Role of a Parasite Lactate Dehydrogenase-Based Immunochromatographic Antigen Detection Assay for the Detection of Malarial Parasites in Human Blood Samples

Introduction ISSN: 2319-7706 Volume 4 Number 3 (2015) pp. 98-107 http://www.ijcmas. com Malaria is a serious disease caused by the protozoal parasite Plasmodium, and if left untreated, can be fatal. Keeping in mind the seriousness of condition and the current availability of diagnostic modalities, the present study was carried out in a tertiary care hospital in Navi Mumbai with the following aims and objectives 1) To study the comparative efficacy of the peripheral smear examination by Leishman stain and rapid immunological techniques viz. SD Bioline (pLDH) for diagnosis of Malaria. 2) To determine the most optimum diagnostic tool for diagnosis of malarial parasites in terms of cost, technical expertise, lab facilities, rapidity, higher sensitivity and specificity. The present study was conducted in the Microbiology Department of a MGM Medical College & Hospital, Navi Mumbai from July 2012 to June 2013. 339 patients with clinical features s/o Malaria were included in the study. For all the patients in the study group, 1ml of blood was collected by venipuncture aseptically in EDTA bulbs. Thick and thin blood films were prepared with Leishman stain. All the samples were then subjected to antigen detection SD Bioline pLDH (Pf & Pv) Kits. Test was performed as per kit instruction manual and interpreted accordingly. A total of 339 cases were studied, 238 males and 101 females with age ranges from 15 yrs to 72 yrs. Of 339 cases, 138 cases were positive for malarial parasites by gold standard viz. Leishman stained thick smear. Sixty eight cases were infected with P. falciparum, 51 with P. vivax and 19 had mixed infection. In case of detection of P. vivax, performance of SD bioline was 96% and better than conventional staining of thin blood smears examination (92%) by Leishman, stain when compared with gold standard thick smear examination. The logistic, economic and technical factors limit rapid access to microscopic confirmation of malaria in many tropical countries including India. So taking into account of all the factors from our study, we recommend SD Bioline pLDH based antigen detection as a tool for diagnosis of malaria in future. Although no test can completely replace the conventional method of peripheral blood smear examination, these newer diagnostic tests can be used as supplement to microscopic examination of peripheral blood smear where the diagnosis cannot be made on microscopy alone. Also, rapid immunochromatography tests can be used in times of urgency and in areas where facilities of microscopy are not available especially during night times when services of laboratory and experienced Microscopists are not available. K e y w o r d s Lactate dehydrogenase, antigen detection assay, diagnosis of Malaria Int.J.Curr.Microbiol. App.Sci (2015) 4(3): 98-107 99 Malaria is the most important parasitic disease of mankind and known since antiquity. The human disease is a protozoan infection of red blood cells transmitted by the bite of a blood feeding female Anopheline mosquito (Snow et al., 2005). Prevalence of malaria is around 300 million people worldwide with a global death rate over 1.5 million/year (WHO, 2000; Snow et al., 2005). Malaria is a serious disease caused by the protozoal parasite Plasmodium, and if left untreated, can be fatal. Only four of the known species of Plasmodium are able to infect humans: P. falciparum, P. vivax, P. ovale, and P. malariae. The symptoms of malaria include high fevers, chills, rigors, and flu-like illness. Because the symptoms are so familiar, they are often misdiagnosed. The increasing incidence of malaria, the need to identify and treat the additional carriers (reservoirs) and to reduce the chances of transmission has given an impetus for development of simple and rapid methods for the diagnosis of malaria. Conventional Leishman or Giemsa stained peripheral blood smear examination remain the gold standard for the diagnosis of malaria in malaria endemic countries. However it has disadvantages such as it is labor-intensive, time consuming and requires expertise (Mendiratta, 2006). Numerous rapid techniques like acridine orange (AO) stain, Quantitative Buffy Coat (QBC), detection of soluble histidine rich protein II antigen (HRP2 Ag), pLDH and aldolase enzymes in whole blood have been evaluated to diagnose malaria. Malaria presents a diagnostic challenge to laboratories in most countries. This study attempts to review the current methodology and approach to the diagnosis of malaria in a practical and helpful way for the laboratory and for the physician caring for the patient. The urgency and importance of obtaining results quickly from the examination of blood samples from patients with suspected acute malaria render some of the more sensitive methods like PCR, DNA Probe assay for malaria diagnosis impractical for routine laboratory use, although they may be considered reference procedures (Mendiratta, 2006; Mendiratta, 2006; Parija, 2009). So, in the present study an attempt is made to evaluate and compare Parasitic LDH based immunochromatographic antigen assay with the Leishman stained thick and thin blood smears which is considered as Gold standard. Keeping in mind the seriousness of condition and the current availability of diagnostic modalities, the present study was carried out in a tertiary care hospital in Navi Mumbai with the following aims and objectives. 1) To study the comparative efficacy of the peripheral smear examination by Leishman stain and rapid immunologically techniques viz; SD Bioline (pLDH) for diagnosis of Malaria. 2) To determine the most optimum diagnostic tool for diagnosis of malarial parasites in terms of cost, technical expertise, lab facilities, rapidity, higher sensitivity and specificity. Materials and Methods