Association Between Infectious Agents and Lesions in Post-Weaned Piglets and Fattening Heavy Pigs With Porcine Respiratory Disease Complex (PRDC)

Ruggeri, Jessica; Salogni, Cristian; Giovannini, Stefano; Vitale, Nicoletta; Boniotti, Maria Beatrice; Corradi, A.; Pozzi, Paolo; Pasquali, Paolo; Alborali, Giovanni Loris

doi:10.3389/fvets.2020.00636

Cited by 32 publications

(49 citation statements)

References 30 publications

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“…These results suggest that viruses and mycoplasmas could have acted in an earlier stage of the life of piglets, probably during nursery, and later on, during the fattening period, bacteria would have taken action. Ruggeri et al [ 32 ] reported pleurisy, followed by pleuropneumonia, catarrhal bronchopneumonia and bronchointerstitial pneumonia, as the most prevalent microscopic lesions in fattening pigs, but animals included in that study died because of respiratory diseases, that is, samples were not collected from healthy animals at abattoir as in the present study. However, to a certain extent, it agrees with our observations, since most of the deaths were consequence of an acute process of fibrinous and suppurative bronchopneumonia.…”

Section: Discussionmentioning

confidence: 66%

Prevalence of mycoplasma-like lung lesions in pigs from commercial farms from Spain and Portugal

Pallarés

Añón²,

Rodríguez-Gómez

et al. 2021

Porc Health Manag

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Background Mycoplasma hyopneumoniae causes a chronic respiratory disease that produces important economic losses due to poor productive performance, increased mortality and costs for several control strategies. The prevalence of mycoplasma-like lesions (MLL) at abattoir has been widely studied in different countries, making use of different scoring systems. However, most of them are difficult to apply in abattoirs with high number of pigs sacrificed per hour. For that reason, it is necessary to adapt the scoring system to the reality of the modern abattoir, even if there is a loss of accuracy. Our purpose was to investigate the prevalence and severity of MLL at abattoirs in Spain and Portugal using a 0 to 5 scoring system adapted to abattoirs with high number of sacrificed pigs per hour and to highlight the histopathological diagnosis as confirmatory method to identify patterns of pneumonia correlated to gross lesions. Results Cranioventral pulmonary consolidation, a typical MLL, was the most frequent lung lesion (30.97 %) detected at the abattoir, followed by dorsocaudal infarcts with pleurisy (12.51 %) and pleurisy alone (6.26 %). The average score for all examined lungs at abattoir was 1.99 out of 5 points. The histopathological study revealed that the 78.17 % of the randomly selected lungs with MLL presented microscopic lesions compatible with M. hyopneumoniae infection. Most bronchointerstitial and interstitial pneumonia lesions had a chronic course while most suppurative and fibrinous bronchopneumonia lesions had an acute course and a higher degree of severity. The combination of microscopic lesions more frequently observed was bronchointerstitial pneumonia + interstitial pneumonia + suppurative bronchopneumonia. Conclusions The prevalence of MLL at abattoir was 30.97 %, however, after microscopic examination the real prevalence of lungs with lesions compatible with M. hyopneumoniae infection was reduced up to 24.21 %. The six more prevalent combinations of lesions in the microscopic study involved the 66.13 % of examined lungs, and in all of them, microscopic lesions characteristic of M. hyopneumoniae infection were found, what supports the importance of M. hyopneumoniae as a primary pathogen in cases of PRDC.

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Section: Discussionmentioning

confidence: 66%

Prevalence of mycoplasma-like lung lesions in pigs from commercial farms from Spain and Portugal

Pallarés

Añón²,

Rodríguez-Gómez

et al. 2021

Porc Health Manag

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show abstract

“…These results suggest that viruses and mycoplasmas could have acted in an earlier stage of the life of piglets, probably during nursery, and later on, during the fattening period, bacteria would have taken action. Ruggeri et al [30] reported that the most prevalent microscopic lesions in fattening pigs were pleurisy, followed by pleuropneumonia, catarrhal bronchopneumonia and bronchointerstitial pneumonia, but animals included in that study died because of respiratory diseases, that is, samples were not collected from healthy animals at abattoir as in the present study. However, to a certain extent, it agrees with our observations since most of the deaths were consequence of an acute process of brinous and suppurative bronchopneumonia.…”

Section: Discussionmentioning

confidence: 68%

Prevalence of Mycoplasma-like Lung Lesions in Pigs From Commercial Farms From Spain and Portugal

Pallarés

Añón²,

Rodríguez-Gómez³

et al. 2020

Preprint

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Background: Mycoplasma hyopneumoniae causes a chronic respiratory disease that produces important economic losses due to poor productive performance, increased mortality and increased costs due to treatment and control. The prevalence of mycoplasma-like lesions (MLL) at abattoir has been widely studied in different countries and different scoring systems have been used. However, most of them are difficult to apply in case of abattoirs with high number of pigs sacrificed per hour. For that reason, it is necessary to adapt the scoring system to the reality of the modern abattoir even if there is a loss of accuracy. Our purpose was to validate a mycoplasma-like scoring system at abattoirs with a high number of pigs per hour in Spain and Portugal using the histopathological diagnosis as confirmatory method to identify pattern of pneumonia correlated to gross lesion. Results: Cranioventral pulmonary consolidation (MLL) was the most frequent lung lesion (30.97 %) detected at the abattoir, followed by dorsocaudal infarcts with pleurisy (12.51 %) and pleurisy alone (6.26 %). The average score calculated for all lungs examined at abattoir was 1.99 out of 5 points. The histopathological study revealed that the 78.17 % of the lungs with MLL randomly selected presented microscopic lesions compatible with M. hyopneumoniae infection. Most bronchointerstitial and interstitial pneumonia lesions had a chronic course while most suppurative and fibrinous bronchopneumonia lesions had an acute course and a higher degree of severity. The combination of microscopic lesions more frequently observed was bronchointerstitial pneumonia + interstitial pneumonia + suppurative bronchopneumonia. The average loss of ADWG calculated for all pigs included in the study according the extension of the lung lesions was 22.33 g/day.Conclusions: The prevalence of MLL at abattoir was 30.97% but the microscopic examination of a sample of randomly selected lungs indicated that the real prevalence of lungs with lesions compatible with M. hyopneumoniae infection would be reduced to 24.21 %. The average score of MLL using a 0 to 5 points was 1.99 and the average loss of ADWG associated to those lesions was 22.33 g/day. The result of our study supports the importance of M. hyopneumoniae as primary pathogen in cases of PRDC.

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“…S. suis rarely induce disease in finisher animals due to the high levels of antibodies present in older animals [ 25 ], and the detection of the pathogen in such mixed infections at slaughter should not be taken into consideration. Indeed, S. suis may be isolated from healthy lungs without lesions, probably due to the fact that some carrier isolates may go from the upper to the lower respiratory tract during agony [ 2 , 36 ].…”

Section: Should S Suis Be Considered a Respiratormentioning

confidence: 99%

“…The authors suggest that the interspecies interactions between S. suis and A. pleuropneumoniae may be cooperative under specific conditions and may play an important role in disease progression and persistent infection [ 136 ]. It should be noted, however, that both pathogens affect piglets of different ages, with A. pleuropneumoniae mainly causing disease in grower-finisher animals and S. suis affecting mostly nursery piglets [ 36 ]. Indeed, the implications of the results obtained in the S. suis - A. pleuropneumoniae co-infection study should be carefully interpreted, as they probably do not reflect the situation in the field.…”

Section: S Suis Mixed And/or Co-infections With Other Bactementioning

confidence: 99%

Review of the speculative role of co-infections in Streptococcus suis-associated diseases in pigs

Obradović

Segura

Segalés

et al. 2021

Vet Res

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Streptococcus suis is one of the most important bacterial swine pathogens affecting post-weaned piglets, causing mainly meningitis, arthritis and sudden death. It not only results in severe economic losses but also raises concerns over animal welfare and antimicrobial resistance and remains an important zoonotic agent in some countries. The definition and diagnosis of S. suis-associated diseases can be complex. Should S. suis be considered a primary or secondary pathogen? The situation is further complicated when referring to respiratory disease, since the pathogen has historically been considered as a secondary pathogen within the porcine respiratory disease complex (PRDC). Is S. suis a respiratory or strictly systemic pathogen? S. suis is a normal inhabitant of the upper respiratory tract, and the presence of potentially virulent strains alone does not guarantee the appearance of clinical signs. Within this unclear context, it has been largely proposed that co-infection with some viral and bacterial pathogens can significantly influence the severity of S. suis-associated diseases and may be the key to understanding how the infection behaves in the field. In this review, we critically addressed studies reporting an epidemiological link (mixed infections or presence of more than one pathogen at the same time), as well as in vitro and in vivo studies of co-infection of S. suis with other pathogens and discussed their limitations and possibilities for improvement and proposed recommendations for future studies.

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Association Between Infectious Agents and Lesions in Post-Weaned Piglets and Fattening Heavy Pigs With Porcine Respiratory Disease Complex (PRDC)

Cited by 32 publications

References 30 publications

Prevalence of mycoplasma-like lung lesions in pigs from commercial farms from Spain and Portugal

Prevalence of mycoplasma-like lung lesions in pigs from commercial farms from Spain and Portugal

Prevalence of Mycoplasma-like Lung Lesions in Pigs From Commercial Farms From Spain and Portugal

Review of the speculative role of co-infections in Streptococcus suis-associated diseases in pigs

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