PORCINE PLEUROPNEUMONIA CAUSED BY ACTINOBACILLUS PLEUROPNEUMONIAE
- THE THREAT FOR YOUR FATTENING PIGS -
By PHẠM Châu Giang, Ceva Animal Health Vietnam
WHAT IS A. PLEUROPNEUMONIAE?
A. pleuropneumoniae is coccobacilli, Gram negative, encapsulated (J.P.Euzéby, 1998).
There are 15 serotypes distributed following the zones. Each serotype can produce exotoxin Apx I, II or III. These exotoxins are the main factor to damage the lungs and seriously decrease the performances (E. Brunier, 2010).
Table: The serotypes of A. pleuropneumoniae with the Apx toxin patterns (Nattavut, 2010)
HOW CAN A. PLEUROPNEUMONIAE SPREAD?
- Pig to pig: by droplets less than 2,5m, by boots, rodents, birds.
- Herd to herd: A. pleuropneumoniae can’t be transmitted by air in a long distance. The main factor is the carrying pigs (D. Maes, 2011).
HOW TO RECOGNIZE A. PLEUROPNEUMONIAE?
(Source: respig.com, E. Brunier and P.C. Giang)
Figure 2 Symptoms of A. pleuropneumoniae
- Usually in the fattening period (from 14 weeks of age).
- The pigs have high fever, cyanosis, anorexia, abdominal breathing, and apathy.
- Dead with blood discharge in the nose. The necropsy lungs have pleurisy, necrosis.
- The mortality can reach 15% (R. Krejci, 2010.
2. Subacute and chronic forms:
- The pigs have coughing, low to moderate fever, dyspnea, decrease of appetite, heterogeneous growth.
- The slaughtered lungs have a high level of pleurisy lesions related to A. pleuropneumoniae: pleurisy, abscess, adherence to the chest (E. Brunier, 2010).
HOW TO CONFIRM A. PLEUROPNEUMONIAE?
To have the general profile in the farm, the farmers can coordinate these methods:
- The herd history: Where do the gilts and boars come from? Are they vaccinated? …
- The situation of the farm: Clinical signs, lung lesions of the sick pigs, lung lesions scoring in the slaughterhouses,…
- The diagnosis in the laboratory: PCR, ELISA.
Figure 3 Lung lesions related A. pleuropneumoniae observed in slaughterhouses
HOW TO TREAT A. PLEUROPNEUMONIAE?
- The sick animal must be marked and all of the batches or groups must be treated. The antibiotic must be applied in a very early stage of A. pleuropneumoniae (E. Brunier, 2010).
- The antibiotherapy can help but cannot remove the Apx toxin. The pigs can die and the losses of performance still happen.
- The survivor pigs after an outbreak can become carriers. The risk of a flare up after an outbreak is very high (D. Maes, 2011).
HOW TO PREVENT A. PLEURONPNEUMONIAE?
The farmers should check the lungs every 3-6 months to know about the situation of their farms.
Image 5 Lung scoring
Then, there are 3 main ways to prevent A. pleuropneumoniae:
- Introduced pigs (gilts, boars) come from the A. pleuropneumoniae-free farm or at least vaccinated (vaccination does prevent carriage by no mean).
- The disinfection is carefully followed.
- The farmers respect the standard of density, ventilation and temperature.
2. Antibio – metaphylaxia
Advantage: This method can help to control the situation at the moment it is applied.
- The losses still happens due to the Apx toxin.
- The risk of resistance against the antibiotic is very high and will decrease the efficacy of the antibiotic in the future.
- The risk of residue of antibiotic in the meat, which can influence the human health.
- This is the long term solution.
- The farmers must use a vaccine that can cover all serotypes to have a full protection.
- The farmers should choose a vaccine avoiding PVR and maximize the technical result.
The Porcine Pleuropneumonia caused by Actinobacillus pleuropneumoniae is an important threat for the farm. The loss can be lead by the mortality (especially in heavy pigs), the decreasing of performance (such as PCR or ADG). The treatment of A. pleuropneumoniae outbreak does not give a good efficacy. To prevent the A. pleuropneumoniae, in associate with the biosecurity, an antibio-metaphylaxis can be done but it is not the long term solution for the farm. The long term solution is the vaccination. This one must be carefully looked at to make it useful. In one next article we will give you more detail about this.