Equine Lyme Disease
A bacterial infection caused by a spirochete class (corkscrew shaped) bacterium
Borrellia Burgdorferi.
First identified in Old Lyme, CT in 1977.
Life Cycle of the Deer Tick
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Ticks have 3 life stages: Larvae, Nymph, Adult and must feed on blood in order to survive
during each stage
Ticks live for 2 years
Ticks must be attached for 12-24 hours to transmit the bacteria
Adult ticks in the spring and fall are the stage that feed on horses
Prevention
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Daily grooming and regularly examining the animal for ticks
o pay special attention to the head, throatlatch, belly, legs, inside of hind legs, in the
mane on the crest area, base of tail
Use permethrin tick and fly repellant
Keep pastures mowed
Remove brush and wood piles from pasture areas (decrease rodent nesting areas)
There are no licensed Equine Lyme Disease Vaccines at this time
Lyme Disease is not transmissible from horse to horse
o However, if a horse is infected, this is an indicator that there are lyme carrying
ticks in the area so other horses are at risk
Symptoms
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Behavior changes, irritability (can worsen with steroids)
Refusal to work
Poor energy levels
General stiffness overall
Low grade fever may be present
Lameness that seems to shift to different limbs
Shifting weight in hind limbs
Swollen joints and/or muscle tenderness
Hyperesthesia (extreme sensitivity to touch),
o this can show as irritation with grooming and tacking
Laminitis (inflammation of tissues inside of the hoof wall)
Unexplained weight loss
Lyme disease causes multi-systemic affects, which result in joint, musculoskeletal or
neurological issues
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Anaplasmosis is another tick borne disease affecting horses, it can present with a high fever
(103 +) and stocking up in all 4 limbs,
Diagnosis
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Diagnosis can be difficult
o Less than 10% of horses have easily diagnosable symptoms
Elisa Titer counts indicate exposure
Western Blot test gives a better picture of current condition
Initial diagnosis should include both tests for a better understanding of exposure
Stress can activate a dormant case of lyme disease
o Stressors include: travel, showing and vaccines
Test results can take 7-10 days
Often treatment is started prior to receiving test results
o If a horse is symptomatic, fast treatment is essential
Treatment
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The most common treatment is currently Doxycycline/Minocycline antibiotics
o length of treatment varies by veterinarian recommendation
o Green Valley Vet's current protocol is 42 days of treatment and a Western Blot
retest performed 12 weeks after treatment ends
If symptoms are caused by Lyme disease, there should be visible improvement within 3-5
days of starting treatment
o full treatment must be continued to achieve full results.
Methods of Doxy treatment include:
o 100mg tablets given whole in feed or crushed and mixed with flavoring
o or compounded doxy with flavoring and a calibrated scoop for proper dosing
Typical recommended dosing at Green Valley Vet for an 800-1,000 lb. horse is 4 grams,
twice daily for 42 days
"Cycline" antibiotics also have strong, non-specific anti-inflammatory properties, which
may also help horses for overall inflammation
As the Borrellia burgdorferi is killed by the antibiotics the bacteria will release toxins which
can cause increased symptoms during the first 3 days of treatment
o This may result in laminitis (presents as: horse doesn’t want to move, looks like they
are walking on eggshells, heat in hooves, digital pulses, “founder stance”)
o Call your vet immediately if this is present. The chance for this can be reduced by
giving an oral dose of phenylbutazone or Banamine paste, once daily for the first 3
days of antibiotic treatment
The antibiotic treatment and anti-inflammatory medication can be tough on a horse’s
digestive tract
o The use of probiotics is beneficial
o Green Valley Vet recommends G.I. Conditioner (only available through a
veterinarian) given at each feeding of medication or Probios (available through
veterinarian, Feed Stores or mail order)
Due to the difficulty in achieving a true cure, veterinarians may recommend additional
immune supportive therapy. This may include a multi-vitamin, vitamin C, echinacea, Gluta
DMG, flaxseed and the homeopathic remedy Ledum
Vitamin supplementation is also recommended if not fed already as a boost to the horse’s
immune system
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two of the products Green Valley Vet recommends are Platinum Performance or
Vetri-Plus (which can be ordered through our practice)
Other antibiotics may be recommended for very severe cases
o this may include: IV treatment with Tetracycline or IM treatment with Naxcel
Each case is handled on an individual basis, taking into consideration the animal’s
condition and the owner’s financial concerns
We hope that this information will give you an over-view of one of the biggest health
issues to face both animals and people alike in the New England area.
Brought to you compliments of:
Green Valley Vet Services
122 Atwoodville Rd,
Mansfield Center, CT 06250
860-420-5002
888-282-8632 fax
www.greenvalleyvetservices.com
Dennis J. Thibeault, DVM
drt@greenvalleyvetservices.com
Karen L. Swanberg
GVVS Assistant
office@greenvalleyvetservices.com
www.cherryledgefarm.com