Published in Scientific Works. Series C. Veterinary Medicine, Vol. LIX (1)
Written by Violeta ENĂCHESCU, Mariana IONIŢĂ, Ioan Liviu MITREA
Serodiagnostic of Neospora caninum infection in cattle is generally based on using the enzyme-linked immunosorbent assay (ELISA) method for detection of specific antibodies in serum samples, but the use of milk is also possible. The present study was undertaken to assess the potential of an ELISA kit for testing individual and pooled milk samples in dairy farms. Pairs of milk and blood samples (n = 60) were collected from 3 dairy farms (A, B, and C) in southern Romania. Additionally, four pooled milk samples were obtained (one pooled milk sample for each farm and a total sample as a pooled sample from all three farms). Skimmed milk was obtained and tested by using a commercially available ELISA kit (HerdChek N. caninum Antibody Test Kit, IDEXX Lab.). The optimized cut-off value of S/P> 0.704 was determined by receiver operating characteristic (ROC) analysis, using serum results as ‘gold standard’. The sensitivity and specificity of the assay at this cut-off were 70.4% and 100.0%, respectively and the agreement with classic serology, expressed as kappa values, was good (K=0.723). When samples with low positive response on sera were excluded, the correlation obtained was even better (K= 0.921). For pooled milk samples a lower cut-off was necessary in order to identify as positive all dairy farms with a 15% or higher within-herd seroprevalence. The results of this study demonstrate that the prevalence of N. caninum in dairy farms can be estimated by using this indirect ELISA kit on individual and pooled milk samples.
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ELISA
