Open AccessAntibody Coefficients for the Diagnosis of Equine Protozoal Myeloencephalitis
Author(s) -
Furr M.,
Howe D.,
Reed S.,
Yeargan M.
Publication year - 2010
Publication title -
journal of veterinary internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.356
H-Index - 103
eISSN - 1939-1676
pISSN - 0891-6640
DOI - 10.1111/j.1939-1676.2010.0658.x
Subject(s) - medicine , antibody , virology , immunology
Background: Diagnosis of equine protozoal myeloencephalitis (EPM) remains a challenge for equine practitioners. Current utilized methods have inadequate sensitivity and specificity, because of a high number of false positive results. Hypothesis/Objective: Evaluation of antibody indices to Sarcocystis neurona should provide high sensitivity and specificity for diagnosis of EPM. Animals: Archived samples from 29 clinical patients. Methods: Archived serum and cerebrospinal fluid (CSF) samples from clinical patients with either EPM (14) or cervical vertebral compressive myelopathy (CVM) (15) were examined and tested for anti‐ S . neurona antibodies by the SnSAG2 ELISA. The results were used to calculate the antibody index (AI) and C ‐value. Sensitivity and specificity were calculated, and the AI, C ‐value, immunoglobulin G (IgG) concentrations, and anti‐ S . neurona titers compared. In addition, negative CSF was spiked in varying concentrations with blood from a horse with a high anti‐ S . neurona titer, and the tests repeated. Results: Results demonstrated that the IgG concentration, anti‐ S . neurona titer, AI, and C ‐value were significantly higher ( P < .05) in horses with EPM than in those with CVM. Sensitivity and specificity of the AI was 71 and 100%, respectively, and that of the C ‐value was 86 and 100%, respectively. In addition, the AI and C ‐value from the samples spiked with S . neurona positive blood remained below 1 (eg, negative) in CSF with a red blood cell (RBC) count up to 10 5 RBC/μL. Conclusions/Clinical Importance: Results of the study demonstrate the value of calculating the AI and C ‐value in the diagnosis of EPM in horses. In addition, the test is robust in the presence of blood contamination.