Diagnostic accuracy of rKLO8 versus rK26 ELISAs for screening of canine visceral leishmaniasis

- The new antigen rKLO8 from an African strain of L. donovani was tested for diagnosis of CVL.
- The rKLO8 protein is suitable for diagnosis of CVL, with a similar performance compared to the reference antigen rK26.
- Combination of rKLO8 and rK26 shows improved diagnostic performance of CVL.
- Inclusion of rKLO8 in the DPP® rapid test deserves further attention.

Canine visceral leishmaniasis (CVL) represents an important public health issue. Despite numerous diagnostic tests available, CVL diagnosis still needs to be improved to achieve a more accurate detection rate. Recently, rKLO8, a new antigenic protein of Sudanese Leishmania donovani, was studied for the first time in diagnosis of human visceral leishmaniasis (HVL) and showed good performance. The present study aimed to evaluate serum reactivity to rKL08 and the reference antigen rK26, and to compare both diagnostic proteins with the combined DPP® CVL rapid test and ELISA (EIE-Bio-Manguinhos) confirmatory test, which are both recommended for the diagnosis of CVL in Brazil. Serum samples of dogs were grouped into: (I) DPP®/EIE negative (n = 100) and (II) DPP®/EIE positive sera (n = 100). Enhanced levels of IgG, mainly IgG2, to both rKLO8 and rK26 were found in group II. Sensitivity was 68% and 77% and specificity was 92% and 91%, for rKLO8 and rK26 antigens, respectively. Moreover, the combination of rKLO8 and rK26 antigens (rKLO8 + rK26) exhibited higher sensitivity (85%) and specificity (93%). Thus, our results show that apart from the improved diagnostic power of rKLO8 in HVL, this new antigen is also suitable for the diagnosis of CVL. Further, the combination of rKLO8 and rK26 antigens increases the diagnostic accuracy of CVL.

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