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Disease Outbreak Alerts

Updates on current disease outbreaks are listed here as they occur and will include the date listed, disease name, location and current status. Specific premises will not be named but the general location by town, county and state will be listed. When locations, events or horses are at risk they will be listed. Updates will be posted as they are received.


December 13, 2016
Equine Herpes Viruses
Los Angeles, CA
Outbreak Update
There are currently five (5) horses in quarantined isolation at the Los Angeles Equestrian Center. Three (3) of these horses are remaining in isolation as additional negative tests are anticipated. Two (2) of the horses continue to shed virus and will be resampled for diagnostic EHV-1 testing. None of these five (5) horses are febrile or showing neurologic symptoms at this time. Barns D, E and F have not had a confirmed EHV-1 case and these three barns have been released from quarantine as of 0700 on December 11, 2016. Barns A and B have not had a confirmed case in three (3) weeks and four (4) weeks, respectively, and have been released from quarantine as of 0700 on December 13, 2016. All horses in C Barn continue to be quarantined. The 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. For more info go to: https://www.cdfa.ca.gov/ahfss/animal_health/equine_herpes_virus.html
December 12, 2016
Equine Herpes Viruses
Inyo County, CA
Outbreak Update
One of the EHV-1 confirmed positive horses developed severe neurologic symptoms on Saturday and is receiving supportive treatment. No additional confirmed cases of EHV-1 or new febrile horses have been identified at this time. This incident now has two (2) EHM cases and one EHV-1 confirmed case. All three cases have been caused with the neurotrophic strain of the EHV -1. The affected horses are part of a wintering pack string of horses and mules on an isolated, high desert ranch. These horses/mules have been placed under quarantine with no movement allowed in order to limit disease transmission. The investigation of this disease outbreak is continuing by CDFA staff. Enhanced biosecurity is in place and we appreciate the cooperation and assistance from owner and private veterinarian. Updates will continue on a 48 hour basis.
December 12, 2016
Equine Herpes Viruses
Los Angeles, CA
Confirmed case(s): Official Quarantine
One new febrile horse was identified in a quarantined barn on December 11th and diagnostic sampling will be forthcoming from CAHFS Laboratory on Monday. Test samples from two horses taken on December 9th indicated one new EHV-1 positive horse in quarantined isolation and the other febrile horse moved to isolation on Friday tested negative for EHV-1. Barns D, E and F have not had a confirmed EHV-1 case and these three barns have been released from quarantine as of 7 AM on December 11, 2016. The Los Angeles Equestrian Center incident has had a total of fourteen (14) EHV-1 confirmed cases, all of those caused by the non-neurotrophic strain EHV-1 virus. Enhanced biosecurity measures continues in all barns under quarantine and all horses’ temperatures continue to be monitored twice daily.
December 10, 2016
Equine Herpes Viruses
Inyo County, CA
Outbreak Update
No additional confirmed cases of EHV-1 or new febrile horses have been identified at this time. The neurotrophic strain of EHV-1 causing EHM has been confirmed in one horse with mild neurologic symptoms in Inyo County, CA. This horse continues to improve and is now negative to PCR diagnostic testing on nasal swab. Additionally, two (2) febrile horses were confirmed positive for the neurotrophic EHV-1 strain and neither horse is exhibiting any neurologic symptoms. This neurotrophic strain identified in Inyo County is biologically distinct from the non-neurotrophic strain identified in all the Los Angeles County confirmed cases. The affected horses are part of a wintering pack string of horses and mules on an isolated, high desert ranch have been placed under quarantine with no movement allowed in order to limit disease transmission. The investigation of this disease outbreak is continuing by CDFA staff. Enhanced biosecurity is in place and we appreciate the cooperation and assistance from owner and private veterinarian.
December 10, 2016
Equine Herpes Viruses
Los Angeles, CA
Outbreak Update
There have been two (2) new febrile horses identified in quarantined barns have been moved to isolation at the LAEC. There are now three (3) horses in quarantined isolation. Results from diagnostic PCR testing for EHV-1 on nasal swabs and blood are forthcoming. The LAEC incident has had a total of thirteen (13) EHV-1 confirmed cases, all of those caused by the non-neurotrophic strain the EHV-1 virus. Enhanced biosecurity measures continue in all barns under quarantine and all horses’ temperatures continue to be monitored twice daily.
December 07, 2016
Equine Herpes Viruses
Inyo County, CA
Outbreak Update
EHM has been confirmed in one horse with mild neurologic symptoms in Inyo County, CA. Additionally, two (2) febrile horses on the same ranch have been confirmed positive for the neurotrophic EHV-1 strain and neither horse is exhibiting any neurologic symptoms at this time. This is the neurologic strain, which is biologically distinct from the non-neurologic strain identified in all the Los Angeles county confirmed cases. The affected horses are part of a wintering pack string of horses and mules on an isolated, high desert ranch. These horses/mules have been placed under quarantine with no movement allowed in order to limit disease transmission. The investigation of this disease outbreak is continuing by CDFA staff. Updates will continue on a 48 hour basis.
December 07, 2016
Equine Herpes Viruses
Los Angeles , CA
Outbreak Update
There have been no new febrile horses identified on this premises and only EHM one horse remains in isolation. The positive horse in isolation continues to shed virus and we are anticipating a negative nasal swab soon. The LAEC incident has had a total of thirteen (13) EHV-1 confirmed cases, all of those caused by the non-neuropathogenic strain EHV-1 virus. Enhanced biosecurity measures continues in all barns under quarantine and all horses’ temperatures continue to be monitored twice daily.
December 05, 2016
Equine Herpes Viruses
Inyo County, CA
Outbreak Update
A different strain of EHV-1 causing EHM has been confirmed in one horse with mild neurologic symptoms in Inyo County, CA.  Although no additional EHM cases have been confirmed on this premises, we are still awaiting confirmatory testing on two febrile horses that have been isolated.  This is the neurologic strain, which is biologically distinct from the non-neurologic strain identified in all the LA County confirmed cases.  The affected horse, a 20 year-old QH gelding, is part of a wintering pack string of twenty-eight (28) horses and four (4) mules on an isolated, high desert ranch. These horses/mules have been placed under quarantine with no movement allowed in order to limit disease transmission.  The investigation of this disease outbreak is continuing by CDFA staff.  Updates will continue on a 48 hour basis.
December 05, 2016
Equine Herpes Viruses
Los Angeles County, CA
Outbreak Update
There have been no new febrile horses identified on this premises and only one horse remains in isolation. The LAEC incident has had a total of thirteen (13) EHV-1 confirmed cases, all of those caused by the non-neuropathogenic strain EHV-1 virus. Enhanced biosecurity measures continues in all barns under quarantine and all horses’ temperatures continue to be monitored twice daily.
December 04, 2016
Equine Herpes Viruses
Inyo County, CA
Confirmed case(s): Official Quarantine
A different strain of EHV-1 causing EHM has been confirmed in one horse with mild neurologic symptoms in Inyo County, CA. Although no additional EHM cases have been confirmed on this premises, two febrile horses have been isolated and are awaiting confirmatory testing. This is the neurologic strain, which is biologically distinct from the non-neurologic strain identified in all the Las Angeles County confirmed cases. The affected horse, a 20 year-old QH gelding, is part of a wintering pack string of twenty-eight (28) horses and four (4) mules on an isolated, high desert ranch. These horses/mules have been placed under quarantine with no movement allowed in order to limit disease transmission. The investigation of this disease outbreak is continuing by CDFA staff. Updates will continue on a 48 hour basis.