Clinical Features of Malaria:
All the clinical features of malaria are caused by the erythrocytic schizogony in the blood. The growing parasite progressively consumes and degrades intracellular proteins, principally hemoglobin, resulting in formation of the 'malarial pigment' and hemolysis of the infected red cell. This also alters the transport properties of the red cell membrane, and the red cell becomes more spherical and less deformable. The rupture of red blood cells by merozoites releases certain factors and toxins (such as red cell membrane lipid, glycosyl phosphatidyl inositol anchor of a parasite membrane protein), which could directly induce the release of cytokines such as TNF and interleukin-1 from macrophages, resulting in chills and high grade fever. This occurs once in 48 hours, corresponding to the erythrocytic cycle.
Analysis of the scale and spread of the disease:
Malaria affects more than 40% of the World’s populations in more than 100 countries; especially in the tropics which provides an ideal breeding ground for the anopheles mosquito. According to statistical data published by W.H.O in Africa a child dies of malaria every 20 sec; and there is one death each 12 sec. across the world. It accounts for 2.6% of total disease burden in the world. Estimated global annual cost (in 1995) for malaria is $2 billion. P. falciparum infection during pregnancy increase the chance of maternal anemia, stillbirth and low birth weight which leads to death in first month of life. Asia harbors a global threat as an epicenter of multi-drug resistant P. falciparum which is gradually encompassing the tropical world. 400 million people live with endemic malaria unchanged by control. In developing countries of South Asia Malaria is a real threat to public health as its outbreak can eradicate populations.
Control and Treatment of Malaria:
Malaria kills one to three million people every year in tropical and subtropical countries such as Africa and India. Hence it is important to control the disease and stop the spread across the world. W.H.O. evolved a Global Strategy for Malaria Control. The strategy broadly suggests de-emphasis on vector control and renewed emphasis on treatment. Early diagnosis and treatment; prevention of deaths; promotion of personal protection measures; epidemic forecasting, monitoring, evaluation and operative research and integration of activity in Primary Health Centres are the salient aspects of this strategy. By far the best development in this field came with the Genetically Modified Mosquitoes which contains the gene to combat the growth of malarial parasite in it. The parasites cannot finish their Life Cycle within these mosquitoes and hence the transmission to humans is restricted. However protection against mosquito’s bites, use of proper drugs amongst the infected patients still remains the major way to stop outbreak. Oral treatment is used for uncomplicated malaria, intravenous or intramuscular treatment for severe cases. Chloroquines, Sulphadoxine-Pyrimethamine, Quinine are amongst the commonest drugs used against malaria. Causing mass alertness against the disease in 3rd World Countries is a major advantage to stop its spread.
Diagram depicting the life cycle of malarial parasite (Asexual phase in human body and sexual phase in the mosquito) (Ref: )
Incidence of Malaria in India over past few years.
(Data from Link: Malaria in India)
Abbreviations: W.H.O – World Health Organisation; R.B.C – Red Blood Corpuscles/Erythrocytes.
References:
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