Serological diagnosis of canine leishmaniosis: comparison of three commercially available tests

Abstract

Quantitative serology is an important tool in canine leishmaniosis diagnostics from clinical and epidemiological points of view. Serologic diagnosis in laboratories is traditionally carried out by immunofluorescent antibody test (IFAT), but enzyme-linked immunosorbent assays (ELISA) are being increasingly employed. Two commercially available ELISAs (LEISHMANIA-ELISA DOG® [LED] and INGEZIM LEISHMANIA® [IL]) for the detection of Leishmania infantum infection in dogs were compared with the classical IFAT technique. Ninety-two canine serum samples covering a broad range of IFAT titers were chosen for evaluation. Titers ranged from negative (<1:50) to high (>1:3,200). Statistical analysis showed high correlation between all three assays for both negative and positive IFAT-tested samples as described by respective Spearman's rank correlation coefficient (r s), but results varied for samples with inconclusive IFAT titers (1:50-1:100) with IL stating samples predominantly negative. The highest accordance was found between LED and IFAT (percentage of identical results = 83.7%; r(s) = 0.90, p < 0.0001). IL showed higher analogy with LED (accordance = 81.5%; r(s )= 0.88, p < 0.0001) than with IFAT (73.9%; r(s) = 0.80, p < 0.0001). The distribution of the different ELISA scores is discussed and grouped according to correspondent IFAT titers to familiarize practitioners with the range of these tests since antibody levels play an important role in clinical management of canine patients with L. infantum infection.

Retrospective Analysis of Canine Vector-borne Diseases (CVBD) in Germany with Emphasis on the Endemicity and Risk Factors of Leishmaniosis

“…As a modification with regard to kit contents, another FITC-conjugated secondary antibody was used at a dilution of 1:1000 (Fluorescein-labeled affinity purified antibody to dog IgG produced in goat from Kirkegaard & Perry Laboratories), with Evans Blue (2.5 ml, Bio-Rad) as counter stain and Biognost ® mounting medium (Bios) to cover the wells prior to microscopy. The presence of IgG antibodies against A. phagocytophilum had been tested in 794 samples by a commercial indirect IFAT (MegaScreen FLUOAN-APLASMA phagocytophilum, Diagnostik MegaCor GmbH, Hörbranz, Austria) according to Pantchev et al (2015b Wolf et al (2014). The test cutoff was set at dilutions of >= 1:50.…”

“…Titres of 50 and 100 were considered low (borderline) and titres >= 200 positive. In 2014-2016, 54,103 samples were examined using an ELISA (Leishmania-ELISA-Dog, Afosa, Luckenwalde, Germany) according to the manufacturer's instructions (see also Wolf et al 2014). This ELISA converts the colorimetric data into test units classed in the following test ranges: negative (<7), borderline (7-12), and positive (>12).…”

“…Canine vector-borne diseases (CVBDs) are caused by parasites, bacteria or viruses transmitted by the bite of hematophagous arthropods (mainly ticks and mosquitoes). The occurrence of some vector-borne diseases of dogs and cats is increasing in Europe, i.e., canine leishmaniosis and filariosis (Otranto et al 2009a, Pantchev et al 2011, Wolf et al 2014 or babesiosis (Pantchev et al 2015a). CVBDs show an impact on animal and human health and a spread to non-endemic areas (Hirsch and Pantchev 2008).…”

Current Surveys of the Seroprevalence of Borrelia burgdorferi, Ehrlichia canis, Anaplasma phagocytophilum, Leishmania infantum, Babesia canis, Angiostrongylus vasorum and Dirofilaria immitis in Dogs in Bulgaria

“…All samples were obtained and examined with the agreement of the owners. Mettler et al 2005;Wolf et al 2014). Twenty-seven samples that reacted positively for anti-Ehrlichia antibodies within the SNAP ® 3Dx ® EIA were additionally examined by means of SNAP ® 4Dx ® Plus EIA in order to detect potential cross-reactions of anti-E. canis antibodies with A. phagocytophilum whole-cell antigen (as present on IFA slides), as described by Harrus and Waner (2011).…”

“…The reference range of the test score (TS; the test converts the colorimetric reaction through a formula into "test scores") is negative below 7, borderline at 7 -12 and positive above 12 according to Wolf et al (2014). Test performance and evaluation in terms of test score, sensitivity, specificity as well as positive and negative predictive values as compared to IFA and another microplate ELISA are described by Wolf et al (2014). L. infantum IFA was performed according to Wolf et al (2014).…”