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

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Pallares, JA Añón, IM Rodríguez-Gómez, J Gómez-Laguna, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-135831/v2 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 08 Mar, 2021 Read the published version in Porcine Health Management → Version 2 posted 9 You are reading this latest preprint version Show more versions Abstract 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. Animal Science Pulmonology Mycoplasma hyopneumoniae lung lesions prevalence histopathology scoring system Figures Figure 1 Background Mycoplasma hyopneumoniae is the primary etiological agent of enzootic pneumonia (EP), a chronic respiratory disease considered as one of the most widespread and economically damaging diseases for the swine industry [1,2,3]. M. hyopneumoniae plays a pivotal role as primary agent of porcine respiratory disease complex (PRDC), a multifactorial disease resulting from the interaction of different infectious agents (viruses, mycoplasmas and bacteria), management and environmental conditions and host factors [4,5]. Typical EP gross lung lesions are characterized by well defined, greyish to reddish depressed cranioventral areas of consolidation. Microscopically, these areas correspond with a pattern of bronchointerstitial pneumonia with lymphoid cells infiltrating the lamina propria of bronchioles to a differing extent and, finally, evolving a hyperplasia of bronchus-associated lymphoid tissue (BALT) at peribronchial, peribronchiolar and perivascular levels [6, 7, 8]. Post-mortem inspection at abattoir is a truly common and useful practice in many countries to gather information about herd health status and to monitor the efficacy of treatments and management conditions. Prevalence and severity of lung lesions, identification of the possible etiology and herd risk factors associated with these lesions, as well as the impact of the lesions on performance indicators and carcass and meat quality have been the subject of many studies [9, 10, 11, 12, 13, 14, 15, 16]. Thus, a high variation among countries in the prevalence of mycoplasma-like lesions (MLL) at abattoir, ranging from 23.85 % in Belgium to 72.60 % in Germany, has been reported [9, 11, 12, 15, 17, 18, 19, 20]. Several and different methods can be performed for evaluating the severity of lung lesions at abattoir [21, 22, 23, 24, 25]. Most of them are based on the quantification of the affected lung surface [22, 23, 24, 25], nevertheless, nowadays, due to the speed of the slaughterline at industrial abattoirs, with more than 500 pigs per hour being slaughtered, some of these methods are impractical and difficult to follow. For that reason, the scoring systems need to be modified and adapted to the new reality, trying to be easy to perform and repeatable, even if there is a tiny loss of accuracy. The association of lung lesions at abattoir, such as pleurisy and lung scars, with poor performances as decreased average daily gain (ADG) and economic return [16, 26] highlights the importance of monitoring lesions at abattoir. However, the prevalence of microscopic lung lesions has been reported to be much higher than the prevalence of macroscopic ones when investigating non-infectious factors associated with gross and microscopic lung lesions in slaughtered pigs [9]. In this sense, whereas gross lesions, such as MLL or pleurisy, can take between 8 to 12 weeks to heal and disappear [6, 7, 27], microscopic lesions may persist for longer [9]. Thus, histopathology can bring to light the presence of lesions that grossly can go unnoticed. The aim of this study was to investigate the prevalence and severity of MLL at abattoirs in Spain and Portugal using a 0 to 5 scoring system adapted to a high number of slaughtered pigs per hour, to know the real prevalence of lesions associated with M. hyopneumoniae infection as well as to highlight the use of histopathology to confirm the lesions and identify other patterns involved in the examined lungs. Results Lung examination at abattoir and scoring The type and percentage of lung lesions observed at abattoir are showed in Table 1. Approximately half of all examined lungs at abattoir did not exhibit any gross lung lesion (100,371 lungs; 50.26 %). Cranioventral pulmonary consolidation (compatible with MLL) was the most frequent lung lesion (61,832 lungs; 30.97 %) (Fig. 1A, C and E), followed by dorsocaudal infarcts with pleurisy (compatible with Actinobacillus pleuropneumoniae infection) (24,970 lungs; 12.51 %) and pleurisy alone, that was recorded in 12,505 lungs (6.26 %). Similar percentages of MLL were found in Spain (31.14 %) and in Portugal (29.95 %). Table 1 includes the number of lungs according to the given score for MLL. Scores 1 and 2 were the most frequent with 13.04 % (26,046 lungs) and 9.02 % (18,008 lungs), respectively. The average score of all lungs exhibiting cranioventral consolidation was 1.99, no finding differences across countries, 2.00 for Spain and 1.93 in the case of Portugal. Histopathology of the lungs As depicted in Table 2, bronchointerstitial pneumonia, compatible with M. hyopneumoniae infection, was the most frequent lesion pattern (78.17 %) (Fig. 1B), followed by suppurative bronchopneumonia (73.47 %) (Fig. 1D), interstitial pneumonia (68.65 %) and fibrinous bronchopneumonia (14.21 %). The highest degree of severity was observed in cases of fibrinous bronchopneumonia (2.89), followed by suppurative bronchopneumonia (2.52), bronchointerstitial (2.17) and interstitial pneumonia (1.74), the latter with the lowest score. With respect to the course, most of the cases of bronchointerstitial and interstitial pneumonia had a chronic course, whereas most of the cases of suppurative and fibrinous bronchopneumonia had an acute course. Moreover, roughly 41 % of the studied lungs showed pleurisy, chronic in most of the cases (89.17 %). The more prevalent combinations of microscopic patterns of lesions are showed in Table 3. Of note, more than one lesion pattern coexisted in most sampled lungs. Thus, from the 788 microscopically examined lungs, 720 (91.37 %) presented more than one microscopic pattern, 59 lungs (7.49 %) only showed one microscopic pattern and, only 9 lungs (1.14 %) did not exhibited any microscopic lesion. The most frequent combination of microscopic patterns was bronchointerstitial pneumonia + interstitial pneumonia + suppurative bronchopneumonia in 171 lungs (21.70 %) and the same combination accompanied by pleurisy in other 108 lungs (13.71 %), followed by the combination of bronchointerstitial pneumonia + suppurative bronchopneumonia (Fig. 1F) found in 77 lungs (9.77 %) and in 62 additional lungs together with pleurisy (7.87 %). The six more prevalent combinations of microscopic patterns of pneumonia represented two thirds (66.13 %) of the lungs microscopically examined, with lesions characteristic of M. hyopneumoniae infection being found in all of them (Table 3). Combinations with an equal number of lesion patterns showed a higher degree of severity when bronchopneumonia was present, irrespective of the type of bronchopneumonia. Discussion Despite the reported efficacy of M. hyopneumoniae vaccines in reducing lung lesions [28] and bacterial load from the respiratory tract [29], they are not capable of fully eliminate the bacteria from the animal, giving them the opportunity to cause typical MLL in a variable percentage of pigs at abattoir in different countries [12, 17, 19, 20]. To investigate the prevalence and severity of MLL at abattoirs in Spain and Portugal using a 0 to 5 scoring system adapted to fast slaughterlines, a study with an elevated number of pigs (199,678) involving a high number of farms (221) was performed. Additionally, a sample of 788 lungs was taken to corroborate microscopically the presence of lesions characteristics of the infection induced by M. hyopneumoniae. In our study, no gross lesions were found in 50.26 % of all examined lungs at abattoir and roughly 31 % showed cranioventral consolidations compatible with mycoplasma lesions, showing similar frequencies in Spain (31.14 %) and Portugal (29.95 %). These prevalence rates of MLL were higher than those reported in Belgium (23.85 % and 24.00 %) [9, 17] but lower than those previously found in Spain (44.61 to 55.69 %) [11, 19], Italy (46.38 %) [12], France (69.30 %) [18] or Germany (72.60 %) [20]. The main difference among studies was the number of examined lungs, with nearly 200,000 lungs evaluated in this study in comparison with numbers ranging from 600 [19] to 10,404 in other studies [11]. However, other factors such as the epidemiological scenario in each country also play a role in these differences. Consequently, considering the high number of farms and the different pig production areas herein reported, we consider that our data provide an accurate percentage of prevalence of MLL in Spain and Portugal. Moreover, if we consider the histopathological results and the percentage of selected lungs with MLL compatible with M. hyopneumoniae infection (78.17 %), the real prevalence of gross lesions caused by this bacterium would be reduced from 30.97 % to 24.21 %. Other lesions, such as suppurative bronchopneumonia, as represented in Fig. 1, exhibited a similar gross appearance [30, 31] and, hence, this type of pneumonia could be mixed up with lesions caused by M. hyopneumoniae . Thereby, those studies, in which a microscopic confirmation has not been performed, could bias the results, overestimating the prevalence. In the study carried out by Luhers et al. [20], 78.30 % of 400 lungs with MLL collected at the abattoir were positive to M. hyopneumoniae by PCR, a percentage very similar to the one found with compatible microscopic lesions in our study (78.17 %). These results highlight the interest of performing additional studies on lungs with MLL to confirm the diagnosis of EP or infection by M. hyopneumoniae . Pleurisy, associated with dorsocaudal infarcts or alone, was the second most prevalent gross lesion of our study, affecting 18.77 % of the examined lungs, a percentage very similar to that found in France (15.00 %) [18] or Belgium (16.00 %) [9], but lower than those previously reported in Italy (25.10 %) [12] or Spain (26.80 %) [11]. In our case, most of the pleurisy (66.65 %) was associated with dorsocaudal infarcts, a hallmark of A. pleuropneumoniae infection, lesion which has been associated with decreased ADG during the grower-finisher period, leading to lower economic return [16]. Therefore, the measures to control this pathogen (management, therapeutic or vaccination) should be revised and/or implemented in the farms included in the study. According to our findings, most of the lesions of bronchointerstitial and interstitial pneumonia, characteristics of mycoplasma and viral infections, respectively, had a chronic course, by contrast, the majority of the lesions of suppurative and fibrinous bronchopneumonia, characteristics of bacterial infection, had an acute course and a higher degree of severity. 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. A recent study carried out in Brazil by Galdeano et al. [15] also found the characteristic lesions of M. hyopneumoniae infection as the most prevalent one, being detected in 63.75 % of the lungs examined microscopically, but different to our study, the second most frequent lesion was chronic bronchopneumonia (57.14 %) whereas other lung lesions common in our study such as suppurative bronchopneumonia, interstitial pneumonia or fibrinous bronchopneumonia, were observed in a lesser extent (15.63 %, 3.61 % and 0.15 %, respectively). Nevertheless, it must be taken into account that porcine reproductive and respiratory syndrome virus (PRRSV) has never been detected in Brazil [33], thus, one of the main primary agents involved in the PRDC [5], alone or in combination with other pathogens, is not taken place in those farms. Therefore, the clinical and lesional picture at abattoir would be totally different in Brazil, when compared with those countries where PRRSV is endemic, such as Spain or Portugal. The histopathological study provided us a more accurate idea of the real prevalence of lesions caused by M. hyopneumoniae but also information about the concomitant action of other pathogens involved in the PRDC that sometimes go clinically unnoticed. In addition, some lesions are unspecific and could be caused by different pathogens, but in association with other techniques, such as serology, bacteriology or PCR, histopathology could provide a more accurate information about which agent is causing the lesion, since a positive result in those diagnostic techniques against some pathogens [i.e. M. hyopneumoniae or porcine circovirus type 2 (PCV2)] does not necessarily always mean that they are causing any lesion. Lesions of bronchointerstitial pneumonia compatible with M. hyopneumoniae infection were found in the six more frequent combinations of lesion patterns in our study, representing 66.13 % of the lungs examined, what support the relevant role of this agent in the PRDC as a primary agent as well as enhancing the action of other pathogens involved in as PRRSV [34], PCV2 [35] or swine influenza virus [36]. The scoring system from 0 to 5 points used in this study for MLL, adapted from a previous one [37], has been showed as a simple and repeatable method that can be easily applied in cases of abattoirs with fast slaughterline, sometimes more than 500 pigs per hour. By contrast, it is not as precise as other methods which express the proportion of affected lung area in percentages [22, 23, 24, 25]. Conclusions The 0 to 5 points scoring system proposed in the present study showed to be a simple, useful and repeatable method that can be easily conducted in cases of abattoirs with a fast slaughterline. An average score of MLL of 1.99 was obtained by using this scoring system and a real prevalence of 24.21 % was determined after confirmation of cranioventral consolidation compatible with mycoplasma lesions by histopathology. Our results highlight the significance of M. hyopneumoniae in PRDC, acting as a primary agent in combination with other pathogens which lead to different patterns of lung lesions, and emphasize the necessity of implementing holistic control measures against this agent. Methods Study population A total of 199,678 pigs from 221 different herds from Spain (170,174 pigs; 85.22 %) and Portugal (29,504 pigs; 14.78 %) were examined at abattoir from 2013 to 2017. All herds herein included belonged to the Mycoguard Program , a project conducted by Ecuphar Veterinaria SLU with the purpose of evaluating the incidence and type of lung lesions at abattoir. A batch from each fattening unit of the herd (average size of 200 pigs) was examined at the abattoir. The average weight and age of the pigs at sacrifice were 100 kg (95-105 kg) and 6 months, respectively. Most of the origin farms (142/221; 64.25 %) were located in southern Spain (regions of Andalusia, Extremadura and Murcia), followed by 25.79 % (57/221) in the north of Spain (regions of Cataluña, Aragón and Castilla y León) and 9.96 % (22/221) in Portugal. All considered farms have historically vaccinated against M. hyopneumoniae with commercial vaccines. Lung examination at abattoir and scoring Lung examination was performed in 46 different abattoirs located in Spain (36) and Portugal (10) by seven veterinarians, which have been thoroughly trained to follow the same scoring criteria in order to avoid individual discrepancies. The slaughterline speed ranged from 350 to 600 pigs per hour, but in most of the abattoirs the speed was comprised between 500 and 600 pigs per hour. All pigs were stunned with CO 2 before bleeding. Lungs were visually appraised and palpated to detect lesions compatible with pneumonia. The system used for scoring cranioventral consolidations in the lung was based on the previously score proposed by Bollo et al. [37] with some modifications. Briefly, score 0: no lesion observed; score 1: consolidation affecting unilaterally the apex of one or two different lung lobes; score 2: consolidation affecting bilaterally the apex of one or two different lung lobes; score 3: consolidation affecting bilaterally the apex and medial part of one or two different lung lobes; score 4: consolidation affecting bilaterally the apex and medial part of one or two different lung lobes and partial involvement of the cranial area of one caudal lung lobe; score 5: consolidation affecting all lobes, including the cranial area of both caudal lobes. The average score was calculated for each batch (data not showed) and each country. The presence of other lesions, such as infarcts, abscesses and pleurisy, was also recorded. Histopathology of the lung Three to four lungs per batch with MLL were randomly selected at the abattoir for histopathological examination. Therefore, a total of 788 lungs, 737 from Spain and 51 from Portugal, were pictured and four samples per lung were collected: one belonging to the cranial lung lobe, other from the middle lung lobe and two from the ventral and dorsal areas of the caudal lung lobe of the right lung. In case of the left lung, the two portions of the cranial lung lobe together with the two samples coming from the caudal lung lobe were collected. The specimens were collected at the boundary junction of affected and unaffected tissue. Samples were fixed in 10 % neutral buffered formalin for 24 hours, embedded in paraffin wax, sectioned at 4 microns and stained with hematoxylin and eosin. Microscopic lung lesions of pneumonia were classified as bronchopneumonia (suppurative or fibrinous), bronchointerstitial and interstitial pneumonia according to the morphological pattern. Briefly, bronchopneumonia was characterized by the presence of inflammatory exudate into bronchi, bronchioles and alveoli that in the case of suppurative bronchopneumonia was predominantly composed of degenerated neutrophils while in fibrinous bronchopneumonia the predominant component of the exudate was fibrin, associated with the presence of necrosis and hemorrhages. Interstitial pneumonia was characterized by the thickening of alveolar walls by the presence of mononuclear cells and hyperplasia and hypertrophy of type II pneumocytes. In the case of bronchointerstitial pneumonia, mononuclear cells encircling airways and infiltrating alveolar septa and BALT hyperplasia were present [30, 31]. Pleurisy, characterized by the presence of fibrin or connective tissue in the pleura, was also recorded. Each microscopic lesion was scored according to its severity in mild (score 1), moderate (score 2) or severe (score 3), except for pleurisy that was scored as 0 (absence) or 1 (presence). The criteria for the scoring of microscopic lung lesions are summarized in Table 4. The microscopic score was calculated for each pattern of pneumonia and the final score was calculated by adding the individual scores for each type of pneumonia. As four samples were microscopically examined per lung, the score selected for each lesion pattern was the most severe one observed in any of the examined samples. Lesions were also differentiated according to their course as acute or chronic lesions. Acute lesions were defined as those with neutrophils as the dominant inflammatory cell type, extensive edema and fibrin exudation. Chronic lesions were characterized by mononuclear cell infiltrate, primarily consisting of lymphocytes and plasma cells, proliferation of connective tissue, epithelial or BALT hyperplasia, and hypertrophy of the smooth muscle layer around bronchioles and alveolar ducts. All the slides were blindly evaluated by two pathologists to determine the pattern and score of pneumonia. Abbreviations ADG: average daily gain; BALT: bronchus-associated lymphoid tissue; EP: enzootic pneumonia; MLL: mycoplasma-like lesions; PCV2: porcine circovirus type 2; PRDC: porcine respiratory disease complex; PRRSV: porcine reproductive and respiratory syndrome virus. Declarations Ethics approval and consent to participate The present article does not include experimental data. Therefore, animal ethics committee approval was not necessary. Consent for publication All authors gave their consent for publication. Availability of data and materials The datasets used and analyzed during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. Funding This study was partially funded by Ecuphar Veterinaria SLU. Authors contribution JAA, LC and FJP designed the study; IMRG, JGL, JMSC and IRT photographed and sampled the lungs. FJP and IMRG performed the histopathological study; RF, JGL and FJP analyzed the data; FJP and JAA wrote the manuscript; LC supervised the study. All authors read and approved the final version of the manuscript. Acknowledgments We express our appreciation to Gema Muñoz, Alberto Alcántara and Juan Sánchez for their technical assistance. J. Gómez-Laguna is supported by a “Ramón y Cajal” contract of the Spanish Ministry of Economy and Competitiveness (RYC-2014-16735). Authors information 1 Department of Anatomy and Comparative Pathology and Toxicology, Faculty of Veterinary Medicine, University of Córdoba, 14014, Córdoba, Spain. 2 Ecuphar Veterinaria SLU, 08016 Barcelona, Spain. * Present address: Olmix Ibérica SLU, 31192 Mutilva, Navarra, Spain. ¶ Present address: Forestal Catalana SA, 08012 Barcelona, Spain. † FJ Pallarés and JA Añón contributed equally as first authors. References Maes D, Verdonck M, Deluyker H, de Kruif A. 1996. Enzootic pneumonia in pigs. Vet Q 1996;18:104-109. Holst S, Yeske P, Pieters M. Elimination of mycoplasma hyopneumoniae from breed-to-wen farms: A review of current protocols with emphasis on herd closure and medication. J Swine Healt Prod 2015;23:321-330. Maes D, Sibila M, Kuhnert P, Segalés J, Haesebrouck F, Pieters M. Update on Mycoplasma hyopneumoniae infections in pigs: knowledge gaps for improve disease control. Transbound and Emerg Dis 2018;65 (Suppl. 1):110-124. Brockmeier S,Halbur PG, Thacker EL. 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In: Proceedings of the 20 th IPVS Congress, Durban, South Africa, 2008. p 104. Tables Table 1. Type, number and percentage of gross lesions observed at abattoir. In case of cranioventral pulmonary consolidation, the number and percentage of lungs belonging to each score (1-5) has been itemized. Gross lung lesion Number of lungs (percentage) Cranioventral pulmonary consolidation 61,832 (30.97 %) Score 1 26,046 (13.04 %) Score 2 18,008 (9.02 %) Score 3 11,408 (5.71 %) Score 4 4,925 (2.47 %) Score 5 1,445 (0.72 %) Dorsocaudal infarcts with pleurisy 24,970 (12.51 %) Pleurisy alone 12,505 (6.26 %) No lesion 100,371 (50.26 %) Table 2. Number, severity and course for each histopathological pattern of pneumonia. Type of microscopic lesion Number (%) Severity (1-3) Course (acute/chronic) Bronchointerstitial pneumonia 616 (78.17 %) 2.17 (3.09 % / 96.91 %) Suppurative bronchopneumonia 579 (73.47 %) 2.52 (72.36 % / 27.64 %) Fibrinous bronchopneumonia 112 (14.21 %) 2.89 (66.07 % / 33.93 %) Interstitial pneumonia 541 (68.65 %) 1.74 (3.51 % / 96.49 %) Pleurisy 323 (40.99 %) - (10.83 % / 89.17 %) Table 3. More prevalent combinations of microscopic patterns of pneumonia including the number and percentage of lungs and lesion severity. Patterns of microscopic lesion Number (%) Severity Bronchointerstitial pneumonia + interstitial pneumonia + suppurative bronchopneumonia 171 (21.70 %) 6.44 Bronchointerstitial pneumonia + interstitial pneumonia + suppurative bronchopneumonia + pleurisy 108 (13.71 %) 7.45 Bronchointerstitial pneumonia + suppurative bronchopneumonia 77 (9.77 %) 4.64 Bronchointerstitial pneumonia + suppurative bronchopneumonia + pleurisy 62 (7.87 %) 5.55 Bronchointerstitial pneumonia + interstitial pneumonia 53 (6.73 %) 4.11 Bronchointerstitial pneumonia + interstitial pneumonia + pleurisy 50 (6.35 %) 5.12 Suppurative bronchopneumonia + interstitial pneumonia 40 (5.08 %) 4.18 Interstitial pneumonia 23 (2.92 %) 1.83 Table 4. Scoring system used to determine the severity of microscopic lung lesions. Type of pneumonia Mild (Score 1) Moderate (Score 2) Severe (Score 3) Bronchointerstitial pneumonia BALT in > 5 bronchi or bronchioles (1-2 BALT per structure) 1.- BALT in > 5 bronchi or bronchioles (50 % of the structure is surrounded by BALT) or 2.- BALT in > 5 bronchi or bronchioles (1-2 BALT per structure) and one bronchus or bronchiole completely surrounded by hyperplasia of BALT 1.- At least two structures are almost completely surrounded (80 %) by hyperplasia of BALT or 2.- All structures of the section are affected Interstitial pneumonia 1-2 lobule/s affected* 50 % affected* All lobuli are affected* Suppurative pneumonia 1-2 lobule/s affected* 50 % affected* All lobuli are affected* Fibrinous pleuropneumonia 1-2 lobule/s affected* 50 % affected* All lobuli are affected* Pleurisy Presence --- --- The term “structure” describes a bronchus or bronchiole, equally. *Every evaluated section included at least 6 lobuli. BALT: bronchus-associated lymphoid tissue. Cite Share Download PDF Status: Published Journal Publication published 08 Mar, 2021 Read the published version in Porcine Health Management → Version 2 posted Editorial decision: Major revision 14 Feb, 2021 Reviewer # 2 agreed at journal 09 Feb, 2021 Reviewers invited by journal 09 Feb, 2021 Reviewer # 1 agreed at journal 09 Feb, 2021 Review # 2 received at journal 09 Feb, 2021 Review # 1 received at journal 09 Feb, 2021 Editor assigned by journal 08 Feb, 2021 Submission checks completed at journal 08 Feb, 2021 Editor invited by journal 08 Feb, 2021 You are reading this latest preprint version Show more versions Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-135831","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research","associatedPublications":[],"authors":[{"id":11272205,"identity":"c1b2894e-f244-4b80-bcfb-9dec34362538","order_by":0,"name":"Francisco J. Pallares","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAxElEQVRIiWNgGAWjYBAC9gYGxgMPoCziAM8BBoYDCTAWiVokEojVIt384EBCzT05+ZlvDD98YLCxJ6xF5pjBgYRjxcYGt3OMJWcwpCU2ENJiL5EA1MKWkLhBOseMmYfhMGHn8UikfziQ8C+hfv7MMyAt/4lwmESOwYHEtoQEhhs8IC0HGAk6jEfmTMGBxL4Eww1n0oolZxgkE/YLj3T7xgcfviXIy7cf3vjhQ4UdYYcxSKDwDAhrQNcyCkbBKBgFowALAACJNTx4wDqVvgAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0001-9913-5420","institution":"Universidad de Murcia","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Francisco","middleName":"J.","lastName":"Pallares","suffix":""},{"id":11272206,"identity":"d004c6c8-0039-4816-beb2-7fd2fda45dfa","order_by":1,"name":"JA Añón","email":"","orcid":"","institution":"Olmix IbéricaSLU","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"JA","middleName":"","lastName":"Añón","suffix":""},{"id":11272207,"identity":"835dbf22-11d9-4920-9db2-8fd16dc746f3","order_by":2,"name":"IM Rodríguez-Gómez","email":"","orcid":"","institution":"Universidad de Córdoba","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"IM","middleName":"","lastName":"Rodríguez-Gómez","suffix":""},{"id":11272208,"identity":"4c437f32-9070-4d39-a327-97375fd1a3aa","order_by":3,"name":"J Gómez-Laguna","email":"","orcid":"","institution":"Universidad de Córdoba","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"J","middleName":"","lastName":"Gómez-Laguna","suffix":""},{"id":11272209,"identity":"3347b17c-e6e6-4094-9d3b-19909e85da34","order_by":4,"name":"R Fabré","email":"","orcid":"","institution":"Forestal Catalana SA","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"R","middleName":"","lastName":"Fabré","suffix":""},{"id":11272210,"identity":"4025022f-3a76-4a29-aefc-b536a05c1780","order_by":5,"name":"JM Sánchez-Carvajal","email":"","orcid":"","institution":"Universidad de Cordoba","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"JM","middleName":"","lastName":"Sánchez-Carvajal","suffix":""},{"id":11272211,"identity":"f1d153c0-1da5-45d8-8434-a47d219a0658","order_by":6,"name":"Inés Ruedas-Torres","email":"","orcid":"","institution":"Universidad de Córdoba","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Inés","middleName":"","lastName":"Ruedas-Torres","suffix":""},{"id":11272212,"identity":"84db60f2-6d32-4848-9d44-b9070b2462f9","order_by":7,"name":"Librado Carrasco","email":"","orcid":"","institution":"Universidad de Córdoba","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Librado","middleName":"","lastName":"Carrasco","suffix":""}],"badges":[],"createdAt":"2020-12-25 00:03:09","currentVersionCode":2,"declarations":"","doi":"10.21203/rs.3.rs-135831/v2","doiUrl":"https://doi.org/10.21203/rs.3.rs-135831/v2","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s40813-021-00204-3","type":"published","date":"2021-03-08T15:00:31+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":6089885,"identity":"ccf14611-d00c-458b-998f-43615fb405b3","added_by":"auto","created_at":"2021-02-18 11:28:48","extension":"tif","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":3831494,"visible":true,"origin":"","legend":"Lungs showing Mycoplasma-like lesions at abattoir (A, C and E) and their corresponding microscopic lesions (B, D and F, respectively). B: Peribronchiolar lymphoid clumps of cells of varying degrees of development infiltrating the lamina propria of the bronchioles to a differing extent (BALT hyperplasia) (arrows). Bronchointerstitial pneumonia. D: Exudate inside bronchi, bronchioles and alveoli, predominantly composed of degenerated neutrophils (asterisks). Suppurative bronchopneumonia. F: Mixed pattern of lesions showing both types of pneumonia described in pictures B and D (arrows and asterisks). Bronchointerstitial pneumonia + suppurative bronchopneumonia.","description":"","filename":"Figure1.tif","url":"https://assets-eu.researchsquare.com/files/rs-135831/v2/63b45f6e1b32400d5ef0a250.tif"},{"id":13666512,"identity":"37b3f0c8-ecbf-4637-8468-5e2fd187586b","added_by":"auto","created_at":"2021-09-17 10:49:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":7156872,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-135831/v2/3a9c33d5-e96c-4226-ab68-3016ea31f5a7.pdf"}],"financialInterests":"","formattedTitle":"Prevalence of mycoplasma-like lung lesions in pigs from commercial farms from Spain and Portugal","fulltext":[{"header":"Background","content":"\u003cp\u003e\u003cem\u003eMycoplasma hyopneumoniae\u003c/em\u003e is the primary etiological agent of enzootic pneumonia (EP), a chronic respiratory disease considered as one of the most widespread and economically damaging diseases for the swine industry [1,2,3]. \u003cem\u003eM. hyopneumoniae\u003c/em\u003e plays a pivotal role as primary agent of porcine respiratory disease complex (PRDC), a multifactorial disease resulting from the interaction of different infectious agents (viruses, mycoplasmas and bacteria), management and environmental conditions and host factors [4,5]. Typical EP gross lung lesions are characterized by well defined, greyish to reddish depressed cranioventral areas of consolidation. Microscopically, these areas correspond with a pattern of bronchointerstitial pneumonia with lymphoid cells infiltrating the lamina propria of bronchioles to a differing extent and, finally, evolving a hyperplasia of bronchus-associated lymphoid tissue (BALT) at peribronchial, peribronchiolar and perivascular levels [6, 7, 8].\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePost-mortem\u003c/em\u003e inspection at abattoir is a truly common and useful practice in many countries to gather information about herd health status and to monitor the efficacy of treatments and management conditions. Prevalence and severity of lung lesions, identification of the possible etiology and herd risk factors associated with these lesions, as well as the impact of the lesions on performance indicators and carcass and meat quality have been the subject of many studies [9, 10, 11, 12, 13, 14, 15, 16]. Thus, a high variation among countries in the prevalence of mycoplasma-like lesions (MLL) at abattoir, ranging from 23.85 % in Belgium to 72.60 % in Germany, has been reported [9, 11, 12, 15, 17, 18, 19, 20].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSeveral and different methods can be performed for evaluating the severity of lung lesions at abattoir [21, 22, 23, 24, 25]. Most of them are based on the quantification of the affected lung surface [22, 23, 24, 25], nevertheless, nowadays, due to the speed of the slaughterline at industrial abattoirs, with more than 500 pigs per hour being slaughtered, some of these methods are impractical and difficult to follow. For that reason, the scoring systems need to be modified and adapted to the new reality, trying to be easy to perform and repeatable, even if there is a tiny loss of accuracy.\u003c/p\u003e\n\u003cp\u003eThe association of lung lesions at abattoir, such as pleurisy and lung scars, with poor performances as decreased average daily gain (ADG) and economic return [16, 26] highlights the importance of monitoring lesions at abattoir. However, the prevalence of microscopic lung lesions has been reported to be much higher than the prevalence of macroscopic ones when investigating non-infectious factors associated with gross and microscopic lung lesions in slaughtered pigs [9]. In this sense, whereas gross lesions, such as MLL or pleurisy, can take between 8 to 12 weeks to heal and disappear [6, 7, 27], microscopic lesions may persist for longer [9]. Thus, histopathology can bring to light the presence of lesions that grossly can go unnoticed.\u003c/p\u003e\n\u003cp\u003eThe aim of this study was to investigate the prevalence and severity of MLL at abattoirs in Spain and Portugal using a 0 to 5 scoring system adapted to a high number of slaughtered pigs per hour, to know the real prevalence of lesions associated with \u003cem\u003eM. hyopneumoniae\u003c/em\u003e infection as well as to highlight the use of histopathology to confirm the lesions and identify other patterns involved in the examined lungs.\u0026nbsp;\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eLung examination at abattoir and scoring\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe type and percentage of lung lesions observed at abattoir are showed in Table 1. Approximately half of all examined lungs at abattoir did not exhibit any gross lung lesion (100,371 lungs; 50.26 %). Cranioventral pulmonary consolidation (compatible with MLL) was the most frequent lung lesion (61,832 lungs; 30.97 %) (Fig. 1A, C and E), followed by dorsocaudal infarcts with pleurisy (compatible with \u003cem\u003eActinobacillus pleuropneumoniae\u0026nbsp;\u003c/em\u003einfection) (24,970 lungs; 12.51 %) and pleurisy alone, that was recorded in 12,505 lungs (6.26 %). Similar percentages of MLL were found in Spain (31.14 %) and in Portugal (29.95 %).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 1 includes the number of lungs according to the given score for MLL. Scores 1 and 2 were the most frequent with 13.04 % (26,046 lungs) and 9.02 % (18,008 lungs), respectively. The average score of all lungs exhibiting cranioventral consolidation was 1.99, no finding differences across countries, 2.00 for Spain and 1.93 in the case of Portugal.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eHistopathology of the lungs\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAs depicted in Table 2, bronchointerstitial pneumonia, compatible with \u003cem\u003eM. hyopneumoniae\u003c/em\u003e infection, was the most frequent lesion pattern (78.17 %) (Fig. 1B), followed by suppurative bronchopneumonia (73.47 %) (Fig. 1D), interstitial pneumonia (68.65 %) and fibrinous bronchopneumonia (14.21 %). The highest degree of severity was observed in cases of fibrinous bronchopneumonia (2.89), followed by suppurative bronchopneumonia (2.52), bronchointerstitial (2.17) and interstitial pneumonia (1.74), the latter with the lowest score. With respect to the course, most of the cases of bronchointerstitial and interstitial pneumonia had a chronic course, whereas most of the cases of suppurative and fibrinous bronchopneumonia had an acute course. Moreover, roughly 41 % of the studied lungs showed pleurisy, chronic in most of the cases (89.17 %).\u003c/p\u003e\n\u003cp\u003eThe more prevalent combinations of microscopic patterns of lesions are showed in Table 3. Of note, more than one lesion pattern coexisted in most sampled lungs. Thus, from the 788 microscopically examined lungs, 720 (91.37 %) presented more than one microscopic pattern, 59 lungs (7.49 %) only showed one microscopic pattern and, only 9 lungs (1.14 %) did not exhibited any microscopic lesion. The most frequent combination of microscopic patterns was bronchointerstitial pneumonia + interstitial pneumonia + suppurative bronchopneumonia in 171 lungs (21.70 %) and the same combination accompanied by pleurisy in other 108 lungs (13.71 %), followed by the combination of bronchointerstitial pneumonia + suppurative bronchopneumonia (Fig. 1F) found in 77 lungs (9.77 %) and in 62 additional lungs together with pleurisy (7.87 %). The six more prevalent combinations of microscopic patterns of pneumonia represented two thirds (66.13 %) of the lungs microscopically examined, with lesions characteristic of \u003cem\u003eM. hyopneumoniae\u003c/em\u003e infection being found in all of them (Table 3). Combinations with an equal number of lesion patterns showed a higher degree of severity when bronchopneumonia was present, irrespective of the type of bronchopneumonia. \u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eDespite the reported efficacy of \u003cem\u003eM. hyopneumoniae\u003c/em\u003e vaccines in reducing lung lesions [28] and bacterial load from the respiratory tract [29], they are not capable of fully eliminate the bacteria from the animal, giving them the opportunity to cause typical MLL in a variable percentage of pigs at abattoir in different countries [12, 17, 19, 20]. To investigate the prevalence and severity of MLL at abattoirs in Spain and Portugal using a 0 to 5 scoring system adapted to fast slaughterlines, a study with an elevated number of pigs (199,678) involving a high number of farms (221) was performed. Additionally, a sample of 788 lungs was taken to corroborate microscopically the presence of lesions characteristics of the infection induced by \u003cem\u003eM. hyopneumoniae.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;In our study, no gross lesions were found in 50.26 % of all examined lungs at abattoir and roughly 31 % showed cranioventral consolidations compatible with mycoplasma lesions, showing similar frequencies in Spain (31.14 %) and Portugal (29.95 %). These prevalence rates of MLL were higher than those reported in Belgium (23.85 % and 24.00 %) [9, 17] but lower than those previously found in Spain (44.61 to 55.69 %) [11, 19], Italy (46.38 %) [12], France (69.30 %) [18] or Germany (72.60 %) [20]. The main difference among studies was the number of examined lungs, with nearly 200,000 lungs evaluated in this study in comparison with numbers ranging from 600 [19] to 10,404 in other studies [11]. However, other factors such as the epidemiological scenario in each country also play a role in these differences. Consequently, considering the high number of farms and the different pig production areas herein reported, we consider that our data provide an accurate percentage of prevalence of MLL in Spain and Portugal. Moreover, if we consider the histopathological results and the percentage of selected lungs with MLL compatible with \u003cem\u003eM. hyopneumoniae\u003c/em\u003e infection (78.17 %), the real prevalence of gross lesions caused by this bacterium would be reduced from 30.97 % to 24.21 %. Other lesions, such as suppurative bronchopneumonia, as represented in Fig. 1, exhibited a similar gross appearance [30, 31] and, hence, this type of pneumonia could be mixed up with lesions caused by \u003cem\u003eM. hyopneumoniae\u003c/em\u003e. Thereby, those studies, in which a microscopic confirmation has not been performed, could bias the results, overestimating the prevalence. In the study carried out by Luhers et al. [20], 78.30 % of 400 lungs with MLL collected at the abattoir were positive to \u003cem\u003eM. hyopneumoniae\u003c/em\u003e by PCR, a percentage very similar to the one found with compatible microscopic lesions in our study (78.17 %). \u0026nbsp;These results highlight the interest of performing additional studies on lungs with MLL to confirm the diagnosis of EP or infection by \u003cem\u003eM. hyopneumoniae\u003c/em\u003e.\u003c/p\u003e\n\u003cp\u003ePleurisy, associated with dorsocaudal infarcts or alone, was the second most prevalent gross lesion of our study, affecting 18.77 % of the examined lungs, a percentage very similar to that found in France (15.00 %) [18] or Belgium (16.00 %) [9], but lower than those previously reported in Italy (25.10 %) [12] or Spain (26.80 %) [11]. In our case, most of the pleurisy (66.65 %) was associated with dorsocaudal infarcts, a hallmark of \u003cem\u003eA. pleuropneumoniae\u003c/em\u003e infection, lesion which has been associated with decreased ADG during the grower-finisher period, leading to lower economic return [16]. Therefore, the measures to control this pathogen (management, therapeutic or vaccination) should be revised and/or implemented in the farms included in the study. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAccording to our findings, most of the lesions of bronchointerstitial and interstitial pneumonia, characteristics of mycoplasma and viral infections, respectively, had a chronic course, by contrast, the majority of the lesions of suppurative and fibrinous bronchopneumonia, characteristics of bacterial infection, had an acute course and a higher degree of severity. 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. A recent study carried out in Brazil by Galdeano et al. [15] also found the characteristic lesions of \u003cem\u003eM. hyopneumoniae\u003c/em\u003e infection as the most prevalent one, being detected in 63.75 % of the lungs examined microscopically, but different to our study, the second most frequent lesion was chronic bronchopneumonia (57.14 %) whereas other lung lesions common in our study such as suppurative bronchopneumonia, interstitial pneumonia or fibrinous bronchopneumonia, were observed in a lesser extent (15.63 %, 3.61 % and 0.15 %, respectively). Nevertheless, it must be taken into account that porcine reproductive and respiratory syndrome virus (PRRSV) has never been detected in Brazil [33], thus, one of the main primary agents involved in the PRDC [5], alone or in combination with other pathogens, is not taken place in those farms. Therefore, the clinical and lesional picture at abattoir would be totally different in Brazil, when compared with those countries where PRRSV is endemic, such as Spain or Portugal. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe histopathological study provided us a more accurate idea of the real prevalence of lesions caused by \u003cem\u003eM. hyopneumoniae\u003c/em\u003e but also information about the concomitant action of other pathogens involved in the PRDC that sometimes go clinically unnoticed. In addition, some lesions are unspecific and could be caused by different pathogens, but in association with other techniques, such as serology, bacteriology or PCR, histopathology could provide a more accurate information about which agent is causing the lesion, since a positive result in those diagnostic techniques against some pathogens [i.e. \u003cem\u003eM. hyopneumoniae\u003c/em\u003e or porcine circovirus type 2 (PCV2)] does not necessarily always mean that they are causing any lesion.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eLesions of bronchointerstitial pneumonia compatible with \u003cem\u003eM. hyopneumoniae\u003c/em\u003e infection were found in the six more frequent combinations of lesion patterns in our study, representing 66.13 % of the lungs examined, what support the relevant role of this agent in the PRDC as a primary agent as well as enhancing the action of other pathogens involved in as PRRSV [34], PCV2 [35] or swine influenza virus [36].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe scoring system from 0 to 5 points used in this study for MLL, adapted from a previous one [37], has been showed as a simple and repeatable method that can be easily applied in cases of abattoirs with fast slaughterline, sometimes more than 500 pigs per hour. By contrast, it is not as precise as other methods which express the proportion of affected lung area in percentages [22, 23, 24, 25].\u0026nbsp;\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe 0 to 5 points scoring system proposed in the present study showed to be a simple, useful and repeatable method that can be easily conducted in cases of abattoirs with a fast slaughterline. An average score of MLL of 1.99 was obtained by using this scoring system and a real prevalence of 24.21 % was determined after confirmation of cranioventral consolidation compatible with mycoplasma lesions by histopathology. Our results highlight the significance of \u003cem\u003eM. hyopneumoniae \u003c/em\u003ein PRDC, acting as a primary agent in combination with other pathogens which lead to different patterns of lung lesions, and emphasize the necessity of implementing holistic control measures against this agent.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStudy population\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 199,678 pigs from 221 different herds from Spain (170,174 pigs; 85.22 %) and Portugal (29,504 pigs; 14.78 %) were examined at abattoir from 2013 to 2017. All herds herein included belonged to the \u003cem\u003eMycoguard Program\u003c/em\u003e, a project conducted by Ecuphar Veterinaria SLU with the purpose of evaluating the incidence and type of lung lesions at abattoir. A batch from each fattening unit of the herd (average size of 200 pigs) was examined at the abattoir. The average weight and age of the pigs at sacrifice were 100 kg (95-105 kg) and 6 months, respectively. Most of the origin farms (142/221; 64.25 %) were located in southern Spain (regions of Andalusia, Extremadura and Murcia), followed by 25.79 % (57/221) in the north of Spain (regions of Catalu\u0026ntilde;a, Arag\u0026oacute;n and Castilla y Le\u0026oacute;n) and 9.96 % (22/221) in Portugal. All considered farms have historically vaccinated against \u003cem\u003eM. hyopneumoniae\u003c/em\u003e with commercial vaccines.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eLung examination at abattoir and scoring\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eLung examination was performed in 46 different abattoirs located in Spain (36) and Portugal (10) by seven veterinarians, which have been thoroughly trained to follow the same scoring criteria in order to avoid individual discrepancies. The slaughterline speed ranged from 350 to 600 pigs per hour, but in most of the abattoirs the speed was comprised between 500 and 600 pigs per hour. All pigs were stunned with CO\u003csub\u003e2\u0026nbsp;\u003c/sub\u003ebefore bleeding. Lungs were visually appraised and palpated to detect lesions compatible with pneumonia. The system used for scoring cranioventral consolidations in the lung was based on the previously score proposed by Bollo et al. [37] with some modifications. Briefly, score 0: no lesion observed; score 1: consolidation affecting unilaterally the apex of one or two different lung lobes; score 2: consolidation affecting bilaterally the apex of one or two different lung lobes; score 3: consolidation affecting bilaterally the apex and medial part of one or two different lung lobes; score 4: consolidation affecting bilaterally the apex and medial part of one or two different lung lobes and partial involvement of the cranial area of one caudal lung lobe; score 5: consolidation affecting all lobes, including the cranial area of both caudal lobes. The average score was calculated for each batch (data not showed) and each country. The presence of other lesions, such as infarcts, abscesses and pleurisy, was also recorded.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eHistopathology of the lung\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThree to four lungs per batch with MLL were randomly selected at the abattoir for histopathological examination. Therefore, a total of 788 lungs, 737 from Spain and 51 from Portugal, were pictured and four samples per lung were collected: one belonging to the cranial lung lobe, other from the middle lung lobe and two from the ventral and dorsal areas of the caudal lung lobe of the right lung. In case of the left lung, the two portions of the cranial lung lobe together with the two samples coming from the caudal lung lobe were collected. The specimens were collected at the boundary junction of affected and unaffected tissue. Samples were fixed in 10 % neutral buffered formalin for 24 hours, embedded in paraffin wax, sectioned at 4 microns and stained with hematoxylin and eosin.\u003c/p\u003e\n\u003cp\u003eMicroscopic lung lesions of pneumonia were classified as bronchopneumonia (suppurative or fibrinous), bronchointerstitial and interstitial pneumonia according to the morphological pattern. Briefly, bronchopneumonia was characterized by the presence of inflammatory exudate into bronchi, bronchioles and alveoli that in the case of suppurative bronchopneumonia was predominantly composed of degenerated neutrophils while in fibrinous bronchopneumonia the predominant component of the exudate was fibrin, associated with the presence of necrosis and hemorrhages. Interstitial pneumonia was characterized by the thickening of alveolar walls by the presence of mononuclear cells and hyperplasia and hypertrophy of type II pneumocytes. In the case of bronchointerstitial pneumonia, mononuclear cells encircling airways and infiltrating alveolar septa and BALT hyperplasia were present [30, 31]. Pleurisy, characterized by the presence of fibrin or connective tissue in the pleura, was also recorded. Each microscopic lesion was scored according to its severity in mild (score 1), moderate (score 2) or severe (score 3), except for pleurisy that was scored as 0 (absence) or 1 (presence). The criteria for the scoring of microscopic lung lesions are summarized in Table 4. The microscopic score was calculated for each pattern of pneumonia and the final score was calculated by adding the individual scores for each type of pneumonia. As four samples were microscopically examined per lung, the score selected for each lesion pattern was the most severe one observed in any of the examined samples.\u003c/p\u003e\n\u003cp\u003eLesions were also differentiated according to their course as acute or chronic lesions. Acute lesions were defined as those with neutrophils as the dominant inflammatory cell type, extensive edema and fibrin exudation. Chronic lesions were characterized by mononuclear cell infiltrate, primarily consisting of lymphocytes and plasma cells, proliferation of connective tissue, epithelial or BALT hyperplasia, and hypertrophy of the smooth muscle layer around bronchioles and alveolar ducts.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll the slides were blindly evaluated by two pathologists to determine the pattern and score of pneumonia.\u0026nbsp;\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eADG: average daily gain; BALT: bronchus-associated lymphoid tissue; EP: enzootic pneumonia; MLL: mycoplasma-like lesions; PCV2: porcine circovirus type 2; PRDC: porcine respiratory disease complex; PRRSV:\u0026nbsp; porcine reproductive and respiratory syndrome virus.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe present article does not include experimental data. Therefore, animal ethics committee approval was not necessary.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors gave their consent for publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was partially funded by Ecuphar Veterinaria SLU.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eJAA, LC and FJP designed the study; IMRG, JGL, JMSC and IRT photographed and sampled the lungs. FJP and IMRG performed the histopathological study; RF, JGL and FJP analyzed the data; FJP and JAA wrote the manuscript; LC supervised the study. All authors read and approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe express our appreciation to Gema Mu\u0026ntilde;oz, Alberto Alc\u0026aacute;ntara and Juan S\u0026aacute;nchez for their technical assistance.\u0026nbsp;J. G\u0026oacute;mez-Laguna is supported by a \u0026ldquo;Ram\u0026oacute;n y Cajal\u0026rdquo; contract of the Spanish Ministry of Economy and Competitiveness (RYC-2014-16735).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e1\u003c/sup\u003eDepartment of Anatomy and Comparative Pathology and Toxicology, Faculty of Veterinary Medicine, University of C\u0026oacute;rdoba, 14014, C\u0026oacute;rdoba, Spain.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e2\u003c/sup\u003eEcuphar Veterinaria SLU, 08016 Barcelona, Spain.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e*\u003c/sup\u003ePresent address: Olmix Ib\u0026eacute;rica SLU, 31192 Mutilva, Navarra, Spain.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e\u0026para;\u003c/sup\u003ePresent address: Forestal Catalana SA, 08012 Barcelona, Spain.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e\u0026dagger;\u003c/sup\u003e FJ Pallar\u0026eacute;s and JA A\u0026ntilde;\u0026oacute;n contributed equally as first authors.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMaes D, Verdonck M, Deluyker H, de Kruif A. 1996. 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Zoonoses Public Health 2018;65:e155-161.\u003c/li\u003e\n\u003cli\u003eThacker EL, Halbur PG, Ross RF, Thanawongnuwech R, Thacker BJ. \u003cem\u003eMycoplasma hyopneumoniae\u003c/em\u003e potentiation of porcine reproductive and respiratory syndrome virus-induced pneumonia. J Clin Microbiol 1999;37:620-627.\u003c/li\u003e\n\u003cli\u003eOpriessnig T, Thacker EL, Yu S, Fenaux M, Meng X-J, Halbur PG. Experimental reproduction of postweaning multisystemic wasting syndrome in pigs by dual infection with \u003cem\u003eMycoplasma hyopneumoniae\u003c/em\u003e and porcine circovirus type 2. Vet Pathol 2004;41:624-640.\u003c/li\u003e\n\u003c/ol\u003e\n\u003col start=\"36\"\u003e\n\u003cli\u003eYazawa S, Okada M, Ono M, Fujii S, Okuda Y, Shibata I, et al. Experimental dual infection of pigs with an H1N1 swine influenza virus (A(Sw/Hok/2/81) and \u003cem\u003eMycoplasma hyopneumoniae\u003c/em\u003e. Vet Microbiol 2004;98:221-228.\u003c/li\u003e\n\u003cli\u003eBollo JM, Menj\u0026oacute;n R, Calvo E. Review of the \u0026ldquo;0 to 5 scoring method\u0026rdquo; for enzootic pneumonia slaughterhouse lesions. In: Proceedings of the 20\u003csup\u003eth\u003c/sup\u003e IPVS Congress, Durban, South Africa, 2008. p 104.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:justify;line-height:200%;'\u003e\u003cstrong\u003eTable 1.\u0026nbsp;\u003c/strong\u003eType, number and percentage of gross lesions observed at abattoir. In case of cranioventral pulmonary consolidation, the number and percentage of lungs belonging to each score (1-5) has been itemized.\u003c/p\u003e\n\u003ctable style=\"border: none;margin-left:.25pt;border-collapse:collapse;\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width:275.95pt;border-top:solid windowtext 1.0pt;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:150%;'\u003e\u003cstrong\u003eGross lung lesion\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width:170.1pt;border-top:solid windowtext 1.0pt;border-left:none;border-bottom:solid windowtext 1.0pt;border-right:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:150%;'\u003e\u003cstrong\u003eNumber of lungs (percentage)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width:275.95pt;border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:115%;'\u003eCranioventral pulmonary consolidation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width:170.1pt;border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:115%;'\u003e61,832 (30.97 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width:275.95pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:115%;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003e\u0026nbsp;\u0026nbsp;\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003eScore 1\u003c/span\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width:170.1pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:115%;'\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003e26,046 (13.04 %)\u003c/span\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width:275.95pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:115%;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003e\u0026nbsp;\u0026nbsp;\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003eScore 2\u003c/span\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width:170.1pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:115%;'\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003e18,008 (9.02 %)\u003c/span\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width:275.95pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:115%;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003e\u0026nbsp;\u0026nbsp;\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003eScore 3\u003c/span\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width:170.1pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:115%;'\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003e11,408 (5.71 %)\u003c/span\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width:275.95pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:115%;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003e\u0026nbsp;\u0026nbsp;\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003eScore 4\u003c/span\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width:170.1pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:115%;'\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003e4,925 (2.47 %)\u003c/span\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width:275.95pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:115%;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003e\u0026nbsp;\u0026nbsp;\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003eScore 5\u003c/span\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width:170.1pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:115%;'\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;line-height:115%;\"\u003e1,445 (0.72 %)\u003c/span\u003e\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width:275.95pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:115%;'\u003eDorsocaudal infarcts with pleurisy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width:170.1pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:115%;'\u003e24,970 (12.51 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width:275.95pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:115%;'\u003ePleurisy alone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width:170.1pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:115%;'\u003e12,505 (6.26 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width:275.95pt;border:none;border-bottom:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:115%;'\u003eNo lesion\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width:170.1pt;border:none;border-bottom:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:115%;'\u003e100,371 (50.26 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-bottom:8.0pt;line-height:107%;'\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-bottom:8.0pt;line-height:107%;'\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:justify;line-height:200%;'\u003e\u003cstrong\u003eTable 2.\u0026nbsp;\u003c/strong\u003eNumber, severity and course for each histopathological pattern of pneumonia.\u003c/p\u003e\n\u003ctable style=\"border-collapse:collapse;border:none;\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"border-top:solid windowtext 1.0pt;border-left:none;border-bottom: solid windowtext 1.0pt;border-right:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e\u003cstrong\u003e\u003cspan style=\"color:black;\"\u003eType of microscopic lesion\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border-top:solid windowtext 1.0pt;border-left:none;border-bottom: solid windowtext 1.0pt;border-right:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e\u003cstrong\u003e\u003cspan style=\"color:black;\"\u003eNumber (%)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border-top:solid windowtext 1.0pt;border-left:none;border-bottom: solid windowtext 1.0pt;border-right:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e\u003cstrong\u003e\u003cspan style=\"color:black;\"\u003eSeverity (1-3)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border-top:solid windowtext 1.0pt;border-left:none;border-bottom: solid windowtext 1.0pt;border-right:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e\u003cstrong\u003e\u003cspan style=\"color:black;\"\u003eCourse (acute/chronic)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:150%;'\u003eBronchointerstitial pneumonia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e616 (78.17 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e2.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e(3.09 % / 96.91 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:150%;'\u003eSuppurative bronchopneumonia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e579 (73.47 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e2.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e(72.36 % / 27.64 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:150%;'\u003eFibrinous bronchopneumonia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e112 (14.21 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e2.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e(66.07 % / 33.93 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:150%;'\u003eInterstitial pneumonia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e541 (68.65 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e1.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e(3.51 % / 96.49 %)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"border:none;border-bottom:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;line-height:150%;'\u003ePleurisy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;border-bottom:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e323 (40.99 %)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;border-bottom:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"border:none;border-bottom:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;line-height:150%;'\u003e(10.83 % / 89.17 %)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:justify;line-height:150%;'\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:justify;line-height:200%;'\u003e\u003cstrong\u003eTable 3.\u0026nbsp;\u003c/strong\u003eMore prevalent combinations of microscopic patterns of pneumonia including the number and percentage of lungs and lesion severity.\u0026nbsp;\u003c/p\u003e\n\u003ctable style=\"width:98.92%;border-collapse:collapse;border:none;\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 76.72%;border-top: 1pt solid rgb(165, 165, 165);border-bottom: 1pt solid rgb(165, 165, 165);border-left: 1pt solid rgb(165, 165, 165);border-image: initial;border-right: none;background: rgb(165, 165, 165);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:justify;'\u003e\u003cstrong\u003e\u003cspan style=\"font-size:13px;color:white;\"\u003ePatterns of microscopic lesion\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13.88%;border-top: 1pt solid rgb(165, 165, 165);border-left: none;border-bottom: 1pt solid rgb(165, 165, 165);border-right: none;background: rgb(165, 165, 165);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cstrong\u003e\u003cspan style=\"font-size:13px;color:white;\"\u003eNumber (%)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9.4%;border-top: 1pt solid rgb(165, 165, 165);border-right: 1pt solid rgb(165, 165, 165);border-bottom: 1pt solid rgb(165, 165, 165);border-image: initial;border-left: none;background: rgb(165, 165, 165);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cstrong\u003e\u003cspan style=\"font-size:13px;color:white;\"\u003eSeverity\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 76.72%;border-right: 1pt solid rgb(201, 201, 201);border-bottom: 1pt solid rgb(201, 201, 201);border-left: 1pt solid rgb(201, 201, 201);border-image: initial;border-top: none;background: rgb(237, 237, 237);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:justify;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003eBronchointerstitial pneumonia + interstitial pneumonia + suppurative bronchopneumonia\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13.88%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);background: rgb(237, 237, 237);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e171 (21.70 %)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9.4%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);background: rgb(237, 237, 237);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e6.44\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 76.72%;border-right: 1pt solid rgb(201, 201, 201);border-bottom: 1pt solid rgb(201, 201, 201);border-left: 1pt solid rgb(201, 201, 201);border-image: initial;border-top: none;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:justify;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003eBronchointerstitial pneumonia + interstitial pneumonia + suppurative bronchopneumonia\u0026nbsp;+ pleurisy\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13.88%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e108 (13.71 %)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9.4%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e7.45\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 76.72%;border-right: 1pt solid rgb(201, 201, 201);border-bottom: 1pt solid rgb(201, 201, 201);border-left: 1pt solid rgb(201, 201, 201);border-image: initial;border-top: none;background: rgb(237, 237, 237);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:justify;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003eBronchointerstitial pneumonia + suppurative bronchopneumonia \u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13.88%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);background: rgb(237, 237, 237);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e77 (9.77 %)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9.4%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);background: rgb(237, 237, 237);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e4.64\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 76.72%;border-right: 1pt solid rgb(201, 201, 201);border-bottom: 1pt solid rgb(201, 201, 201);border-left: 1pt solid rgb(201, 201, 201);border-image: initial;border-top: none;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:justify;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003eBronchointerstitial pneumonia + suppurative bronchopneumonia\u0026nbsp;+ pleurisy\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13.88%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e62 (7.87 %)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9.4%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e5.55\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 76.72%;border-right: 1pt solid rgb(201, 201, 201);border-bottom: 1pt solid rgb(201, 201, 201);border-left: 1pt solid rgb(201, 201, 201);border-image: initial;border-top: none;background: rgb(237, 237, 237);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:justify;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003eBronchointerstitial pneumonia + interstitial pneumonia \u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13.88%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);background: rgb(237, 237, 237);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e53 (6.73 %)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9.4%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);background: rgb(237, 237, 237);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e4.11\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 76.72%;border-right: 1pt solid rgb(201, 201, 201);border-bottom: 1pt solid rgb(201, 201, 201);border-left: 1pt solid rgb(201, 201, 201);border-image: initial;border-top: none;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:justify;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003eBronchointerstitial pneumonia\u0026nbsp;+ interstitial pneumonia\u0026nbsp;+ pleurisy\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13.88%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e50 (6.35 %)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9.4%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e5.12\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 76.72%;border-right: 1pt solid rgb(201, 201, 201);border-bottom: 1pt solid rgb(201, 201, 201);border-left: 1pt solid rgb(201, 201, 201);border-image: initial;border-top: none;background: rgb(237, 237, 237);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:justify;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003eSuppurative bronchopneumonia\u0026nbsp;+ interstitial pneumonia\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13.88%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);background: rgb(237, 237, 237);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e40 (5.08 %)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9.4%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);background: rgb(237, 237, 237);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e4.18\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 76.72%;border-right: 1pt solid rgb(201, 201, 201);border-bottom: 1pt solid rgb(201, 201, 201);border-left: 1pt solid rgb(201, 201, 201);border-image: initial;border-top: none;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:justify;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003eInterstitial pneumonia\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 13.88%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e23 (2.92 %)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 9.4%;border-top: none;border-left: none;border-bottom: 1pt solid rgb(201, 201, 201);border-right: 1pt solid rgb(201, 201, 201);padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-top:1.5pt;text-align:center;'\u003e\u003cspan style=\"font-size:12px;color:black;\"\u003e1.83\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-bottom:8.0pt;line-height:107%;'\u003e\u003cspan style=\"color:black;\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n\u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;margin-bottom:8.0pt;line-height:107%;'\u003e\u003cspan style=\"color:black;\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n\u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:justify;line-height:150%;'\u003e\u003cstrong\u003eTable 4.\u0026nbsp;\u003c/strong\u003eScoring system used to determine the severity of microscopic lung lesions.\u0026nbsp;\u003c/p\u003e\n\u003ctable style=\"border: none;width:108.7%;border-collapse:collapse;\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 0%;border-top: 1pt solid windowtext;border-left: none;border-bottom: 1pt solid windowtext;border-right: none;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003eType of pneumonia\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;border-top: 1pt solid windowtext;border-left: none;border-bottom: 1pt solid windowtext;border-right: none;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003eMild\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003e(Score 1)\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;border-top: 1pt solid windowtext;border-left: none;border-bottom: 1pt solid windowtext;border-right: none;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003eModerate\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003e(Score 2)\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;border-top: 1pt solid windowtext;border-left: none;border-bottom: 1pt solid windowtext;border-right: none;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003eSevere\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:center;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003e(Score 3)\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 0%;border: none;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:left;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003eBronchointerstitial pneumonia\u0026nbsp;\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:left;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;border: none;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003eBALT in \u0026gt; 5 bronchi or bronchioles (1-2 BALT per structure)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;border: none;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cstrong\u003e\u003cspan style=\"font-size:13px;\"\u003e1.-\u003c/span\u003e\u003c/strong\u003e\u003cspan style=\"font-size:13px;\"\u003e\u0026nbsp;BALT in \u0026gt; 5 bronchi or bronchioles (50 % of the structure is surrounded by BALT)\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003eor\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cstrong\u003e\u003cspan style=\"font-size:13px;\"\u003e2.-\u003c/span\u003e\u003c/strong\u003e\u003cspan style=\"font-size:13px;\"\u003e\u0026nbsp;BALT in \u0026gt; 5 bronchi or bronchioles (1-2 BALT per structure) and one bronchus or bronchiole completely surrounded by hyperplasia of BALT\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;border: none;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cstrong\u003e\u003cspan style=\"font-size:13px;\"\u003e1.-\u003c/span\u003e\u003c/strong\u003e\u003cspan style=\"font-size:13px;\"\u003e\u0026nbsp;At least two structures are almost completely surrounded (80 %) by hyperplasia of BALT\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003eor\u003c/span\u003e\u003c/p\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cstrong\u003e\u003cspan style=\"font-size:13px;\"\u003e2.-\u003c/span\u003e\u003c/strong\u003e\u003cspan style=\"font-size:13px;\"\u003e\u0026nbsp;All structures of the section are affected\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 0%;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:left;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003eInterstitial pneumonia\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:left;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003e1-2 lobule/s affected*\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003e50 % affected*\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003eAll lobuli are affected*\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 0%;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:left;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003eSuppurative pneumonia\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:left;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003e1-2 lobule/s affected*\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003e50 % affected*\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003eAll lobuli are affected*\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 0%;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:left;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003eFibrinous pleuropneumonia\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:left;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003e1-2 lobule/s affected*\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003e50 % affected*\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003eAll lobuli are affected*\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 0%;border-top: none;border-right: none;border-left: none;border-image: initial;border-bottom: 1pt solid windowtext;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:left;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003ePleurisy\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:left;'\u003e\u003cstrong\u003e\u003cem\u003e\u003cspan style=\"font-size:13px;\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;border-top: none;border-right: none;border-left: none;border-image: initial;border-bottom: 1pt solid windowtext;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003ePresence\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;border-top: none;border-right: none;border-left: none;border-image: initial;border-bottom: 1pt solid windowtext;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; ---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 0%;border-top: none;border-right: none;border-left: none;border-image: initial;border-bottom: 1pt solid windowtext;padding: 0in 5.4pt;vertical-align: top;\"\u003e\n \u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;'\u003e\u003cspan style=\"font-size:13px;\"\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; ---\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp style='margin:0in;font-size:16px;font-family:\"Times New Roman\",serif;text-align:justify;'\u003e\u003cspan style=\"font-size:13px;\"\u003eThe term \u0026ldquo;structure\u0026rdquo; describes a bronchus or bronchiole, equally. *Every evaluated section included at least 6 lobuli. BALT: bronchus-associated lymphoid tissue.\u003c/span\u003e\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"porcine-health-management","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"phmj","sideBox":"Learn more about [Porcine Health Management](http://porcinehealthmanagement.biomedcentral.com/)","snPcode":"40813","submissionUrl":"https://submission.nature.com/new-submission/40813/3","title":"Porcine Health Management","twitterHandle":"@animalplantsci","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Mycoplasma hyopneumoniae, lung lesions, prevalence, histopathology, scoring system","lastPublishedDoi":"10.21203/rs.3.rs-135831/v2","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-135831/v2","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003e\u003cem\u003eMycoplasma hyopneumoniae\u003c/em\u003e\u003cstrong\u003e \u003c/strong\u003ecauses 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.\u0026nbsp;\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eCranioventral 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 \u003cem\u003eM. hyopneumoniae\u003c/em\u003e 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. \u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConclusions: \u003c/strong\u003eThe prevalence of MLL at abattoir was 30.97 %, however, after microscopic examination the real prevalence of lungs with lesions compatible with \u003cem\u003eM. hyopneumoniae\u003c/em\u003e infection was reduced up to 24.21 %. \u0026nbsp;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 \u003cem\u003eM. hyopneumoniae\u003c/em\u003e infection were found, what supports the importance of \u003cem\u003eM. hyopneumoniae\u003c/em\u003e as a primary pathogen in cases of PRDC.\u0026nbsp;\u003c/p\u003e","manuscriptTitle":"Prevalence of mycoplasma-like lung lesions in pigs from commercial farms from Spain and Portugal","msid":"","msnumber":"","nonDraftVersions":[{"code":2,"date":"2021-02-18 11:25:47","doi":"10.21203/rs.3.rs-135831/v2","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2021-02-15T00:00:00+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2021-02-10T01:00:00+00:00","index":2,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2021-02-10T00:00:00+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2021-02-10T00:00:00+00:00","index":1,"fulltext":""},{"type":"editorInvitedReview","content":"","date":"2021-02-10T00:00:00+00:00","index":2,"fulltext":"Recommendation: Reviewer's comments unavailable due to the journal's policy.\n"},{"type":"editorInvitedReview","content":"","date":"2021-02-10T00:00:00+00:00","index":1,"fulltext":"Recommendation: Reviewer's comments unavailable due to the journal's policy.\n"},{"type":"editorAssigned","content":"","date":"2021-02-09T00:00:00+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2021-02-08T23:00:00+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2021-02-08T23:00:00+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"porcine-health-management","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"phmj","sideBox":"Learn more about [Porcine Health Management](http://porcinehealthmanagement.biomedcentral.com/)","snPcode":"40813","submissionUrl":"https://submission.nature.com/new-submission/40813/3","title":"Porcine Health Management","twitterHandle":"@animalplantsci","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}},{"code":1,"date":"2020-12-31 00:39:16","doi":"10.21203/rs.3.rs-135831/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2021-01-20T00:00:00+00:00","index":2,"fulltext":"Recommendation: Reviewer's comments unavailable due to the journal's policy.\n"},{"type":"decision","content":"Major revision","date":"2021-01-20T00:00:00+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2021-01-18T00:00:00+00:00","index":1,"fulltext":"Recommendation: Reviewer's comments unavailable due to the journal's policy.\n"},{"type":"reviewerAgreed","content":"","date":"2021-01-01T00:00:00+00:00","index":2,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2020-12-28T00:00:00+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2020-12-28T00:00:00+00:00","index":1,"fulltext":""},{"type":"editorAssigned","content":"","date":"2020-12-27T00:00:00+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2020-12-26T23:00:00+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2020-12-25T00:03:09+00:00","index":"","fulltext":""},{"type":"submitted","content":"","date":"2020-12-22T00:00:00+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"porcine-health-management","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"phmj","sideBox":"Learn more about [Porcine Health 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