Validation of a Leishmania infantum ELISA rapid test for serological diagnosis of Leishmania chagasi in dogs

Canine visceral leishmaniasis (CVL) is caused by Leishmania donovani complex parasites including L donovani, Leishmania infantum and Leishmania chagasi. As some studies suggest that L. chagasi and L infantum may be very similar or even the same species, the aim of the present study was to evaluate a commercial rapid ELISA test, originally designed for L. infantum, in the diagnosis of CVL in dogs naturally infected by L chagasi. A total of 400 serum canine samples, including 283 positive dogs for CVL from an endemic area, 86 clinically healthy dogs from a non-endemic area and 31 dogs seropositive for confounding infectious agents (Trypanosoma cruzi,Toxoplasma gondii, Neospora caninum, Babesia canis and Ehrlichia canis) were used for test validation. An overall sensitivity of 94.7% (95% CI = 91.41-97.01%) and specificity of 90.6% (95% CI = 83.80-95.21%) was found, with a high degree of agreement (k = 0.8445) to the indirect ELISA. When confounding infectious diseases were excluded, specificity increased to 100% (95% CI = 95.8-100%), with a higher degree of agreement (k = 0.8928). In conclusion, the commercial kit designed for L infantum was a highly sensitive and specific device for detection of L chagasi infection in dogs, which indicates high immunoreactivity similarities between L infantum and L chagasi. (C) 2010 Elsevier B.V. All rights reserved.