Seroprevalence and the Associated Risk Factors of Neospora caninum in Egyptian Dairy Cattle with Evaluation of Diagnostic Agreement Between Serum and Milk Samples.

PURPOSE: Neospora caninum is a common infectious cause of abortion in cattle globally. This study aimed to investigate the seroprevalence of N. caninum, identify associated risk factors, and assess the diagnostic agreement between serum and milk samples.

METHODS

A total of 254 individual serum samples were collected from dairy cattle in two Egyptian governorates. The seroprevalence of N. caninum antibodies was determined using a commercial ELISA kit (ID Vet - France). For assessment of diagnostic agreement between individual serum and milk samples, 92 milk samples from the same animals representing different days in milk (DIM) were tested using the same ELISA kit.

RESULTS

The overall seroprevalence of N. caninum antibodies was 31.9%. The seroprevalence rates for Faiyum and Alexandria governorates were 28% and 40.5%, respectively. For seropositive animals to N. caninum, the odds of suffering from abortion are 5.5 times greater than the odds for seronegative animals (P < 0.001), reaching 12.4 times in multivariable analysis. While the animal's location was found to have a significant relationship with the seroprevalence of N. caninum (P = 0.048) in univariable analysis, multivariable logistic regression showed no significant effect (P = 0.33). The age, parity, animal productive category, gynecological disorders, and the average milk production had no significant relation with the seroprevalence of N. caninum (P > 0.05). The Kappa coefficients between individual serum and milk samples were 0.59, 0.52, and 0.64 for all samples (n = 92), ≤ 220 DIM (n = 42), and ˃ 220 DIM (n = 50), respectively.

CONCLUSION

N. caninum is prevalent in Egypt. Abortion history can be used as a key predictor factor for Neospora in the examined herds. The late lactation period is the preferred time for testing milk samples; however, we do not recommend replacing individual serum samples with milk samples.