Published Date: 2012-01-14 23:25:50
Subject: PRO/AH/EDR> Equine herpesvirus, equine - North America (02): USA (CA)
Archive Number: 20120114.1010899
EQUINE HERPESVIRUS – NORTH AMERICA (02): USA (CALIFORNIA)
A ProMED-mail post
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International Society for Infectious Diseases
Date: 14 Jan 2012
Three EHV-1 cases in Orange County, California
Three horses have been confirmed positive for the neurological form of equine herpes virus 1 (EHV-1) in California, authorities report.
The California Department of Food and Agriculture said a gelding displaying neurologic signs at an Orange County premises was confirmed positive for the neuropathogenic strain of Equine Herpes Virus-1 on Wednesday. The gelding was isolated, quarantined and was under veterinary care, the department said.
The large multi-discipline facility where the horse was living was placed under quarantine, with no movement of horses on or off the property. Potentially exposed horses on the premises were being monitored, it said. A full epidemiologic investigation at the premises was being undertaken by the department's Animal Health Branch.
On Thursday, the department reported that 2 additional horses displaying fever and respiratory signs had been confirmed positive for the neurological strain.
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[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.
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Readers are also encouraged to view the list of resources regarding this disease listed in the moderator’s comments of ProMED-mail post 20120108.1003516. - Mod.TG
A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/r/1hcv.]