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Contagious Porcine Pleuropneumonia (view source)
Revision as of 11:06, 7 March 2011
, 11:06, 7 March 2011no edit summary
*Tending to spread throughout all lung lobes: therefore a cranioventral distribution may not be particularly evident
*Tending to spread throughout all lung lobes: therefore a cranioventral distribution may not be particularly evident
[[Category:Respiratory_Diseases_-_Pig]] [[Category:To_Do_-_Kate]] [[Category:Respiratory_Bacterial_Infections]]
*Contagious Porcine Pleuropneumonia especially of pigs under 6 months
*Endemic in UK
*12 serotypes causing the same disease
*Different serotypes in different regions, with serotypes 3,6 and 8 the most common in the UK
*Pathogenesis and pathogenicity:
**Virulent strains possess capsules which are antiphagocytic and immunogenic
**Fimbriae allow the bacteria to attach to cells of the respiratory tract
**Damaged [[Neutrophils|neutrophils]] in the lungs produce lytic enzymes
**The sustained inflammatory response causes tissue necrosis
**Lungs consolidated and necrotic with fibrinous pleuisy at post mortem
**Produce three cytotoxins which belong to the repeats-in-structural-toxin (RTX) cytolysin family
**RTX toxins:
***Several peptide repeats within the molecules
***Produced by various Gram-negative bacteria
***Possess four contiguous genes, A, B, C and D
***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
***ApxI is a strong haemolysin with cytolytic activity
***ApxII is a weak haemolysin
***ApxIII is a cytotoxin
***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
*Causative agent: ''[[Actinobacillus pleuropneumoniae]]''
*Expolsive outbreaks of [[Pneumonia Overview#Infectious causes of pneumonia|pneumonia]]
*Spread by direct contact and aerosol
*Lesions
**Largely from toxin produced
**In diphragmatic lobes of the lungs
*Haemorrhage with [[Pleuritis|fibrinous pleuritis]]
*Usually localised, sometimes generalised
[[Category:Actinobacillus_species]][[Category:Pig Bacteria]]
[[Category:Respiratory_Bacterial_Infections]]
[[Category:Respiratory_Diseases_-_Pig]] [[Category:To_Do_-_Kate]]