Latent equine herpesvirus-1 in trigeminal ganglia and equine idiopathic headshaking.
BACKGROUND
Trigeminal neuralgia or neuropathic pain has been regarded as a putative cause of idiopathic headshaking in horses. Equine herpesvirus-1 (EHV-1) infection and resultant postherpetic pain have been suggested as a possible cause of such neuropathic pain.


OBJECTIVE
To determine the presence of EHV-1 in the trigeminal ganglia of horses with idiopathic headshaking.


METHODS
Nineteen horses: control (n = 11, 9 geldings, 2 mares, median age 11 years) and headshaking (n = 8, all geldings, median age 11.5 years) horses were sourced from the equine research herd and caseload at the Veterinary Medical Teaching Hospital.


METHODS
Prospective study to determine the presence of EHV-1 latency in trigeminal ganglia of horses with idiopathic headshaking by real-time PCR detection of the glycoprotein B (gB) gene and the DNA polymerase (ORF 30) gene of EHV-1 in the absence of detectable late structural protein gene (gB gene) mRNA. Control horses were used for comparison. A house keeping gene (equine GAPDH) and positive and negative samples for EHV-1 were used for quality control.


RESULTS
All samples from control horses and 7 of 8 headshaking horses were negative for EHV-1. One headshaking horse tested positive for a single copy of EHV-1 gene.


CONCLUSIONS
This study does not support a role for EHV-1 infection and presumed postherpetic pain in the etiopathogenesis of equine headshaking.
Department of Medicine and Epidemiology, University of California, Davis, CA, USA. mraleman@ucdavis.edu
M
M
Aleman
K J
KJ
Pickles
G
G
Simonek
J E
JE
Madigan
D000818:Animals; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D005260:Female; D006566:Herpesviridae Infections / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D004861:Herpesvirus 1, Equid / Q000235:genetics / Q000302:isolation & purification*; D006734:Horse Diseases / Q000473:pathology* / Q000821:virology*; D006736:Horses; D008297:Male; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D012668:Trigeminal Ganglion / Q000473:pathology* / Q000821:virology; D017735:Virus Latency / Q000502:physiology
D004279:DNA, Viral