Detection of Neospora spp. antibodies in horses from La Pampa, Argentina.

ROJAS, M.C.; MORÉ, G.; CAMPERO, L.M.; FORT, M.; GIMENEZ, H.; VENTURINI, M.C.

Buenos Aires

Conferencia; 10th International Equine Infectious Diseases Conference (IEIDC X); 2016

Neospora caninum and N. hughesi are apicomplexan parasites affecting several animal species worldwide. Horses have been reported as intermediate hosts of these protozoans. Neospora caninum is an important cause of bovine abortion and neurological signs in dogs while N. hughesi is reported as potential cause of equine protozoal myeloencephalitis (EPM). Little is known about neosporosis in Argentinean horses. The aim of the present study was to indentify antibodies against Neospora spp. in horses from La Pampa, Argentina. Serum samples (n=42) were randomly selected from a group of 300 horses belonging to rural areas from La Pampa province, Argentina. All animals were clinically healthy. The samples were processed by 4 serological tests using N. caninum antigen: indirect ELISA (CIVTEST HIPRA) with G protein as conjugate; a competitive ELISA (VMRD) proceeding according to manufacturer instructions; indirect fluorescence antibody test (IFAT) and Immunoblot (IB) both using Nc1 strain as antigen. Serum sample from an experimentally infected (Nc1 strain) young horse was used as positive control. Positive serological results were detected as follows: 30% of samples (n=13) by ELISA-HIPRA, 28% (n=12) by IFAT, 26% (n=11) by IB and 16% (n=7) by ELISA-VMRD. A total of 12 samples resulted positive to 2 or more tests. Most of the positive samples (n = 9) were seropositive by IFAT and IB. Considering the positivity to these 2 tests as ?true positive?, 21.4% of horses showed antibodies against N. caninum antigens. Since potential cross reactions between Neospora spp. are plausible we considered the detected antibodies as genus-specific. Further studies should be conducted with specific N. hughesi serological tests for specific differentiation of the immunological responses observed. The present study is the first report of Neospora spp. antibodies detection in Argentinean horses. The seropositivity rate detected suggests that horses from La Pampa have a frequent contact with Neospora spp. Future studies will be conducted in horses with clinical signs.