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
- Cause peritonitis in horses
- A. pleuropneumoniae causes pneumonia in pigs
- Cause granulomatous inflammation.
- E.g. Actinobacillus lignieresii causes wooden tongue in cattle -> myositis
- A. equuli in arthritis of horses
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