”, Morbidity & Mortality Weekly Report 57.26 (2008): 720-723. 11. “West Nile virus”. 2008. MayoClinic.com. 25 Nov 2009. . Read More