Difference between revisions of "Actinobacillus species"

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*12 serotypes causing the same disease
 
*12 serotypes causing the same disease
 
*Different serotypes in different regions, with serotypes 3,6 and 8 the most common in the UK
 
*Different serotypes in different regions, with serotypes 3,6 and 8 the most common in the UK
*
+
*Acute disease in susceptible herds with high morbidity and mortality
 +
*Carrier herds have some immunity, protecting from acute disease, where lesions are often subclinical, and deaths sporadic
 +
*Lung scarring and pleural adhesions in many recovered animals
 +
*Solid immunity develops in recovered animals to all serotypes

Revision as of 18:02, 17 December 2007

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Overview

Actinobacillus characteristics

  • Small Gram negative coccobacilli
  • Oxidase negative
  • Do not grow on MacConkey


Actinobacillus lignieresii

  • Commensal in the mouth of sheep and cattle
  • Penetrates damaged mucosa to cause a granuloma, a condition known as Actinobacillosis
  • Enodogenous, sporadic and chronic infection
  • Lesions in the tongue, cheek, lips and sometimes in the lower gut and lungs from aspiration
  • Often spreads from the site of infection to lymphatics
  • Formation of fibrous tissue in the lesions lead to hardening of the tissue, hence the condition is known as 'wooden tongue' in cattle
  • In sheep abscesses with thick walls are produced
  • Feeding is impaired, causing loss of condition
  • Recovery with antibiotics


Actinobacillus equuli

  • Commensal of the equine intestinal mucosa
  • Infection at birth causes severe enteritis and septicaemia within 24 hours, known as sleepy foal disease
  • In foals that survive neonatal infection the condition progresses to cause joint infections and purulent nephritis
  • RTX group cytotoxin present


Actinobacillus suis

  • Fatal septicaemia in pigs 1-8 weeks old
  • 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


Actinobacillus pleuropneumoniae

  • Contagious porcine pleuropneumonia
  • Endemic in UK
  • Most strains are NAD-dependent (grow on Heated Blood agar)
  • Positive CAMP reaction
  • 12 serotypes causing the same disease
  • Different serotypes in different regions, with serotypes 3,6 and 8 the most common in the UK
  • Acute disease in susceptible herds with high morbidity and mortality
  • Carrier herds have some immunity, protecting from acute disease, where lesions are often subclinical, and deaths sporadic
  • Lung scarring and pleural adhesions in many recovered animals
  • Solid immunity develops in recovered animals to all serotypes