Submitted to: American Journal of Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 18, 1995
Publication Date: N/A
Interpretive Summary: Neospora caninum is a recently discovered single-celled parasite of livestock and companion animals. It causes abortion and neonatal mortality in cattle and other animals. Its life cycle and sources of infection are unknown. Diagnosis of neosporosis is a problem because N. caninum structurally and antigenically resembles a closely related parasite of livestock, Toxoplasma gondii. Scientists at the Beltsville Agricultural Research Center, Auburn University, and Washington State University report on the specificity of a indirect fluorescent antibody (IFA) test for the diagnosis of neosporosis in cattle and other animals. They found that the IFA test was specific for the diagnosis of neosporosis. These results will be useful to veterinarians and diagnosticians.
The serum antibody responses and antibody reactivity to Neospora caninum and Toxoplasma gondii were investigated in cows and/or calves experimentally infected with the 3 tissue cyst-forming protozoan parasites N caninum, T gondii and Sarcocystis species and in calves monospecifically-inoculated with the intestinal coccidia, Eimeria bovis and Cryptosporidium parvum. Similar studies were done in laboratory rabbits inoculated with N caninum, T gondii, Hammondia hammondi and Sarcocystis species. Additionally, sera from ewes, lambs, goats, sows, cats, rats and mice inoculated with N caninum tachyzoites were examined for antibody production and cross-reactivity to T gondii. The indirect fluorescent antibody (IFA) and ELISA antibody tests (cattle only) were used to examine reactivity to N caninum and the modified direct agglutination, dye test, and IFA tests were used to evaluate reactivity to T gondii. There was minimal or no serologic cross-reactivity among N caninum, T gondii, and Sarcocystis species in the IFA test. There was some reactivity to N caninum by the use of ELISA in cattle inoculated with Sarcocystis species.