Introduction and aim of the study: Canine leishmaniasis (CanL) due to Leishmania infantum infection is a life-threatening zoonotic disease. The availability of reliable and rapid in-clinic serological tests could enable an immediate diagnosis in clinically suspected cases. Aim of this study is to compare the rapid immunochromatographic Theratest Leishmania® kit (Tt) with a quantitative reference method, Immunofluorescence Antibody Test (IFAT), for the detection of L. infantum antibodies in naturally infected dogs.
Material and Methods: Serum samples were obtained from 40 dogs, including 10 healthy control dogs and 30 dogs with confirmed CanL; the samples were evaluated with both tests. IgG-IFAT titres ≥ 1: 80 were considered positive. The sensitivity, specificity, and positive and negative predictive values were calculated; the concordance between the 2 tests was assessed with the Kappa (K) statistic test with a 95% CI.
Results: IFAT detected anti-Leishmania infantum IgG antibodies in 30/40 samples, with titres ranging between 1:80 and 1:5120. Using the qualitative Theratest Leishmania® kit, 31/40 samples tested positive. Compared to IFAT, the sensitivity and specificity of Tt were of 100% and 95%, respectively. The Kappa coefficient of 0.935 demonstrated a very good concordance between the two tests.
Discussion: The immunochromatographic test reliably identified canine sera with anti-Leishmania infantum IgG antibody titres ≥ 1:80. Tt requires neither special preparation of the serum nor specialized equipment; it can be used as a field test as it is easy to use and provides rapid results.