Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
13 Cards in this Set
- Front
- Back
|
What is the etiologic agent of Tetanus? Morphology?
|
Clostridium tetani; obligate anaerobic, gram pos spore-forming rods
|
|
|
What are the characteristics of the tetanus and botulism exotoxins?
|
potent; toxin activity is specific for target and Rc sites in CNS; toxins are polypeptides; toxins may be denatured by heating; toxins can be altered to toxoids for vaccine use
|
|
|
How is infection with C tetani acquired?
|
local wound infection
|
|
|
What is the name of the neurotoxin released by C tetani? How does it work?
|
*Tetanospasmin: cleaves *vesicle-associated membrane protein (VAMP/synaptobrevin) in the synaptic vesicles of neurons --> this blocks the release of inhibitory NTs glycine and GABA (inhibits the inhibitor)
|
|
|
What are the two forms of tetanus (named by their progression in the body)?
|
ascending (reaches the CNS via *retrograde axonal transport- limb stiffness followed by CNS infection) and descending (enters bloodstream resulting in cranial nerves affected first followed by body and limbs) tetanus
|
|
|
In what spp is tetanus most commonly seen?
|
horses > ruminants > swine (cats and dogs relatively resistant
|
|
|
What are the clinical signs of tetanus?
|
stiffness, sawhorse stance, risus sardonicus, lock jaw, erect ears, prolapse of third eyelid; spasms may be precipitated by external stimuli such as sudden movement or noise
|
|
|
How is tetanus diagnosed?
|
*clinical signs and history (incubation period is 1-2wks); serum (test for toxin by mouse inoculation); wound (C tetani in necrotic tissue)
|
|
|
What is the characteristic appearance of C tetani rods?
|
"tennis racket" or "drumstick"-shaped endospores
|
|
|
What is the treatment for tetanus?
|
tetanus antitoxin (to neutralize unbound toxin); wound cleansing and debridement; penicillin; tetanus toxoid (can be given with antitoxin); provide dark, quiet environment; sedation as needed; good supportive care
|
|
|
How is tetanus prevented?
|
1. good hygeine in tetanus-associated procedures: castration, tail-dockings, dehornings, etc; 2. tetanus toxoid (routinely given in horses); 3. antitoxin: given to unvaccinated animals with tetanus-prone wounds - give toxoid at same time but at diff injection site
|
|
|
What dz has been associated with tetanus antitoxin in horses?
|
hepatic dz (serum hepatitis/Theiler's dz)
|
|
|
Is tetanus zoonotic?
|
no; humans are very susceptible to tetanus but they do not obtain dz from animals
|
