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Diseases and Biosecurity (AVS 2040)

Terms in this set (49)

Equine Encephalitis
- sleeping sickness
- mosquito-borne (birds are vectors)
- incubation period 5-15 days
- 3 strains (EEE, WEE, VEE)
Symptoms of Equine Encephalitis
- fever
- lethargy
- anorexia
- neurological symptoms 5 d after exposure
- impaired vision
- ataxia, convulsions, death 2-3 d after neuro
WEE - somnolence - sleeping for long periods of time
West Nile
- worldwide distribution, endemic to all states
- mosquito-borne
- birds are reservoirs (vectors)
- zoonotic
Fatality of West Nile
30-40%
60-80% if unable to rise
Fatality of EEE
90%
Symptoms of West Nile
- fever
- anorexia
- ataxia
- circling, hind limb weakness, recumbency, inability of stand
- partial paralysis (limbs, lips)
- teeth grinding
- colic
Equine Herpes Virus (EHV)
- aka Rhinopneumonitis
- 9 diff. strains
- most concerned with EHV-1 and EHV-4 in US
- direct contact, indirect contact (up to 1 mo), airborne
- highly contagious
- supportive care, isolation for 28 d
EHV-1
4 diff. manifestations
- neurological
- respiratory
- abortion
- neonatal death
EHV-4
- mostly upper respiratory and mostly effects young horses
- rarely associated with abortions or neurological manifestations
Symptoms of EHV
- high fever (2 phases)
- nasal discharge
- lethargy
- anorexia
- neurological symptoms
- loss of tail bone
- urine dribbling
Equine Influenza (Flu)
- Influenza A - H3N8 is the main subtype
- highly contagious upper respiratory disease
- incubation period 1-3 days
- airborne, direct/indirect contact
- low mortality - most return to work within 3-6 wks
- pneumonia can develop
- supportive care, isolation, rest
Symptoms of Equine Influenza
- sudden high fever (up to 106)
- coughing
- clear, runny discharge
- swollen lymph nodes
Tetanus
- from clostridium tetani in the soil
- most likely affected are horses with puncture wounds or deep lacerations, mare with retained placentas, foals via the umbilical stump
- 80% mortality
- incubation period 8-14 d
Symptoms of Tetanus
- stiffness and muscle spasms
- difficult chewing/swallowing
- erect ears, tail stiff, and extended
- "sawhorse" stance
- high fever in severe cases
Treatment for Tetanus
- if caught early -> antitoxin
- antibiotics
- supportive care
Rabies
- from saliva of infected animals
- relatively uncommon
- long incubation period (2-6 wks)
- death within 5-7 d after onset of clinical signs
What is the only way to diagnose rabies?
Examination of brain tissue post-mortem
Symptoms of Rabies
- highly variable
- depression and/or manic behavior
- lameness
- anorexia
- difficulty urinating
- persistent erection
- neurological
Treatment for rabies
- no treatment
- isolation
- humane euthanasia
Vaccine Schedule - WEE/EEE
once or twice per year (S & F)
Vaccine Schedule - W.Nile
Once per year (up to 4x/year)
- spring if once
Vaccine Schedule - Rhino (EHV-1 and EHV-4)
twice per year (S & F)
Vaccine Schedule - Influenza
Twice per year (S & F)
Vaccine Schedule - Rabies
Once per year (Spring)
Vaccine Schedule - Tetanus
once per year (if wound sustained or surgery more that 6 months from vaccine -> revaccinate)
What does the Coggins Test test for?
Equine Infectious Anemia (EIA) aka swamp fever
How often is a Coggins Test done?
once a year or when ownership is changed
Treatment of EIA
- RNA virus, rapidly mutates so no vaccine
- positive horses must be euthanized or permanently quarantined
Symptoms of EIA
- transient fever
- progressive weakness/depression
- weight loss
- disorientation
- some may not show symptoms and be carriers of the disease
Strangles
aka Equine Distemper
- upper respiratory infection caused by streptococcus equi
- highly contagious
- natural immunity after exposure
- vaccine available
Symptoms of Strangles
- fever
- nasal discharge (thick, purulent)
- swelling of submandibular lymph nodes -> abscess of those lymph nodes
Equine Protozoal Myeloencephalitis (EPM)
- caused by protozoa
- carried by opossums -> contaminate feed/water
- extremely long incubation period (could be years, stress can cause it to flare up)
- if infect, protozoa take up in brain/spinal cord from digestive tract
Symptoms of EPM
- loss of coordination/ataxia/paralysis
- facial paralysis
- head tilting
- abnormal sweating
- seizures
Treatment of EPM
- diagnose using spinal fluid
- treat with anti-protozoal drugs ($$$) - variable outcomes
Potomac Horse Fever
- bacteria was found primarily in the Potomac River Area (VD, MD)
- bacteria infects snails -> water loving insects -> larva ingested by horse
- bacteria attacks intestines (colic like symptoms)
- vaccine available (annually or biannually)
Mortality rate of Potomac Horse Fever
50% mortality
- 25-30% of survivors have chronic laminitis
Symptoms of Potomac Horse Fever
- fever
- lethargy/depression
- loss of appetite
- colic like symptoms
- diarrhea
- abortion
Vesicular Stomatitis
- viral disease spread through direct contact with saliva or ruptured blisters
- sporadic disease, re-emerging
- vaccine available during outbreaks
Symptoms of Vesicular Stomatitis
- lesions on tongue, gums, teats, and coronet bands
- effects horses, cattle, and swine
- lesions in mouth will cause drooling, chomping, rubbing mouth
- lesions on coronet can cause lameness
Treatment for Vesicular Stomatitis
- supportive treatment
- antibiotics for secondary infection
Pigeon Fever
- soil-inhabiting bacteria releases toxin that causes severe inflammation and local tissue damage
- enters through small wounds and causes external abscesses mostly commonly on the the pectoral and barrel regions
Treatment of Pigeon Fever
- abscesses should be lanced and drained
- infected horses isolated during active draining
- daily cleaning/flushing of abscesses with dilute betadine
Equine Viral Arteritis (EVA)
- caused by Equine Arteritis Virus (EAV)
- transmitted through respiratory secretions, indirect contact, shed in semen, and in utero
Do stallions with EVA remain carriers?
Yes
Vaccine Schedule for EVA
- Breeding stallions vaccinate annually
- Vaccinate mares 3 weeks prior to breeding to a carrier stallion
What is the problem with EVA?
Cannon distinguish carriers from vaccinates
- must keep record of vaccination
Symptoms of EVA
- depression
- anorexia
- conjunctivitis
- nasal discharge
- skin rash
- abortion
- pneumonia and death in foals
- not typically fatal except young foals
Should you vaccinate a horse with a fever?
No! This is a reason vets require a brief exam prior to vaccination
Can modified-life virus vaccines be given to pregnant mares?
No! While most vaccines are killed make sure to pay attention to what you're giving when vaccinating broodmares.
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