Published Date: 2012-01-22 15:16:17
Subject: PRO/AH> Equine herpesvirus, equine - North America (05): Canada (ON)
Archive Number: 20120122.1018550
EQUINE HERPESVIRUS, EQUINE – NORTH AMERICA (05): CANADA (ONTARIO)
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: 22 Jan 2012
Fatal case of EHV-1 in southern Ontario
A fatal case of the neurological form of equine herpesvirus-1 (EHV-1) has been confirmed in southern Ontario, Canada.
The Ontario Ministry of Agriculture Food and Rural Affairs said a blood sample from a horse with severe neurological signs tested positive for EHV-1 in early January. The horse was euthanized after its condition deteriorated.
On a 2nd farm in the same area, another horse with similar signs was euthanized in late December. No samples were collected from that horse. [Please note: the horse did not have laboratory confirmation, but similar clinical signs. – Mod.TG]
In 2011, there was 1 laboratory-confirmed case and 1 suspect case of the disease in Ontario.
EHV-1 infection in horses can cause respiratory disease, abortion, neonatal foal death, and/or neurological disease. Neurological signs include loss of muscle coordination, lethargy, inability to urinate, reduced tail tone and/or head tilt.
It is not a federally reportable disease.
EHV-1 is easily spread by sharing contaminated equipment, contact with an animal carrying the virus, or by the clothing, hands or equipment of visitors to farms who recently had contact with an infected horse.
The department urged all horse owners to practice vaccination and appropriate biosecurity protocols and procedures for horses and equipment coming on and off farms, particularly if traveling to shows or events. It said current EHV vaccines may reduce viral shedding but are not protective against the neurological form of the disease. Implementing routine biosecurity practices is the best way to minimize the spread of this disease, it said.
"Increased vigilance is needed in the equine industry at this time," a spokesman said. "In cases of neurological disease, a veterinarian's first obligation is to rule out rabies if the animal dies or is euthanized, by submitting a brain sample to Canadian Food Inspection Agency. Appropriate personal protection, such as gloves and a face shield, should be used when collecting samples."
ProMED-mail from HealthMap alerts
[Usually the disease is abbreviated as EHV for equine herpes virus or EHM for equine herpesvirus myeloencephalopathy.
Equine herpesvirus (EHV-1) infection in horses can cause respiratory and neurological disease, abortion in mares, and neonatal foal death. The neurological form of the disease is known as equine herpes myeloencephalopathy (EHM) and has the potential to cause high morbidity and mortality.
EHV-1 is easily spread and typically has an incubation period between 2-10 days. Respiratory shedding of the virus generally occurs for 7-10 days but may persist longer in infected horses. For this reason, the isolation period recommendation for confirmed positive EHM cases is 21 days. Clinical signs of EHM in horses may include nasal discharge, incoordination, hindquarter weakness, recumbency, lethargy, urine dribbling, and diminished tail tone. The prognosis for EHM positive horses depends on the severity of signs and the period of recumbency. Employing supportive treatment with intravenous fluids, anti-inflammatory drugs, anti-viral drugs, and other supportive measures may be beneficial, since there is no specific treatment for EHM.
Currently, no EHV-1 equine vaccine has a label claim for protection against the neurological strain of the virus.
Portions of this comment have been extracted from http://www.cdfa.ca.gov/ahfss/animal_health/equine_herpes_virus.html.
Ontario, Canada may be located on the HealthMap interactive map at http://healthmap.org/r/172n. - Mod.TG]