EQUINE RESPIRATORY DISEASES

1. EQUINE RESPIRATORY DISEASES Strangles Influenza Equine herpesvirus Equine viral arteritis Recurrent airway obstruction (RAO)

2. RECURRENT AIRWAY OBSTRUCTION (RAO)A.KA. HEAVES • Formerly known as Chronic obstructive pulmonary disease (COPD) • Also known as “broken wind” • Chronic, noninfectious respiratory disease • Thought to be an allergic airway disease that causes bronchoconstriction & excessive mucous production

3. HEAVE LINE

5. RAO - TREATMENT • House in a dust-free environment • Outside is best (pasture) • Pelleted rations vs. hay • Medications • No long-term scientific data to support any one treatment medically • http://www.youtube.com/watch?v=zJRoYWjVfbk

6. EQUINE VIRAL ARTERITIS (EVA) • 1st isolated in Ohio in 1953 • Togaviridae • Reportable disease • Most cases are subclinical

11. EVA VIRUS SURVIVAL • Inactivated by lipid solvents • Inactivated by common disinfectants & detergents • Eva survives 75 days at 4c • Will survive in frozen semen

12. EVA - PREVENTION • Vaccine available • All mares should be vaccinated three weeks prior to breeding • Modified live attenuated virus (in the US) • Quarantine for carrier stallions • Have stallions routinely tested

13. STRANGLES • Streptococcus equi • Name – some untreated horses sound like they are strangling • Most commonly affects horses 1-5 years of age, but can affect horses of any age • Worldwide • Contagious

14. STRANGLES

15. STRANGLES - CLINICAL SIGNS

16. STRANGLES - PREVENTION • Vaccination available – however has the potential to cause the dz. • Isolation – recovered horses can remain contagious for up to 6 weeks after recovering from clinical dz.

17. Strangles

20. EQUINE INFLUENZA VIRUS • Orthomyxovirdae family • Genera: Influenza A, B, C, Thogoto and Isa viruses • Horses get Influenza A virus • Influenza A also infects human beings, swine and avian species • On rare occasions will jump to different species • In 2000, an Equine Influenza A virus spread to some dogs

21. EQUINE INFLUENZA VIRUS

22. EQUINE INFLUENZA VIRUS • Virus rapidly mutates, frequently producing different strains • Highly contagious • Most common respiratory virus • Spreads rapidly • “Explosive Outbreaks” • 2 – 3 year-old horses most commonly affected

23. EQUINE INFLUENZA VIRUS • The lower respiratory track is primarily affected in foals • Can develop bronchopneumonia • The upper respiratory track is primarily affected in adult horses

24. EQUINE INFLUENZA VIRUS • Infected animals shed the virus for 1-8 days • Short incubation period • Typically 48-72 hours, but can be as short as 24 hours

25. EQUINE INFLUENZA VIRUSTransmission • Inhalation of virus – air born • Direct contact w/nasal secretions • Fomites – water buckets, feed bins, etc.

26. EQUINE INFLUENZA VIRUSClinical Signs • Rapid onset • exposed horses can get sick in 24 hours, 1-3 days is typical • Lethargy, weakness, Decreased appetite • Fever – typically around 104, but can exceed 106

27. EQUINE INFLUENZA VIRUSClinical Signs • Nonproductive cough • Hacking cough • Mucopurulent discharge • Retropharyngeal lyphadenopathy is not uncommon • Tachypnea

28. EQUINE INFLUENZA VIRUSDiagnosis • C.S. typically clear up in 7-14 days, however in more severe cases the cough can last up to 21 days • A history of “Explosive Outbreak” in barn or area • Fever for less than 5 days • Mucopurulent discharge • Demonstrate acute & convalescent antibody titers 3-4 weeks apart

29. EQUINE INFLUENZA VIRUSTreatment • Symptomatic treatment • NSAIDs • Isolation if possible • Antiviral medication • Strict rest (stall) - 1 week for each day the horse had a fever - Can be longer – up to 2-3 months - Hand walking only

30. EQUINE INFLUENZA VIRUSPrevention • Adequate nutrition • Regular vaccination • Regular exercise followed by adequate rest between workouts • Proper ventilation and sanitation in barn • Quarantine new horses for two weeks before introduction to herd

31. EQUINE HERPESVIRUSRhinopneumonitis • EHV-1 & EHV-4 are the two strains of importance • EHV-1 – Causes abortion, CNS, death • The neurologic form of EHV-1 is called Equine Herpesvirus Myeloencephalopathy (EHM) • EHV-4 – Respiratory signs

32. EQUINE HERPESVIRUSRhinopneumonitis • There are four separate syndromes • Respiratory – most common • Abortion storms – have become increasingly rare • Neonatal • Neurologic

33. EQUINE HERPES VIRUS

34. EQUINE HERPESVIRUS • Incubation period is typically 2-10 days • Rapidly spreads thru a herd • High morbidity • Low mortality (non-neuro form) • Infected horses are typically ill for 4-5 days

35. EQUINE HERPESVIRUSTransmission • Inhalation – air born • Fomites • Carrier animal

36. EQUINE HERPESVIRUSClinical Signs – Respiratory Signs • Runny nose • Conjunctivitis • Anorexia • Malaise • Dry cough • Secondary bacterial infections • Lymph node involvement – submandibular & retropharyngeal • Fever (102-106F)

37. EQUINE HERPESVIRUSTreatment • Usually self limiting • Give antibiotics if secondary bacterial infection develops • Stall rest • NSAIDS • Isolation of infected animals • Disinfect environment

38. EQUINE HERPESVIRUSClinical Signs – Neurological • Neurological signs appear as a result of damage to blood vessels in the brain and spinal cord associated with EHV infection. • Mild ataxia which may progress to complete recumbency – inability to rise • Inability to urinate • Poor anal tone • Recovery in 2-3 months if at all

39. EQUINE HERPESVIRUSTreatment - Neuro • Keep animal clean to prevent urine scalding • Keep animal up – sling • Keep plenty of clean bedding in stall • Monitor for development of decubital ulcers or urine scalding • Keep tail clean from both feces & urine • Supportive care

40. EQUINE HERPESVIRUSPrevention • Isolate new horses for 3-4 weeks • Reduce stress • Vaccine available, but effectiveness for EHM is very limited • Don’t share equipment between horses at events

41. EQUINE HERPESVIRUSAbortion Storms • EHV can be asymptomatic in mares • The mare is exposed to EHV during gestation • Then abortion storms occur weeks to months later

42. EQUINE HERPESVIRUSAbortion Storms • The most infectious cause of abortions • ¼ of all diagnosed abortions are due to EHV • The future breeding of the mare is not affected • Vaccinate according to schedule

43. EQUINE HERPESVIRUSOutbreak 2011 • National Cutting Horse Association (NCHA) Western National Championship event in Ogden, Utah April 29 – May 9, 2011 • State and Federal official contacted all owners and quarantined and monitored all animals thought to have been exposed at the event – 421 horses in total

44. EQUINE HERPESVIRUSOutbreak 2011 • Once those exposed horses went back to their homes states and exposed other horses – 1,685 now had to be monitored • A total of 242 individual premises were affected

45. EQUINE HERPESVIRUSOutbreak 2011 • EHV-1 in the neurological form (EHM) was implicated • A total of 90 confirmed EHV-1 or EHM cases have been reported in 10 states

46. EQUINE HERPESVIRUSOutbreak 2011 • Of those 90 confirmed cases, 54 cases were at the Ogden, Utah event • Out of those 88 cases, 13 horses died from the disease or were euthanized by June 8th, 2011 • 10 were at the event, 3 were exposed by animals from the event

47. EQUINE HERPESVIRUSOutbreak 2011 • http://www.youtube.com/watch?v=JpgNzlnZAO8