Indigenous development and evaluation of Leishmanin skin test for diagnosis of Cutaneous Leishmaniasis

Abstract

Leishmaniasis is caused by a protozoan parasites belong to genus Leishmania and this disease is endemic in certain areas of Pakistan. The clinical diagnosis of disease can be confirmed by various laboratory investigations like Direct Agglutination Test (DAT), Enzyme Linked Immunoabsorbent Assay (ELISA), Immunofluorescence Assay (IFA), Polymerase Chain Reaction (PCR), direct microscopy, culture and Leishmanin. In this research study the total sample size was 95 male patients with suspected CL of not more than 2 week duration. Leishmanin test, Direct Microscopy and Leishmania culture was performed on all these patients. These patients were serving soldiers referred by PNS Shifa, deployed in different regions of Baluchistan where Cutaneous Leishmaniasis is prevalent. A few civilians as private patients also reported and were included in the study. All patients of Cutaneous Leishmaniasis who reported for the first time were included in our study. Those patients who were inhabitants of Baluchistan were suspicious of having developed active immunity by virtue of previous sand fly exposure was excluded from the study. Similarly patients were also excluded from the study if they had taken drugs that could in any way influence the LST result. LST was done by intradermal injection of 0.1ml Leishmanin suspension on the volar surface of forearm. The site of injection was examined for nodule formation /indurations after 48-72 hours and the size of induration was recorded and the response was graded. Saline Aspirates were collected from the lesions by an expert person. The Saline Aspirate was processed and examined microscopically for the presence of promastigotes and the results of the two diagnostic tools were compared. All the information was recorded and compiled. Leishmanin skin test (LST) was positive in 87 patients out of 95(92%), and saline aspirate was positive in 36 patients (38%), 02 patients did not reported, back for observation. LST test is sensitive and effective even in those Cutaneous Leishmaniasis patients with lesions of very recent onset.