Vaccinations Seminar-How to Protect Your Horse

April 26, 2024 93 view(s)

HOW TO PROTECT YOUR HORSE SEMINAR

In-Depth Conversation about Core Vaccinations by Sean Allison, DVM from Cleveland Equine Clinic

CLICK HERE -- PRESENTATION

CLICK HERE -- VIDEO

What core vaccinations does your horse need? Why is a coggins important?

Talk about EHV-1 and what precautions you should take.

What is a vaccine?

Per Britannica a vaccine is a suspension of weakened, killed, or fragmented microorganisms or toxins or other biological preparation, such as those consisting of antibodies, lymphocytes or messenger RNA, that is administered primarily to prevent disease…
Basically a weakened version of a disease that is given to promote an immune response and cause the body to create antibodies for that disease
It causes an immune response but does not cause the disease itself

What can they protect and treat?

Viruses: West Nile, Herpes 1-4, EEE/WEE
Bacteria: Tetanus, strangles, botulism
Fungus: Treatment of Equine Pythiosis
Melanoma: Treatment of equine melanoma (Oncept)

Vaccine Types

Live (attenuated): Weakened form of disease
Modified Live
Recombitant: Uses small piece of bacteria or virus
Inactivated/killed: Also use a piece or part of a virus/bacteria

A few facts

Vaccines do NOT prevent an animal from contracting a disease, rather minimize the risk
Immunity decreases with lack of proper vaccination
Typically vaccines initially require a booster(s)
Vaccines do not afford immediate protection to a disease
Occasionally there can be reactions to the vaccine, very rarely can be severe

Core Vaccines

American Veterinary Medical Association (AVMA) defines as those that protect from disease that are endemic to a region, those with potential public health significance, required by law, virulent/highly infections, and/or those that posing a risk of significant disease
These types of vaccines show enough benefit and low enough level of risk to justify their use
Core Vaccines: West Nile Virus (WNV), Eastern and Western Encephalitis (EEE/WEE), Tetanus, Rabies (per AAEP)

Risk Based Vaccines

Equine Influenza
Equine Herpes 1-4 (Rhinopneumonitis) i.e. EHV 1-4
Potomac Horse Fever (PHF)
Strangles
Botulism
Leptospirosis
Anthrax, Rotavirus, Snake bite, Venezuelan Encephalitis, Equine Viral Arteritis (EVA) (per AAEP)

Broodmare Vaccination Schedule

EHV 1→ Pneumabort:
Give at 3, 5, 7, and 9 months
Pre-foaling vaccines:
Tetanus, WNV, EEE &WEE, Rabies, PHF, EHV 1/4
Give 4-6 weeks prior to foaling

CEC Protocol

Potomac Horse Fever (annual)
Rabies (annual)
Eastern/Western Encephalitis (annual)
West Nile Virus (annual)
Equine Herpes 1-4 (bi-annual)
Influenza( bi-annual)
Tetanus (*annual)

West Nile Virus

Virus
Leading cause of arboravirus encephalitis (inflammation of tissue of brain) in humans and horses
Transmitted by mosquitos but carried by birds
Not directly contagious from horse to horse
Highly unlikely a horse with disease can pass to another horse via mosquito
Vaccine- annually (spring):
Inactivated
Recombinant
Diagnosed with blood or tissue sample

West Nile Virus Clinical Signs

Neurologic signs:
Hind limb weakness, circling, muscle fasciculations, impaired vision, inability to swallow, hyperexcitability, paralysis, seizures, death
Loss of appetite
Depression (impaired mentation)
Fever
Blindness

West Nile Treatment

Supportive care:
Fluids
Oral/intravenous feeding
Anti inflammatory drugs
Slinging

Eastern & Western Equine Encephalitis

Transmitted via mosquito
Virus
Birds are reservoir
Horses dead end host (as are people)
EEE fast acting and highly fatal
WEE less deadly compared to EEE
Vaccine- annually (spring):
Killed
Diagnosed by blood test or cerebral spinal fluid (CSF)

WEE and EEE Clinical Signs

Fever
Impaired vision
Depression
Ataxia
Head pressing
Paralysis
Convulsions
Coma and death

WEE and EEE Treatment

Supportive care
Corticosteroids

Rabies

Virus
Zoonotic
Carried by mammals and passed via bites, scratches, and saliva
Horses are very susceptible but relatively rare
Once clinical signs seen, death is typically inevitable
Reportable disease in the US
Vaccine:
inactivated

Rabies Clinical Signs

Ataxia and muscle weakness
Sensitivity to touch
Loss of sensory perception
Fever
Self mutilation
Aggressive behavior
Drooling and inability to swallow
Death
Furious vs paralytic (stuporous) form**

Rabies Treatment

No treatment
IF properly vaccinated post vaccine booster dose needed

Equine Influenza

One of the most common respiratory diseases of horses
Virus
Highly contagious
Transmitted via coughing, droplets and fomites
Diagnosed via nasal swab PCR
Vaccine options:
Inactivated given in muscle
Modified live given intranasal

Equine Influenza Clinical Signs

Virus effects cells of throat and causes horse to be susceptible to bacterial infection
Fever
Nasal discharge
Cough
Lethargy and loss of appetite

Equine Influenza Treatment

Supportive care
Treatment of secondary bacterial infection

Equine Herpes 1 & 4

Rhinopneumonitis
Virus
Many horses may be infected with EHV 1 early on in life and lies latent:
Some studies say 80-90%
Can vary from subclinical to severe
EHV 1 can cause abortion in mares as well as mutate into Equine Herpes Myeloencephalopathy (EHM)
Vaccines:
Inactivated
Modified live
Diagnosed nasal swab or blood test

EHV 1-4 Clinical Signs and Treatment

Biphasic fever:
Peaking at 1-2 days and then again at 6 days
Enlarged lymph nodes
Discharge from eyes and nose
Typically not much of a cough
Treatment includes supportive care

EHM

Equine Herpes Myeloencephalopathy
Form of EHV 1 (and rarely EHV 4)
Signs start approximately 7 days post infection:
Incubation typically 2-10 days
Can cause incoordination, weakness, urine dribbling, head tilt, fever, loss of tail tone, inability to rise:
Typically starts at hind end and moves forward
IMPORTANT to remember that the EHV 1-4 vaccine does not protect against the neurologic form
Can be diagnosed by blood test or nasal swab:
Important to not to screen for EHV 1
Treatment includes supportive care

Tetanus

Bacteria Clostridium tetani, neurotoxin
Also called “lock jaw”
Attacks nerves controlling muscles and causes muscle stiffness and spasm
Live in GI tract of horses as well as in the soil
Not contagious between horses
Comes form punctures, wounds, surgical incisions
Vaccine- annually:
Inactivated, toxoid
Diagnosed by clinical signs or culture

Tetanus Clinical Signs

Stiffness and difficulty moving, “saw horse” appearance
Third eyelid protrusion especially when startled
Tail may stick out
Loud sounds and bright lights can worsen symptoms
May have “anxious” look as facial muscles stiffe
Inability to open mouth (lock jaw)
May die from respiratory failure (diaphragm cannot move)

Tetanus Treatment

Antibiotic (typically penicillin)
Tetanus antitoxin
Typically kept in dark quiet stalls that may be padded
If disease is significant enough a sling may also be used

Potomac Horse Fever

Neorickettsia risticcii (bacteria)
Late spring to early fall but can be seen later into year:
Have had diagnosed cases in December in this region
Ingest aquatic insects that have bacteria inside them (typically mayfly)
If found on farm it will mostly occur in the future
Vaccine-annually:
Killed (many times combined with Rabies)
Diagnosed by blood or feces

PHF Clinical Signs

Fever
Colitis/diarrhea
Laminitis
Abortion in pregnant mares

PHF Treatment

Antibiotics
Anti-inflammatories
Anti-diarrhea medications
Treatment of laminitis
Fluid therapy

Strangles

Streptococcus equi subspecies equi (bacteria)
Horse infected via inhalation or ingestion
Highly contagious
Diagnosed by blood, or culture/swab/tracheal wash
Currently an intra-muscular and intra-nasal vaccine
Discussion of whether horses should be vaccinated for strangles:
Many horses may have contracted the disease early on in life. Pulling a titer in older horses may be more ideal.

Strangles Clinical Signs

Fever
Nasal discharge
Lymph node swelling and/or abscessation:
Especially in the jaw area
Purpura hemorraghica
“Bastard” strangles:
Metastatic abscessation in other lymph nodes in the body

Strangles Treatment

Isolation
Antibiotics:
Penicillin
Ceftiofur
Anti-inflammatories
Tracheotomy

Purpura hemorraghica

Sequela to strangles
Swelling of head, legs and under belly
Blood vessels swell to immune response to strangles
Treatment include corticosteroids, antibiotics, tracheostomy in advanced cases
Difficult to predict cases
If horse has had previous reactions to strangles vaccine recommend not doing again

Botulism

Clostridium botulinum
Can be found in soil and decaying animals
Hay can be contaminated
Horse is infected by ingestion or less likely a wound
“Shaker foal syndrome”
8 types (A,B,C effect horses)
Diagnosed off clinical signs and history (no blood test etc.)

Botulism Clinical Signs

Flaccid paralysis:
Eyelids/tongue
Difficulty standing
Bladder paralysis and colic
Paralysis of respiratory system
Normal mentation*

Botulism Treatment

Antitoxin
Supportive care
Mechanical ventilation in foals

Botulism Clinical Signs

Flaccid paralysis:
Eyelids/tongue
Difficulty standing
Bladder paralysis and colic
Paralysis of respiratory system
Normal mentation*

Leptospirosis

Leptospira bacteria (pomona, interrogans)
Zoonotic (passed through urine)
Can be infected via mucus membranes of mouth, eyes, or nose with urine
Also infected via cuts or scratches
Can also be ingested
Diagnosed by blood or other tissues

Leptospirosis Clinical Signs

Fever
Depression
Lack of appetite
Uveitis (moon blindness)
Severe infections can cause kidney and liver issues and potentially death
Abortion
Treatment of Leptospirosis:
Antibiotics
Treatment of uveitis

Equine Melanoma

Common nodular tumors typically found in grey horses
May or may not be malignant
Can develop at any age
Melanoma in non grey horse should be considered much more dangerous
Can occur around mouth, eyes, sheath, vulva, behind jaw, internal organs
Malignant form can be more severe and effect horse to greater extent

Equine Melanoma Clinical Signs

Varied size of black “bumps”
Firm swelling particularly in the jaw area
Can break open and ooze a black substance
Can be locally invasive which may cause more severe issues like:
Colic, compression of spinal cord, not allow penis to retract, cause horse to have difficulty passing manure

Equine Melanoma Treatment

Oncept:
Made for oral melanoma in dogs
Stimulates body to mount immune response against melanoma

Equine Pythiosis

Pythium insidiosum
“Swamp cancer”
Fungus like infection that can affect skin, bones, intestines etc.
Wounds develop kunker (not canker)
Diagnosed by presentation or blood test
Cannot be spread from horse to horse
Vaccine can help acute as well as chronic cases
**Has also some application of being used to help equine sarcoids

Autologous Vaccines

Immunotherapy
Equine Melanoma:
Sample of melanoma removed and sent to specialty lab and made into injectable vaccine
Torigen:
Melanoma, sarcoid, squamous cell carcinoma
Administered once a week for 6 weeks

Autologous Vaccines

Equine Infectious Anemia

Coggins test
Swamp fever
Virus (lentivirus)
Potentially fatal blood borne disease causing persistent infection (life long carriers)
Can affect horses, ponies, zebras, donkeys, mules and found worldwide
Passed by biting flies (i.e. horsefly, deerfly)
Edema, weight loss, anemia, depression, petechia, epistaxis, death, fever

Equine Infectious Anemia Protocol

No treatment
No vaccine
With testing has dropped from 4% to .004%
If a horse is confirmed positive:
Euthanasia
Quarantine at least 200 yards from any equid species for life

Biosecurity & Isolation