EJMS

Abstract

Malaria affects more than 300 million and kills at least one million people every year. Early diagnosis and prompt treatment is the key to minimize the morbidity and mortality due to malaria. In Yemen, a strategy for malaria elimination in Socotra was developed in 2009. Malaria diagnoses has traditionally been made using thick blood smears, but more sensitive and faster techniques are required to process large numbers of samples in clinical and epidemiological studies and in blood donor screening. Serology detects antibodies against malaria parasites, using indirect immunofluorescence (IFA) as a gold standard test. It is a simple and sensitive method, but it is time consuming and difficult to automate. Therefore, the use of an immunochromatographic test to detect malaria-specific antibodies may be an alternative technique for the processing of large numbers of samples, which is necessary for blood therapy services and epidemiological studies. Objective: The main objective of this study was to compare the performance of the SD Bioline Malaria Pf/Pv test with immune fluorescence antibody test for serological diagnosis of covert cases of malaria in an endemic area in Hadramout governorate, Yemen. Methodology: The study was performed from July 2008 to May 2009 in three villages: Mosinaa, Hodathom, and Hesaa as endemic areas of malaria in Hadramout governorate,Yemen. A total of 263 venous blood samples (5 ml) were obtained randomly by active searches of individuals from the three villages, of both genders and all age groups and who had a recent history of fever within the previous three months. Thick and thin films were prepared directly from blood samples, stained with 10% Giemsa solution and examined at ×1,000 by an expert microscopist. The parasite density (if present) was counted per 500 leukocytes and was then expressed as the number of trophozoites and gametocytes per microliter by assuming a leukocyte count of 7,000/µL. The coagulated blood samples were centrifuged and serum was collected and kept till used in SD Bioline test and indirect IFAT. Results: The sensitivity and specificity of IFA test for the diagnosis of P. falciparum malaria using expert microscopy as a gold standard were 98.41% and 90.5%, respectively. The corresponding sensitivity and specificity for the diagnosis of P. vivax malaria were 100% and 100%. The sensitivity and specificity of SD Bioline test for the diagnosis of P. falciparum malaria were 88.1% and 85.4% respectively. The corresponding sensitivity and specificity for the diagnosis of P. vivax malaria were 100% and 99.14%. Conclusion: The present study demonstrated that for the endemic areas the use of an immuno-chromatographic test to detect malaria-specific antibodies may be an alternative technique for the processing of large numbers of samples, which is necessary for blood therapy services and epidemiological studies and diagnosis of fever of unknown origin, especially in patients inadequately treated for malaria and patients with tropical splenomegaly. The SD Bioline Malaria Pf/Pv test can be useful in areas where specialized laboratories or even microscopy are unavailable and when urgent malaria diagnosis is needed by a practitioner without the delay associated with the laboratory.