External Parasites INAG 120 – Equine Health Management November 26, 2008
Ectoparasites <ul><li>= parasites that attack skin and body openings </li></ul><ul><li>Flies </li></ul><ul><li>Black Flies...
Mechanism of blood feeding <ul><li>Females:  Blood = Protein </li></ul><ul><li>Males generally subsist on sugars from nect...
Mechanism of blood feeding <ul><li>Most flies can detect  Carbon Dioxide </li></ul><ul><li>Flies are also sensitive to hea...
Life cycles <ul><li>Four major phases of life: </li></ul><ul><ul><li>Egg </li></ul></ul><ul><ul><li>Larva </li></ul></ul><...
Disease transmission <ul><li>Insects that transmit diseases = vectors </li></ul><ul><li>Two types of transmission: </li></...
Flies <ul><li>Horseflies </li></ul><ul><li>Deer flies </li></ul><ul><li>Stable flies </li></ul><ul><li>Horn flies </li></u...
Horseflies & Deerflies <ul><li>Breed in boggy areas </li></ul><ul><li>Active only during the day in warm weather </li></ul...
Horseflies & Deerflies <ul><li>Larvae overwinter in the soil </li></ul><ul><li>Prefer wet mud near or under ponds, marshes...
Stable Flies and Horn Flies <ul><li>Introduced from Europe </li></ul><ul><li>Spend almost entire adult lives on their host...
Stable Flies and Horn Flies <ul><li>Mouth parts are jabbed into skin like a needle </li></ul><ul><li>Curved spines at the ...
Face Flies <ul><li>Non-biters </li></ul><ul><li>Closely resemble  house flies, larger than horn flies </li></ul><ul><li>Fe...
Bot Flies <ul><li>Lay their eggs on legs and chests of horses </li></ul><ul><li>Horses lick that area ingest eggs </li></u...
Bots
Black Flies/Midges - Onchocerca  <ul><li>Spread a parasitic roundworm,  Onchocerca , which causes bumps to form in skin, c...
 
Ticks <ul><li>Lyme disease </li></ul><ul><li>Rocky Mountain Spotted Fever </li></ul>
Lyme Disease <ul><li>Spirochetal (corkscrew-shaped) bacteria – Borrelia burgdorferi </li></ul><ul><li>Transmitted through ...
 
Borrelia burgdorferi
Lyme Disease Transmission <ul><li>Larval deer ticks can become infected with bacteria if they take a blood meal from a rod...
Two-Year Life Cycle of Deer Tick SPRING SUMMER WINTER FALL EGGS LARVAE <ul><li>MEAL 1 </li></ul><ul><li>Mouse </li></ul><u...
Lyme Disease Transmission <ul><li>Ticks live for 2 years </li></ul><ul><li>Must attach to animal host and feed for 12-24 h...
Lyme Disease <ul><li>Multisystem disease! </li></ul><ul><li>Clinical Signs: </li></ul><ul><ul><li>Joints </li></ul></ul><u...
Lyme Disease and Horses <ul><li>Spring and Fall    adult tick most active </li></ul><ul><li>Found commonly around head, t...
Lyme Disease and Horses <ul><li>Diagnosis is difficult – VERY political! </li></ul><ul><ul><li>Blood test detects antibodi...
Lyme Disease Treatment <ul><li>Antibiotics – </li></ul><ul><ul><li>“ Gold Standard” = IV Tetracycline (6.6 mg/kg) for 10 d...
Lyme Disease Prevention <ul><li>No Vaccine licensed for horses </li></ul><ul><li>TICK CONTROL!! </li></ul><ul><li>Daily gr...
Mosquitoes <ul><li>May be encountered day and night </li></ul><ul><li>Many different species </li></ul><ul><li>Attracted t...
Lice <ul><li>Most common of external parasites </li></ul><ul><li>Two varieties: </li></ul><ul><ul><li>Chewing/Biting – fee...
Lice <ul><li>Can cause weight loss, general unthriftiness, anemia </li></ul><ul><li>Winter  spring problem! </li></ul><ul...
Mites <ul><li>Microscopic! </li></ul><ul><li>Can cause mange </li></ul><ul><ul><li>Sarcoptic mites (head neck, shoulders, ...
 
Psoroptic Mange…
Fly Control
More Fly Control
Premise Control <ul><li>Control standing water </li></ul><ul><li>Compost manure far away from animals </li></ul><ul><li>Ch...
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External Parasites INAG 120 – Equine Health Management

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External Parasites INAG 120 – Equine Health Management

  1. 1. External Parasites INAG 120 – Equine Health Management November 26, 2008
  2. 2. Ectoparasites <ul><li>= parasites that attack skin and body openings </li></ul><ul><li>Flies </li></ul><ul><li>Black Flies/Midges </li></ul><ul><li>Ticks </li></ul><ul><li>Mosquitoes </li></ul><ul><li>Lice </li></ul><ul><li>Mites </li></ul>
  3. 3. Mechanism of blood feeding <ul><li>Females: Blood = Protein </li></ul><ul><li>Males generally subsist on sugars from nectar, etc. </li></ul><ul><li>EXCEPT: stable flies and horn flies </li></ul><ul><ul><li>Both sexes feed on blood </li></ul></ul><ul><li>Flies can detect and follow an “odor plume” at great distances </li></ul>
  4. 4. Mechanism of blood feeding <ul><li>Most flies can detect Carbon Dioxide </li></ul><ul><li>Flies are also sensitive to heat and moisture </li></ul><ul><li>Mouth-parts differ between species </li></ul><ul><ul><li>Blade- or sword-like with serrated edges </li></ul></ul><ul><li>Once blood starts flowing, fly secretes saliva that prevents coagulation </li></ul><ul><ul><li>Saliva is allergenic and causes swelling and irritation </li></ul></ul>
  5. 5. Life cycles <ul><li>Four major phases of life: </li></ul><ul><ul><li>Egg </li></ul></ul><ul><ul><li>Larva </li></ul></ul><ul><ul><li>Pupa </li></ul></ul><ul><ul><li>Adult </li></ul></ul><ul><li>Lifecycles vary in timing and duration depending on species </li></ul>
  6. 6. Disease transmission <ul><li>Insects that transmit diseases = vectors </li></ul><ul><li>Two types of transmission: </li></ul><ul><ul><li>Mechanical </li></ul></ul><ul><ul><li>Biological </li></ul></ul><ul><li>Deerflies, horseflies, stable flies are thought to be able to transmit anthrax on their mouthparts </li></ul><ul><li>Mosquitoes and ticks serve as biological reservoirs for other diseases </li></ul>
  7. 7. Flies <ul><li>Horseflies </li></ul><ul><li>Deer flies </li></ul><ul><li>Stable flies </li></ul><ul><li>Horn flies </li></ul><ul><li>Face flies </li></ul><ul><li>Bot flies </li></ul>
  8. 8. Horseflies & Deerflies <ul><li>Breed in boggy areas </li></ul><ul><li>Active only during the day in warm weather </li></ul><ul><li>Deerflies have patterned wings and are smaller </li></ul><ul><li>Horseflies have transparent wings </li></ul>
  9. 9. Horseflies & Deerflies <ul><li>Larvae overwinter in the soil </li></ul><ul><li>Prefer wet mud near or under ponds, marshes, or streams </li></ul><ul><li>One cow can lose one quarter liter of blood per day in heavily infested areas! </li></ul>
  10. 10. Stable Flies and Horn Flies <ul><li>Introduced from Europe </li></ul><ul><li>Spend almost entire adult lives on their host (horses and cattle) </li></ul><ul><li>Stable flies look like house flies </li></ul><ul><li>Bite ankles of people, legs of horses </li></ul>
  11. 11. Stable Flies and Horn Flies <ul><li>Mouth parts are jabbed into skin like a needle </li></ul><ul><li>Curved spines at the tip move back and forth making hole deeper and wider </li></ul><ul><li>Larvae develop in manure and decaying vegetation </li></ul>
  12. 12. Face Flies <ul><li>Non-biters </li></ul><ul><li>Closely resemble house flies, larger than horn flies </li></ul><ul><li>Feed on mucous secretions around eyes, nose, mouth </li></ul><ul><li>Lay eggs in fresh manure </li></ul><ul><li>Can transmit eye problems </li></ul>
  13. 13. Bot Flies <ul><li>Lay their eggs on legs and chests of horses </li></ul><ul><li>Horses lick that area ingest eggs </li></ul><ul><li>Eggs hatch in intestines </li></ul><ul><li>Internal/External parasites! </li></ul><ul><li>Deworming program to control bots </li></ul>
  14. 14. Bots
  15. 15. Black Flies/Midges - Onchocerca <ul><li>Spread a parasitic roundworm, Onchocerca , which causes bumps to form in skin, can also be found in the eye! </li></ul>Onchocerciasis in the eye of a horse. By permission from Knottenbelt DC, Pascoe RR, Diseases and Disorders of the Horse, Saunders, 2003
  16. 17. Ticks <ul><li>Lyme disease </li></ul><ul><li>Rocky Mountain Spotted Fever </li></ul>
  17. 18. Lyme Disease <ul><li>Spirochetal (corkscrew-shaped) bacteria – Borrelia burgdorferi </li></ul><ul><li>Transmitted through the bite of a deer or black-legged tick </li></ul><ul><li>Endemic areas for Lyme disease: </li></ul><ul><ul><li>Northeast </li></ul></ul><ul><ul><li>Mid-Atlantic </li></ul></ul><ul><ul><li>Northern Midwest states </li></ul></ul><ul><ul><li>Northern California </li></ul></ul>
  18. 20. Borrelia burgdorferi
  19. 21. Lyme Disease Transmission <ul><li>Larval deer ticks can become infected with bacteria if they take a blood meal from a rodent already infected </li></ul><ul><li>Transmit disease with subsequent blood meals </li></ul><ul><li>Ticks have 3 developmental stages: </li></ul><ul><ul><li>Larvae, nymph, adult </li></ul></ul><ul><ul><li>Must have a blood meal before they can molt to next stage </li></ul></ul>
  20. 22. Two-Year Life Cycle of Deer Tick SPRING SUMMER WINTER FALL EGGS LARVAE <ul><li>MEAL 1 </li></ul><ul><li>Mouse </li></ul><ul><li>Bird </li></ul>Larvae molt into nymph stage Nymphs dormant NYMPHS Nymphs molt into adults ADULTS <ul><li>Meal 3 </li></ul><ul><li>Person </li></ul><ul><li>Deer </li></ul><ul><li>Horse </li></ul><ul><li>Meal 3 (for adults that didn’t feed in fall) </li></ul><ul><li>Person </li></ul><ul><li>Deer </li></ul><ul><li>Horse </li></ul>Eggs laid adults die MEAL 2 Peak Feeding in people, horses, mice
  21. 23. Lyme Disease Transmission <ul><li>Ticks live for 2 years </li></ul><ul><li>Must attach to animal host and feed for 12-24 hours before the bacteria can be transmitted to new host! </li></ul><ul><li>Natural host of larval ticks = white-footed mouse </li></ul><ul><li>Host of nymph ticks = humans, rodents, dogs, cats, birds, etc. </li></ul><ul><li>Host of adult = deer plus others </li></ul>
  22. 24. Lyme Disease <ul><li>Multisystem disease! </li></ul><ul><li>Clinical Signs: </li></ul><ul><ul><li>Joints </li></ul></ul><ul><ul><li>Musculoskeletal system </li></ul></ul><ul><ul><li>Neurological system </li></ul></ul><ul><ul><li>Subclinical infection is common! </li></ul></ul><ul><ul><li>Development of clinical signs only occurs in 10% of infected animals! </li></ul></ul>
  23. 25. Lyme Disease and Horses <ul><li>Spring and Fall  adult tick most active </li></ul><ul><li>Found commonly around head, throatlatch area, belly, under tail </li></ul><ul><li>Prompt removal of tick reduces risk of infection </li></ul><ul><li>Most common signs = behavioral changes and shifting lameness </li></ul>
  24. 26. Lyme Disease and Horses <ul><li>Diagnosis is difficult – VERY political! </li></ul><ul><ul><li>Blood test detects antibodies/exposure to bacteria </li></ul></ul><ul><ul><li>History of tick exposure (or endemic area) </li></ul></ul><ul><ul><li>Veterinary clinical exam suggestive of Lyme disease </li></ul></ul><ul><ul><li>Elimination of other possible diagnoses (lameness exams, x-rays, blood work for other diseases, etc.) </li></ul></ul><ul><ul><li>Positive blood tests for Lyme Disease </li></ul></ul>
  25. 27. Lyme Disease Treatment <ul><li>Antibiotics – </li></ul><ul><ul><li>“ Gold Standard” = IV Tetracycline (6.6 mg/kg) for 10 days followed by oral doxycycline for 30 days </li></ul></ul><ul><ul><li>Oral doxycycline alone more common (10 mg/kg 2x per day) </li></ul></ul><ul><ul><li>Several weeks – with response to therapy within 2-5 days </li></ul></ul><ul><ul><li>Monitor titers </li></ul></ul><ul><li>Anti-inflammatories </li></ul><ul><li>Pro-biotics to replenish gut microbes killed by antibiotics </li></ul><ul><li>Side Effects! </li></ul>
  26. 28. Lyme Disease Prevention <ul><li>No Vaccine licensed for horses </li></ul><ul><li>TICK CONTROL!! </li></ul><ul><li>Daily grooming and removal of ticks </li></ul><ul><li>Tick repellents applied to head, neck, legs, belly and under tail </li></ul><ul><ul><li>Permethrin or DEET are particularly effective </li></ul></ul><ul><li>Keep pastures mown </li></ul><ul><li>Remove brush, woodpiles, etc. to decrease rodent nesting areas </li></ul>
  27. 29. Mosquitoes <ul><li>May be encountered day and night </li></ul><ul><li>Many different species </li></ul><ul><li>Attracted to incandescent light but not to fluorescent light! </li></ul>
  28. 30. Lice <ul><li>Most common of external parasites </li></ul><ul><li>Two varieties: </li></ul><ul><ul><li>Chewing/Biting – feed on skin cells </li></ul></ul><ul><ul><li>Sucking – feed on blood </li></ul></ul><ul><li>Horse with lice: </li></ul><ul><ul><li>Heavy dandruff </li></ul></ul><ul><ul><li>Greasy skin </li></ul></ul><ul><ul><li>Bald spots </li></ul></ul>
  29. 31. Lice <ul><li>Can cause weight loss, general unthriftiness, anemia </li></ul><ul><li>Winter  spring problem! </li></ul><ul><li>Lice are host-specific and spend their entire lives on the animal! </li></ul><ul><li>Transmitted by direct contact </li></ul><ul><li>Control with pesticide </li></ul>
  30. 32. Mites <ul><li>Microscopic! </li></ul><ul><li>Can cause mange </li></ul><ul><ul><li>Sarcoptic mites (head neck, shoulders, flanks, abdomen) </li></ul></ul><ul><ul><li>Psoroptic/scab mites – skin surface  gooey scabs and crusts </li></ul></ul><ul><ul><li>Chorioptic mites  most common, seen on skin, cause scaling on legs “Clydesdale itch” </li></ul></ul>
  31. 34. Psoroptic Mange…
  32. 35. Fly Control
  33. 36. More Fly Control
  34. 37. Premise Control <ul><li>Control standing water </li></ul><ul><li>Compost manure far away from animals </li></ul><ul><li>Chain-drag fields and paddocks </li></ul><ul><li>Feed pelleted feed vs. sweet feed </li></ul><ul><li>Stall fans </li></ul><ul><li>Spray barn with Permectrin or Buzz Off </li></ul>

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