Development and Clinical Evaluation of Loop-Mediated Isothermal Amplification (LAMP)‎ Assay for the Diagnosis of Human Visceral Leishmaniasis in Brazil

Abstract EN

Visceral leishmaniasis (VL) is considered a major public health concern in Brazil and several regions of the world.

A recent advance in the diagnosis of infectious diseases was the development of loop-mediated isothermal amplification (LAMP).

The aim of this study was to develop and evaluate a new LAMP assay for detection of K26 antigen-coding gene of L.

donovani complex.

A total of 219 blood samples of immunocompetent patients, including 114 VL cases and 105 non-VL cases, were analyzed for the diagnosis of VL in the present study.

Diagnostic accuracy was calculated against a combination of parasitological and/or serological tests as a reference standard.

The results were compared to those of kDNA Leishmania-PCR.

The detection limit for the K26-Lamp assay was 1fg L.

infantum purified DNA and 100 parasites/mL within 60 min of amplification time with visual detection for turbidity.

The assay was specific for L.

donovani complex.

Sensitivity, specificity, and accuracy were 98.2%, 98.1%, and 98.2%, respectively, for K26-LAMP and 100%, 100%, and 100%, respectively, for kDNA Leishmania-PCR.

Excellent agreement was observed between K26-LAMP and kDNA Leishmania-PCR assays (K = 0.96).

A highly sensitive and specific LAMP assay targeting K26 antigen-coding gene of L.

donovani complex was developed for diagnosis in peripheral blood samples of VL patients.