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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 21, 2016
Equine Herpes Viruses
Los Angeles County, CA
Outbreak Update
No new cases. CDFA continues to monitor the situation onsite. As of today, C Barn and the isolation area of the Los Angeles Equestrian Center remain under quarantine. Enhanced biosecurity measures continue for quarantined horses and horses’ temperatures continue to be monitored twice daily. The last febrile case occurred on December 12, 2016. Two (2) horses from isolation qualified to return to their home stalls through negative testing. There are currently two (2) horses in isolation and diagnostic testing indicates that neither of these two horses continues to shed the virus. Neither of the two (2) horses in isolation are febrile and neither are showing neurologic signs. Quarantine release will be based on no additional cases and horses in isolation continuing to test negative. As background information, the initial quarantine was placed on November 3, 2016. A total of 228 exposed horses were under quarantine at the peak of the outbreak. To date, fifteen (15) cases of equine herpesvirus-1 have been confirmed by the California Animal Health and Food Safety (CAHFS) Laboratory. Eight (8) of these horses displayed neurologic signs and were classified as equine herpesvirus myeloencephalopathy (EHM) cases. The remaining seven (7) horses were febrile with no signs of neurologic disease. One EHM horse was euthanized due to the severity of clinical signs.
December 21, 2016
West Nile Virus
McCurtain County, OK
Confirmed Case(s): No Quarantine
The 16th reported WNV positive horse has been confirmed for 2016 in Oklahoma. The 24 year old gelding located in McCurtain County was showing mild neurologic signs and was not vaccinated. For more information visit: http://www.ag.ok.gov
December 19, 2016
Equine Herpes Viruses
Inyo County, CA
Outbreak Update
As of December 19, 2016, two horses with equine herpesvirus myeloencephalopathy (EHM) due to the neuropathogenic strain of EHV-1 and one EHV-1 positive horse with a fever show improvement and are recovering. All confirmed positive horses continue to show improvement and are recovering. The premises remains in quarantine with enhanced biosecurity requirements. For background information on the Inyo county outbreak to date go to: https://www.cdfa.ca.gov/ahfss/animal_health/equine_herpes_virus.html
December 19, 2016
Equine Herpes Viruses
Los Angeles County, CA
Outbreak Update
As of December 19, 2016, C Barn and the isolation area of the Los Angeles Equestrian Center remain under quarantine. There are currently four (4) horses in isolation and diagnostic testing indicate three (3) of these horses are no longer shedding the virus. One horse continues to shed virus and will be re-sampled for EHV-1 testing. Currently, none of the four (4) horses in isolation are febrile and none are showing neurologic signs. Quarantine release will be based on having no additional cases with horses in isolation testing negative. For background information for the LAEC equine herpesvirus myeloencephalopathy outbreak to date go to: https://www.cdfa.ca.gov/ahfss/animal_health/equine_herpes_virus.html
December 17, 2016
Equine Herpes Viruses
Inyo County, CA
Outbreak Update
No additional confirmed cases of EHM, EHV-1 or new febrile horses have been identified at this time. This incident has two (2) EHM cases and one EHV-1 confirmed case. Both of the EHM cases continue to show improvement and all three are no longer shedding virus. 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 were 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 17, 2016
Equine Herpes Viruses
Los Angeles County, CA
Outbreak Update
There are currently four (4) horses in quarantined isolation at the Los Angeles Equestrian Center. 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. 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.
December 16, 2016
Equine Herpes Viruses
Inyo County, CA
Outbreak Update
12-15-2016: No additional confirmed cases of EHM, EHV-1 or new febrile horses have been identified at the ranch in Inyo county. This incident has two (2) EHM cases and one EHV-1 confirmed case. Both of the EHM cases continue to show improvement. 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 were 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 16, 2016
Equine Herpes Viruses
Los Angeles, CA
Outbreak Update
12-15-2016: There are currently four (4) horses in quarantined isolation at the Los Angeles Equestrian Center. One horse was able to return to home based on a series of negative tests. Two (2) horses are remaining in isolation as additional negative tests are anticipated. Two (2) horses continue 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 three (3) days in C Barn. 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 continue in C Barn under quarantine and all horses’ temperatures continue to be monitored twice daily.
December 15, 2016
Equine Infectious Anemia
Wasatch County, UT
Confirmed case(s): Official Quarantine
The Utah Department of Agriculture and Food (UDAF) Animal Industry Division has confirmed the first EIA positive horse in Utah in several years. The 14-year old dark bay QH gelding located in Wasatch County was originally tested for sale and movement to California but was not moved due to a positive EIA test. The horse was immediately quarantined and retested for EIA as well as equine piroplasmosis. The EIA test was again positive but the EP test was negative. The owner has decided to euthanize the horse. This horse was imported from Mexico in April of 2016 with NVSL negative test results for EIA, EP, Glanders, Dourine. Ten other cohort horses that are also quarantined on this ranch have been tested for EIA and results are pending. Twelve other cohort horses that had tested negative to EIA in the spring of this year and sent to Arizona recently are in the process of being identified and located. The State Veterinarian of Arizona has been notified by the Utah State Veterinarian and they are working together to get these horses isolated and retested. UDAF recommends regular EIA testing for all horses, including those that do not leave the property, preferably yearly but at least every 3 years.
December 13, 2016
Equine Herpes Viruses
Inyo County, CA
Outbreak Update
No additional confirmed cases of EHM, EHV-1 and no new febrile horses have been identified at this time in Inyo county. This incident now has two (2) EHM cases and one EHV-1 confirmed case. Both of the EHM cases continue to show improvement. 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. For more info go to: https://www.cdfa.ca.gov/ahfss/animal_health/equine_herpes_virus.html