Evaluation of clinical, histological and immunological changes and qPCR detection of Mycoplasma hyopneumoniae in tissues during the early stages of mycoplasmal pneumonia in pigs after experimental challenge with two field isolates

Woolley, Lauren K.; Fell, Shayne A.; Gonsalves, Jocelyn R.; Walker, Mark J.; Djordjevic, Steven P.; Jenkins, Cheryl; Eamens, G. J.

doi:10.1016/j.vetmic.2012.07.025

Cited by 47 publications

(54 citation statements)

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“…Also other diagnostic methods could be used. In addition to the already mentioned oral fluids, tracheobronchial swabs [51] or lavage [52] would be of help. Their disadvantage is the need for special equipment and/or sedation of the pig, which might limit this sampling method under field conditions.…”

Section: Discussionmentioning

confidence: 99%

Etiology of acute respiratory disease in fattening pigs in Finland

et al. 2017

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BackgroundThe objective of our study was to clinically and etiologically investigate acute outbreaks of respiratory disease in Finland. Our study also aimed to evaluate the clinical use of various methods in diagnosing respiratory infections under field conditions and to describe the antimicrobial resistance profile of the main bacterial pathogen(s) found during the study.MethodsA total of 20 case herds having finishing pigs showing acute respiratory symptoms and eight control herds showing no clinical signs suggesting of respiratory problems were enrolled in the study. Researchers visited each herd twice, examining and bleeding 20 pigs per herd. In addition, nasal swab samples were taken from 20 pigs and three pigs per case herd were necropsied during the first visit. Serology was used to detect Actinobacillus pleuropneumoniae (APP), swine influenza virus (SIV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine respiratory coronavirus (PRCV) and Mycoplasma hyopneumoniae antibodies. Polymerase chain reaction (PCR) was used to investigate the presence of porcine circovirus type 2 (PCV2) in serum and SIV in the nasal and lung samples. Pathology and bacteriology, including antimicrobial resistance determination, were performed on lung samples obtained from the field necropsies.ResultsAccording to the pathology and bacteriology of the lung samples, APP and Ascaris suum were the main causes of respiratory outbreaks in 14 and three herds respectively, while the clinical signs in three other herds had a miscellaneous etiology. SIV, APP and PCV2 caused concurrent infections in certain herds but they were detected serologically or with PCR also in control herds, suggesting possible subclinical infections. APP was isolated from 16 (80%) case herds. Marked resistance was observed against tetracycline for APP, some resistance was detected against trimethoprim/sulfamethoxazole, ampicillin and penicillin, and no resistance against florfenicol, enrofloxacin, tulathromycin or tiamulin was found. Serology, even from paired serum samples, gave inconclusive results for acute APP infection diagnosis.ConclusionsAPP was the most common cause for acute respiratory outbreaks in our study. SIV, A. suum, PCV2 and certain opportunistic bacteria were also detected during the outbreaks; however, viral pathogens appeared less important than bacteria. Necropsies supplemented with microbiology were the most efficient diagnostic methods in characterizing the studied outbreaks.

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Section: Discussionmentioning

confidence: 99%

Etiology of acute respiratory disease in fattening pigs in Finland

et al. 2017

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“…Differences in strain virulence have been observed for M. hyopneumoniae (Vicca et al, 2003;Villarreal et al, 2009;Woolley et al, 2012;). Moreover, the most closely related Mycoplasma flocculare is a commensal of the pig not causing any disease (Siqueira et al, 2013).…”

Section: Comparative Studies With Other Mycoplasmasmentioning

confidence: 97%

Update onMycoplasma hyopneumoniaeinfections in pigs: Knowledge gaps for improved disease control

Maes

Sibila

Kuhnert

et al. 2017

Transbound Emerg Dis

207

229

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SummaryMycoplasma hyopneumoniae (M. hyopneumoniae) is the primary pathogen of enzootic pneumonia, a chronic respiratory disease in pigs. Infections occur worldwide and cause major economic losses to the pig industry. The present paper reviews the current knowledge on M. hyopneumoniae infections, with emphasis on identification and analysis of knowledge gaps for optimizing control of the disease. Close contact between infected and susceptible pigs is the main route of M. hyopneumoniae transmission. Management and housing conditions predisposing for infection or disease are known, but further research is needed to better understand M. hyopneumoniae transmission patterns in modern pig production systems, and to assess the impor-

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“…hyopneumoniae broth culture (CT) was applied in the majority of cases. The dosage given per pig was greatly variable, reaching a maximum of 1.50 x 10 15 CCU [23]. Such a large dose displaced the mean to a high value, but the median dose per animal was 7 x 10 8 CCU, being 10 7 CCU/pig the most prevalent inoculum dose.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the obtained results support the already reported high virulence of some M . hyopneumoniae strains such as Hillcrest [23] or even the lack of pathogenicity of J strain [35, 36], from which some current M . hyopneumoniae commercial vaccines are based [37].…”

Section: Discussionmentioning

confidence: 99%

Determinants for swine mycoplasmal pneumonia reproduction under experimental conditions: A systematic review and recursive partitioning analysis

et al. 2017

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One of the main Mycoplasma hyopneumoniae (M. hyopneumoniae) swine experimental model objectives is to reproduce mycoplasmal pneumonia (MP). Unfortunately, experimental validated protocols to maximize the chance to successfully achieve lung lesions induced by M. hyopneumoniae are not available at the moment. Thus, the objective of this work was to identify those factors that might have a major influence on the effective development of MP, measured as macroscopic lung lesions, under experimental conditions. Data from 85 studies describing M. hyopneumoniae inoculation experiments were compiled by means of a systematic review and analyzed thereafter. Several variables were considered in the analyses such as the number of pigs in the experiment, serological status against M. hyopneumoniae, source of the animals, age at inoculation, type of inoculum, strain of M. hyopneumoniae, route, dose and times of inoculation, study duration and co-infection with other swine pathogens. Descriptive statistics were used to depict M. hyopneumoniae experimental model main characteristics whereas a recursive partitioning approach, using regression trees, assessed the importance of the abovementioned experimental variables as MP triggering factors. A strong link between the time period between challenge and necropsies and lung lesion severity was observed. Results indicated that the most important factors to explain the observed lung lesion score variability were: (1) study duration, (2) M. hyopneumoniae strain, (3) age at inoculation, (4) co-infection with other swine pathogens and (5) animal source. All other studied variables were not relevant to explain the variability on M. hyopneumoniae lung lesions. The results provided in the present work may serve as a basis for debate in the search for a universally accepted M. hyopneumoniae challenge model.

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Evaluation of clinical, histological and immunological changes and qPCR detection of Mycoplasma hyopneumoniae in tissues during the early stages of mycoplasmal pneumonia in pigs after experimental challenge with two field isolates

Cited by 47 publications

References 46 publications

Etiology of acute respiratory disease in fattening pigs in Finland

Etiology of acute respiratory disease in fattening pigs in Finland

Update onMycoplasma hyopneumoniaeinfections in pigs: Knowledge gaps for improved disease control

Determinants for swine mycoplasmal pneumonia reproduction under experimental conditions: A systematic review and recursive partitioning analysis

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