Transcript Vaccination Program for Horses4

Preventative
Health Program
for Horses
Vaccinations
CTVT pages 228-236
LACP 314-316
Overview
General overview
• History
• Physical examination
• Why vaccinate?
• How do I vaccinate?
• What diseases should
I vaccinate for?
• When should I
vaccinate
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.
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
Why Vaccinate?
Prevent some FATAL diseases
• Rabies
• Tetanus
• Encephalomyelitis (EEE/WEE/VEE)
• WNV
How vaccines work:
• Passive
Immunization
How vaccines work:
• Active Immunization
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
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
How?
• Most vaccines are given IM (in
muscle)
• Some are available to give IN
(intranasal)
􀂄 Influenza
􀂄 Strangles
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.
Vaccine Reactions
• Anaphylactoid reactions:
allergic reactions
• Fever
• Lameness
• Swelling or abscess formation
at the injection site
What should I vaccinate for?
ALL HORSES
• Tetanus
• Encephalomyelitis
• West Nile Virus
• Rabies
(Risk-based vaccines)
MOST/PERFORMANCE
• Influenza
• Equine Herpesvirus
SOME
• Strangles
• Potomac Horse Fever
• Botulism
• Rotavirus
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.
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
Clinical Signs of Tetanus
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Muscle stiffness
Sawhorse stance
Third eyelid prolapse
Lockjaw
Flaring nostrils
Hypersensitive to touch
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.
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
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
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 mosquitos.
• In areas where winter freezes are uncommon,
semiannual vaccination may be advisable.
EEE is a mosquito spread disease of birds that
Sometimes is transmitted via a mosquito bite
To horses and people.
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
Clinical Signs of Encephalomyelitis
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Result from inflammation of the brain and/or spinal cord
Fever
Depression
Staggering gait (ataxia)
Paralysis
Seizures
Abnormal Mentation
Abnormal Gait - Ataxia
Encephalomyelitis
• EEE/VEE – mortality rate 70-90%
die
• WEE – mortality rate about 50%
• Vaccination is safe and generally
very effective against these
diseases
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
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.
West Nile Vaccine
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Another mosquito transmitted virus
Humans and horses are dead-end hosts.
Spread by mosquitoes-Culicoides spp. and some birds.
Prevalent throughout the U.S.
Causes inflammation of the brain an spinal cord
Not contagious from horse to horse
Clinical Signs of West Nile
Virus
Can vary
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Fever
Muscle tremors
Incoordination/ ataxia
Hypersensitive
Facial nerve or other paralysis
West Nile Virus
• Mortality rate about 33%
• Associated with inability to stand, prolonged
recumbency
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
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.
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.
Equine Influenza
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Incubation period 1-3 days
High fever (1-5 days)
Young horses are at risk!
Spread by aerosolized droplets, infected fomites – highly
contagious
Equine Influenza – Clinical Signs
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Cough (several weeks) and fever
Lethargy, depression, reduced appetite, muscle soreness
Nasal discharge
Most horses recover in 10-14 days with supportive care
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
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)
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
Strangles – Clinical Signs
• Cough, fever, lymph node
enlargement
• Respiratory distress due
to retropharyngeal lymph
node enlargement
• Complications
-Purpura
-Metastatic (“Bastard”)
strangles
Vaccination for Strangles
• Previously affected
farms
• May lessen disease
severity
• Vaccine reactions
-Purpura
-Abscesses if IM
vaccines become
contaminated
• Annual booster
• Intranasal vaccine
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.
Potomac Horse Fever Vaccine
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It is believed that aquatic insects are the vectors: 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.
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.
Botulism
Clostridium botulinum
• Causes flaccid paralysis
• Endemic in KY
• 2 Forms
􀂄 Shaker foal syndrome
􀂄 Forage poisoning
• Vaccinate for type B usually in broodmares
Anthrax Vaccine
• Anthrax vaccines are available for use but are not widely
used except where a genuine risk is identified.
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!
Clinical Signs of Rabies
• Can look like anything!
• Behavioral changes,
blindness
• Ataxia and
incoordination
• Fever
• Hypersalivation
• Paralysis
• Colic
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.
When to vaccinate - Rabies
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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
Rotavirus
• Most common cause of infectious diarrhea in foals
• Clinical Signs- profuse watery diarrhea, fever, lethargy
• Highly contagious
Rotavirus Vaccination
• Prevention- vaccination of pregnant mares 30 days
before foaling in endemic herds may confer modest
protection
Vaccine
Pleasure or
Show
Pregnant
Mare
Pasture
Horse
Boarding
Facility
Weanling
(> 6 mo)
Frequency
EEE/WEE*
X
X
X
X
X
X
X
X
X
X
Annual
Rabies*
X
X
X
X
X
Annual
Tetanus*
X
X
X
X
X
Annual
Herpes
(Rhino)
X
X
X
+/-
Q6
months
Influenza
X
X
X
+/-
Q6
months
Strangles
X
+/-
X
+/-
+/+/-
Annual
+/-
X
+/-
Maternal
Protect
High rate of
West Nile
Virus*
PHF
EPM
Botulism
Atlantic
states
High rate of
May/Sept
April/June
Management Practices
• Quarantine and monitoring of new
horses
• Isolation facility and protocol
• Requirements prior to introduction
of new horse
• Separation of groups of horses
according to use, susceptibility to
infection
Management Practices
• Vector control
• Management of sick horses
• Keep good records!
THE END FOLKS….