November 2013

Horse with scoliosis

A four-year old horse presented with severe scoliosis of the cervical vertebrae.

Treatment was not attempted and necropsy was performed. Histologic examination of the cervical spinal cord revealed cross-sections of nematodes at the level of the curvature. 

What is your diagnosis?

Answer

These are most likely cross-sections of Parelaphostrongylus tenuis. White-tailed deer are considered the definitive host for P. tenuis. This metastrongylid occasionally infects abnormal hosts including horses, sheep, alpacas, and goats among others. Infections of P. tenuis in horses were first reported in 2004 and a few additional cases have been recognized since.

​Please click on the links below for additional information:
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Johnson, AL. 2011. Update on infectious diseases affecting the equine nervous system. Veterinary Clinics of North America: Equine Practice 27: 573–587. DOI: 10.1016/j.cveq.2011.08.008

Reinstein SL, Lucio-Forster A, Bowman DD, Eberhard ML, Hober EP, Pot SA, and Miller PE. 2010. Surgical extraction of an intraocular infection ofParelaphostrongylus tenuis in a horse. Journal of the American Veterinary Medical Association 237: 196–199. DOI: 10.2460/javma.237.2.196

Tanabe M., Gerhold RW, Beckstead RB, de Lahunta A, Wade SE. 2010. Molecular confirmation of Parelaphostrongylus tenuis infection in a horse with verminous encephalitis. Veterinary Pathology 47: 759. DOI: 10.1177/0300985810363488

Van Biervliet J, de Lahunta A, Ennulat D, Oglesbee M, Summer B. 2004. Acquired cervical scoliosis in six horses associated with dorsal grey column chronic myelitis. Equine Veterinary Journal 36: 86–92. DOI: 10.2746/0425164044864624