Ehrlichia risticii

Potomac horse fever

• Caused by Ehrlichia risticii
• Occurs during the summer
• Fluke vector
• Infects epithelial cells of colon and Monocytes, macrophages and mast cells

• Clinical signs
  • Fever, anorexia, depression, diarrhoea, colic, leukopenia, laminitis
• 30% mortality
• Can cause abortion
• Hyperaemia of large intestine at post mortem

• Diagnosis
  • Seroconversion detected by indirect immunofluorescence or ELISA

• Treatment and control
  • Oxytetracycline for 1 week
  • Inactivated vaccines