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| − | == Synonyms ==
| + | #redirect[[Actinobacillus pleuropneumoniae]] |
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| − | [[Actinobacillus pleuropneumoniae]]
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| − | == Clinical signs ==
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| − | and epidemiology:
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| − | Acute disease in susceptible herds with high morbidity and mortality (up to 50%)
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| − | In acute outbreaks, pigs may be dyspnoeic, pyrexic or anorexic
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| − | Blood-stained froth surrounding nose and mouth
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| − | Cyanosis
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| − | Pregnant sows abort
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| − | Causes [[Respiratory Bacterial Infections - Pathology#Actinobacillus_pleuropneumoniae|pneumonia]] in pigs
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| − | Carrier herds have some immunity, protecting from acute disease, where lesions are often subclinical, and deaths sporadic
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| − | Lung scarring and pleural adhesions in many recovered animals
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| − | Solid immunity develops in recovered animals to all serotypes
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| − | The disease is spread between herds by carrier 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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| − | **Most strains are NAD-dependent (grow on Heated Blood agar)
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| − | **Immunofluorescent- or PCR-based techniques
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| − | **The bacteria on the [[Tonsils - Anatomy & Physiology#Palatine|palatine tonsil]] may remain undetected by serological tests and swabbing, and can therefore cause an outbreak in naive pigs
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| − | *Treatment:
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| − | **Antibiotics depending on the strain of bacteria
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| − | **Prophylactic antibiotics for in-contact pigs
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| − | *Control:
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| − | **Killed and polyvalent bacterin vaccines as well as a subunit vaccine are available
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| − | **Improve ventilation, avoid chilling and overcrowding
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| − | *Caused by [[Haemophilus pleuropneumonia|''Haemophilus (Actinobacillus) pleuropneumonia'']]
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| − | *Seen mainly between 6wks-6mths of age but will affect any age
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| − | *Highly pathogenic strains are capable of initiating disease on their own with high mortality in young pigs
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| − | *A fibrinonecrotic [[Bronchitis#Infectious_causes_of_bronchitis_or_bronchiolitis|broncho]][[Pneumonia Overview#Infectious_causes_of_pneumonia|pneumonia]] with [[Pleuritis|pleurisy]]
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| − | *Foci of haemorrhagic consolidation or necrosis, mainly around major bronchi, tend to sequestrate
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| − | *Tending to spread throughout all lung lobes: therefore a cranioventral distribution may not be particularly evident
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| − | *Contagious Porcine Pleuropneumonia especially of pigs under 6 months
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| − | *Endemic in UK
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| − | *12 serotypes causing the same disease
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| − | *Different serotypes in different regions, with serotypes 3,6 and 8 the most common in the UK
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| − | *Pathogenesis and pathogenicity:
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| − | **Virulent strains possess capsules which are antiphagocytic and immunogenic
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| − | **Fimbriae allow the bacteria to attach to cells of the respiratory tract
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| − | **Damaged [[Neutrophils|neutrophils]] in the lungs produce lytic enzymes
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| − | **The sustained inflammatory response causes tissue necrosis
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| − | **Lungs consolidated and necrotic with fibrinous pleuisy at post mortem
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| − | **Produce three cytotoxins which belong to the repeats-in-structural-toxin (RTX) cytolysin family
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| − | **RTX toxins:
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| − | ***Several peptide repeats within the molecules
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| − | ***Produced by various Gram-negative bacteria
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| − | ***Possess four contiguous genes, A, B, C and D
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| − | ***A is the structural gene; B and D are required for secretion; C allows post-translational activation of the gene product of A into a functional product
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| − | ***ApxI is a strong haemolysin with cytolytic activity
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| − | ***ApxII is a weak haemolysin
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| − | ***ApxIII is a cytotoxin
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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
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| − | ***Toxins introduce pores into cell membranes
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| − | *Causative agent: ''[[Actinobacillus pleuropneumoniae]]''
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| − | *Expolsive outbreaks of [[Pneumonia Overview#Infectious causes of pneumonia|pneumonia]]
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| − | *Spread by direct contact and aerosol
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| − | *Lesions
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| − | **Largely from toxin produced
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| − | **In diphragmatic lobes of the lungs
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| − | *Haemorrhage with [[Pleuritis|fibrinous pleuritis]]
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| − | *Usually localised, sometimes generalised
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| − | [[Category:Actinobacillus_species]][[Category:Pig Bacteria]]
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| − | [[Category:Respiratory_Bacterial_Infections]]
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| − | [[Category:Respiratory_Diseases_-_Pig]] [[Category:To_Do_-_Kate]]
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