Transcript Preventative Health Program for Horses

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
togive 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
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
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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.
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
• 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
• 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
• 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
• 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
• 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.
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!
Questions