Efficacy of an inactivated aqueous vaccine for the control of enzootic pneumonia in pigs infected with Mycoplasma hyopneumoniae

Abstract

The efficacy of an inactivated aqueous vaccine against Mycoplasma hyopneumoniae was evaluated at two M hyopneumoniae-infected farrow-to-finish commercial farms (A and B) in Greece. In a prospective, randomised double-blind study, two groups on each farm received intramuscular doses of either the vaccine or the adjuvant when they were one and four weeks of age. The pigs were observed daily for clinical signs of disease; morbidity and mortality were recorded; and bodyweight was recorded at intervals. At slaughter, the lungs of the animals were examined and the chest cavities were examined for signs of pleuritis. No adverse reactions to the treatments were observed in any of the pigs. On farm A the vaccinated pigs were on average 6 kg heavier at slaughter, and on farm B they were on average 4 kg heavier; on both farms the average daily gain of the pigs was greater than that of the unvaccinated pigs. The prevalence and severity of enzootic pneumonia in the affected lungs were significantly lower in the vaccinated than in the unvaccinated pigs.

Efficacy of combined porcine reproductive and respiratory syndrome virus andMycoplasma hyopneumoniaevaccination in piglets

“…A meta-analysis by Jensen and others (2002) confirmed, by assessing average daily weight gain as an output, that vaccination against M hyopneumoniae resulted in a significant economic benefit. This finding was confirmed by Tzivara and others (2007), who demonstrated that vaccination against M hyopneumoniae also resulted in significant economic benefit when used in pigs on PRRSV-free farms with endemic enzootic pneumonia. Vaccination of pigs against the European strain of PRRSV using a live attenuated vaccine has also been reported to result in improved disease control (Pejsak and Markowska-Daniel 2006, Martelli and others 2007).…”

“…However, field studies have shown that a reduction in M hyopneumoniae -induced lung lesions is correlated with improved weight gain (Jensen and others 2002, Stipkovits and others 2003, Tzivara and others 2007). …”

“…For M hyopneumoniae , reduction of lung lesions was used as a measure of vaccine efficacy, as the interval between challenge and postmortem examination was too short to observe any effect on an economically important parameter such as weight gain. However, field studies have shown that a reduction in M hyopneumoniae ‐induced lung lesions is correlated with improved weight gain (Jensen and others 2002, Stipkovits and others 2003, Tzivara and others 2007).…”

New insights into host adaptation to swine respiratory disease revealed by genetic differentiation and RNA sequencing analyses

“…Great efforts have been devoted to controlling the prevalence of swine respiratory disease, including improving the feeding environment and management, implementing vaccination schedules, and creating pathogen eradication schemes (Bargen, 2004;Maes, Verdonck, Deluyker, & Kruif, 1996;Tzivara, Kritas, Bourriel, Alexopoulos, & Kyriakis, 2007). On the other hand, increasing host immunity or resistance to the pathogens of swine respiratory disease would be an alternative important approach to control disease development.…”

Postweaning mortality in commercial swine production II: review of infectious contributing factors

“…More commonly, disease results due to multifactorial infections ( Thacker and Minion, 2012 ). Vaccination for MHP has variable impact on absolute mortality in field trials, ranging from slightly greater mortality to a reduction in mortality of 4% or a relative reduction up to 100% ( Bilic et al, 1996 ; Maes et al, 1998 ; Maes et al, 1999 ; Pallares et al, 2000 ; Stipkovits et al, 2003 ; Holyoake et al, 2006 ; Tzivara et al, 2007 ; Tassis et al, 2012 ; Kristensen et al, 2014 ). Commercial production records from flows that were MHP negative had an absolute finishing mortality that was 1.26% lower compared with MHP-positive flows ( Silva et al, 2019 ).…”