Preventative Health Program for Horses

1. Preventative Health Program for Horses Vaccinations CTVT pages 228-236

2. Overview General overview • History • Physical examination • Why vaccinate? • How do I vaccinate? • What diseases should I vaccinate for? • When should I vaccinate

3. Physical Examination • New additions to a stable or established herd should be Coggins’ test-negative for EIA and quarantined for 1 month before introducing them into general population. • Physical Examination: TPR, weight, eyes, dental, musculoskeletal system and skin should be examined. • You must always obtain a history in conjunction with your exam on the horse.

4. Why Vaccinate? • Critical component of a horse health maintenance program • Primes the immune system for a quick response when exposed to infection • Prevent life-threatening diseases • Minimize or eliminate contagious diseases that affect performance or herd health

5. Why Vaccinate? Prevent some FATAL diseases • Rabies • Tetanus • Encephalomyelitis (EEE/WEE/VEE) • WNV

6. How vaccines work: • Passive Immunization

7. How vaccines work: • Active Immunization

8. How vaccines work: • Passive Immunization • Brief period of protection • Antibody absorption one time only • Active Immunization • Prolonged period of protection • Boosting of protective response by additional exposure

9. Vaccination can NOT guarantee disease prevention in all cases • Vaccination should be used in conjunction with good nutrition, deworming, pasture management, and minimizing stress in your herd

10. How? • Most vaccines are given IM (in muscle) • Some are available togive IN (intranasal) 􀂄 Influenza 􀂄 Strangles

11. Technician Note Horses that are immunologically naïve or have An unknown immunization history should Receive an initial immunization, Followed in 4 weeks by a second Immunization.

12. Vaccine Reactions • Anaphylactoid reactions: allergic reactions • Fever • Lameness • Swelling or abscess formation at the injection site

13. ALL HORSES Tetanus Encephalomyelitis West Nile Virus Rabies MOST/PERFORMANCE Influenza Equine Herpesvirus SOME Strangles Potomac Horse Fever Botulism Rotavirus What should I vaccinate for?

14. Tetanus Vaccines • Caused by Clostridium tetani • The toxoid version of this vaccine is given to immunize horses against a disease characterized by muscle rigidity and spasms that may result in respiratory arrest and convulsions. • Administration of antitoxin to unvaccinated horses induces immediate protection that lasts approximately 2 weeks.

15. Tetanus • Caused by bacteria found in soil and ingested by horses or enters a wound. • Called “lockjaw” because it especially effects the muscles of the neck and jaw. • Present in intestine, manure, and soil • Spores can exist for years in soil • Spores enter through wounds, lacerations, umbilicus

16. Clinical Signs of Tetanus • Muscle stiffness • Sawhorse stance • Third eyelid prolapse • Lockjaw • Flaring nostrils • Hypersensitive to touch

17. Stiff legged gait. The muscle of the legs become Rigid and stiff that the horse may fall and not Be able to get up again. Convulsions may Occur and death is caused by paralysis The breathing muscles.

18. Tetanus • Not contagious • Mortality rate is high • All horses should be vaccinated annually • Tetanus toxoid vaccine is safe and provides good protection • Tetanus antitoxin is for previously unvaccinated horses

19. When to vaccinate - Tetanus • Not typically seasonal, vaccinate any time of year • Most horses in spring, in combination with EEE/WEE • Boost if wound or surgery >6 months from last dose

20. Equine Encephalomyelitis Vaccine • EEE=Eastern Equine Encephalomyelitis • WEE=Western Equine Encephalomyelitis • VEE=Venezuelan • Often referred to as “sleeping sickness” • This vaccine protects against a viral neurologic disease transmitted by biting insects. • In areas where winter freezes are uncommon, semiannual vaccination may be advisable.

21. EEE is a mosquito spread disease of birds that Sometimes is transmitted via a mosquito bite To horses and people.

22. Encephalomyelitis • WEE seen throughout North America • EEE seen mostly in the East and Southeast, prevalent in Texas • VEE not in US for many years – reportable foreign disease

23. Clinical Signs of Encephalomyelitis • Result from inflammation of the brain and/or spinal cord • Fever • Depression • Staggering gait (ataxia) • Paralysis • Seizures

24. Abnormal Mentation

25. Abnormal Gait - Ataxia

26. Encephalomyelitis • EEE/VEE – mortality rate 70-90% die • WEE – mortality rate about 50% • Vaccination is safe and generally very effective against these diseases

27. When to Vaccinate – EEE/WEE • ALL horses should be vaccinated annually in the spring, prior to mosquito season • In Texas, recommend boosting every 6 months for EEE/WEE • Foals should receive first dose at 3-4 months of age, and 2 additional doses one month apart

28. ENCEVAC™ Line of Equine Vaccines • For vaccination of healthy horses against Eastern and Western Equine Encephalomyelitis. (Sleeping Sickness). Encevac™ is a formaldehyde inactivated, adjuvanted bivalent equine vaccine consisting of Eastern and Western Equine Encephalomyelitis viruses.

29. West Nile Vaccine • Another mosquito transmitted virus • Humans and horses are dead-end hosts. • Spread by mosquitoes • Prevalent throughout the U.S. • Causes inflammation of the brain an spinal cord • Not contagious from horse to horse

30. Clinical Signs of West Nile Virus Can vary • Fever • Muscle tremors • Incoordination/ ataxia • Hypersensitive • Facial nerve or other paralysis

31. West Nile Virus • Mortality rate about 36% to 44% • Associated with inability to stand, prolonged recumbency

32. When to Vaccinate - WNV • Several vaccines available -Fort Dodge West Nile Innovator – killed -Merial’s RecombiTek – recombinant vaccine -Intervet’s PreveNile – modified live chimera vaccine • Annual vaccination recommended • In Texas and states with larger mosquito populations, may boost every 4-6 months

33. Equine Rhinopneumonitis Vaccine (herpes #1) • Pregnant mares should be vaccinated with this vaccine in the 5th, 7th, and 9th months of gestation to prevent a viral disease whose strains can cause upper respiratory disease, abortions, stillbirths, and weak neonatal foals that fail to survive.

34. Equine Influenza Vaccine • The duration of protective immunity from this vaccine is short-lived, requiring vaccination every 2 to 3 months during periods of exposure. • Disease outbreaks usually occur in horses 1 to 3 yrs. of age after mixing with infected horses at the racetrack or showgrounds.

35. Equine Influenza • Incubation period 1-3 days • High fever (1-5 days) • Young horses are at risk! • Spread by aerosolized droplets, infected fomites – highly contagious

36. Equine Influenza – Clinical Signs • Cough (several weeks) and fever • Lethargy, depression, reduced appetite, muscle soreness • Nasal discharge • Most horses recover in 10-14 days with supportive care

37. When to Vaccinate - Influenza • Intranasal vaccine every 6 months • Intramuscular vaccine every 4 months • Start foals at 9 months of age • FLU AVERT® Intra-nasal spray vaccine for Equine Influenza

38. Strangles Vaccine • Respiratory disease caused by infection with Streptococcus equi. • Spread by mucous or contaminated fomites. What are fomites? • Intranasal and IM vaccines • Vaccination not 100% effective but can lessen the severity of incidence. • 2 Types: Atypically (transient-cold like) and Bastard (spread of infection to the organs)

39. Strangles: Streptococcus equi spp. equi • Transmission: Ingestion or inhalation of infected discharge • Horse-horse contact or fomites • Highly contagious • High morbidity, low mortality • Incubation period 3-5 days

40. Strangles – Clinical Signs • Cough, fever, lymph node enlargement • Respiratory distress due to retropharyngeal lymph node enlargement • Complications -Purpura -Metastatic (“Bastard”) strangles

41. Vaccination for Strangles • Previously affected farms • May lessen disease severity • Vaccine reactions -Purpura -Abscesses if IM vaccines become contaminated • Annual booster • Intranasal vaccine

42. Equine Viral Arteritis • Vaccine induces partial to complete protection against the clinical signs of disease, but if virus challenged the virus can replicate in the animals body. • Clinical signs: fever, depression, nasal discharge, lacrimation, coughing, and limb swelling.

43. Potomac Horse Fever Vaccine • It is believed that aquatic insects are the vectors: ticks, snails • Efficacy of the vaccine is unknown. • Prevalent in the eastern states near large waterways. • Use of this vaccine is usually in areas where it is a problem.

44. Botulism Vaccine • Usually given to mares 30 days prior to foaling for the prevention of shaker foal syndrome. • Given in areas of high incidence geographically.

45. Botulism Clostridium botulinum • Causes flaccid paralysis • Endemic in KY • 2 Forms 􀂄 Shaker foal syndrome 􀂄 Forage poisoning • Vaccinate for type B usually in broodmares

46. Anthrax Vaccine • Anthrax vaccines are available for use but are not widely used except where a genuine risk is identified.

47. Rabies Vaccine • 100% FATAL in all cases • Virus affecting the nervous system • Vaccinate horses where wildlife (skunks, foxes, raccoons, bats) rabies is endemic in the Houston area. • Spinalcord or brainstem signs. • Very, very commonly vaccinated for here in Texas!

48. Clinical Signs of Rabies • Can look like anything! • Behavioral changes, blindness • Ataxia and incoordination • Fever • Hypersalivation • Paralysis • Colic

49. Rabies • The rabies virus is killed by most disinfectants. Only lives in dried saliva or carcass for 24 hours. But it can live for days in refrigerated carcasses.

50. When to vaccinate - Rabies • Incubation period 2-9 weeks • Death in 3-5 days once signs develop • Vaccinate once a year • Vaccine is safe and effective EquiRab, a rabies vaccine designed specifically for horses