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Flashcards in infect dz prev equine (Mallicote) Deck (69):
1

Vaccination guidelines

  • vaccinate all the horses at the same time
  • consider seasonal incidence of diseases
  • follow manufacturer's recommendations 
    • storage
    • handling
    • administration

2

Record

administration and any reaction

-manufacturer warranty

3

Vaccine efficacy

  • Depends on type of vaccine and route of administration
  • Individual response to vaccination may be affected by 
    • stress
    • illness
    • nutrition
    • concurrent medications
    • presence of colostral antibodies

4

Vaccination of foals

  • Foals usually require 3
    • begin at 6 months old
    • 6 weeks later give booster
    • more shots 2 months later
  • exceptions
    • maternal interference

5

Vaccine Titers

  • no research to establish protective titers or challenge duration of immunity
  • prolonging intervals may leave horses at risk of disease
  • horses aren't good at mounting immune responses

6

Core vaccines def

prevent life-threatening dz

7

Risk based vaccines

minimize or eliminate diseases that affect performance or herd health

8

The core vaccines

  • Tetanus
  • Encephalidities
    • EEE, WEE, West Nile virus
  • Rabies

9

Tetanus

about

  • Clostridium tetani
  • Neurologic disease
  • present in intestines, manure, soil
  • spores can exist for years in soil
  • spores enter horse through wounds, lacerations, umbilicus

10

Tetanus

Clinical signs

  • stiff gait, facial muscle spasm, third eyelid prolapse
  • Sawhorse stance
  • Excessive response to external stimuli
    • noise, touch
  • Recumbency

11

Tetanus

TX

  • Sedatives, muscle relaxants
  • tetanus antitoxin
  • Penicillin or metronidazole

12

Tetanus

Prevention

  • Not contagious
  • mortality: 80%
  • All horses should be vaccinated annually
    • tetanus toicoid vaccine, safe and good protection
    • tetanus antitoxin for previously unvaccinated horses or neonates
      • risk serum sickness
  • Booster if open wound or sx procedure > 6 months since vaccine

13

Tetanus

prevention foals

  • begin at 6 months old if foal received colostrum from vaccinated mare
    • first dose 4-6 mo
    • booster 4-6 weeks later
    • then @ 10-12 months

14

Viral encephalomyelitis

  • Diseases
    • Eastern Equine Encephalomyelitis (alphavirus)
      • more common than western
    • Wester Equine Encephalomyelitis (alphavirus)
    • Venezuelan Equine Encephalomyelitis (alphavirus)
      • foreign animal dz
    • West Nile Virus (flavivirus)
      • seen first in 2001
  • Arboviruses

15

Life cycle and host status of viral encephalomyelitises

  • life cycle involves birds and mosquitos
  • dead end hosts involves people and horses

16

Mortality of viral encephalomyelitises

  • EEE: 75-90%
  • WEE: 19-50%
  • VEE: 40-90%
  • WNV: 30-35%

17

WNV

CS

  • muscle fasciculations: head/neck
  • fever
  • weakness/ataxia
  • flaccid paralysis
  • changes in mentation
  • cranial nerve deficits

18

EEE

Clinical signs

  • neuro signs 5 days after exposure
  • death 2-3 days later
  • low grade fever first
    • viremia for 2 days
  • fever (up to 106 deg F)
    • during viral proliferation

19

EEE

Behavoir change

  • irritable
  • somnolent
  • self-mutilation
  • hyperesthesia
  • hyperexcitable
  • dec food/water consumpt

20

EEE

Neuro signs

  • dementia
    • head-pressing
    • leaning against wall
    • compulsive walking
    • blindness
  • progressing to seizures

21

Reportability encephalitis

  • In Florida reportable
    • can be a sign of increased risk
  • public health dep does good surveillance of arboviruses

22

summary encephalomyelitis

  • EEE mortality: 75-95%
  • EEE-cerebral cortex
  • WNV mortality: 30-33%
  • WNV - mind-hind Brain/Spinal cord
  • vaccination = prevention

23

EEE vaccination

  • In Florida booster EEE/WEE every 4-6 months
  • Naive horses
    • 2 vaccinations 3-4 weeks apart
  • Time to booster
    • 1 month prior to peak mosquito season

24

West Nile - vaccination

  • Depends on vaccine used
    • fort dodge innovator/Boehringer Ingelheim: 2 times a year
    • merial recombitec - 1 time a year
    • intervet PreveNile - 1 time a year

25

EEE/WNV

vaccination Broodmares and foals

  • Broodmares
    • 30-60 days prior to foaling
  • Foals
    • begin vaccination series at 3-4 months
      • maternal antibody interference
      • subclinical exposure
    • need 3 vaccines as foals

26

Rabies

  • Exposure of horses to potentially infected wildlife
  • most common reservoir in FL is Racoons
  • Horses = contact between people and wildlife

27

Rabies public health concerns

  • fatality is 100% in humans and animals
  • cost of post-exposure treatment
    • money, time, personnell
    • number of people exposed

28

Rabies

CS

  • Rabies can look like anything
  • incubation 2-9 weeks
  • dumb form
  • furious form
  • ascending paralysis

29

Rabies Vaccination

  • Annual vaccine - Killed vax IM
  • Foals
    • begin at 6 months
    • boost 4-6 weeks later
    • boost at 10-12 mos

*DDX for the rabies case was EEE (but signs progressed too quickly-one day)

30

Risk based vaccines

(Common)

  • Influenza
  • Equine herpesvirus (Rhinopneumonitis)
  • Strangles

31

Equine Influenza (about)

  • Incubation period: 1-3 days
  • Susceptible population < 3 years old
  • Stressful conditions/travel

32

Influenza

Clinical signs

  • High fever (1-5 days)
  • Cough (several weeks) and nasal d/c
  • lethargy, depression
  • reduced appetite
  • muscle soreness

*rest is essential: 1 week off per day of fever (risk for secondary bact infections)

33

Equine Influenza

vaccination

  • vaccinate every 6-12 months (young traveling horses, show horses, sale horses, horses in training)
    • decreases viral shedding
  • 3 vaccine types
    • traditional inactivated IM
    • Modified live cold-adapted IN
    • Canarypox vector vaccine IM

34

Influenza

vaccination of foals and broodmares

  • Broodmares
    • give IM vaccine in last 30 days pregnancy
  • vaccinate foals at 6 months of age

*Mallicote is ok with pushing flu and rhino to 7/8 months (prolonged immunity from dam)

35

EHV

  • EHV 1
    • abortion, neonatal death, neurologic dz, respiratory dz
      • fever and nasal d/c prior to neuro signs
  • EHV 4
    • respiratory dz

*aka: rhinopneumonitis

36

Equine herpesvirus - respiratory CS

  • Nearly identical to influenza
  • incubation time 2-10 days
  • shed virus for 2-3 weeks
  • most common in weanlings and yearlings

37

How is EHV transmitted?

  • respiratory route
  • contaminated equiptment
  • many horse carriers with no evidence of clinical signs
  • stress can recrudesce

38

Prevention of respiratory EHV

  • vaccination decreases shedding of virus and severity of clinical signs
  • Foals and weanlings
    • start between 4-6 months
      • vaccinate 4 weeks later
      • third dose at 10-12 months
  • Yearlings
    • every 6 months

39

EHV abortion

  • typically occurs 7-9 months gestation

40

Vaccination of Broodmares EHV

  • Pregnant mares
    • booster at 5, 7, 9 months pregnancy to prevent abortion
  • Vaccinate 30 days prior to foaling for colostral immunity
    • EHV 1
    • EHV 4

41

EHV 1 Neurological dz

  • usually  happens after resp signs
  • dog sitting common
  • considered contagious
  • 'neurotropic' strain has high mortality
  • can look like anything
  • vaccination does not prevent dz
    • MLV vaccine may minimize clinical dz and reduce viral shedding

42

Control of outbreaks - EHV

  • Iso all new arrivals for 21 days
  • disinfect transport vans
  • Iso horses with fever: check 2x a day
  • keep aborted material away from herd
    • lost of virus in aborted material
    • isolate mare

43

Strangles

  • streptococcus equi equi
  • reportable dz in Florida
    • variable between states

44

Strangles

CS

  • Fever (102-105)
  • lymph node enlargement and abscessation
  • purulent nasal discharge
  • respiratory distress
    • retropharyngeal lymph node enlargement

45

Transmission strangles

  • Transmission: ingestion or inhalation of infected d/c
    • horse to horse contact
    • fomites (humans)
    • highly contagious
  • High morbidity, low mortality

46

Incubation of strangles

  • incubation period 3-14 days
  • isolate horses with a fever asap
  • shedding of bacteria does not begin until 1-2 days after pyrexia onset
  • Use PCR and culture of pharynx/GP to detect disease

47

Strangles infectious for 

  • at least 4 weeks after clinical signs resolve
    • nasal d/c
  • guttural pouch is clear
    • more testing may indicate sooner safe period but expensive
  • after guttural pouch samples are negative

48

Confirming strangles

  • Nasal/pharyngeal culture
    • supposedly gold standard
  • PCR: nasal swab or nasal flush/guttural pouches (90$)
    • recent outbreaks: three neg PCR to be released from quarantine
    • ideal to sample back of airway instead of just nasal swab
  • Serology for SeM protein
    • helpful for confirming purpura or bastard strangles
    • weak positive - repeat in 7-14 days
    • mod positive - exposure in last 2-3 weeks and/or infection in last 6 mo to 2 yrs
    • high positive - complications of S. equi infections or recent vaccination

49

Hygiene in strangles outbreak

  • protective clothing
  • gloves, booties
  • foot baths
  • disinfect stables/transport vehicles
  • rest pastures - 4 weeks (may be excessively long)

50

Strangles vaccination

  • not perfect, adverse side-effects
  • use on farms previosly effected
  • farms with young stock
  • sale/show stables

51

Types of strangles vaccines

  • M-protein based given IM
    • strepguard
    • strepvaxII (2-3 initial series)
  • Need to booster 1-2 times a year
  • Can cause abscesses at injection site and purpura
  • Start vaccination at 4-6 months of age

52

Strangles IN vaccine

  • Pinnacle IN (3 initial vaccines)
  • may be more effective
    • won't induce colostral immunity
  • can cause abscesses
  • start vaccination at 6-9 months of age
  • Do this last or only

*Pinnacle will pay for testing if horse is sick after vaccine

53

Strangles vaccine risks

  • immune mediated purpura hemorrhagica
  • mild form of the dz
  • abscess formation
  • no vaccination in face of dz => purpura hemorrhagica

54

Regionally used vaccine

  • Botulism
    • KY, PA-broodmares
  • Potomac Horse Fever
  • Equine Viral Arteritis (EVA)
  • Rotavirus
    • Endemic farms

55

Botulism

  • Toxicoinfectious botulism
    • shaker foal syndrome
    • forage poisoning (round bale with rotten middle)
  • Toxin blocks transmission of impulses in nerves
    • weakness, dysphagia, death
    • flaccid paralysis
  • Most horses affected by types B and C
  • Endemic areas
    • kentucky, mid-Atlantic seaboard states

*very regional dz

56

Botulism vaccination

  • Equine vaccine for type B toxoid
    • no cross protection
    • type C toxoid not approved for horses
  • Vaccination recommended in pregnant mares in endemic areas
    • prevent disease in foals
    • give last trimester

57

Potomac Horse Fever

  • Neorickettsia risticii (parasites in fresh water snails and mayflies)
    • endemic to eastern US and CA
    • seasonal: July-September
  • Transmission through trematode parasites of fresh water snails
    • horses eat caddis flies

58

Potomac Horse Fever

CS

TX

  • Clinical signs
    • severe diarrhea, fever (102-107 deg F)
    • Laminitis (secondary)
  • Treatment
    • oxytetracycline, supportive care

59

PHF vaccination

  • questionable efficacy
    • lack of seroconversion
    • vaccine is only 1 strain (multiple strains exist)
  • Initial series: 2 doses 3-4 weeks apart
  • Booster every 6-12 months
  • Appears to lessen severity of disease

60

Equine Viral Arteritis

  • Abortion is main concern
  • Transmission: respiratory / semen
  • Diagnosis - EVA titers and virus iso

*ventral and limb edema, respiratory signs, vasculitis (causes the abortion)

 

61

EVA Vaccination

  • Used to control EVA outbreaks, to prevent transmission from carrier stallions to unaffected broodmares
  • Seroconversion caused by vaccination may interfere with requirements for export of semen or stallions
    • document negative blood test before vaccination
  • Vaccine: modified life, approved for use in stallions and open mares
  • Vaccinate colts 6-12 months of age
    • seronegative mares if bred to infected stallion

62

Rotavirus

  • Coronavirus
  • Most common cause of infectious diarrhea in foals
  • CS
    • profuse watery diarrhea, fever, lethargy
  • highly contagious

63

Rotavirus

TX

Prevention

  • TX
    • Supportive care
  • Prevention
    • vaccination of pregnant mares before foaling in endemic herds may provide some protection

64

Lyme disease

  • some practitioners use canine lyme vaccine in endemic areas
    • some evidence of seroconversion
    • off label
  • DX and TX are challenging

65

Leptospirosis

  • associated with recurrent uveitis, kidney infections, abortion
    • no evidence if vaccine will help/hurt in cases of ERU (equine recurrent uveitis)
  • not currently labeled for pregnant mares

66

Equine Infectious Anemia

  • Retrovirus
  • transmitted by biting flies or blood contaminated needles
    • flies don't harbor will be on mouthparts
  • Acute:
    • fever, depression, petechiation
  • Chronic:
    • icterus, anemia, dependent edema

67

EIA control

  • Coggins test (AGID) or ELISA
    • control program instituted after test developed in 70s
    • some asymptomatic carriers remain
  • Need negative test q 6-12 months
    • travel, show, heath certificates
  • reportable in all states
  • positives tests require euthanasia

68

Piroplasmosis

  • Tickborne
    • Theileria equi (formerly Babesia equi)
    • Babesia caballi
  • Transmission
    • tick-borne disease (Dermacentor nitens)
    • mechanical vector transission
  • US considered non-endemic
    • no tick vectors except southern texas
    • treated as FAD
    • International events quarantine horses from endemic areas

69

Piroplasmosis

CS

DX

  • CS (mild or severe)
    • chronic: weak, dec appetite
    • Acute: fever, anemia, jaundice, hemogobinuria
  • DX: cELISA
    • all imports must be tested