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− | == Synonyms == | + | == Synonyms == |
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| [[Actinobacillus pleuropneumoniae]] | | [[Actinobacillus pleuropneumoniae]] |
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| + | <br> |
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| + | == Introduction == |
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− | == Clinical signs ==
| + | Contagious Porcine Pleuropneumonia is a highly contagious and often fatal respiratory disease, seen in weanlings, growers and finishers ranging from 6 weeks to 6 months. It also causes abortion in sows and will cause milder respiratory signs in pigs of all ages. It is endemic in the UK. |
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| + | The presence of Actinobacillus in the lungs causes a fibrinous pleurisy and pneumonia. |
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| + | It is a disease of acute onset in naive/ susceptable herds and can cause high morbidity and mortality (up to 50%).Carrier herds have some immunity, protecting from acute disease, where lesions are often subclinical, and deaths sporadic <br> The disease is transmitted by carrier pigs or new pigs brought into the herd and is spread by direct contact or aerosol transmission. |
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− | and epidemiology:
| + | == Clinical signs == |
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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. There will often be presence of blood-stained froth surrounding nose and mouth. Cyanosis follows later along with a sub-normal rectal temperature; death will then ensue. Pregnant sows will abort. |
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− | In acute outbreaks, pigs may be dyspnoeic, pyrexic or anorexic | + | In sub-acture outbreaks, some pigs will be found dead but others in the group may show varying degrees of exercise intolerance and respiratory distress. |
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− | Blood-stained froth surrounding nose and mouth
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− | Cyanosis
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− | Pregnant sows abort
| + | == Diagnosis == |
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− | Causes [[Respiratory Bacterial Infections - Pathology#Actinobacillus_pleuropneumoniae|pneumonia]] in pigs
| + | Clinical signs especially if in the acute form are suggestive of this diagnosis as inlfuenza rarely causes mortality and does not primarily effect young pigs. |
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− | Carrier herds have some immunity, protecting from acute disease, where lesions are often subclinical, and deaths sporadic
| + | The post mortem findings will confirm the dignosis. These will include; haemorrhagic consolidation close to the main bronchi or the diaphragmatic lung lobe, which is usually localised. Necrosis and fibrinous pleuritis may also be visible. Lung scarring and pleural adhesions may have developed in recovered animals. |
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− | Lung scarring and pleural adhesions in many recovered animals
| + | Samples can be cultured on chocolate agar and diagnosed by immunofluorescent or PCR-based techniques. 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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− | 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:
| + | == Treatment and Control == |
− | **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'']]
| + | Antibiotics should be administered as soon as clinical signs are suggestive of the disease. Water and feed intake is usually very reduced so in-water or in-feed treatments are of little use and treatment should be administered parenterally.Prophylactic antibiotics may be used for in-contact pigs. |
− | *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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| + | As a control mechanism, killed and polyvalent bacterin vaccines as well as a subunit vaccine are available. They are given as two injections, two weeks apart to pigs no younger than six weeks of age. The sow can also be vaccinated pre and early pregnancy to allow passive immunity to occur. |
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− | *Contagious Porcine Pleuropneumonia especially of pigs under 6 months
| + | Isolation on farms using all in all out systems will also dramatically reduce signs of infection, although not prevent it. Hygiene should be improved by improving ventilation and avoiding chilling and overcrowding. |
− | *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]]''
| + | <br> |
− | *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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| + | == References == |
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| + | Cowart, R.P. and Casteel, S.W. (2001) An Outline of Swine diseases: a handbook Wiley-Blackwell <br>Jackson, G.G. and Cockcroft, P.D. (2007) Handbook of Pig Medicine Saunders Elsevier <br>Straw, B.E. and Taylor, D.J. (2006) Disease of Swine Wiley-Blackwell <br>Taylor, D.J. (2006) Pig Diseases (Eighth edition) St Edmunsdbury Press ltd <br> |
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− | [[Category:Actinobacillus_species]][[Category:Pig Bacteria]] | + | [[Category:Actinobacillus_species]] [[Category:Pig_Bacteria]] [[Category:Respiratory_Bacterial_Infections]] [[Category:Respiratory_Diseases_-_Pig]] [[Category:To_Do_-_Review]] |
− | [[Category:Respiratory_Bacterial_Infections]] | |
− | [[Category:Respiratory_Diseases_-_Pig]] [[Category:To_Do_-_Kate]] | |