Prevalence of Neospora hughesi and Sarcocystis neurona antibodies in horses from various geographical locations

Parasite-specific antibody responses to Neospora antigens were detected usi ng the immunofluorescent antibody test (IFAT) and immunoblot analysis in se lect equine populations. For comparison, a naturally infected Neospora hugh esi horse and an experimentally inoculated Neospora caninum horse were used . In addition, all samples were tested for antibodies to Sarcocystis neuron a by immunoblot analysis. A total of 208 samples was evaluated. The equine populations were derived from five distinct geographic regions. Locations w ere selected based on distribution of Didelphis virginiana, the native Nort h American opossum which serves as the definitive host for S, neurona. Only 11% of the samples that had positive titers of 1:100 using the IFAT were a lso positive for antibodies by immunoblot analysis in this study. Overall, there was a 2% seroprevalence for Neospora antibodies in all horses tested based on immunoblot analysis described. The seroprevalence for S. neurona a ntibodies varied from 0% (New Zealand and Montana) to 54% (Missouri). We co ncluded that, in testing for antibodies against Neospora antigens using eit her IFAT or immunoblot analysis, as described, positive results should not be attributed to the presence of antibodies to S. neurona. (C) 2001 Elsevie r Science B.V. All rights reserved.