Diagnostic utility of an immunochromatography test for the detection of Leptospira IgM antibodies in domestic dogs

Abstract

A cross-sectional study using 99 serum samples of dogs from southern Chile was conducted to determine the diagnostic utility of a rapid immunochromatography assay for the detection of Leptospira specific IgM antibodies as screening test and as a potential aid in the diagnosis of leptospirosis in animals with and without clinical suspicion of the disease. The Microscopic Agglutination Test (MAT) was used as reference assay. Anti-Leptospira antibodies were detected in 37.3% of the dogs with MAT. Using the immunochromatography test, specific IgM antibodies were found in 13.1% of sampled dogs. The sensitivity of the rapid test as screening assay was 29.7% (95% Confidence Interval=16.4-47.2) and the specificity was 96.7% (95% Confidence Interval=87.8-99.4). 40.0% of the canines with clinical suspicion of leptospirosis and 37.1% of dogs without clinical signs were serological reactors to MAT, but none of MAT reactive dogs with clinical suspicion tested positive in the rapid test. Rapid and user-friendly diagnostic procedures for canine leptospirosis such as this immunochromatography assay could be important tools to use in clinical practice, however, further studies are needed to obtain more information about their utility, considering that diagnostic tests could not have similar performances in different geographic locations, clinical and epidemiological contexts.

Differential diagnoses in 83 dogs with icterus

“…Increased activities of enzymes indicating hepatic dysfunction was also detected in dogs from this study. ALT, AST and ALP, which are almost always associated with azotemia, are usually described in dogs with leptospirosis (Azócar-Aedo et al 2017). Increased sera concentrations of ALP usually occur in association with biliary tree lesions (Valli et al 2016).…”

“…This test was performed on 13 out of 40 dogs suspected of leptospirosis. The results were interpreted according to WHO (2003) and Azócar-Aedo et al (2017).…”

“…The highest titer (1:800) was detected for serovars Icterohaemorrhagiae, Bratislava, Autumnalis, Bataviae and Pomona. Considering the clinical history (vaccinated or not vaccinated dogs), titers above 1:200 were considered positive results (Azócar-Aedo et al 2017). PCR for Leptospira interrogans resulted positive in 37/40 dogs, for one or more organs.…”