Actinobacillus suis

• May be present in upper respiratory tract of sows
• Pathogenicity and clinical signs:
  • Infection of piglets via aerosol or possibly skin abrasions
  • Fatal septicaemia in piglets 1-8 weeks old
  • Mortality up to 50% in some litters
  • Fever, respiratory distress, prostration and paddling of forelimbs seen in piglets
  • Petechial and ecchymotic haemorrhages in many organs
  • Interstitial pneumonia, pleuritis, meningoencephalitis, myocarditis and arthritis
  • Causes abscesses in joints and lungs of older pigs
  • Carried in the nasopharynx of pigs and nose of horses
  • Carriage may confer immunity to the more severe pleuropneumonia
• Diagnosis:
  • Specimens cultured on blood agar and MacConkey agar for 1-3 days
  • Sticky haemolytic colonies
  • Pink, lactose-fermenting colonies on MacConkey agar
• Treatment and control:
  • Bacteria usually susceptible to ampicillin, carbenicillin, potentiated sulphonamides and tetracyclines
  • Disinfect contaminated pens
• Other animals:
  • Septicaemia and pneumonia in foals
  • Pneumonia in pigs and horses