Interpretation of the detection of Sarcocystis neurona antibodies in the serum of young horses

• Published in: Veterinary parasitology Vol. 95; no. 2; pp. 187 - 195
• Main Authors: Cook, A.Grimsley, Buechner-Maxwell, V., Morrow, J.K., Ward, D.L., Parker, N.A., Dascanio, J.J., Ley, W.B., Cooper, W.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 26-02-2001
• Subjects: Age Factors; Animals; Antibodies, Protozoan - analysis; Blotting, Western - veterinary; Colostrum - immunology; Equine protozoal myeloencephalitis; Female; Foals; Horse Diseases - diagnosis; Horse Diseases - parasitology; Horses; Immunity, Maternally-Acquired; Immunoglobulin G - analysis; Immunoglobulins; Male; Maternal antibodies; Passive transfer; Sarcocystis - immunology; Sarcocystis - isolation & purification; Sarcocystis neurona; Sarcocystosis - diagnosis; Sarcocystosis - veterinary; Time Factors; Western blot; Western blot; Foals; Immunoglobulins; Maternal antibodies; Equine protozoal myeloencephalitis; Sarcocystis neurona; Passive transfer
• ISSN: 0304-4017; 1873-2550
• DOI: 10.1016/S0304-4017(00)00390-3

Horses that are exposed to
Sarcocystis neurona, a causative agent of equine protozoal myeloencephalitis, produce antibodies that are detectable in serum by western blot (WB). A positive test is indicative of exposure to the organism. Positive tests in young horses can be complicated by the presence of maternal antibodies. Passive transfer of maternal antibodies to
S. neurona from seropositive mares to their foals was evaluated. Foals were sampled at birth (presuckle), at 24
h of age (postsuckle), and at monthly intervals. All foals sampled before suckling were seronegative. Thirty-three foals from 33 seropositive mares became seropositive with colostrum ingestion at 24
h of age, confirming that passive transfer of
S. neurona maternal antibodies occurs. Thirty-one of the 33 foals became seronegative by 9 months of age, with a mean seronegative conversion time of 4.2 months. These results indicate that evaluation of exposure to
S. neurona by WB analysis of serum may be misleading in young horses.