Molecular monitoring of treatment efficacy in human visceral leishmaniasis.

Background: Focused efforts of the visceral leishmaniasis elimination program have led to a drastic decline in cases, and the present challenge is disease monitoring, which this study aimed to assess.

Methods: A Leishmania kinetoplastid-targeted qPCR quantified parasite load at disease presentation, and following treatment completion (n=49); an additional 80 cases were monitored after completion of treatment.

Results: The parasite load at disease presentation was 13 461.00 (2560.00-37764.00)/µg gDNA, which upon completion of treatment reduced in 47 of 49 cases to 1(1-1)/µg gDNA, p<0.0001. In 80 cases that presented >2 months post-treatment, their parasite burden similarly decreased to 1(1-1)/µg gDNA except in 6 of 80 cases, which were qPCR positive.

Conclusion: In 129 cases of visceral leishmaniasis, qPCR by quantification of parasite burden proved effective for monitoring treatment.