A Review of Alternatives to Conventional Microscopy in the Laboratory Diagnosis of Malaria.

Lokeshwari, G (2013) A Review of Alternatives to Conventional Microscopy in the Laboratory Diagnosis of Malaria. Masters thesis, Coimbatore Medical College, Coimbatore.


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BACKGROUND: Malaria is the disease of antiquity, having been recognized since Vedic times in India. It is distributed worldwide with a great socioeconomic impact on the countries with intense transmission particularly in tropical regions 3. Patients affected with malaria present with varied clinical picture from fever and malaise to life threatening symptoms like cerebral malaria. Diagnosing malaria based on clinical features alone may lead to over-diagnosis especially in endemic areas. Thus parasite based diagnosis is recommended for all patients by WHO. This study is focused on alternatives to conventional microscopy in the laboratory diagnosis of malaria. OBJECTIVES: 1.To identify malarial parasite in patients with low parasite densities. 2. To compare the sensitivity and specificity of Rapid Diagnostic Test (RDT) with conventional microscopy. 3. To evaluate the diagnostic performance of pLDH Antigen detection ELISA. 4. To evaluate the role of PCR in the diagnosis of malaria. MATERIALS AND METHODS: This is a cross-sectional study conducted over a period of one year from September 2011 to September 2012. The study group included patients of all age groups and both sexes who were clinically suspected to have malarial fever (both inpatients and outpatients). Blood samples from these 242 patients were collected in a vacutainer with EDTA anticoagulant. Leishman’s staining of the Peripheral smear, Rapid diagnostic test and ELISA for parasite specific pan malarial antigen (LDH) detection were done on all the samples. PCR was done with plasma for a total of 40 samples (20 microscopy positive and 20 microscopy negative samples). RESULTS: Peripheral smear was considered as the Gold standard test. ICT, ELISA and PCR were compared with the Gold Standard peripheral blood smear. Microscopy detected 42 cases (17.4%), ICT was able to detect 44 cases (18.8%) and ELISA detected 43 cases (17.8%). ICT detected mixed infection of Plasmodium falciparum with other Plasmodium species in 6 cases whereas microscopy detected only one mixed infection. RT-PCR detected 4 cases as positive for malaria among the 20 microscopy negative samples. All the three recent diagnostic methods (ICT, ELISA and PCR) were found to be 100% sensitive when compared to microscopy in the diagnosis of malaria. CONCLUSION: Of the diagnostic methods studied, non-microscopic method like ICT is a good adjunct to microscopy in diagnosis of malaria, ICT and ELISA are good alternatives to microscopy in blood banks and RT-PCR is the best method in diagnosis of malaria especially in cases of Pyrexia of Unknown Origin with low parasitemia i.e., below the detection limit of peripheral smear.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Malaria ; Immunochromatography ; Enzyme Linked Immunosorbent assay ; Real Time - Polymerase Chain Reaction.
Subjects: MEDICAL > Microbiology
Depositing User: Subramani R
Date Deposited: 14 Aug 2017 04:56
Last Modified: 14 Aug 2017 04:56
URI: http://repository-tnmgrmu.ac.in/id/eprint/1432

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