Evaluation of an ELISA rapid device for the serological diagnosis of Leishmania infantum infection in dog as compared with immunofluorescence assay and Western blot

In this study we compared a commercial enzyme linked immunosorbent assay (ELISA) rapid test (Snap® CLATK Canine Leishmania Antibody Test Kit, IDEXX-Snap®) with indirect immunofluorescence assay (IFA) and Western blot (WB) for the detection of Leishmania infantum antibodies in dogs. In total sera from 234 dogs were collected: 59 positives and 51 doubtful sera (IFA 1:40–1:80) from an L. infantum endemic area and 124 negative sera from a non-endemic area were tested. To evaluate the Snap® CLATK's performances on whole blood, blood in EDTA and sera from 37 dogs were tested in parallel with Snap® CLATK.Snap® CLATK sensitivity and specificity compared to IFA were 91.1% and 99.2%, while compared to WB were 93.4% and 98.3%, respectively. When IFA doubtful sera (titers of 1:40 or 1:80) were tested Snap® CLATK, using WB as reference, sensitivity and specificity were 90.9% and 100%, respectively. Moreover, a complete concordance was observed when Snap® CLATK rapid assay was carried out on whole blood or sera from 37 dogs. The Snap® CLATK has demonstrated simplicity and performance and can be considered a quick and reliable alternative for the diagnosis of L. infantum infection in dogs.