Actinobacillus equuli

• Commensal of the equine intestinal and reproductive tract
• Pathogenesis and clinical signs:
  • Foals infected in utero or or after birth via the umbilicus
  • Infection at birth causes severe enteritis and septicaemia within 24 hours, known as sleepy foal disease
  • Foals become pyrexic and recumbent
  • Death usually occurs within 1-2 days
  • In foals that survive neonatal infection the condition progresses to cause joint infections and purulent nephritis, enteritis or pneumonia
  • A. equuli in arthritis of horses
  • Abortion, septicaemia and peritonitis in horses
• Diagnosis:
  • Specimens cultured on blood agar and MacConkey agar and incubated aerobically for 1-3 days
  • Sticky colonies with variable haemolysis on blood agar
  • Lactose-fermenting colonies on MacConkey agar
• Treatment and control:
  • Antimicrobials ineffective unless early in course of disease
  • Blood trasfusion and administration of colostrum
  • Good hygiene
  • Consider prophylactic antibiotics for new-born foals
  • Bacteria susceptible to streptomycin, tetracyclines and ampicillin
• In other animals:
  • Septicaemia in piglets
  • Arthritis and enteritis in pigs
  • Enteritis in calves
  • RTX group cytotoxin present

Hepatitis

• foals
• bacteria from the septicaemia localise in the liver and other tissues, including the kidney