Detection of antibodies against Neospora caninum in individual and bulk milk samples from cattle by the technique of indirect immunofluorescence assay

Camillo G., Cezar A. S., Antonello A. M., Sangioni L. A., Flores E. F., Pereira G. R., Goncalves P. B. D. & Vogel F. S. F. 2011. [Detection of antibodies against Neospora caninum in individual and bulk milk samples from cattle by the technique of indirect immunofluorescence assay.] Deteccao de anticorpos anti-Neospora caninum em amostras individuais e coletivas de leite de bovinos pela reacao de imunofluorescencia indireta. Pesquisa Veterinaria Brasileira 31(6):482-486. Laboratorio de Doencas Parasitarias, Universidade Federal de Santa Maria, Av. Roraima 1000, Santa Maria, RS 97105-900, Brazil. E-mail: giovanacamillo@yahoo.com.br Neospora caninum is a major causative agent of reproductive losses in cattle and the diagnosis of neosporosis is essential for control and eradication programs. Therefore, this study aimed to: (1) standardize an indirect immunofluorescence assay (IFAT) for detection of antibodies against N. caninum in bovine milk, starting from a standard IFAT used for blood serum samples; (2) check the agreement between antibodies detection by IFAT in blood serum and in milk of cows; (3) evaluate the suitability of IFAT for detection of anti-N. caninum antibodies in bulk milk samples. We tested samples of blood serum and milk collected from 112 lactating cows for detection of antibodies against N. caninum, furthermore, six bulk milk samples, each one corresponding to each dairy farm studied. Agreement between the detection of antibodies in blood serum (with antibody titer >= 50) and in milk, with 90% of sensitivity and 100% of specificity for the IFAT in milk samples were found in 78% of the animals. However, for cows with antibody titers >= 100 in blood serum, the agreement, the sensitivity and the specificity of the IFAT in milk were of 100%. It is shown that, considering the dairy farm conditions. The most appropriate diagnostic approach to be adopted regarding the collection of blood serum or milk can elect for search anti-N. caninum antibodies by IFAT. Moreover, detection of antibodies in bulk milk samples can serve for diagnosis and screening of herds with infected animals.