Evaluation of suitability of two tools for the diagnosis of canine visceral leishmaniasis.

Background: Leishmaniasis still imposes a heavy burden on many health systems and remains a public health problem. Early diagnosis in dogs, which act as a major reservoir for the pathogen, is central. The intention of epidemiologic studies is to identify the disease early, allowing rapid intervention to reduce its effects. This study aimed to develop two types of diagnostics tools, an enzyme-linked immunosorbent assay (ELISA) and a lateral flow immunochromatography assay for recognizing canine visceral leishmaniasis (CVL).

Methods: Multiwell ELISA plates were sensitized and strips were designed with the same chimeric recombinant antigen from Leishmania spp. (LeQuiDi) and the results were compared. The sera panel contained 409 samples, including 244 positives and 165 negatives. Of the 165 negative sera, 67 were obtained from Corrientes city, an endemic area for CVL in Argentina, and 98 of this group from La Plata city, a non-endemic area in Argentina (they were seropositive for other infections, as specificity control).

Results: Serum with an elevated concentration of lipids, or bilirubin, or a variable percentage of haemolysis were tested without interference. Both the sensitivity and specificity of the LeQuiDi-based tests were high: ≥93% for ELISA and ≥87% for LFIA.

Conclusions: Our study introduces LeQuiDi as a promising antigen for CVL diagnosis, regardless of the test format.