Tetanus Exam 2 Flashcards
Is tetanus contagious?
no
What is tetanus characterized by?
rigid (stiff) paralysis
When and where was tetanus first described in horses?
over 3000 years ago in Egypt
Where can tetanus be found in the world?
everywhere
What is one of the oldest diseases recorded in horses?
tetanus
What is tetanus caused by?
exotoxins of Clostridium tetani
When are the exotoxins released from Clostridium tetani?
while the bacteria is still alive
Clostridium tetani
-mobile
-anaerobic
-gram +
Where is does tetanus reside?
in soil and isolated from horse feces
What are the routes of infection of tetanus?
-puncture wounds contaminated with manure or soil
-contaminated surgical wounds
-injection abscesses
-navel
What % of horses with tetanus are causative wounds not found?
15-30%
What animal is the most sensitive to the tetanus toxin?
horses
How often are humans vaccinated for tetanus?
every 10 years
What do humans often get tetanus from?
road rash
What two toxins are produced by tetanus?
-tetanolysin (lyses breakdown tissue)
-tetanospasmin
How does tetanolysin act?
damages tissue, creating favorable conditions for the anaerobic infection
How does tetanospasmin act?
reaches the bloodstream, then goes to the peripheral nerve terminals throughout the body
-binds irreversibly to inhibitory neurons
Inhibitory neurons
allows you to reach for a glass of water and inhibits your from knocking it over
What is the result of tetanolysin and tetanospasmin?
sustained excitatory discharge of motor neurons (muscle spasms and muscle rigidity)
What is required for recovery?
growth of new nerve terminals
How long can it take to grow new nerve terminals?
weeks
Clinical signs of tetanus
-rigidity of neck and head muscles (lockjaw, inability to eat/drink)
-prolapse of third eyelid
-sawhorse stance (muscles of limbs, trunk and tail are contracting, so spreading everything out)
-recumbency (laying down)
-tonic spasms initiated by external stimuli (sound, light, touch)
-no reflex inhibitory control of movement
What environment is best for a horse with tetanus?
a dark, quiet, padded stall
Rhabdomyolysis
-symptom of tetanus
-breakdown of muscle, release of myoglobin can cause the kidney to fail
What happens when there is no reflex inhibitory control of movement?
flexor and extensor muscles contract simultaneously with full power
-this causes rhabdomyolysis, hemorrhage, tendon avulsion, and fracture of bones
What would cause death from tetanus?
respiratory failure
-laryngeal spasm and asphyxia
-contraction of chest wall, diaphragm and abdomen
What is a diagnosis of tetanus based off of?
clinical signs and history of poor vaccination
Are horses fully aware while having tetanus?
yes
What is the first step of treatment?
if a wound is found/seen, clean with hydrogen peroxide
What is the second step of treatment?
eliminate the unbound toxin with anti-toxin administration
How does the anti-toxin work?
prevents tetanus from binding to neurons
What is the third step of treatment?
sedate the horses and give muscle relaxants
What is the final (general) step of treatment?
provide general support
-put in sling or flip the horse every few hours
-catheter for emptying bowels
-administering fluids
-eye ointment
What is the mortality rate of tetanus?
up to 75%
What raises the chances of survival?
if it is detected early
What is the tetanus vaccination series?
-2-3 does initial series
-annual booster afterwards
When should broodmares be vaccinated?
4-6 weeks pre-partum
What should prevention be for injured horses?
-administer anti-toxin and vaccine (in different syringes at different sites on the body-both sides of the neck)
