Exam 4: Biological Toxins Flashcards
How does botulism occur?
Ingestion of preformed toxin
Ingestion of spores
Contamination of wounds with spores
What does botulism cause?
Acetylcholine release is blocked in the presynaptic neuron resulting in flaccid paralysis
What are the best prevention strategies for botulism?
Vaccination
Proper ensiling of poultry litter
Examine feed for evidence of decaying carcasses
Rodent control
Proper disposal of dead animals (deep burial)
How is tetanus different from botulism?
“Lockjaw” = uncontrolled muscle contractions
Prevents release of inhibitory NTs (interrupts translocation and exocytosis of NTs at spinal cord)
What clinical signs are indicative of tetanus and in what group of affected animals do they occur?
Horses and ruminants are more susceptible
Generalized musculoskeletal stiffness, nictitating membrane elevation, “sardonic grin”, locked jaw, sawhorse stance, recumbency, convulsions
What are the best prevention strategies for tetanus?
Prevent introduction into any wounds or sx sites
Good husbandry practices including clean needles and blades, tagging, and castration
Vaccination
What are the general toxicities that can be associated with blue-green algae ingestion?
Acute death with few clinical signs
Microcystin/nodularin = liver toxicity, lethargy, vomiting
Anatoxin-a = muscle tremors, rigidity, lethargy, rep distress, convulsions
Anatoxin-a(s) = inhibition of AChE, increased SLUDGE, tremors, dyspnea, convulsions
What are the treatments utilized for dogs that ingest blue green algae?
GI decontamination (emesis, activated charcoal, cathartic)
Bathing if on haircoat
Hepatotoxicity = fluids, corticosteroids
Neurotoxicity = respiratory support, seizure control
Why is blister beetle toxicosis most often observed in horses?
Cantharidin
Most cases of blister beetle toxicosis occur when livestock eat alfalfa hay that was baled with blister beetle infestation
What does cantharidin cause clinically?
Vesicant - causes irritation characterized by acantholysis and vesicle formation leading to ulcers or erosions where the compound contacts a mucosal surface
What is the mechanism of action of toxins associated with toads?
Parotid glands on the toad’s dorsum release toxins that are absorbed via the buccal mucous membranes of the dog
Secretions contain epinephrine, norepinephrine, ergosterol, and bufodienolides (cardiac glycoside)
What species is most likely to be affected by toad toxins? Why?
Dogs mouth or bite toads
What are the clinical signs associated with toad toxins?
Hypersalivation, vomiting, anxiety initially
Convulsions, ataxia, nystagmus, stupor, coma
What are the treatment options for toad toxins?
Initial = decontamination of oral cavity by rinsing with water (if not seizing)
Diazepam (seizures)
Check HR = bradycardia (atropine), tachycardia (beta-antagonists)
Hyperkalemia = insulin, glucose, and sodium bicarbonate
