Lectures 4-5 Flashcards
General considerations for vaccines
Schedule- vaccinate all horses at same time, consider seasonal incidence of diseases
Standard vx program does NOT exist
Site of injection
Individual response
How many rounds of vx do foals need?
When should you begin vx in foals?
Three rounds
6 months of age usually
Vaccine titers in horses?
No research in horse world!
Core vaccines
Tetanus
Encephalitities (EEE, WEE, WNV)
Rabies
Overview of tetanus
Neuro disease caused by C. Tetani
Present in intestines, manure, and soil (can exist for years)
Spores can enter horse through wounds, lacerations, umbilicus
Tetanus clinical sigsn
Stiff gait, facial spasm, third eyelid prolapse
Sawhorse stance
Excessive response to stimulation
Recumbency
Tetanus prevention
Not contagious between horses but mortality is very high!
All horses should be vx annually
Tetanus toxoid vx is very safe and provides good protection
*always booster if open wound or surgical procedure and its been more than 6 months since vaccination
Tetanus antitoxin can be dangerous and not used willy nilly
When start tetanus prevention
Begin at 6 months age if foal received colostrum from vaccinated mare then ooster 4-6 weeks later and again at 10-12 months
When use antitoxin
Previously unvaccinated horses or neonates
What are the viral encephalomyelitis diseases
EEE
WEE
WNV
VEE (foreign animal disease)
Describe host status of encephalitities
Birds transmit to mosquitos who transmit to humans and horses where its a dead end
WNV clinical signs
Fever Muscle fasciculations! Weakness/ataxia Flaccid paralysis Changes in mentation Cranial nerve deficits
EEE clinical signs
Neuro signs 5 days after exposure
Death 2-3 days later
Low grade fever first (viremic for 2 days) but quickly increases during viral proliferation
Behavior changes- dementia, self mutilating, head pressing, compulsive walking, blindness, seizures
Most serious encephalitity- 90% die
Is EEE reportable
YES!
When does EEE usually occur?
WNV?
EEE= late spring
WNV= early fall
Describe vaccine for EEE/WEE
Naive horses 2 vx 3-4 weeks part
Booster every 4-6 months (1 month prior to peak mosquito)
*three times in FL
WNV vaccine
Once a year
WNV and EEE vx for broodmares and foals
Broodmares- 30 to 60 days prior to foaling
Foals- begin vaccinating at 3-4 months and continue at least 3 vaccines!
Most common reservoir for rabies in FL
Raccoon
Clinical signs of rabies in horses
Can look like anything in horses!
Incubation is 2-9 weeks
Ascending paralysis
Describe rabies vx
Annual vx- killed vax IM
Foals- begins at 6 months then boost at 4-6 weeks and again at 10-12 months
Risk based vaccines for horses
Influenza
Equine herpesvirus (rhinopneumonitis)
Strangles
Incubation period of influenza?
Susceptible population?
1-3 days= incubation period
Susceptible population is less than 3 years old
Stressful conditions and travel
Clinical signs of influenza
High fever Cough/ nasal discharge Lethargy, depression Reduced appetite Muscle soreness
rest is essential following infection**
Influenza vaccine
Every 6-12 months- decreases viral shedding
Vaccine types influenza
Traditional inactivated IM
Modified live cold-adaptive IN
Canarypox vector vaccine IM
Influenza vx in broodmares and foals
Broodmares- IM vx in last 30 days of pregnancy
Vaccinate foals at 6 months of age
EHV types
1- abortion, neonatal death, neuro disease, resp disease
4- resp disease
Aka rhinopneumonitis
Clinical signs and incubation of resp EHV
Who is it most common in?
Clin signs identical to influenca
Incubation time= 2 to 10 days
Shed virus 2 to 3 weeks
Most common in weanlings and yearlings
How is EHV transmitted
Resp route
Contaminated equipment
Many horses are carriers with no sigs
Stress can cause recrudescence
Prevention of resp EHV
Vaccine decreases shedding of virus and severity of clinical signs
Foals and weanlings- start at 4-6 months booster 4 weeks later then again at 10-12 months
Yearlings- every 6 months
EHV abortion- when does it occur?
7-9 months gestation
Vaccination of broodmares for abortion EHV
Pregnant mares- booster at 5, 7, and 9 months of pregnancy; vaccinate 30 dats prior to foaling for colostrum
EHV neuro disease
aka EHM- equine herpes myeloencephalopathy
Considered directly contagious
High mortality
Can really look like anything
EHV neuro vaccine
Does not prevent this disease!
There is a MLV that may minimize clinical disease
Complications of EHV 1
Abortion, EHM
How to control outbreaks of EHV
Isolate new arrivals for 21 days
Disinfect transport vans
Isolate horses with fever
Keep aborted material away from herd/ isolate mare
Strangles- is it reportable
Yes!
Clinical signs of strangles
Fever, lymph node enlargement and abscessation
Purulent nasal discharge
Resp distress due to retropharyngeal lymph node enlargment
How is strangles transmitted
Ingestion or inhalation of infected discharges- horse to horse contact or fomites; highly contagious
High morbidity, low mortality
Incubation period of strangles
When does the bacteria shed
3-14 days
Sheds 1-2 days after onset of fever
Isolate horses with fever ASAP
How to confirm strangles
Nasal/pharyngeal culture- gold standard
PCR- need three negative PCRs to be released from quarantine
Serology SeM protein
What does serology for SeM protein tell you
Helpful for confirming purpura or bastard strangles
Weak positive- repeat in 7-14 days
Moderate positive- exposure in last 2 to 3 weeks or/and infection in the last 6 months to 2 years
High positive- complications of S. Equii or recent vaccination
How long is a horse infectious with strangles
4 weeks after clinical signs resolve
Guttural pouch is clear
Guttural pouch samples are negative
Who/when to vaccinate?
Previously affected farms
Farms with young stock
Sale/show stables
Strangles vaccines
M protein based given IM- can cause intranasal abscesses so not used as much
Pinnacle IN- intrasal: can also cause abscesses; let this be the only thing or at least last thing you give that day because horse might snort it out on your
Start vaccination at 6-9 months
Strangles vaccine risks
Immune mediated purpura hemorrhagica
Mild form of the disease
Abscess formation
Regionally used vaccines
Botulism
Potomac horse fever
Equine viral arteritis
Rotavirus
Describe botulism
Kentucky, pennsylvania
Flaccid paralysis
Botulism vaccine
Only type B toxoid
No cross protection with type C and no vaccine for Type C
Recommended to give to pregnant mares in endemic areas to prevent disease in foals
What causes potomac horse fever?
Where is it at and when?
Neorickettsia risticii
Endemic to eastern US and CA from july to september
Transmitted through trematode parasites of fresh water snails and caddis flies
Clin signs of PHF
Severe diarrhea and fever
Laminitis
PHF vaccine
Questionable- evidence of benefit is lacking
What does equine viral arteritis cause?
How is it transmitted?
How to diagnose?
Abortion
Transmitted through respiratory and semen
Diagnose through EVA titers and virus isolation
**unlike other resp diseases horses get edema and lots of ocular discharge!
Rotavirus
Most common cause of infectious diarrhea in foals
Highly contagious
Vaccinate mares before foaling in endemic areas
What is important about vaccinating a stallion for EVA
Make sure to appropriately document that the stallion is negative before vaccinating because the vaccine can cause tests to show he is positive
Lyme disease
No vaccine
Some ppl may use canine vx
Leptosporosis
Associated with recurrent uveitis, kidney infections, abortion
There is a vx but not labelled for pregnant mares
Corynebacterium pseudoTB
Aka pigeon fever
Colic side effects of vaccine so recalled
Re-released this spring
Equine infectious anemia- transmission, clinical signs
Retrovirus transmitted by biting flies or blood contaminated needles
Acute- fever, depression, petechiation
Chronic- icterus, anemia, dependent edema
How to diagnose EIA
Coggins test annually
Reportable disease
Rarely see this ever but if a horse does get infected it is infected for life
Piroplasmosis- what is it caused by? Transmission?
Theileria equi and babesia caballi
Transmitted through ticks and mechanical vectors
Non-endemic in US so treated as foreign animal disease
Clinical signs of piroplasmosis
Acute- fever, anemia, jaundice, hemoglobinuria
Chronic- weak, decreased appetite
