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Actinobacillus species (view source)
Revision as of 19:08, 20 December 2007
, 19:08, 20 December 2007no edit summary
**Virulent strains possess capsules which are antiphagocytic and immunogenic
**Virulent strains possess capsules which are antiphagocytic and immunogenic
**Fimbriae allow the bacteria to attach to cells of the respiratory tract
**Fimbriae allow the bacteria to attach to cells of the respiratory tract
**Damaged 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
**Produce three cytotoxins which belong to the repeats-in-structural-toxin (RTX) cytolysin family
**RTX toxins:
**RTX toxins:
***ApxIII is a cytotoxin
***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
***Different ''Actinobacillus pleuropneumonia'' serotypes secrete a particular combination of toxins; American serotypes secrete ApxI and II; European serotypes secrete ApxII and III
*Acute disease in susceptible herds with high morbidity and mortality
***Toxins introduce pores into cell membranes
*Causes [[Bacterial infections#Actinobacillus pleuropneumoniae|pneumonia]] in pigs
*CLinical signs
*Carrier herds have some immunity, protecting from acute disease, where lesions are often subclinical, and deaths sporadic
**Acute disease in susceptible herds with high morbidity and mortality
*Lung scarring and pleural adhesions in many recovered animals
**In acute outbreaks, pigs may be dyspnoeic, pyrexic or anorexic
*Solid immunity develops in recovered animals to all serotypes
**Blood-stained froth surrounding nose and mouth
*The disease is spread between herds by carrier pigs
**Cyanosis
*The bacteria on the palatine tonsil are undetected by serologucal tests and swabbing, and can therefore cause an outbreak in naive pigs
**Pregnant sows abort
*Killed and bacterin vaccines are available
**Causes [[Bacterial infections#Actinobacillus pleuropneumoniae|pneumonia]] in pigs
**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
**The disease is spread between herds by carrier pigs
**The bacteria on the palatine tonsil are undetected by serological tests and swabbing, and can therefore cause an outbreak in naive pigs
**Killed and bacterin vaccines are available