Horse Health and Disease: Lesson 3
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- What is preventative medicine?
- Procedures done on a routine basis to protect and insure peak performance of a horse.
- What are some examples of preventative procedures?
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-deworming
-vaccinations
-tooth care
-hoof care
-Coggins testing - Which horses have parasites?
- ALL horses except foals immediately after birth (no transplacental infections).
- What two situations can give rise to parasitic problems?
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-too many parasites (acute infestation)
-stress on host - What are some stress factors to a horse?
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-disease
-malnutrition
-work
-pregnancy
-lactation
-shipping - What injurious effects can parasites do? (6)
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-blood loss
-tissue destruction
-mechanical obstruction
-intoxification
-competition for nutrition
-carry disease - What affects the depth of injury from parasites?
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-number of parasites
-pathogenic potential
-resistance status of host
-acute vs chronic - What are some signs a horse has internal parasites?
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-underweight
-pot bellied
-rough hair coat
-dull, listless - What are the blood worms known as?
- Large strongyles
- What is the most common large strongyles?
- Strongylus vulgaris
- What is so important or damaging about Strongylus vulgaris?
- It migrates to the cranial mesenteric artery where it causes severe damage. Embolus' can come lose and lodge in a vessel causing necrosis of GI tract.
- What is the life cycle of Strongylus vulgaris?
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-adults in cecum/lg. colon where they suck blood and damage mucosa.
-eggs out in feces
-eggs develop into infective larvae (can survive for months)
-larvae ingested by horse
-larvae undergo extensive migration to liver, lungs, pancreas, kidneys, and then into cranial mesenteric artery.
-when adults, they return to lg. colon - What is the name of colic possibly responsible for 90% of total colic cases?
- thromboembolic colic
- What are the small strongyles called? Are they problematic?
- cyathostomes are not very problematic.
- Where do you find adult cyathostomes?
- Since migration is limited to intestinal wall, adults are in cecum and intestestinal wall.
- How many species of cyathostomes are there? What are symptoms of them?
- 40-50 species causing weight loss, diarrhea, and colic.
- What are roundworms commonly known as? What is their latin name.
- Ascarids. Parascaris equorum is latin name.
- Which horse most often have ascarids?
- Young horses under 2 y/o. (Resistance develops around 6 months of age.
- How large are roundworms?
- 10-12" long, the largest of all equine endoparasites
- What is the ascarid life cycle?
-
-adults in small intestine
-eggs out in feces
-eggs ingested
-larvae penetrate intestinal wall and migrate to lungs and liver
-horse coughs up and swallows
-matures in small intestine - Describe ascarid eggs and why they're so problematic.
- Ascarid eggs are very resisten and can live for years in stables and pastures. Furthermore, females can lay 200,000 eggs per day.
- What can you do to prevent intestinal blocking during de-worming?
- Split medicine in two doses.
- What are stomach worms known as?
- Habronemiasis
- What are the three species of Habronema?
- Habronema muscae, Habronema microstoma, Draschia megastoma.
- What does Habronema do?
- They cause stomach ulcers and "summer sores".
- How are summer sores developed?
-
-larvae deposited by horse and carried by stable flies
-stable flies deposit eggs in existing wounds or warm, moist areas
-this causes large, non-healing wounds in hypersensitive horses - What are pinworms called?
- Oxyuris equi
- What is a sign of pinworms?
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-The horse rubs it's back end on walls (rupture of gravid female on anus and perineum causing intense pruritis).
-crusts or flakes can be seen around anus. - Where do adults pinworms live?
- distal large colon
- What are tapeworms called?
- cestodiasis
- What are two types of tapeworms?
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Anaplocephala perfoliata
Anaplocephala magna - Where are adult tapeworms found in body and how do they get there?
- Adults found in small and large intestine. They require a mite as an intermediate host and must be ingested.
- What is intussusception?
- The intestine telescopes into itself.
- What can tapeworms cause internally?
- ulcerations and ileo-cecal intussusception
- What are bots?
- The bot fly!
- What are some types of bots?
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Gasterophilus intestinalis,
Gasterophilus nasalis
Gasterophilus hemorroidalis - What is the life cycle of bots?
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-adult deposits eggs on hair of legs, lips, and chin
-humid breath promotes hatching
-larvae migrate through mouth to stomach where they attach
-10 months later they detach and pass out of feces
-they pupate in manure and become adults in 1-2 months. - What are the 6 common ways to diagnose parasitism?
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1) Direct smear
2) Cellophane tape
3) Fecal flotation
4) Quantitative tests
5) Fecal culture
6) Post-mortem - What are the 6 vaccines vet's recommend to do?
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1) Rabies
2) West nile virus
3) influenza
4) rhinopneumonitis
5) tetanus
6) Eastern/Western encephalomyelitis - What neurotoxin causes tetanus?
- Clostridium tetani
- How does tetanospasmin work?
- It blocks the inhibitory neurotransmitter causing extended contraction of muscles.
- What does a horse do if it has tetanus?
- It over-reacts to normal stimuli: trismus (clenched jaw), disphagia (trouble swallowing), anxious expression, erect ears and tail, flared nostrils, prolapsed 3rd eyelid, saw-horse stance.
- How can you prevent tetanus?
- TAT (tetanus antitoxin) at birth (or after wounds), and tetanus toxoid yearly.
- When do you vaccinate with tetanus toxoid?
- give foals first shot at 3-4 months and booster with 2-4 week shot. Continue yearly.
- What disease can be prevented with an Eastern/ Western version of the shot.
- Encephalomyelitis (EEE;WEE)
- What transmits Encephalomyelitis?
- Mosquito's, natural reservoir is birds and rodents.
- Is Encephalomyelitis communicable with other horses?
- No, they are dead-end hosts.
- What does Encephalomyelitis target?
- CNS
- What are the signs of Encephalomyelitis as it attacks the central nervous system?
- dementia, head pressing, circling, depression, dysphagia, weakness, ataxia (drunken behavior), seizures.
- What is the incubation period of Encephalomyelitis?
- 1-3 weeks
- What type of infection is Encephalomyelitis?
- RNA virus (alphavirus)
- What is the Herpes virus?
- Rhinopneumonitis
- What are the 3 forms of Rhinopneumonitis?
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1) respiratory form (most common)
2)abortion form
3) neurologic form - What are the signs of the respiratory form of Rhinopneumonitis?
-
-fever, cough nasal, discharge.
-Found mostly where many young horses congregate - When does abortion occur in Rhinopneumonitis?
- 3rd trimester
- In the neurologic form of Rhinopneumonitis what are the symptoms?
- posterior paresis, ataxia, and paralysis. This may be self limiting and reversible.
- What virus can you vaccinate for of influenza?
- Myxovirus
- What are the symptoms of influenza?
- Upper respiratory signs: fever, depression, cough, nasal discharge.
- Are medicines given for influenza?
- No, it is a virus so ab's are only needed if an infection is secondary to influenza.
- Is influenza communicable with other horses?
- VERY! It often occurs where large groups of horses congregate (like children in schools).
- What preventative vax's can be given for Influenza?
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2 vax, 3weeks apart ~4-6m/o.
Continue yearly or as needed depending on exposure. - What is Rabies also known as?
- Rhabdovirus
- What mammals are primary targets?
- skunks, fox, and racoons
- What is bad about rabies?
- It is always fatal and cases are increasing yearly (3 cases since 1992).
- What is the virus name of West Nile Virus?
- Flavivirus
- Where did West Nile Virus originate from?
- Africa, Asia, and Southern Europe. In 1999, it began in N.Y.
- What are the natural hosts for West Nile Virus?
- birds and mosquitos. mammals are dead-end hosts.
- What is the incubation for West Nile Virus?
- 1-6 days.
- What are clinical signs of West Nile Virus?
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-incoordination
-depression/apprehension
-weakness
-muscle tremors
-fever, anorexia, sweating, teeth grinding - How can you diagnose West Nile Virus? Treatment?
- Use blood tests, CSF tests, and clinical signs. No definative treatment.
- What is the vaccine schedule for West Nile Virus?
- 2-3 vax given at 3 weeks apart prior to mosquito season.
- What is the secondary immune response to a booster called?
- anamnestic response
- What are 6 other available vax's given based on necessity?
-
1) Potomac Horse Fever
2) Strangles
3) Leptospirosis
4) Venezuelan equine encephalomyelitis
5) Equine viral arteritis
6) Equine protozoal myelitis (EPM) - What is Potomac Horse fever called? How does a horse get it?
- Ehrlichia risticii. It is gotten through aquatic insect ingestion.
- What are the signs of Potomac Horse fever?
- fever, depression, diarrhea, founder, fatal in about 30%.
- What is Streptococcus equi commonly know as? Describe it fully.
- A very contagious Strangles. Vax given IN (intranasal). Symptoms include fever, lymph nose abscessation, and snotty nose.
- What are some signs of tooth problems?
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-weight loss
-poor performance
-abnormal chewing
-odor
-colic
-salivation - What is the wolf tooth?
- Vestigial tooth that is usually removed to prevent pain. It is the first Premolor (PM1).
- What do vets check for in routine dental work?
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-Any problem behaviors
-wolf-teeth
-caps
-floating - Why do you pick and clean a horses foot daily?
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Check for material that may cause:
-abscesses
-bruises
-thrush impaction - What is Coggins testing?
- A blood test for antibodies to equine infectious anemia (Lentivirus).
- Who requires Cogins testing?
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-shows and boarders
-interstate travel
-selling of horse (60 days) - What are clinical signs of Lentivirus?
- fever, depression, anemia, and edema
- How long does a Coggins test take to run?
- 48 hours.
- How is Lentivirus spread?
- Through flies and mosquitos as a viral disease.
- Is this communicable with other horses?
- Yes, this is contagious among horses. Some horses can even be carriers and spread it around!
- Which part of the upper teeth in a horse are sharp?
- outside of teeth
- Which part of the bottom teeth in a horse are sharp?
- inside of teeth