Lab diagnosis of leishmaniasis

Lab diagnosis of leishmaniasis

1. LABORATORY DIAGNOSIS OF LEISHMANIASIS

2. Laboratory diagnosis : Direct evidences i . Microscopy ii. Culture Indirect evidences i . Non - specific test ii. Animal inoculation iii. Leishmania skin or Montenegro test iv. Detection of antigen v. Detection of antibody vi. Blood picture

3. Microscopic observation - Specimen obtained from spleen, bone marrow, liver and lymph nodes Aspirates are fixed in methanol and stained with Giemsa - Presence of kinetoplast distinguish from T. gondii and M. capsulatum - Grading of L - D bodies in splenic aspirate : 6 + = > 100 parasites/field 5 + = 10 - 100 parasites/field 4 + = 1 - 10 parasites / field 3 + = 1 - 10 parasites/10 fields 2 + = 1 - 10 parasites /100 fields 1 + = 1 - 10 parasites/1000 fields 0 = nil parasites /1000 fields

4. Culture - Monophasic media: Schneider's Drosophila medium Grace's insect medium - Biphasic media: Novy MacNeal Nicolle (NNN) medium Brain Heart infusion agar medium Novy - MacNeal - Nicolle (NNN) medium : Most widely used and best medium. The material (splenic aspirate, bone marrow, liver aspirate or blood) is inoculated in water of condensation and culture is incubated at 24˚C for 7 days. Parasites grow as promastigotes and Sample is declared negative after 5 - 6 weeks of incubation.

5. Napier's aldehyde test One ml of patient’s serum is mixed with a drop of 40% formaldehyde, shaken and kept at room temperature Positive reaction: gellification and opacification of the test serum Patients with disease of 3-4 months or more give positive reaction Chopra’s antimony test To 1-2ml of patient serum in test tube, few drops of 4% urea stibamine solution is added Positive test: Formation of profuse flocculant precipitate

6. Detection of antigen Concentration of antigen in blood & body fluids is low ELISA and indirect immunoflorescence is done Detection of antibody Complement fixation test (CFT) Counter immunoelectrophoresis (CIEP) Indirect immunoflorescence (IIF) Enzyme linked immune sorbent assay (ELISA) Immunochromatographic test (ICT)

7. Animal inoculation Material from patient is injected intraperitoneally in hamster or mice and later parasite is recovered from the animal. Very sensitive method but takes long time Leishmania skin or Montenegro test Negative in kalaazar Delayed hypersensitivity reaction 0.1 ml of killed promastigote suspension is injected on dorsoventral aspect of forearm + ve result is indicated by induration and erythema of 5mm or more after 48-72 hours

8. Blood picture - Pancytopenia - Erythrocyte sedimentation rate (ESR) is elevated - Leucocyte : Erythrocyte is greatly altered

9. CONTENT SOURCES PANIKERS TEXTBOOK OF MEDICAL PARASITOLOGY 8e 2. ESSENTIALS OF MEDICAL PARASITOLOGY

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