Diarrhoea in Horses Flashcards
What are some differential diagnoses for diarrhoea in foals?
–Foal heat diarrhoea
–Necrotising enterocolitis
–Neonatal sepsis (variety of organisms e.g. Actinobacillus, E coli, Strep. spp.)
–Viral diarrhoea (Rotavirus)
–Bacterial causes (e.g. Clostridia)
–Parasitic causes – S. westeri
–(Cryptosporidium – mild and self-limiting except if immunocompromised
What are clinical signs of foal heat diarrhoea?
–5-14 days
–mild, self-limiting
–foal remains bright and sucking
–normothermic (remember foals always normally 0.6C hotter than adults)
What is the pathogenesis of foal heat diarrhoea?
Likely a change in gastro-intestinal function (or with dietary changes)
What is the diagnosis and treatment for foal heat diarrhoea?
- Dx – hx and clinical signs
- Tx – none required
Which foals are most at risk of rotavirus?
–all foals esp those housed in large groups with their dams
–common cause and highly infectious
What is the pathogenesis of rotavirus in foals?
–Invade epithelial cells lining the intestinal villi
–Cell death and blunting of villi
- Maldigestion through loss of intestinal enzymes
- Malabsorption through loss of surface area
What are the clinical signs of rotavirus in foals?
–Anorexia, depression, profuse watery diarrhoea
–Hypovolaemia and electrolyte derangements (low Na and Cl)
How old are foals usually when infected with rotavirus?
- 7 - 28 days of age (occasionally younger)
- May be secondary pathogen too
What is the diagnosis of rotavirus in foals?
•Diagnosis – faeces – PCR, EM, ELISA (practice kits) – all low sensitivity
What is the management and treatment for rotavirus in foals?
•Management
–Isolation policy needs to be implemented
•Treatment
–Vaccination of mares – suggested efficacy
–Supportive therapy – IV (occasionally only oral) fluids, PPN, sucralfate, vaseline to prevent skin abrasion, young foals may benefit from plasma & AB’s
–Prevention -colostrum
What age of foals is bacterial diarrhoea most common in?
What should you always do?
What are the most common organisms?
- In foals <7dd, always rule out sepsis w blood culture if possible
- C.perfringens and C. difficile
- Individual cases and outbreaks (dam source)
What are the clinical signs of bacterial diarrhoea in foals?
Colic, hypovolaemia, profuse watery diarrhoea (smells bad!!), sometimes red-tinged and haemorrhagic (poorer px)
What is the diagnosis for bacterial diarrhoea in foals?
–Faecal ELISA for toxin
–US
What is the treatment for bacterial diarrhoea in foals?
Usually sick – a minimum of IV fluids and broad spectrum parenteral antibiotics, oral metronidazole and often need more support with hospitalisation, vaseline, occ whole blood transfusions or plasma required
NB – about 50% of sick foals presenting with D++ will be bacteraemic
What is S. westeri?
How is it transmitted to foals?
Clinical signs?
Treatment?
Causes parasitic diarrhoea
•S. westeri
–Transmammary transmission
–8-12 days
–Mild diarrhoea
–Self-limiting
–Responds to deworming with BZ or avermectins
What are some differential diagnoses for diarrhoea in weanlings?
- Lawsonia intracellularis
- Rhodococcus equi
- Strongylus vulgaris
- (Also diseases of the adult)
What is Lawsonia intracellularis?
What age of foal does it affect?
Proliferative enteropathy
- Affects horses at 2-8 months of age – usually weaned
- Common in some areas and never reported in others
What are the clinical signs of Lawsonia intracellularis?
•Clinical signs
- Depression, rapid and significant weight loss, subcutaneous oedema, diarrhoea and colic. Often poor hair coat and pot-bellied
What is the clinical pathology and pathophysiology of Lawsonia intracellularis?
•Clinical pathology
–SEVERE hypoalbuminaemia, inc WBC, anaemia (of chronic dx)
•Pathophysiology
–Intracellular bacteria, spread by faeco-oral transmission - proliferative enteropathy of small intestine
What is the diagnosis for Lawsonia intracellularis?
–Difficult to get definitive dx
–Clinical signs, low albumin, ruling out other causes
–Abdominal ultrasound
•Marked SI thickening
–Faecal PCR - insensitive
What do you see on abdominal ultrasound with Lawsonia intracellularis?
Marked SI thickening
What is the treatment for Lawsonia intracellularis?
–Oxytetracycline IV BID or doxycycline PO BID
–Eyrthromycin, clarithromycin or azithromycin PO with or without rifampin
–Colloidal support
•Plasma
What age is Strongylus vulgaris usually seen?
What are clinical signs seen with?
- 6 months onwards
- Now a rare condition in the UK due to widespread use of avermectins
- See clinical signs with L4 migration through arterioles of caecum and descending colon
- Colic and SIRS
What is the diagnosis for Strongylus vulgaris?
Clinical exam, hx, clinicopathology, REMEMBER pre-patent disease so WEC a good rule-in but not rule-out!!
What is the treatment for Strongylus vulgaris?
Avermectins