South Shore Equine Clinic Client Seminar

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South Shore Equine Clinic Client Seminar

• Mark T. Reilly, DVM, Dipl. ABVP
• Linda J. Cimetti, DVM
• Suzanne P. Shaw, MVB
• Heather A. Beach, DVM
• South Shore Equine Clinic Diagnostic Center
• April 2, 2008

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TICK BORNE DISEASES

• LYME DISEASE
• ANAPLASMOSIS
• EHRLICHIOSIS
• (POTOMAC HORSE FEVER)

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LYME DISEASE

• 1975 51 residents from Old Lyme, Lyme and East
  Haddam, CT
• 1982 Willy Burdorfer, PhD discovered slender,
  spirally undulating bacteria from blacklegged
  tick (Ixodes dammini -gt scapularis)

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LYME DISEASE

• Erythema Migrans

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LYME DISEASE

• 1983 spirochete named
• Borrelia burdorferi
• 1984 First case of canine Lyme arthritis
  reported

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LYME DISEASE

• The CDC reported that Lyme disease accounted
  for 81 of all reports of arthropod-transmitted
  diseases in the US between 1986 1991.

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LYME DISEASE

• In HORSES

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LYME DISEASE

• 2000 Might not be the most prevalent equine
  disease you face with your horses, but it does
  exist, and can seriously impact a horses health.
  Although documented cases of Lyme disease in
  horses are relatively rare, there are indications
  that the disease is on the increase.

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LYME DISEASE

• 2003 50 of horses in the Northeast US are
  positive for exposure.
• - Successful treatment of Lyme infected horses
  (Oxytetracyline)
• - rDNA canine vaccine success in ponies

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LYME DISEASE

• 2004 Up to 50 of adult horses in the
  northeast may be infected.

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LYME DISEASE

• 2005 Lyme disease is a problem more commonly
  thought to occur in our canine and human friends.
  However, it does occur and can have a wide range
  of signs and symptoms.

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LYME DISEASE

• 2006 As many as 20 of adult horses in certain
  areas of the US are infected with Borrelia
  burdorferi. Many horses in endemic areas are, or
  have been, infected, which is evidenced by the
  fact that 75 of horses in the Northeast and
  Mid-Atlantic states already have antibodies
  against the organism.

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LYME DISEASE

• Human cases parallel animal cases
• 1982 523 cases
• 1988 4,507 cases
• 1989 8,552 cases
• 1994 13,043 cases
• 2003 1,503 cases in MA
• 2004 1,532 cases in MA
• 2005 23,300 cases (2,336 cases in MA)

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LYME DISEASE

• 23,300 human cases in 2005
• 7.9 per 100,000 nationally
• 31.6 per 100,000 in the ten states where
  infection is most common
• 50 increase in MA (18 nationally)

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LYME DISEASE

• US Department of Health and Human Services has
  included Lyme disease among its prevention
  priorities.
• Goal of reducing the overall incidence by more
  than 40 in endemic areas by 2010.

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LYME DISEASE

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LYME DISEASE

• Horses are more likely to have a higher
  prevalence than humans because ticks stay on
  longer.

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LYME DISEASE

• The chances of your horse being infected with
  Lyme disease may be 25 times greater than horses
  in other parts of the country.
• Found in 44 states, Canada, Europe, Asia, Africa,
  Japan, Australia

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LYME DISEASE

• Ixodes scapularis (deer tick)

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LYME DISEASE

• LIFE CYCLE
• LARVAL
• NYMPH
• ADULT
• Each feeding stage requires one vertebrate blood
  meal for its development

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LYME DISEASE

• LARVAE
• Size of a grain of sand
• 6-legged
• May August
• Need high humidity
• Rarely infected
• Need host for blood meal
• (Small mammals)
• Feed for 3-5 days
• Leaf litter for metamorphosis

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LYME DISEASE

• NYMPH
• Size of a poppy seed
• 8-legged
• May-August
• Need host for blood meal
• Easily undetected
• 2nd chance to become infected
• Leaf litter for metamorphasis

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LYME DISEASE

• ADULT
• Fall gt Spring when gt40 degrees
• Feed on large mammals
• Female drops off and lays eggs (3,000)
• 24 hours

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LYME DISEASE

• LIFE STAGES
• Larvae
• Nymph
• Adult male
• Adult female

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LYME DISEASE

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LYME DISEASE

• TRANSMISSION of DISEASE
• Via Salivation or Regurgitation of tick to host
• Minimum of 24 hours of tick attachment
• Nymph gtgtgt Adult stages
• (50 adults infected)

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LYME DISEASE

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LYME DISEASE

• White footed mouse

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LYME DISEASE

• White-tailed Deer

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LYME DISEASE

• VAGUE VARIABLE SIGNS
• Stiffness/lameness
• Muscle tenderness
• Hyperaesthesia (sensitivity)
• Swollen/sore joints
• Behavioral changes
• Lethargic, grumpy

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LYME DISEASE

• SIGNS MAY MIMIC OTHER DISEASES
• Aches, fatigue viral infection
• Joint pain arthritis
• Weakness neuro diseases (EPM)
• Muscle soreness tying up

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LYME DISEASE

• A DIFFICULT DIAGNOSIS
• Most common complaint LAMENESS
• Often no history of tick infestation OR may take
  a few weeks to develop clinical signs after tick
  bite
• May be episodic OR chronic
• Forelimbs, Hindlimbs, Pelvis

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LYME DISEASE

• DIAGNOSIS
• Submission of infected tick
• Blood Tests
• IFA antibody
• ELISA (Kela)
• Western Blot
• C6 antibody ELISA

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LYME DISEASE

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LYME DISEASE

• ANTIBODY TESTS
• IFA
• patients serum placed on antigen-coated slide
  and then add anti-body conjugate
• Titer must be interpreted
• Whole-cell method

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LYME DISEASE

• ANTIBODY TESTS
• ELISA (Kela units)
• IgG level reported
• Chronic infection
• lt130 or gt380
• Whole-cell method

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LYME DISEASE

• ANTIBODY TESTS
• WESTERN BLOT
• Need all 4 Bands specific markers
• 4 day test
• Whole cell method

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LYME DISEASE

• ANTIBODY TESTS
• C6 ANTIBODY TEST
• 3 weeks post-infection
• 100 consistent with Western Blot
• C6 Peptide is highly specific ONLY present
  during LIVE infection
• Declines rapidly and significantly after
  successful therapy
• Highly sensitive specific

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LYME DISEASE

• ANTIBODY TESTS
• C6 ANTIBODY TEST
• Variable region on the spirochete

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LYME DISEASE

• 4 DX SNAP TEST
• 8 minutes

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LYME DISEASE

• TREATMENT
• ANTIBIOTICS
• NSAIDs
• CHONDROPROTECTIVE AGENTS
• PROBIOTICS

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LYME DISEASE

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LYME DISEASE

• ANTIBIOTICS
• Study done at Cornell
• - Doxycycline orally 25 effective
• - Naxcel IM 25 effective
• - Oxytetracycline IV 100 effective

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LYME DISEASE

• OXYTETRACYLCINE
• IV once daily for 3 weeks
• Superior to oral Doxy and IM Naxcel
• Retest at 60 post treatment
• C6 Antibody tests dropped by at least 50 if not
  completely

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LYME DISEASE

• OXYTETRACYLCINE
• Treatment at SSEC
• IV once daily for 5-7 days
• Then switch to oral Oxytetracycline Powder
  Probiotic
• Retest at 60 days post treatment

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LYME DISEASE

• Other Antibiotics
• Rise in titers and clinical signs when treatment
  is stopped in 75 of each group
• Appear to inhibit reproduction, not eradication
  of B.burdoferi
• Doxy has anti-inflammatory effects false sense
  of improvement

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LYME DISEASE

• PREVENTION
• rOSP canine vaccine
• 3 doses (day 1, 20 , 80)
• Horses plasma has antibodies
• inhibits spirochete within the tick

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LYME DISEASE

• PREVENTION
• Dogs
• bring ticks in from woods
• - roll in leaves go into tick habitats
• - 50 more likely to get disease
• - act as sentinels for disease

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LYME DISEASE

• PREVENTION
• rOSP canine vaccine
• Problems
• frequency to vaccinate?
• no safety studies
• questionable value once infected

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LYME DISEASE

• PREVENTION
• HORSES
• - Examine on daily basis (24 hours)
• - Neck, base of mane, ears, under tail
• - fine tweezers as close to skin as
  possible and pull straight up
• - Avoid tick infested areas
• - Repellents with permethrins (sweat)

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LYME DISEASE

• PREVENTION
• - Clean up brush piles
• - Mow fields
• - Stack wood in dry areas
• - Restrict Tick migration
• - Bait boxes for wild rodents with acaracides

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LYME DISEASE

• PREVENTION
• -Do not feed deer
• - Plant deer resistant plants

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LYME DISEASE

• White footed mouse

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LYME DISEASE

• PREVENTION???
• - Vaccination of white-footed mice with canine
  vaccine
• - Prevented the tick from the spreading the
  disease to the next host
• - Measured a reduction in prevalence of disease
  in nymphs

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LYME DISEASE

• MYTHS
• No evidence of transmission directly from animal
  to human
• Cannot get from urine of infected animal
• Cannot get from eating a tick or portion of mouse
  (in baled hay)

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LYME DISEASE

• KEY POINTS
• 24 hour feeding
• Clean up brush and debri
• Control ticks on dog and cats
• Use permethrin sprays
• Good diagnostic test available
• Treatable very successfully
• Re-infection always possible!

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LYME DISEASE

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EHRLICHIOSIS

• 2nd most common canine infectious disease in the
  U.S.
• Anaplasmosis
• Ehrlichiosis

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EHRLICHIOSIS

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EHRLICHIOSIS

• 2001 E. equi and E. phagocytophila reclassified
  
• Anaplasma phagocytophila

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EHRLICHIOSIS

• Co- infection common
• - 45.9 of dogs in one study tested positive for
  Lyme disease as well as Anaplasma
• - 9-26 of humans with Lyme disease are
  co-infected

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EHRLICHIOSIS

• Worldwide distribution

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EHRLICHIOSIS

• Anaplasmosis
• - intracellular bacteria transmitted by ticks
• - prefers neutrophils (granulocytes)

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EHRLICHIOSIS

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EHRLICHIOSIS

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EHRLICHIOSIS

• Morulae mulberry

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EHRLICHIOSIS

• Similar to Lyme disease cycle
• - maintained in white-tailed deer and
  white-footed mouse
• - Incubation period of 1 week
• (1 21 days)

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EHRLICHIOSIS

• SIGNS
• Fever (104-106)
• Swollen legs
• Depression
• Anorexia
• Polyarthritis

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EHRLICHIOSIS

• 3 STAGES
• ACUTE brief, symptoms often missed
• SUBCLINICAL no symptoms
• CHRONIC weeks to months

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EHRLICHIOSIS

• ACUTE STAGE
• Passing viral infection?
• Change in behavior?
• Best chance for cure
• Self-resolution

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EHRLICHIOSIS

• SUBCLINICAL STAGE
• No symptoms
• Containment and/or resolution
• /- Platelet count decreases
• /- Antibody titer increases

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EHRLICHIOSIS

• CHRONIC STAGE
• Severe symptoms
• Thrombocytopenia
• Bone marrow lines altered

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EHRLICHIOSIS

• DIAGNOSIS
• IFA Titers
• Several variables
• SNAP Test
• Synthetic peptide to detect abs

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EHRLICHIOSIS

• SNAP Test
• Synthetic peptide mimics a specific region of an
  outer membrane protein found on the Anaplasma
  organism

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EHRLICHIOSIS

• SNAP Test
• Not subjective like IFA
• Good correlation with IFA titer of 180
• Little cross reactivity (A.platys)
• Detects IgM and IgG
• Highly sensitive and specific

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EHRLICHIOSIS

• TREATMENT
• -Oxytetracycline IV once daily for 5-8 days
• - NSAIDs

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EHRLICHIOSIS

• See improvement in behavior
• Attitude improves

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EHRLICHIOSIS

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POTOMAC HORSE FEVER

• Caused by Neorickettsia risticii
• Requires Water nearby
• Liver flukes and insects which feed off them
• Drinking the water?
• Tick borne?

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POTOMAC HORSE FEVER

• Vaccine available
• Efficacy?
• Who is at risk?
• 2 different vaccines available

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TICK BORNE DISEASES

• Thank you for your attention

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TICK BORNE DISEASES

• QUESTIONS???

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South Shore Equine Clinic Diagnostic
CenterClient Education Series

• Wednesday, April 23rd
• Maintaining the Equine Athlete
• Emphasis on Foot Lameness
• 600 pm
• Wednesday May 7th (Marthas Vineyard)
• Nutrition and Colic Prevention
• 700pm