Qualitative evaluation of selective tests for detection of Neospora hughesi antibodies in serum and cerebrospinal fluid of experimentally infected horses.

The study is about experimenting with various serological tests to detect antibodies for Neospora hughesi, a pathogen causing neurological disorders in horses. The researchers formed a bank of horse sera through experimental infections for these tests, concluding that the indirect fluorescent antibody test proved most consistently effective.

Overview of the Study

• In this research article, scientists extensively study a protozoan parasite, Neospora hughesi, which recently came to light as a cause of myeloencephalitis in horses. Due to the novelty of this pathogen, currently, no validated serological tests are available to detect specific antibodies for the parasite to indicate cases of antemortem exposure or estimate its prevalence in horses.
• To address this, the research team’s goals for this study included establishing a bank of ‘gold standard’ sera, obtained through experimental infections with this parasite, and to evaluate many serological tests to detect related antibodies.

Experimental Procedure and Methods

• The researchers infected seven horses with N. hughesi, and seven were given uninfected cell culture material as a control. Regular monitoring over four months, along with repeated collection of blood and cerebrospinal fluid, furnished serum samples for the testing.
• These serum samples were utilized to evaluate four distinctive serological techniques. These included a whole-parasite lysate enzyme-linked immunosorbent assay (ELISA), a recombinant protein ELISA, a modified direct agglutination test, and an indirect fluorescent antibody test (IFAT).

Results and Conclusions

• The study’s qualitative and quantitative findings exhibited that the indirect fluorescent antibody test (IFAT) for N. hughesi was the most reliable in distinguishing between infected and non-infected horses, using a cutoff of 1:640.
• Evidence of this test’s accuracy is noted from sera from three naturally infected horses having titers greater than 1:640. Furthermore, cerebrospinal fluid in all but one infected horse presented very low titers, less than 1:160, from the 30th day post-inoculation, supporting the inferred specificity of IFAT.
• Therefore, the study progresses by proposing the utility of N. hughesi IFAT as an effective serological test for detecting antibodies to the parasite in horses.