Evaluation of the Efficacy of a Vaccination Program against Actinobacillus pleuropneumoniae Based on Lung-Scoring at Slaughter

Actinobacillus pleuropneumoniae is a serious infectious agent in pigs, inducing pleuropneumonias and often leading to death if left untreated. In order to document and quantify the effects of a specific vaccination campaign (Coglapix(R)) in a chronically diseased farrow-to-finish farm suffering from an acute episode in the fattening unit, lungs of 61 slaughter pigs in the mean in each run were evaluated using the electronic CLP(R) lung score program three times between 2016 and 2020, with the last measurement during the acute episode before the start of specific vaccination, followed by two analyses, one 8 months after implementation of vaccination measures, and one five months after cessation of the vaccination program. Percentages of lungs affected by dorsocaudal pleurisy immediately before and during vaccination were 43 and 5, respectively. The APP-index decreased from 1.2 to 0.1. The incidence of bronchopneumonic lungs also decreased by 75%, showing that pathophysiologies of pneumonias and pleurisies are closely correlated. Remarkably, EP (enzootic pneumonia)-indices seemed to correlate better with the severity of clinical signs than APP-indices, especially when comparing the chronic phase of swine pleuropneumonia and the acute episode with peracute fatalities. In summary, vaccination measures against Actinobacillus pleuropneumoniae proved to be very effective in restoring lung health in the affected herd, which was underpinned by an increase in APP-related parameters after cessation of vaccination. Porcine pleuropneumonia is of serious concern regarding lung health in pig production. Besides optimizing hygiene and pig management, specific vaccination against the causative agent, Actinobacillus pleuropneumoniae, is an important tool in the fight against this disease. As porcine pleuropneumonia may present with different clinical courses of disease, it is not always easy to objectively assess herd lung health state or to monitor improvements following specific therapeutic or prophylactic measures. Here, the effects of specific vaccination on lung health in a chronically diseased farrow-to-finish farm in Lower Austria experiencing an acute episode were monitored by means of an app-based electronic tool, enabling the scorers to document lung pathologies real-time at slaughter. At the time, when vaccination measures took effect, percentages of lungs affected by dorsocaudal pleurisy had decreased from 43 to 5 and the APP-index from 1.2 to 0.1, respectively. But not only pleurisies were diminished, also incidences and severities of bronchopneumonic alterations had dramatically decreased and exhibited interesting trends when set in connection to clinical signs. Overall, vaccination measures against Actinobacillus pleuropneumoniae proved to be very effective in restoring herd lung health.

Automated summary

Vaccination measures against Actinobacillus pleuropneumoniae have been shown to be highly effective in restoring lung health in affected swine herds, reducing the incidence and severity of pleurisy and bronchopneumonia.