Herpesvirus-1 (EHV-1) Outbreak
On Dec. 23, 2015
the Pennsylvania Department of Agriculture (PDA) received laboratory
confirmation that three horses euthanized over a two-day period due to acute,
severe neurological impairment were infected with the neuropathogenic variant
These horses were at a private, pleasure-horse boarding
facility in the Doylestown area of Bucks County (Mile View Farm.) This facility has been and remains under a
formal quarantine by PDA.
Animals on the premises are being monitored carefully for
signs compatible with active EHV-1 infection.
Barn owners, management, staff and horse owners have been very proactive
and are compliant with quarantine and biosecurity requirements.
Private practitioners involved with this facility are
also very involved and have been providing guidance to affected horse owners as
well as their many other concerned clients.
PDA is responding to this situation, as it has for the
past several years, based on a science-based protocol involving minimum
quarantine of 21 days from the last significant clinical finding (e.g. fever)
as well as the use of polymerase chain reaction (PCR) testing for EHV-1 when
Private veterinarians can help PDA by correcting
any misinformation related to this issue, helping clients to avoid assigning
blame for this situation that is simply a disease that can happen anywhere
there are horses, and, as always, reminding their equestrian clients of some of
the biosecurity practices they can utilize to mitigate risk. The American Association of Equine
Practitioners (AAEP) website has resource information available at http://www.aaep.org/info/equine-herpesvirus-resources.
Veterinarians are also reminded to review their own
biosecurity precautions so that, should they be called upon to see a patient
that may have this highly contagious disease or a patient with an unrelated
condition on an affected premises, they do not carry EHV-1 to other patients at
that site or, even worse, to patients at other locations. It is very important that the veterinary
community set a good example for horse owners by maintaining sound sanitation
and infection control practices.
The same advice applies to other professionals such as
farriers, equine dentists, chiropractors, trainers, equine massage therapists
and others who travel to equine facilities.
As a reminder, neuropathogenic EHV-1 is reportable to PDA
on suspicion. That means a veterinarian must report a
suspected case to PDA right away even if they do not have confirmatory test
results. PDA can then post a quarantine for the premises to ensure that no
equine animals leave while test results are confirmed and all parties involved
can immediately begin to focus efforts on reducing disease transmission. The veterinarians involved with these initial
cases reported this situation promptly, enabling PDA to respond much sooner
than if we had waited for confirmatory laboratory results.
Also, although the veterinarians involved with
these cases knew the appropriate samples to take, there is often confusion about
what samples should be submitted for EHV diagnosis from a live animal. Veterinarians, please make note of the
supplies you would need to take the proper samples and obtain them now. The time to find the right-sized blood tubes
or the right swabs is NOT when you are looking at a neurologically-impaired
horse. Please refer to the submission
guidelines for the laboratory where you will be sending the samples for their
specific preferences, but whole blood in purple top (EDTA) tubes and polyester
tip/plastic shaft nasal swabs in empty red top tubes are usually preferred for
RRT-PCR testing for EHV-1.
you for everyone’s continued vigilance in identifying cases of reportable
diseases and assistance with the dissemination of clear, calm, factual
information to the equestrian community.
Please go to the following link for up-to-date information regarding
this outbreak: http://www.equinediseasecc.org/outbreaks.aspx.