Infectious disease and vaccinations

Question 1

core vaccine diseases

Answer 1

• rabies
• tetanus
• west nile virus
• eastern equine encephalitis

Question 2

optional vaccinated diseases

Answer 2

-equine influenza, equine herpesvirus, stragnles, potomac horse fever, botulism, equine viral arteritis

Question 3

epidemiologic triad

Answer 3

-spreading disease requires 1. susceptible hosts 2. infective agent 3. supportive environment

Question 4

risk factors of vaccination

Answer 4

• geography
• pregnancy
• age
• exposure to other horses
• in and out traffic
• stress

Question 5

geography, horses, and vaccines

Answer 5

-horses in rural areas with little contact with other horses have little risk of exposure to agents
-if exposed, however, can show severe signs because of no previous contact and thus reduced immunity
RECOMMENDATION: CORE VACCINES

Question 6

broodmares, pregnancy, and vaccines

Answer 6

• HIGH RISK: agents can kill fetus, damage placenta, cause hyperthermia, and result in abortions
• ie. herpes can become active and cause abortion STORMS amongst herds
• vaccines AND mares must be separated
• recommend core and optional vaccines like influenza, equine herpesvirus and strangles

Question 7

age, foals

Answer 7

• passive immunity from mare’s colostrum provides most of foal’s antibodies for first 9-12 weeks
• foals produce own antibodies, but not enough for first 2 months
• recommend vaccinate mare 4-6 weeks BEFORE foaling, and foal at 6 months; if mare not vaccinated, foal at 3 months

Question 8

in and out traffic

Answer 8

• barns with many horses lead to high exposure rates
• horses attending competitions and travelling have high risk of exposure and stress that can reduce immunity
• recommend core + vaccines for influenza, equine herpesvirus, and strangles

Question 9

rabies virus

Answer 9

causes fatal disease in mammals

• virus shed in saliva and transmitted inbites
• approx 1 case each year past 3 years

Question 10

rabies hosts in NA

Answer 10

skunks, fox, raccoon, coyote,

bat most common case, only reservoir of rabies in BC

Question 11

rabies symptoms

Answer 11

rapidly progressive but preventable with vaccines

• symptoms develop in 10 days
• furious, dumb, paralytic, consider all neurological cases potentially rabies
• rabies vaccines are licensed and must be used by veterinarian

Question 12

livestock exposed to rabies must be revaccinated in…

Answer 12

45 days; unvaccinated are to be slaughtered immediately or kept under watch for 6 months

Question 13

tetanus

Answer 13

aka lockjaw, often fatal and caused by clostridium tetani

• spores present in soil and contaminate wounds and umbillici of foals
• C. tetani produces neurotoxin causing muscle spasms
• vaccine neutrilizes toxin

Question 14

west nile virus

Answer 14

• spread by moquitoes and cause encephalitis (inflammation of brain)
• zoonotic
• low mortality and sickness in horses
• fatal in 30% of horses showing neuro signs
• 40% of survivors have residual neuro deficits for months or even permanent disability
• severe cases may have ataxia, weakness of hind limbs, recumbency, muscle fasciculations, fever

Question 15

west nile treatment

Answer 15

supportive care, slings, fluids, anti-inflammatories

-vaccination prior to mosquito season

Question 16

eastern equine encephalitis

Answer 16

-virus spread by mosquitoes that feed on birds
-immediately notify in canada
-occurs in eastern canada
-NOT zoonotic
80-90% of horses get lethal neurological disease
rapid progression in 24 hours-10 days: fever, mania propulsive walking hyperesthesia aggression, recumbency and death
NO TREATMENT only prevention
-vaccine covers both EEE and WEE

Question 17

optional vaccines

Answer 17

diseases that have

• variable impact on health of horses
• low risk of life-threatening
• vaccine is not great at prevention
• occur in a specific region
• vaccines increase risk, ie. botulism

Question 18

equine influenza

Answer 18

acute, contagious, resp disease

• unique ability to mutate rapidly and spread between species
• high infection rate but low mortality in horses
• incubation of 2-3 days
• sudden onset and rapid spread

Question 19

influenza vaccine

Answer 19

-does not always prevent influenza
-most susceptible between aages 1-5
-vaccinate pregant mares 4-6 weeks prior to foaling
-must revaccinate at 6 weeks, 6 month intervals
clinical signs: fever, dry cough, nasal discharge