Definition <ul><li>Malaria is a mosquito -borne infectious disease of humans caused by eukaryotic protists of the genus Plasmodium . It is widespread in tropical and subtropical regions, including much of Subsaharan Africa , Asia and the Americas . The disease results from the multiplication of malaria parasites within red blood cells , causing symptoms that typically include fever and headache , in severe cases progressing to coma , and death. </li></ul>
Etiology <ul><li>Malaria is caused by obligate intracellular protozoan parasites of the genus "Plasmodium" . The four species of human malarial parasites are: </li></ul><ul><li>Plasmodium vivax </li></ul><ul><li>P falciparum </li></ul><ul><li>P malariae </li></ul><ul><li>P ovale . </li></ul>
Signs and symptoms: <ul><li>fever </li></ul><ul><li>shivering </li></ul><ul><li>arthralgia (joint pain) </li></ul><ul><li>vomiting, anemia (caused by hemolysis ) </li></ul><ul><li>hemoglobinuria </li></ul><ul><li>retinal damage </li></ul><ul><li>convulsions </li></ul>
Mode of transmission <ul><li>Malaria is transmitted by the bite of an infective female Anopheles mosquito. Rarely, transmission can be congenital (via the placenta) or can occur through transfusions or the use of contaminated needles. </li></ul>
Period of communicability <ul><li>Malaria is not directly communicable from person to person, except through congenital transmission; however, during parasitemia, the disease may be transmitted to other persons through blood transfusion or through shared, contaminated needles. Infected human hosts can be a source of infection for Anopheles mosquitoes for prolonged periods of time (1-3 or longer, depending on the species of malaria) if not adequately treated. </li></ul>
Susceptibility and resistance <ul><li>The role of red blood cell polymorphisms in resistance and susceptibility to malaria. </li></ul><ul><li>In regions highly endemic for Plasmodium falciparum malaria, red cell polymorphisms that confer resistance to severe disease are widespread. Sickle cell trait, alpha-thalassemia, glucose-6-phosphate dehydrogenase deficiency, and blood groups were determined in 100 children from Gabon with severe malaria who were matched with 100 children with mild malaria and followed up for evaluation of reinfections. The sickle cell trait was significantly associated with mild malaria and blood group A with severe malaria. During follow-up, the original severe cases had significantly higher rates of reinfection than the original mild cases, with higher parasitemia and lower hematocrit values. Incidence rates did not differ in the context of erythrocyte polymorphisms, but patients with sickle cell trait presented with markedly lower levels of parasitemia than those without. Thus, the severity of malaria is partly determined by the presence of blood group A and the sickle cell trait. The different presentation of reinfections in severe versus mild cases probably reflects different susceptibility to malaria. </li></ul>
Methods of control <ul><li>removing or poisoning the breeding grounds of the mosquitoes or the aquatic habitats of the larva stages, for example by filling or applying oil to places with standing water </li></ul><ul><li>Using of bednets </li></ul><ul><li>spraying with DDT . </li></ul>
Program for prevention <ul><li>The Malaria Research Program of the Research Institute for Tropical Medicine has provided research activities on disease epidemiology and immunology, molecular biology of the parasite, vector behavior, social health research on treatment patterns and disease perceptions, clinical trials for anti-malarial drugs and malaria diagnostic kits, anti-malarial drug resistance and pharmacokinetic studies and community-based strategies to improve disease control. </li></ul><ul><li>The Global Malaria Programme (GMP) is responsible for malaria surveillance, monitoring and evaluation, policy and strategy formulation, technical assistance, and coordination of WHO's global efforts to fight malaria. </li></ul>
Diagnosis <ul><li>Antigen tests </li></ul><ul><ul><li>Tests use finger-stick or venous bloo, the completed test takes a total of 15-20mins., and results are read visually as the presence or absence of colored stripes on the dipstick. </li></ul></ul><ul><ul><li>Molecular methods </li></ul></ul><ul><ul><li>polymerase chain reaction </li></ul></ul>
Prevention and control /treatment <ul><li>Early diagnosis and prompt treatment </li></ul><ul><li>Vector control – insecticide-treated mosquito net as main vector control strategy, complemented by indoor residual spraying </li></ul><ul><li>early management and disease surveillance </li></ul><ul><li>monitoring and evaluation – drug and insecticide resistance monitoring </li></ul><ul><li>Antimalarial drugs </li></ul>
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