A Study on Recent Advances in Laboratory Techniques for Diagnosis of Malaria.

INTRODUCTION : “Humanity has but three great enemies fever, famine and war; Of These by far the greatest, by far the most terrible is fever”. William Osler. Human malaria is basically a febrile illness caused by species belonging To the genus Plasmodium. Malaria has always been a major public health Concern, probably representing the most important parasitic disease in human. Malaria is one of the most common cause for school absentism. Malaria is a protozoan (Coccidiean-Apicomplexa) disease transmitted By the bite of infected female Anopheles mosquitoes, which breed in fresh Water. The species that infect humans are four in number. P.falciparum, P.vivax, P.ovale and P.malariae. P.falciparum is predominantly a pathogen of The tropics and produces a more severe form of disease. P.vivax and P. Ovale Tend to produce infections in more temperate zones that are less severe. Infections induced by P. Malariae tend to be more benign. AIMS AND OBJECTIVES : (i) To meet the need for a reliable diagnostic adjunct to microscopy for malaria in the clinical settings.(ii) To overcome the problem of time constraints and low sensitivity in diagnosing malaria with a low level of parasitemia by peripheral blood smear microscopy. (iii) To study the efficacy and accuracy of recent techniques to diagnose malaria. MATERIALS AND METHODS : The present study on “Recent advances in laboratory techniques for diagnosis of malaria” was conducted in the Department of Microbiology, Stanley Medical College and Hospital during the period from May 2004 to April 2005 in collaboration with the Department of Medicine and Jawaharlal Nehru Institute of Social Paediatrics. The study group includes : I. 190 patients clinically diagnosed as malaria. II. 20 patients diagnosed as Enteric fever - Disease Control III. 20 apparently healthy individuals - Healthy Control. Total of 230 blood samples were collected, of these 190 blood samples were collected from clinically diagnosed as malaria patients with symptoms of fever and chills irrespective of age and sex. 20 blood samples each were collected from patients diagnosed with enteric fever (disease control) and from healthy individuals (healthy control). The criteria for the selection of healthy control were the history of absence of fever for a period of one month prior to the study. RESULTS : 190 cases were tested with peripheral blood smear and QBC. Out of this 61 samples were selected by simple random method and tested with recent techniques such as ICT, Dot ELISA for P. falciparum and PCR. Control groups (Disease control n=20 and Healthy control n=20) were also tested with Peripheral blood smear, QBC and ICT Dot ELISA for P. falciparum and PCR assay. All these new technologies were evaluated by comparing with the acceptated “gold standard” method. The results were analyzed statistically. CONCLUSION : 1. 190 clinically diagnosed cases of malaria were tested by JSB stained Peripheral blood smear and QBC assay. 2. 29.4% were positive by JSB stained Peripheral blood smear 3. 57.3% were QBC positive . 4. Out of this 61 blood samples were selected by simple random method and tested by ICT, DOT ELISA for P. falciparum (DRDE) and PCR assay. 5. 52.4% were positive by antigen detection assay (HRP-2, PMA) by ICT P.f/P.v method. 6. 50.8% were PCR positive. 7. 3 cases were positive by DOT ELISA for P. falciparum (DRDE). 8. P. vivax was the predominant species causing malarial infection. Malaria rapid diagnostic devices (MRDD) have been developed with the hope that they would offer accurate, reliable, rapid, cost effective and easily available alternatives to traditional methods of malaria diagnosis