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 Introduction of Visceral leishmaniasis  Rapid diagnostic test

Visceral Leishmaniasis (VL), also known as Kala-azar, is a vector‐borne parasitic disease that is nearly always fatal if left untreated. Protozoa of the leishmania complex cause an obligate intra‐ macrophage infection. The clinical syndrome is characterized by fever, weight loss, splenomegaly,
lymphadenopathy, and hepatomegaly. It is one of the world’s most neglected diseases, largely affecting the poorest people, mainly in developing countries. It is endemic in 60 countries and some 500,000 new cases occur annually, though 90% of all reported cases occur in just 6 countries: Bangladesh, Brazil, Ethiopia, India, Nepal, and Sudan. The disease is transmitted through the bite of an infected phlebotomine sandfly.

Lateral flow immuno‐ chromatographic tests (ICT), commonly referred to as rapid diagnostic tests (RDT). The first ICT was based on a 39‐amino‐ acid‐repeat recombinant leishmanial antigen from L. chagasi (rK39) and was seen as a potential breakthrough allowing user and patient-friendly, rapid diagnosis in peripheral health care settings. The initial validation study of an rK39 ICT
(Arista Biologicals, Allentown, PA, USA) reported 100% sensitivity and 98%
specificity in an Indian setting when combined with a strict clinical case definition. However, an RDT from the same manufacturer evaluated in Sudan showed only 67% sensitivity.

Principle  of the test

The Kala-azar Detect Test for Visceral Leishmaniasis (VL) is a rapid immunochromatographic strip assay for the qualitative detection of antibodies to members of Leishmania donovani  (L-D body) in human serum to aid in the presumptive diagnosis of visceral eishmaniasis.

Test requirements

Test kit contains

• Kala-azar Detect Rapid Test Strip
• Chase Buffer
• plastic droppers

Extra we need-

• Test sample (blood)
• Test tube rack
• Centrifuge

Procedure for Visceral leishmaniasis Rapid diagnostic test

1. Remove the test cassette from the foil pouch.
2. Add 20µl of serum to the sample well.
3. Add 2-3 drops (150µl) of the chase buffer solution.
4. Finally, read the result in 15 minutes.

Result Interpretation

Only one band at control region: Test negative

Both bands at the control and test regions: Test Positive

No band at all or band only at test region: Test invalid, in this condition, repeat the test using a new test cassette (device)

Impression: Our test is positive due to having both bands at the control and test regions as shown above picture.

Bibliography

1. Matlashewski, G., Arana, B., Kroeger, A., Battacharya, S., Sundar, S., Das, P., Sinha, P. K., Rijal, S., Mondal, D., Zilberstein, D., and Alvar, J. 2011 Visceral leishmaniasis: elimination with existing interventions. Lancet Infect.Dis. 11,322‐325
2. Zijlstra, E. E., Nur, Y., Desjeux, P., Khalil, E. A., el‐Hassan, A. M., and Groen, J. 2001
   Diagnosing visceral leishmaniasis with the recombinant K39 strip test: experience from Sudan. Trop. Med.Int.Health 6,108‐113
3. Sundar, S., Reed, S. G., Singh, V. P., Kumar, P. C., and Murray, H. W. 1998 Rapid accurate field diagnosis of Indian visceral leishmaniasis. Lancet 351,563‐565
4. https://www.researchgate.net/publication/281773800_Imunochromatographic_strip_test_detection_of_anti-rK39_antibody_for_the_diagnosis_of_kala-azar_in_an_endemic_zone_of_Bangladesh