Los Angeles County Equine Herpes Virus outbreak: 4 horses currently quarantined
In a follow-up to the Equine Herpes Virus (EHV-1) outbreak in Los Angeles County, the California Department of Food and Agriculture (CDFA) reported Saturday there are currently four (4) horses in quarantined isolation. Three (3) of these horses are no longer shedding EHV-1 virus. One of the horses continues to shed virus and will be resampled for diagnostic EHV-1 testing. None of these four (4) horses are febrile or showing neurologic symptoms at this time.
Only horses in C Barn continue to be quarantined. There have been no new febrile horses over the past five (5) days in C Barn.
Los Angeles Equestrian Center (LAEC) incident has had a total of fifteen (15) EHV-1 confirmed cases, all of those caused by the non-neurotrophic strain EHV-1 virus. Enhanced biosecurity measures continues in C Barn under quarantine and all horses’ temperatures continue to be monitored twice daily.
Equine Herpes Virus (EHV-1) infection in horses can cause respiratory disease, abortion in mares, neonatal foal death and neurological disease. The neurological form of the disease is known as Equine Herpes Myeloencephalopathy (EHM) and may be caused by damage to blood vessels of the brain and spinal cord associated with EHV-1 infection. EHM is most often due to the neuropathogenic strain of EHV-1, but may occasionally be caused by the non-neuropathogenic strain of the virus.
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, a twenty-one day isolation period of confirmed positive EHM cases is recommended along with stringent biosecurity protocols. Similar to herpes viruses in other species, the latent form of EHV-1 can reactivate at a later date, but generally with a low viral load posing a low risk of infecting other horses. Humans are not at risk of contracting the virus, however humans can act as an indirect mode of transmission.