Preliminary Data in Comparative Serodiagnostic of Neospora Caninum in Dogs

For serological investigation of N. caninum infection in dogs more tests are available, including indirect fluorescent antibody test (IFAT), often considered as the reference test, and enzyme-linked immunosorbent assay (ELISA). A total of 28 dogs were screened with a commercially multi-species indirect ELISA, including a subset of 9 samples previously tested by IFAT 1:50. A partial correlation was attempted between the two tests at the cutoff recommended by the manufacturer. Seroprevalence on ELISA was 10.7% (3/28, CI95%=2.26-28.23), and all positive samples were also positive on IFAT. From previously tested samples by IFAT (8 positive and one negative), only 4 samples had the same result by ELISA (3 positive and one negative sample) and one sample was doubtful. Regarding the double tested samples, a poor agreement was found between the two tests (k=0.135) and difference between the prevalence obtained by the two techniques was statistically significant (p=0.05). Sensitivity and specificity were not determined because of the low number of samples tested so far, but is already planned in an outgoing experiment, as well as testing Neospora IFAT positive samples for Toxoplasma, to exclude false positive results. It seems that IFAT is more appropriate than indirect ELISA for seroprevalence studies, and use of this indirect ELISA may require some techniques for adjustment of misclassifications.