By Dr. Amber Itle |
WA State Veterinarian
Rodeos,
events and shows are in full swing this spring!
Horses are on the move and so are equine diseases. Since the first of
the year, 19 States have reported contagious disease outbreaks in horses nationally.
Washington is also seeing an uptick in reports. The most commonly reported diseases in the
State are Strangles, Equine Influenza Virus, Pigeon Fever,
Equine Herpes Virus and West Nile Disease.
Now is the
time to update your horse’s vaccinations to mitigate disease severity and allow
for continuity of business. Talk to
your veterinarian about the right protocol and cadence for you depending on
your risk to include Flu/Rhino (equine influenza and herpes), West Nile and
maybe even Strep equi (strangles) in addition to the core vaccines recommended
by AAEP.
This is especially critical in boarding facilities where horses come and
go to shows, events and even trail rides. Any commingling event is an
opportunity for disease spread. Although horses that are vaccinated can still contract the virus or
bacterial infection and spread it, but the course of disease should be less
severe.
As soon as
the attending veterinarian gets positive laboratory results for any of these
diseases, they must be reported through the Reportable
Animal Disease
database. WSDA also reports to the Equine
Disease Communication Center
and they distribute minimal information that protects personally identifying
information through an alert to subscribers. Usually private practitioners manage individual cases of equine diseases
by performing diagnostics, addressing individual horse treatment, implementing
on farm biosecurity practices, and helping the barn manager institute a
self-quarantine of infected or exposed horses.
In some
cases, when there are lots of sick horses and/or stable compliance is a problem
with horse movement, the State Veterinarian can be requested to assist. WSDA field veterinarians can issue
quarantines in order to mitigate the spread of disease by not allowing any
movement of horses on or off the premises. A quarantine will be in place until 14-21 days after the last “new”
case, allowing for a full incubation period to pass by without clinical signs. Horses
can remain contagious for 10 days after clinical signs or fever starts. The
quarantine will require that rectal temperatures be recorded daily whenever
possible so that febrile horses can be rapidly isolated, tested and monitored
for clinical signs. Often viral
infections can be “dose dependent” so rapid removal of sick horses can reduce
viral load and transmission.
Airborne
transmission or direct contact is the most common way horses become infected
with respiratory disease. Infected
horses release infective droplets into the air by coughing or snorting which
are then inhaled by horses in close proximity. Horses can also be exposed to
the organism by coming into contact with contaminated surfaces such as stalls,
wash racks, stocks, water sources, feed, tack, grooming equipment such as wipe
rags, and transport vehicles. Humans can spread microorganisms from horse
to horse by contaminated hands and clothing, so the adoption of biosecurity
measures is paramount.
WSDA Field
veterinarians can also assist with on-farm biosecurity plans to help mitigate
viral spread. Here are some biosecurity
tips you can customize for your ranch during a quarantine period to help ensure
the health and welfare of your horse.
Horse owners can find this biosecurity poster on our website to be printed and
posted in your barn.
- Observe
Strict Biosecurity
- Limit
Stress to horses
- Control
flies, vermin, vectors
- Monitor
all horses on the premises with twice-a-day temperature recording
- Keep
hoses out of free-standing water such as ponds or creeks
- Remove
compost and manure promptly
- Wash
hands frequently
- Prevent
direct contact with infected horses
- Do not
share equipment, buckets or tack
- Tape off an “off limits” perimeter outside
any symptomatic horse stall approximately 3 feet by six feet. Only people that need to enter the
stall are permitted into this area.
- Place a foot bath outside the stall with
disinfectant, to dip feet into prior to entering and again after exiting
the stall. Be sure to clean your boots before you disinfect.
- Clean
and disinfect the stall frequently
- Designate
one person to care for your horse and limit contact of personnel with
exposed horses
- Notify
your veterinarian immediately if you notice any clinical signs or changes
in behavior. Horses with viral
infections are prone to secondary bacterial infections.
- Coughing
horses aerosolize the organism and can spread the organism as far as 150
feet
- Horse
Management
- Do not
move any horses on or off the farm
- Designate
an isolation stall or quarantine barn for sick horses.
- Supportive
care and treatment as prescribed by your veterinarian
- Keep in
well-ventilated stall and or paddocks to reduce inhalation of dust
- Consider
staggering outdoor paddock access to avoid nose-to-nose contact
i.
Spray
any common contact areas with 10% bleach.
- Consider
physical barriers between outdoor runs to avoid nose-to-nose contact
- Keep
dust down in the stall and hay (by wetting if needed)
- Exercise- No sick horses should be
allowed in the main arena or in shared wash racks.
- Symptomatic horses (fever, lethargy,
nasal discharge, coughing, etc)
i.
Febrile
horses should remain in their stalls and allowed to rest.
ii.
Avoid
strenuous exercise and hand walk or exercise lightly for short periods of time.
·
Remember, your horse is not feeling well and
may be lethargic, have painful muscles or a cough that can be exasperated by
exercise. The idea is to stretch the
horses legs and provide some stress relief from being stalled.
iii.
Lightly
exercise horses in the designated round pen area away from other horses
iv.
When
moving horses down the alleyway, use the closest exit and be cautious to avoid
direct nose-to-nose contact with other horses.
v.
Only
one horse should be exercised at a time and a schedule should be posted if
needed.
- Exposed, non-clinical horses (No fever, no nasal
discharge, rare or occasional cough)
i.
Avoid
strenuous exercise, but light riding or exercise is acceptable.
·
Remember
that your horse’s immune system may be under stress from recent exposure and
fighting off potential infection. Too much exercise may exasperate clinical
signs or illness.
ii.
All
horses should exit the barn in a way that avoids clinical horses if possible.
iii.
Exercise
horses in the designated outdoor arena space
iv.
Only
one horse should be exercised at a time and a schedule should be posted if
needed.
Mapping
the farm can also be helpful when thinking about horse movement patterns on the
farm as well as identifying access points, parking, cleaning and disinfection
stations and carcass pick-up areas.
Additional Equine Biosecurity Resources can be found on our website.
