Lecture 34 4/15/25 Flashcards
What are the characteristics of cyathosominosis?
-small strongyles; parasitic helminths
-ubiquitous in grazing horses
-fecal-oral route of transmission
-larval stages encyst in intestinal mucosa; can be inhibited up to 3 years
What are the clinical signs of cyathostominosis?
-can be subclinical
-ill thrift/weight loss
-acute or chronic diarrhea
-colic
-acute larval cyathostominosis
What are the characteristics of acute larval cyathostominosis?
-en masse re-emergence of larvae
-causes severe typhlocolitis (inflammation of cecum and colon)
-50% mortality
What causes the clinical signs of cyathostominosis?
-dysbiosis of gut microbiota
-inflammation from emerging larvae
What is the treatment for cyathostominosis?
-high dose fenbendazole
-moxidectin
-possible corticosteroids
-supportive care for diarrhea
What are the characteristics of cantharidin toxicosis?
-blister beetle toxicity
-lethal dose is 4 to 6 grams of beetles; around 120 beetles
What is the main mechanism of cantharidin toxicosis?
irritation
What are the clinical signs of cantharidin toxicosis?
-salivation
-oral ulcerations
-colic
-diarrhea
-tachycardia
-cardiovascular collapse
-frequent urination
-fasciculations from hypocalcemia
-laminitis
How is cantharidin toxicosis diagnosed and treated?
dx:
-beetle presence
-cantharidin in the urine
-gastric content analysis
tx:
-supportive care only; no antidote
What are the prognostic indicators for cantharidin toxicosis?
persistent elevations in heart rate and CK are poor prognostic indicators
How can cantharidin toxicosis be prevented?
-know hay/alfalfa producer and buy locally
-buy and feed first cutting hay (before beetles are active)
-cut hay prior to flowering
-inspect hay for beetles
Which diseases are added to a diarrhea panel for foals (in addition to everything on the adult panel)?
-rotavirus
-cryptosporidium
-Rhodococcus equi
What are the characteristics of Lawsonia intracellularis?
-causes equine proliferative enteropathy
-primarily seen in weaning-age foas (3 to 8 mo.)
-gram- curved or sigmoid rod
-obligate intracellular
-primarily found in SI in the apical cytoplasm of intestial epithelial enterocytes
What are the clinical signs of Lawsonia intracellularis?
-weight loss
-lethargy
-diarrhea/chronically soft stool
-colic
-edema (due to PLE)
How is Lawsonia intracellularis diagnosed?
Living Animal:
-ultrasound (supportive)
-cell culture
-PCR
-serology
Necropsy:
-silver stain to find bacteria within crypt cells
-PCR
-immunohistochemistry
What are the characteristics of Lawsonia intracellularis treatment, prognosis, and control?
tx:
-erythromycin +/- rifampin
-oxytet.
-chloramphenicol
prognosis:
-good response to antibiotics, esp. when caught early
prevention:
-unsure of where it comes from, hard to control
-pig vx available, unclear efficacy in horses
What are the characteristics of Giardia as a diarrheal cause?
-seen in a good percentage of horses
-seen in all age groups
-not considered a significant cause of dz
Which age group primarily has Cryptosporidial diarrhea?
foals; not common in adults
What are the characteristics of foal heat diarrhea?
-self-limiting; generally resolves in 2 to 4 days
-occurs around 6 to 14 days of age
-foal remains BAR
-likely due to transient state of development
What are the most common pathogen associated with diarrhea in foals?
rotavirus
How can foals be protected against rotavirus?
vaccine for pregnant mares that can help to increase antibodies in the colostrum
What can cause chronic diarrhea?
-diet
-parasitism
-sand impaction
-non-GI causes
-peritonitis/abscess
-Lawsonia
-Salmonellosis
-Clostridia
-right dorsal colitis
-IBD
-neoplasia
How is the cause of chronic diarrhea diagnosed?
-fecal culture or PCR
-fecal float looking for parasites
-evaluation for sand impaction
-glucose absorption test
What are the characteristics of IBD and the associated PLE?
-submucosal layer is thickened
-can see histiocytes, lymphocytes, plasmacytes, and/or eosinophils
-can occur in small intestine, large intestine, or both
-leads to malabsorption and hypoproteinemia
