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

  • 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

  • Daily grooming and regularly examining the animal for ticks
  • 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
  • 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

  • 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),
  • 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
  • Anaplasmosis is another tick borne disease affecting horses, it can present with a high fever (103 +) and stocking up in all 4 limbs,

Diagnosis

  • Diagnosis can be difficult
  • 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
  • Stressors include: travel, showing and vaccines
  • Test results can take 7-10 days
  • Often treatment is started prior to receiving test results
  • If a horse is symptomatic, fast treatment is essential

Treatment

  • The most common treatment is currently Doxycycline/Minocycline antibiotics
  • length of treatment varies by veterinarian recommendation
  • 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
  • full treatment must be continued to achieve full results.
  • Methods of Doxy treatment include:
  • 100mg tablets given whole in feed or crushed and mixed with flavoring
  • 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
  • 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”)
  • 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
  • Green Valley Vet recommends Probiotic Wise
  • 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
  • two of the products Green Valley Vet recommends are Platinum Performance or Missing Link (which can be ordered through our practice)
  • Other antibiotics may be recommended for very severe cases
  • 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

Dennis J. Thibeault, DVM

Karen L. Swanberg

GVVS Assistant