EVALUATION OF DOT ENZYME-LINKED-IMMUNOSORBENT-ASSAY (DOT-ELISA) FOR THE SERODIAGNOSIS OF CANINE LEISHMANIASIS AS COMPARED WITH INDIRECT IMMUNOFLUORESCENCE ASSAY

A dot enzyme-linked immunosorbent assay (dot-ELISA) was developed and compared with a standard indirect immunofluorescence assay (IFA) for t he rapid serodiagnosis of canine leishmaniosis. The two tests were use d to examine sera from Leishmania infantum-infected and control dogs, Using the doe-ELISA, 137 of 149 sera (91.9%) from infected animals gav e a clearly positive reaction, whereas in the standard IFA technique 1 47 (98.7%) were positive at a reciprocal titer of 40 or over (titer ra nge 40-10 240), Control sera from 75 healthy dogs, not living in endem ic areas, and Il dogs with other diseases (babesiosis, cryptococcosis, ehrlichiosis, dermatitis, and chronic hepatitis) but Leishmania-negat ive were used to determine the specificity of the assays. All the sera were negative with IFA (100%), whereas using the dot-ELISA only 74 se ra (86%) from controls gave a negative result. In the standard IFA no cross-reactivity was noted, in the dot-ELISA a weak cross-reaction was observed with a serum sample from a dog with babesiosis. The interpre tation of dot-ELISA could be easily performed by visual inspection of the nitrocellulose disks. The most remarkable feature of dot-ELISA was the high sensitivity (91.9%) and positive predictive value (92.6%), e ven if the test showed a specificity lower than IFA. Because of its ea sy performance and high sensitivity, the dot-ELISA may be a useful tes t to be executed in the field for the diagnosis of canine leishmaniosi s.