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Actinobacillus species (view source)

Revision as of 11:28, 21 December 2007

351 bytes added , 11:28, 21 December 2007

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*Endemic in UK

*Most strains are NAD-dependent (grow on Heated Blood agar)

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*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

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***Different ''Actinobacillus pleuropneumonia'' serotypes secrete a particular combination of toxins; American serotypes secrete ApxI and II; European serotypes secrete ApxII and III

***Toxins introduce pores into cell membranes

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*~~CLinical~~ signs

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*Clinical signs and epidemiology:

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**Acute disease in susceptible herds with high morbidity and mortality

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**Acute disease in susceptible herds with high morbidity and mortality (up to 50%)

**In acute outbreaks, pigs may be dyspnoeic, pyrexic or anorexic

**Blood-stained froth surrounding nose and mouth

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**Solid immunity develops in recovered animals to all serotypes

**The disease is spread between herds by carrier pigs

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**The bacteria on the palatine tonsil ~~are~~ undetected by serological tests and swabbing, and can therefore cause an outbreak in naive pigs

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*Diagnosis:

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**Haemorrhagic consolidation close to the main bronchi and fibrinous pleuritis may be suggestive

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**Specimens are cultured on chocolate agar and blood agar in 5-10% carbon dioxide for 2-3 days

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**Small colonies surrounded by clear haemolysis

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**No growth on MacConkey agar

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**Positive CAMP reaction with ''Staphylococcus aureus''

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**The bacteria on the palatine tonsil may remain undetected by serological tests and swabbing, and can therefore cause an outbreak in naive pigs

**Killed and bacterin vaccines are available

Flawrence

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