Testing of Remedial Measures in Fattening Pig Herds Affected with Subclinical Infections of Actinobacillus pleuropneumoniae serotype 2

Abstract

Summary The present investigation comprised 5 specialized herds of slaughter pigs, each with a production of 1,500 to 4,000 fatteners per year. High prevalence of pleuritis was demonstrated in all herds at slaughter. Serological investigations by means of ELISA were carried out to determine antibody titres to Actinobacillus pleuropneumoniae (A. pl.) serotype 2 during the fattening period and at slaughter. The investigations showed that this agent was a predominant cause of the subclinical pleuritis although A. pl. was difficult to isolate. An environment study was performed in all herds and major environmental deficiencies were corrected during the course of the investigation. Similarly, all herds changed to a strict routine of batch rearing. In 4 herds out of 5, the animals were vaccinated on arrival to the growing‐finishing units and again generally 3–4 weeks later with an inactivated vaccine against A. pl. serotype 2. The prevalence of pleuritis decreased with 25–75% during the three‐year observation period. Also the prevalence of pneumonia decreased at the same time. Conversely, daily weight gain and feed conversion improved. The prevalence of pleuritis and pneumonia registered at slaughter was lower in the three‐breed crosses (including Hampshire, Landrace and Yorkshire) than in the two‐breed crosses with Landrace and Yorkshire.

Actinobacillus pleuropneumoniae

“…This was also in accordance with a number of other studies performed over the years which have demonstrated that pigs which were exposed to a natural infection were immune to subsequent reinfections (Krejci et al, 2005;Nechvatalova et al, 2005;Cruijsen et al, 1995a;Cruijsen et al, 1995b;Cruijsen et al, 1995c;Loftager et al, 1993;Bosse et al, 1992). Therefore, vaccinations have been considered a tempting way to prevent actinobacillosis, but so far have different vaccines and vaccination strategies not been very successful (Jirawattanapong et al, 2008;Ramjeet et al, 2008;Haesebrouck et al, 2004;Beskow et al, 1993;Beskow et al, 1989).…”

“…In general, vaccination is used to induce immunity towards defined pathogens in naïve individuals, providing protection against disease. Vaccinations against actinobacillosis have also been employed (Ramjeet et al, 2008;Haesebrouck et al, 2004;Valks et al, 1996;Beskow et al, 1993;Beskow et al, 1989), but have generally not been very effective unless other preventive measures have also been undertaken.…”

The Variation of Nasal Microbiota Caused by Low Levels of Gaseous Ammonia Exposure in Growing Pigs

“…The results obtained in the study based on the nasal microbiota in pigs with Glässer's disease indicated that the Proteobacteria, Firmicutes , and Bacteroidetes were the most prevalent phyla, suggesting similarities between the pigs exposed to ammonia and Glässer's disease (Correa-Fiz et al, 2016). Glässer's disease is often accompanied by pneumonia and respiratory disease, which may be caused by high levels of ammonia exposure in pig farming (Beskow et al, 2010). This study also showed that 20 abundant genera accounted for over 98.3% of the total sequences in the samples.…”

Immunoproteomic analysis of bacterial proteins of Actinobacillus pleuropneumoniae serotype 1

“…To control APP pathogenesis, several types of vaccines have been developed that offer various degrees of protection. The traditional chemically- [2,3], genetically-, and irradiation-inactivated [4] whole cell vaccines used thus far have been shown to provide protection against a homologous challenge from APP, but were ineffective in staving off infection by different serotypes.…”