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Porcine respiratory disease is one of the most important health problems in pig production worldwide. Cranioventral pulmonary consolidation (CVPC) and pleurisy are the two most common lesions in the respiratory tract of slaughtered pigs. The present review paper discusses pathogens involved in the lesions, lesion prevalence, scoring systems, advantages and disadvantages of slaughterhouse examination, and the impact of CVPC and pleurisy on performance, carcass, and meat quality. Cranioventral pulmonary consolidation and pleurisy in slaughter pigs are characteristic for infections with Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae, respectively, although other pathogens may cause similar lesions and/or be involved in their development. The overall prevalence of CVPC and pleurisy in slaughter pigs are still high, being the prevalence of CVPC generally higher than that of chronic pleurisy. The advantages and disadvantages of slaughterhouse examination are discussed in relation to practical aspects, the assessment of lesions, the number and representativeness of the examined animals and the interpretation and value of the results for the stakeholders. The main scoring methods for CVPC and pleurisy are shortly reviewed. In general, scoring methods can be applied rapidly and easily, although significant variation due to abattoir and observer remains. Artificial intelligence-based technologies that automatically score lesions and facilitate processing of data may aid solving these problems. Cranioventral pulmonary consolidation and pleurisy have a major negative impact on pig performance, and the effects increase the extension of the lesions and/or presence of multiple lesions. The performance losses caused by these lesions, however, vary significantly between studies and farms, possibly due to differences in study population and used methodology. Both lesions also have a negative impact on different carcass and meat quality parameters, leading to increased risk for poor processing and storage of the carcasses. Monitoring lung lesions of slaughter pigs should be optimized and implemented routinely; however, it is recommended to complement this information with farm data and laboratory results for specific pathogens.

Mycoplasma hyopneumoniae remains one of the most problematic bacterial pathogens for pig production. Despite an abundance of observational and laboratory testing capabilities for this organism, diagnostic interpretation of test results can be challenging and ambiguous. This is partly explained by the chronic nature of M. hyopneumoniae infection and its tropism for lower respiratory tract epithelium, which affects diagnostic sensitivities associated with sampling location and stage of infection. A thorough knowledge of the available tools for routine M. hyopneumoniae diagnostic testing, together with a detailed understanding of infection dynamics, are essential for optimizing sampling strategies and providing confidence in the diagnostic process. This study reviewed known information on sampling and diagnostic tools for M. hyopneumoniae and summarized literature reports of the dynamics of key infection outcomes, including clinical signs, lung lesions, pathogen detection, and humoral immune responses. The information gathethered in this manuscript can facilitate better understanding of the performance of different diagnostic approaches at various stages of infection with Mycoplasma hyopneumoniae.

Current knowledge on porcine circovirus diseases (PCVD) caused by Porcine circovirus 2 (PCV-2) includes the subclinical infection (PCV-2-SI), systemic (PCV-2-SD) and reproductive (PCV-2-RD) diseases, and porcine dermatitis and nephropathy syndrome (PDNS). Criteria to establish the diagnosis of these conditions have not changed over the years; thus, the triad composed by clinical signs, lesions and viral detection in lesions are still the hallmark for PCV-2-SD and PCV-2-RD. In contrast, PCV-2-SI diagnosis is not usually performed since this condition is perceived to be controlled by default through vaccination. PDNS is diagnosed by gross and histopathological findings, and PCV-2 detection is not recognized as a diagnostic criterion. Molecular biology methods as a proxy for PCVD diagnoses have been extensively used in the last decade, although these techniques should be mainly considered as monitoring tools rather than diagnostic ones. What has changed over the years is the epidemiological picture of PCV-2 through the massive use of vaccination, which allowed the decrease in infectious pressure paralleled with a decrease in overall herd immunity. Consequently, the need for establishing the diagnosis of PCVD has increased lately, especially in cases with a PCV-2-SD-like condition despite vaccination. Therefore, the objective of the present review is to update the current knowledge on diagnostic criteria for PCVDs and to contextualize the interest of using molecular biology methods in the overall picture of these diseases within variable epidemiological scenarios of PCV-2 infection. info:eu-repo/semantics/publishedVersion

Altres ajuts: Instituto Nacional de Investigación y Tecnologia Agraria y Alimentaria RTA2017-00007-00-00 Porcine circovirus 3 (PCV-3) was discovered in 2015 using next-generation sequencing (NGS) methods. Since then, the virus has been detected worldwide in pigs displaying several clinical-pathological outcomes as well as in healthy animals. The objective of this review is to critically discuss the evidence existing so far regarding PCV-3 as a swine pathogen. In fact, a significant number of publications claim PCV-3 as a disease causal infectious agent, but very few of them have shown strong evidence of such potential causality. The most convincing proofs of disease association are those that demonstrate a clinical picture linked to multisystemic lymphoplasmacytic to lymphohistiocytic perivascular inflammation and presence of viral nucleic acid within these lesions. Based on these evidence, individual case definitions for PCV-3-reproductive disease and PCV-3-systemic disease are proposed to standardize diagnostic criteria for PCV-3-associated diseases. However, the real frequency of these clinical-pathological conditions linked to the novel virus is unknown, and the most frequent outcome of PCV-3 infection is likely subclinical based on its worlwide distribution.

This study evaluated different gilt vaccination protocols againstMycoplasma (M.) hyopneumoniaeat acclimationand their effect on the genetic diversity. A total of 180M. hyopneumoniaenaïve gilts were selected 1 week post-entry (wpe) at the acclimation barn in a clinically affectedM. hyopneumoniaefarm. Gilts were distributed ac-cording to theM. hyopneumoniaeantibodies levels into three different vaccination schedules: A) four doses of aM. hyopneumoniaecommercial vaccine at 2, 4, 6 and 8 wpe; B) two vaccine doses at 2 and 6 wpe and PBS at 4 and8 wpe; and C) four PBS doses at the same wpe. Detection ofM. hyopneumoniae(rt-PCR) and antibodies (ELISA)were assessed in gilts at 1, 14, 27 and 34 wpe and in 6 of their piglets at weaning. Rt-PCR positive gilts weredetected at 14 wpe, being the proportion significantly lower in groups A and B (3/120, 3%) than C (27/60, 45%).Seroconversion was detected at 14 wpe, showing significant differences in percentage of inhibition (PI) betweengroups A (median 4.9, range 3.1–19.9) and B (5.5, 3.7–13.5), and C (14.3, 3.3–53.2). Gilts remained seropositiveover the study and significant differences in PI were detected between groups A and B versus C. All piglets werert-PCR negative, but the proportion of seropositive piglets coming from vaccinated gilts was significantly higherthan the non-vaccinated group.M. hyopneumoniaecharacterization showed high variability. Hence, gilt vacci-nation with 2 or 4 doses significantly decreased the pathogen infectious pressure, variability, and provided highantibody levels to gilts and their offspring. info:eu-repo/semantics/acceptedVersion

Altres ajuts: acords transformatius de la UAB Porcine circovirus 3 (PCV-3) has been detected in diseased and healthy pigs of different ages. Several reports have associated the agent with reproductive failure and mummified and stillborn piglets. One report from North America has proposed a consistent potential association with postweaning disorders. Thus, the present case report aimed to describe the histopathological lesions and their association with the presence of PCV-3 genome in postweaning pigs showing growth-retardation and thrown-back ears. All affected animals displayed multi-organic lymphoplasmacytic periarteritis, lymphocytic myocarditis and/or lymphoplasmacytic meningoencephalitis. PCV-3 genetic material was detected by in situ hybridization within the lesions and confirmed by PCV-3 real-time quantitative PCR detection in tissues. This study represents the first report of PCV-3 associated with clinical disease in postweaning pigs in Europe.

Altres ajuts: INITA/E-RTA2017-00007-00-00 PCV-2 is considered one of the most economically important viral agents in swine worldwide. Recently, PCV-3 has been found in pigs affected by different disorders and in healthy animals. The objective of this epidemiological work was to describe the frequency of detection of PCV-2 and PCV-3 in pig farms of 9 European countries. Moreover, a second aim was to assess the most frequent PCV-2 genotypes found in the studied farms. Sera from 5 to 10 pigs per farm were collected from 2 to 11 farms per studied country. A total of 624 sera of fattening pigs (10-25 week old) from 64 farms from Spain (n = 11), Belgium (n = 10), France (n = 8), Germany (n = 8), Italy (n = 7), Denmark (n = 8), the Netherlands (n = 5), Ireland (n = 5) and Sweden (n = 2) were analysed by conventional PCR. In addition, one or two PCV-2-positive samples per farm were genotyped by sequencing the ORF2 gene. PCV-3 PCR-positive samples with relatively low Ct values were also sequenced and phylogenetically analysed. PCV-2 DNA was detected in pig sera from all European tested countries, but Sweden. A total of 132 out of 624 (21%) sera were positive for PCV-2 PCR, corresponding to 30 out of the 64 (47%) tested farms. PCV-3 DNA was detected in 52 out of 624 (8%) sera, corresponding also to 30 out of the 64 (47%) studied farms from all tested countries. A total of 48 PCV-2 PCR-positive samples were successfully sequenced and genotyped, being PCV-2d the most frequently genotype found (n = 28), followed by PCV-2b (n = 11) and PCV-2a (n = 9). These results pointed out PCV-2d as the most prevalent genotype currently in Europe. The PCV-3 phylogenetic analysis showed high identity (>98%) among sequences from all the analysed countries. The relatively low co-infection (3%), likely suggest an independent circulation patterns of PCV-2 and PCV-3.

Porcine circovirus 3 (PCV‐3) prevalence has been minimally investigated in wild boar; dynamics of infection and viral tissue distribution are currently unknown. In this study, serum samples from 518 wild boar (from years 2004 to 2018) were used to study frequency of infection. Also, serum samples from 19 boar captured and recaptured at least two times for a period of time from 1 month to 1 year were collected to determine PCV‐3 infection dynamics. Finally, to elucidate PCV‐3 DNA organic distribution, sera, different tissues and faeces were obtained from 35 additional wild boar. PCV‐3 DNA was extracted and amplified with a conventional PCR. For the PCV‐3 PCR‐positive sera from the longitudinally sampled and different tissue types, a quantitative PCR was performed. Genome sequence was obtained from a number of PCV‐3 PCR‐positive samples from different years, different time‐points of infection and tissues. Obtained results confirmed the susceptibility of wild boar to the virus, showing high frequency of PCV‐3 detection (221 out of 518, 42.66%) and demonstrating circulation at least since 2004. Compiled data indicate the possibility of long‐term infections, since 5 out of 10 PCV‐3 PCR‐positive boars longitudinally sampled showed positivity in samplings separated for more than 5 months. All tested tissue types' harboured PCV‐3 genome, with the highest percentage of PCR positivity in submandibular lymph node, tonsil, lung, liver, spleen and kidney. The amount of DNA in all tested PCV‐3 PCR‐positive samples was moderate to low. All partial and complete PCV‐3 sequences obtained from wild boar displayed high nucleotide identity, higher than 98%. In conclusion, this study further confirms that wild boar is susceptible to PCV‐3 infection, showing high frequency of detection in this animal species. Furthermore, PCV‐3 can be found in different tissues of wild boar and is apparently able to cause persistent infection. Instituto Nacional de Investigación y Tecnologia Agraria y Alimentaria. Grant Number: E‐RTA2017‐00007‐00‐00

This study was aimed to evaluate the effect of Porcine circovirus 2 (PCV2) sow vaccination on cell-mediated immune responses in sows and their progeny. At 7 weeks before farrowing, fifteen PCV2 PCR negative pregnant sows with medium-low antibody values were selected and randomly distributed in two groups according to the antibody levels. Seven sows were vaccinated with a commercial PCV2 vaccine and eight were injected with phosphate-buffered saline at 6 and 3 weeks before farrowing. Blood samples were taken from sows and their piglets (n = 90) during the study duration. PCV2 DNA and antibodies were tested in sera, and cytokine (IFN-α, IFN-γ, IL-12p40, TNF-α, IL-1β, IL-8, IL-4, IL-6 and IL-10) levels were assessed in supernatant from cultured peripheral blood mononuclear cells. All sows and piglets were negative by PCV2 PCR throughout the study. Significantly higher PCV2 antibody levels were detected in vaccinated sows after vaccination and in their offspring after colostrum ingestion compared to the non-vaccinated counterparts. Vaccinated sows did not show significant differences in cytokine secretion levels at farrowing compared to unvaccinated dams. In contrast, piglets from vaccinated sows had significantly higher levels of cytokines linked to Th1 memory cells (IFN-γ and TNF-α) in comparison to the ones from non-vaccinated dams. In conclusion, PCV2 sow vaccination, apart from triggering a humoral immunity response in sows and their progeny, might be associated to an increased transfer of cell-mediated immunity from the dam to the piglet. info:eu-repo/semantics/acceptedVersion

Mycoplasma hyopneumoniae(M. hyopneumoniae) is the primary pathogen of enzooticpneumonia, a chronic respiratory disease in pigs. Infections occur worldwide andcause major economic losses to the pig industry. The present paper reviews the cur-rent knowledge onM. hyopneumoniaeinfections, with emphasis on identificationand analysis of knowledge gaps for optimizing control of the disease. Close contactbetween infected and susceptible pigs is the main route ofM. hyopneumoniaetrans-mission. Management and housing conditions predisposing for infection or diseaseare known, but further research is needed to better understandM. hyopneumoniaetransmission patterns in modern pig production systems, and to assess the impor-tance of the breeding population for downstream disease control. The organism isprimarily found on the mucosal surface of the trachea, bronchi and bronchioles. Dif-ferent adhesins and lipoproteins are involved in the adherence process. However, aclear picture of the virulence and pathogenicity ofM. hyopneumoniaeis still missing.The role of glycerol metabolism, myoinositol metabolism and theMycoplasmaIgbinding protein—MycoplasmaIg protease system should be further investigated fortheir contribution to virulence. The destruction of the mucociliary apparatus,together with modulating the immune response, enhances the susceptibility ofinfected pigs to secondary pathogens. Clinical signs and severity of lesions dependon different factors, such as management, environmental conditions and likely alsoM. hyopneumoniaestrain. The potential impact of strain variability on disease sever-ity is not well defined. Diagnostics could be improved by developing tests that maydetect virulent strains, by improving sampling in live animals and by designing ELI-SAs allowing discrimination between infected and vaccinated pigs. The currentlyavailable vaccines are often cost-efficient, but the ongoing research on developingnew vaccines that confer protective immunity and reduce transmission should becontinued, as well as optimization of protocols to eliminateM. hyopneumoniaefrompig herds. info:eu-repo/semantics/acceptedVersion

Mycoplasma hyopneumoniae (M. hyopneumoniae) is the aetiologic agent of enzootic pneumonia in swine, a prevalent chronic respiratory disease worldwide. Mycoplasma hyopneumoniae is a small, self‐replicating microorganism that possesses several characteristics allowing for limited biosynthetic abilities, resulting in the fastidious, host‐specific growth and unique pathogenic properties of this microorganism. Variation across several isolates of M. hyopneumoniae has been described at antigenic, proteomic, transcriptomic, pathogenic and genomic levels. The microorganism possesses a minimal number of genes that regulate the transcription process. Post‐translational modifications (PTM) occur frequently in a wide range of functional proteins. The PTM by which M. hyopneumoniae regulates its surface topography could play key roles in cell adhesion, evasion and/or modulation of the host immune system. The clinical outcome of M. hyopneumoniae infections is determined by different factors, such as housing conditions, management practices, co‐infections and also by virulence differences among M. hyopneumoniae isolates. Factors contributing to adherence and colonization as well as the capacity to modulate inflammatory and immune responses might be crucial. Different components of the cell membrane (i.e. proteins, glycoproteins and lipoproteins) may serve as adhesins and/or be toxic for the respiratory tract cells. Mechanisms leading to virulence are complex and more research is needed to identify markers for virulence. The utilization of typing methods and complete or partial‐gene sequencing for M. hyopneumoniae characterization has increased in diagnostic laboratories as control and elimination strategies for this microorganism are attempted worldwide. A commonly employed molecular typing method for M. hyopneumoniae is Multiple‐Locus Variable number tandem repeat Analysis (MLVA). The agreement of a shared terminology and classification for the various techniques, specifically MLVA, has not been described, which makes inferences across the literature unsuitable. Therefore, molecular trends for M. hyopneumoniae have been outlined and a common terminology and classification based on Variable Number Tandem Repeats (VNTR) types has been proposed. info:eu-repo/semantics/acceptedVersion

Highlights • UV-C light as an additional safety step for spray-dried plasma production is proposed. • Swine bioassay is a sensitive technique able to detect infectivity of raw liquid plasma. • Inoculated pigs with UV-C irradiated liquid porcine plasma did not seroconvert or become PCR positive against tested viruses. • UV irradiation at 3000 J/L or more (9000 J/L) was enough to avoid transmission of any of the tested viruses to the animals. • UV-C treatment is useful step to inactivate potential pathogen contamination of commercially collected animal plasma., Liquid porcine plasma is an animal origin raw material for the manufacturing process of spray-dried porcine plasma that is used in pig nutrition worldwide. In previous studies we found that the application of ultraviolet light C (UV-C) in liquid plasma that was inoculated with a variety of bacteria or viruses of importance in the swine industry can be considered as redundant safety steps because in general achieve around 4 logs reduction for most of these pathogens. However, the final validation of the UV-C light as safety feature should be conducted with commercial liquid plasma and using the pig bioassay model. As a first objective, the potential infectivity of a raw liquid plasma product collected from an abattoir was tested by means of a swine bioassay. We used Porcine circovirus 2 (PCV-2), a ubiquitous virus that has been systematically detected by PCR in porcine plasma at abattoirs as selection criteria for commercial liquid plasma lot. As a second aim of the study, the effects of different doses of UV-C irradiation on the selected raw liquid plasma were assayed in the animal bioassay. Moreover, other swine infecting agents, including Porcine reproductive and respiratory syndrome virus (PRRSV), were also determined in the original plasma and monitored in the inoculated animals. Pigs negative for PCV-2 and PRRSV genome and antibodies were allotted to one of five groups (6 to 8 pigs/ group) and injected intra-peritoneally with 10 mL of their assigned inoculum at 50 d of age. Negative control pigs (group 1) were injected with PBS. Positive control pigs (group 5) were injected with a PCV-2 inoculum. Groups 2, 3 and 4 were injected with liquid porcine plasma that had been subjected to 0 (raw plasma), 3000 or 9000 J/L UV-C irradiation, respectively. Group 2 pigs (0 J/L UV-C) got infection by PRRSV but no PCV-2 infection or seroconversion. However, one pig from group 2 seroconverted to Rotavirus A (RVA) and Hepatitis E virus (HEV) and three group 2 pigs seroconverted to Porcine parvovirus (PPV). Groups 1, 3 and 4 pigs showed no evidence of infection or seroconversion associated with the tested viruses or any other pathogens found in the liquid plasma before UV-C irradiation. Group 5 pigs developed PCV-2 infectivity as expected. UV-C irradiation of liquid plasma at 3000 and 9000 J/L was effective in preventing PRRSV and other pathogens transmission. Moreover, raw liquid plasma was non-infectious for PCV-2 in naïve pigs.

Altres ajuts: Secretaria del Departament d'Economia i Creixement de la Generalitat de Catalunya DI2013-0039 Information on the in vitro growth of pathogenic and non-pathogenic Mycoplasma hyopneumoniae (M. hyopneumoniae) strains is scarce and controversial. Despite its limitations, the colour changing units (CCU) assay is still considered the golden standard titration technique for M. hyopneumoniae culture. Thus, the aims of the present study were: (1) to describe the growth dynamics and kinetics of pathogenic and non-pathogenic M. hyopneumoniae strains, and (2) to monitor the strains' daily growth by ATP luminometry, CCU, colony forming units (CFU), and DNA quantification by real time quantitative PCR (qPCR) and by fluorescent double-stranded DNA (dsDNA) staining, to evaluate them as putative titration methodologies. The growth of the non-pathogenic J (ATCC ® 25934™) type strain and the pathogenic 11 (ATCC ® 25095™) reference strain and 232 strain was modelled by the Gompertz model. Globally, all three-strain cultures showed the same growing phases as well as similar maximal titres within a particular technique, but for CFU. However, the J strain displayed the fastest growing. During the logarithmic phase of growing, CCU, ATP and M. hyopneumoniae copy titres were strongly and linearly associated, and correlation between techniques could be reliably established. In conclusion, real-time culture titration by means of ATP or molecular assays was useful to describe the in vitro growth of the tested strains. Knowledge about the in vitro growth behaviour of a specific strain in a specific medium may provide several advantages, including information about the time required to reach maximal titres by the culture. Noteworthy, the obtained results refers to the three strains used, so extrapolation to other M. hyopneumoniae strains or culture conditions should be made cautiously.

Background This study sought to evaluate the effect of sow vaccination against Porcine circovirus 2 (PCV2) on reproductive parameters during two consecutive reproductive cycles. The study was performed in a PCV2 subclinical infected breeding herd (PCV2 circulation but absence of major reproductive problems). Ninety-four pregnant sows were primo-immunized with a commercial PCV2 vaccine and ninety-seven were injected with phosphate-buffered saline at 6 and 3 weeks before the first studied farrowing, and then boosted at 2 weeks before the second one. Blood samples were taken throughout the study to assess PCV2 DNA load and antibodies. At farrowing, main reproductive parameters and piglet vitality index were registered. In addition, in those litters with more than three mummified or stillborn piglets, microscopic examination and PCV2 antigen detection in foetal myocardium was done. Results Vaccinated sows showed significantly higher antibody levels compared to the non-vaccinated counterparts. PCV2 DNA was only detected at farrowing in 2 (4.2%) non-vaccinated sows. Vaccinated sows had 1.3 more live-born piglets per litter at the second cycle than non-vaccinated counterparts. Piglets from vaccinated sows had significantly higher (+ 12.7%) vitality score than the ones born from non-vaccinated sows. No PCV2 compatible lesions neither PCV2 antigen were detected in the tested foetal hearts. Conclusions The present study represents a first attempt to demonstrate that PCV2 sow vaccination may have a positive influence on prolificacy and vitality of the offspring in a subclinical infected breeding herd. However, since reproductive outcomes at farm level may be affected by a number of factors, further studies would be needed to confirm this association.

This paper discusses what can be expected with regard to efficacy of antibacterial vaccines used in swine, based on the present knowledge of pathogen–host interactions. First, vaccination against bacteria that mainly cause disease by production of exotoxins is considered. Vaccines containing the inactivated toxin or a non-toxic but antigenic recombinant protein derived from the exotoxin can be expected to provide protection against disease. The degree of protection induced by such vaccines varies, however, depending amongst other things on the pathogenesis of the disease. Vaccination against clostridial infections, Actinobacillus pleuropneumoniae infections, progressive atrophic rhinitis and enterotoxigenic Escherichia coli, is considered. The second part of the article deals with vaccination against extracellular bacteria. Protection against these bacteria is generally mediated by antibodies against their surface antigens and certain secreted antigens, but cellular immunity may also play a role. Efficacy of vaccines against swine erysipelas, Streptococcus suis infections, Mycoplasma hyopneumoniae infections and swine dysentery is discussed. Finally, vaccination against facultatively intracellular bacteria is considered. For protection against these bacteria cell-mediated immunity plays an important role, but antibodies may also be involved. It is generally accepted that live-attenuated vaccines are more suitable for induction of cell-mediated immunity than inactivated vaccines, although this also depends on the adjuvant used in the vaccine. As an example, vaccination against Salmonella enterica serotype Typhimurium is discussed. info:eu-repo/semantics/acceptedVersion

Porcine circovirus 3 (PCV-3) is a recently described virus belonging to the family Circoviridae. It represents the third member of genus Circovirus able to infect swine, together with PCV-1, considered non-pathogenic, and PCV-2, one of the most economically relevant viruses for the swine worldwide industry. PCV-3 was originally found by metagenomics analyses in 2015 in tissues of pigs suffering from porcine dermatitis and nephropathy syndrome, reproductive failure, myocarditis and multisystemic inflammation. The lack of other common pathogens as potential infectious agents of these conditions prompted the suspicion that PCV-3 might etiologically be involved in disease occurrence. Subsequently, viral genome was detected in apparently healthy pigs, and retrospective studies indicated that PCV-3 was already present in pigs by early 1990s. In fact, current evidence suggests that PCV-3 is a rather widespread virus worldwide. Recently, the virus DNA has also been found in wild boar, expanding the scope of infection susceptibility among the Suidae family; also, the potential reservoir role of this species for the domestic pig has been proposed. Phylogenetic studies with available PCV-3 partial and complete sequences from around the world have revealed high nucleotide identity (>96%), although two main groups and several subclusters have been described as well. Moreover, it has been proposed the existence of a most common ancestor dated around 50 years ago. Taking into account the economic importance and the well-known effects of PCV-2 on the swine industry, a new member of the same family like PCV-3 should not be neglected. Studies on epidemiology, pathogenesis, immunity and diagnosis are guaranteed in the next few years. Therefore, the present review will update the current knowledge and future trends of research on PCV-3. info:eu-repo/semantics/publishedVersion

Porcine circovirus 3 (PCV‐3) is an emerging circovirus species that has recently been reported in different countries around the world, suggesting a widespread circulation. In this study, sera samples originating from 654 pigs of different production phases and clinical/pathological conditions, submitted for diagnostic purposes between 1996 and 2017, were randomly selected. Detection of PCV‐3 genome in such samples was attempted with a previously described PCR method, and the partial genome sequence was obtained from selected PCV‐3‐positive samples from different years. Compiled data confirmed that PCV‐3 has been circulating in the Spanish pig population since 1996. The overall frequency of PCV‐3 PCR‐positive samples in the study period was 11.47% (75 of 654). Phylogenetic analysis of twelve PCV‐3 partial sequences obtained showed a high nucleotide identity with the already known PCV‐3 sequences, with minor variations among years. No significant correlation was found between the detection of PCV‐3 and any production phase nor clinical/pathological condition. These results confirm PCV‐3 circulation at least since 1996 in the Spanish pig population with a low/moderate frequency. Although the information obtained was limited, PCV‐3 did not appear to be linked to any specific pathological condition or age group. info:eu-repo/semantics/publishedVersion

Genetic heterogeneity of Mycoplasma hyopneumoniae in pigs has been reported, however there has been limited reproducibility on the molecular methods employed so far. The aim of this study was to modify and standardize a high-resolution multiple locus variable number tandem repeat analysis (MLVA), to investigate the genetic variability of M. hyopneumoniae circulating in the United States of America (USA), Brazil, Mexico and Spain. The MLVA was standardized on the basis of the number of tandem repeats in two Mycoplasma adhesins, P97 and P146, which are proteins involved in the adherence of the pathogen to cilia. A total of 355 samples obtained from the four countries were analyzed. The Simpson's diversity index for the assay was D = 0.976 when samples from all countries were combined. A large number of MLVA types ( n = 139) were identified, suggesting that multiple M. hyopneumoniae variants are circulating in swine. The locus P97 had 17 different types with 2–18 repeats. The P146 locus showed higher heterogeneity, with 34 different types, ranging from 7 to 48 repeats. MLVA types that presented more than 30 repeats in P146 were found in Spain and Brazil, while shorter repeats were observed in the USA and Mexico. This simplified MLVA method proved to be an efficient tool for typing M. hyopneumoniae with a high degree of stability, repeatability, and discriminatory power. In conclusion, M. hyopneumoniae showed a high variable number tandem repeat heterogeneity and this assay can be applied in molecular epidemiology investigations within farms and productions systems.

Porcine circovirus type 2 (PCV2) is a ubiquitous virus that mainly affects nursery and fattening pigs causing systemic disease (PCV2-SD) or subclinical infection. A characteristic sign in both presentations is reduction of average daily weight gain (ADWG). The present study aimed to assess the relationship between PCV2 load in serum and ADWG from 3 (weaning) to 21 weeks of age (slaughter) (ADWG 3-21). Thus, three different boar lines were used to inseminate sows from two PCV2-SD affected farms. One or two pigs per sow were selected (60, 61 and 51 piglets from Pietrain, Pietrain × Large White and Duroc × Large White boar lines, respectively). Pigs were bled at 3, 9, 15 and 21 weeks of age and weighted at 3 and 21 weeks. Area under the curve of the viral load at all sampling times (AUCqPCR 3-21) was calculated for each animal according to standard and real time quantitative PCR results; this variable was categorized as “negative or low” ( 4.3 PCV2 genome copies/ml of serum), “medium” (≥10 4.3 to ≤10 5.3 ) and “high” (>10 5.3 ). Data regarding sex, PCV2 antibody titre at weaning and sow parity was also collected. A generalized linear model was performed, obtaining that paternal genetic line and AUCqPCR 3-21 were related to ADWG 3-21. ADWG 3-21 (mean ± typical error) for “negative or low”, “medium” and “high” AUCqPCR 3-21 was 672 ± 9, 650 ± 12 and 603 ± 16 g/day, respectively, showing significant differences among them. This study describes different ADWG performances in 3 pig populations that suffered from different degrees of PCV2 viraemia.

ENZOOTIC pneumonia, most commonly caused by Mycoplasma hyopneumoniae , is a chronic respiratory condition affecting pigs worldwide. It can lead to a decrease in production performance in affected pig herds, but also, importantly, has the potential to increase susceptibility to coinfections with other bacterial and viral agents, contributing to the development of the porcine respiratory disease complex (Thacker and Minion 2012). Therefore, controlling M hyopneumoniae in the field remains a high priority for pigs practitioners and producers. Means to control infections caused by M hyopneumoniae include improving management practices, using antimicrobials, and administrating vaccines (Maes and others 2008), as well as focusing strategies on eliminating the disease (Holst and others 2015). Although there is widespread use of specific management practices and antibiotic treatments to combat the disease, use of vaccine products to control M hyopneumoniae infections is by far the most commonly used strategy. Originally introduced to the market several decades ago, commercial vaccines against M hyopneumoniae are mainly bacterins, based on different bacterial strains and adjuvants (Haesebrouck and others 2004, Maes 2014). The advantages and limitations of M hyopneumoniae bacterins have been characterised over the years (Haesebrouck and others 2004, Maes and others 2008, Maes 2014), and a wealth of literature supports the use of vaccination as part of a comprehensive disease control programme (Thacker and Minion 2012), even …

The feasibility to eradicate Porcine circovirus type 2 (PCV2) in a conventional PCV2 infected farm by vaccinating both sows and piglets using a commercially subunit vaccine was assessed. Vaccination strategy implied that all sows, boars and gilts of the farm were vaccinated every four months, and all piglets vaccinated and revaccinated with the same vaccine at 4 and 7 weeks of age, respectively. This vaccination strategy was applied during 12 consecutive months. Blood samples from 15 piglets of 4, 8, 12, 16, 20 and 24 weeks of age and 15 sows were taken monthly PRE, DURING and POST mass vaccination strategy. From all the collected sera (n=1796), a representative proportion of them (n=1235, 69%) were analysed (n=1121 from piglets and n=114 from sows). All these samples were tested by PCV2 ELISA and PCV2 PCR (and quantitative-PCR when PCR positive). All tested sows were negative by PCR but seropositive. ELISA mean OD values of sows decreased throughout the study. Percentages of PCV2 PCR positive samples in piglets were 8% (12/150), 0.9% (6/659) and 3.5% (11/312) PRE, DURING and POST application of the mass vaccination program, respectively. ELISA mean OD values of PCV2 seropositive animals progressively decreased until the end of the mass vaccination period, but a clear seroconversion was observed after stopping such strategy. In conclusion, one year period of mass PCV2 vaccination (without implementing further farm management practices or biosafety measures) was not able to clear out PCV2 infection, and the virus became detectable again when vaccination was stopped.

International audience; This study aimed to determine the porcine circovirus type 2 (PCV2) serological and virological dynamics in piglets vaccinated at different ages in a PCV2 subclinical infection (PCV2-SI) scenario. Six hundred and forty-four 2 week-old healthy piglets were selected and distributed into four treatment groups: vaccination at 3, 6 or 10 weeks of age (3W-VAC, 6W-VAC and 10W-VAC groups, respectively) and unvaccinated pigs (NON-VAC group). Blood (n = 112 pigs) and oral fluid (OF) (n = 40 pens) samples were taken throughout the study to assess PCV2 load, humoral immunity and viral genotyping. Percentage of PCV2-DNA positive sera mainly raised by 10 weeks of age, being maximum at 14 weeks of age, and then started to decrease at 18 and 25 weeks of age. Specifically, PCV2 vaccination at 3 or 6 weeks of age yielded similar results, since they produced an earlier seroconversion and reduced, at different sampling points, the proportion of viremic animals in comparison to the unvaccinated group. In contrast, PCV2 vaccination at 10 weeks of age only achieved such reduction at 25 weeks of age; in this case, vaccination coincided with the increase of the percentage of viremic pigs in the population. Both serological techniques used in sera and OF offered similar results with a high and statistically significant correlation. In contrast, a higher percentage of PCV2 DNA positivity was detected in OF in comparison with sera. In conclusion, under the present study conditions, the optimal time for PCV2 piglet vaccination was at either 3 or 6 weeks of age.

Porcine circovirus type 3 (PCV-3) is a recently discovered virus in domestic pigs and wild boar. The virus has been described in pigs with different clinical/pathological presentations and healthy animals, but the dynamics of infection is currently unknown. The aim of this study was to longitudinally monitor PCV-3 infection in 152 pigs from four different healthy farms (A, B, C and D) by means of PCR in serum. The selected animals were sampled five (farm A) or six (farms B–D) times from weaning until the end of the fattening period. PCV-3 genome was found in pigs from all tested ages and farms; few animals had an apparent long-term infection (4–23 weeks). PCV-3 frequency of detection remained fairly uniform along tested ages within farms A and C, but was more variable among sampling times in farms B and D. Eight partial genome sequences were obtained from six different animals. Phylogenetic tree and pairwise distance analysis showed high similarity among sequences and with available genomes from different countries. This is the first study on PCV-3 infection dynamics in longitudinally sampled pigs. Most pigs got infection during their life, although PCV-3 did not appear to be linked with any specific age. info:eu-repo/semantics/acceptedVersion

International audience; AbstractThe purpose of this study was to assess the effect of three different inoculation routes into mycoplasmal pneumonia (MP) in pigs challenged with Mycoplasma hyopneumoniae (M. hyopneumoniae). Thirty six-week-old M. hyopneumoniae seronegative piglets were randomly assigned to four groups: three challenged groups with experimentally inoculated pigs by either the endotracheal (ET; n = 8), intranasal (IN; n = 8) or aerosol (AE; n = 8) routes and one uninfected group (Control; n = 6). Blood samples were collected 1 day before challenge and at necropsy, 28 days post-inoculation (dpi), to assess seroconversion. Laryngeal swabs were collected at −1, 7, 14, 21 and 28 dpi in order to evaluate colonization. At necropsy, lung lesions were scored and lung tissue was collected for histopathological studies and M. hyopneumoniae DNA detection. Broncho-alveolar lavage fluid (BALF) was also obtained to detect M. hyopneumoniae DNA, specific IgA antibodies and cytokines. MP was observed in all inoculated groups, but the ET group displayed a significantly higher number of animals affected by MP as well as a higher mean lung lesion score. These results were paralleled with an earlier seroconversion and upper respiratory tract colonization of M. hyopneumoniae. Additionally, in the ET group, higher levels of pro-inflammatory cytokines and specific IgA antibodies in BALF were found. Under the conditions of the present study, MP was reproduced by the three evaluated inoculation routes. Obtained results suggest that the ET route is the most effective in order to induce MP in pigs experimentally challenged with M. hyopneumoniae.

The present study aimed to compare the efficacy of a porcine circovirus type 2 (PCV2) commercial vaccine in terms of average daily weight gain (ADWG) as well as infection dynamics in pigs with different maternally derived antibody (MDA) levels. A total of 337 animals from a PCV2 subclinically infected farm were distributed into two groups based on weight and PCV2 antibody levels (high [H] or low [L]) at 2 weeks of age. One week later, these animals were subdivided in four groups according to the treatment received. Vaccinated pigs (H-V and L-V) received 1 mL of a commercial vaccine and NV (H-NV and L-NV) received 1 mL of PBS. All piglets were subsequently bled at 7, 12, 18, 22 and 25 weeks of age and weighted at 12 and 25 weeks of age. V animals showed significantly lower PCV2 infection rates and viral load as well as higher ELISA S/P ratios and ADWG than NV ones. Compared with H-V piglets, L-V pigs showed numerically lower PCV2 infection rates, lower area under the curve of viral load, an earlier seroconversion and a numerically, but not significantly, higher ADWG. In this study, MDA did not seem to interfere with the effect of PCV2 vaccination on ADWG. However, only when a small subpopulation of pigs with the highest ELISA S/P ratios at vaccination was considered, an apparent interference of vaccine efficacy on ADWG was noticed. Therefore, the impact of the putative interference under field conditions is probably negligible for most farms. This study was funded by the European PCV2-Award 2012 sponsored by Boehringer Ingelheim. The authors wish to thank to the farmer (Álvaro Abadías) and the veterinarians (Lluís Cons and Paula Alcubierre) for their collaboration in conducting the field study and Eva Huerta, Rosa López, and Diego Pérez (CReSA) for their excellent technical assistance. Hua Feng was grant awarded by the Chinese Scholarship Council (No. 2011704032).

Porcine circovirus type 2 (PCV2) negatively modulates the immune response in vitro. The objective of this study was to investigate if PCV2 interferes with the development of the immune response to Aujeszky's disease virus (ADV) vaccine, using an in vivo experimental subclinical model. Pigs were divided into four groups: (group CC) not infected with PCV2 and not vaccinated against ADV; (group IC) infected with PCV2 but not vaccinated against ADV; (group CV) not infected with PCV2 but vaccinated against ADV, and (group IV) infected with PCV2 and vaccinated against ADV. Pigs in groups IC and IV were inoculated intranasally with PCV2 and 14 days later, pigs in the CV and IV groups were vaccinated IM with a gE(-)tk(-) attenuated ADV vaccine. Clinical signs and weight gains were recorded from days 0 to 35 post-PCV2 inoculation (PI), at which point the pigs were euthanased and examined post-mortem. Throughout the experiment the PCV2 load was quantified in serum, antibodies to PCV2 and ADV were determined and antigen-specific cellular responses against both viruses were measured using an interferon-γ ELISPOT. PCV2 inoculated animals developed subclinical infection and had lower weight gain relative to non-infected controls. No differences were observed between the CV and IV groups in terms of the humoral or cellular immune responses to vaccination against Aujeszky's disease, suggesting that subclinical infection with PCV2 does not alter the response to this vaccine.

Torque teno viruses (TTV) are small, non-enveloped viruses with a circular single-stranded DNA genome, which are considered non-pathogenic. However, TTVs have been eventually linked to human diseases. TTVs infecting pigs, Torque teno sus virus 1 (TTSuV1) and 2 (TTSuV2), have been recently associated to porcine circovirus diseases (PCVD). To get more insights into such potential disease association, the aim of this study was to quantify TTSuV1 and TTSuV2 viral loads in serum of pigs affected by two PCVDs, postweaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS). Such study was carried out by means of a newly developed real-time quantitative PCR (qPCR) method. Both TTSuVs were highly prevalent among studied pigs. TTSuV2 viral loads were significantly higher in PMWS affected animals, further supporting the previously suggested association between TTSuV2 and PMWS. On the contrary, TTSuV1 prevalence and loads were not related with the studied PCVDs.

Changes in porcine circovirus type 2 (PCV-2) genotypes were evaluated before, during and after outbreaks of post-weaning multisystemic wasting syndrome (PMWS) in (1) a retrospective study using pig sera collected in Spain from 1985 to 2008 and (2) a longitudinal study using pig sera collected from two farms in Spain over periods of 7 and 14 years. In both studies, there was a rapid genotypic shift from PCV-2a to PCV-2b that was related to the peak of PMWS epizootics in Spain and the appearance of PMWS on the two farms studied longitudinally.

The aim of the present study was to investigate the role of the capside (Cap) and replicase (Rep) proteins of Porcine circovirus type 2 (PCV2) as well as the whole PCV2 (both PCV2a and PCV2b genotypes) in the induction of cell-mediated immunity upon infection. At 6 weeks of age, six pigs were intranasally inoculated with the Stoon 1010 (Stoon) isolate (PCV2a) and seven with the Sp-7-10-54-13 (Sp) isolate (PCV2b). None of the pigs developed clinical disease but the Sp group had significantly higher proportion of pigs with PCV2-associated lesions and PCV2 load in tissues compared to the Stoon group. In both groups, development of IFN-gamma secreting cells (SC) in response to the whole PCV2 and Cap protein was detected by means of an ELISPOT from day 7 post-inoculation (PI) to the end of the study (21 days PI). Significant responses against Rep protein were only detected in Sp-inoculated pigs. No differences in ELISPOT results were seen when either PCV2a or PCV2b was used in vitro to recall peripheral blood mononuclear cells (PBMC) in any group. Stimulation of PBMC with the whole virus but not with Cap or Rep protein induced IL-10-SC in all pigs regardless of their PCV2 infection status, indicating an innate origin of this response. The results from this study demonstrate that PCV2-infected pigs developed cell-mediated immunity to Cap and Rep proteins and that, in the course of a sub-clinical infection, development and strength of such responses are possibly related to the levels of PCV2 replication.

Haemophilus parasuis is the etiologic agent of Glässer's disease in pigs, which is pathologically characterized by serofibrinous polyserositis and arthritis. H. parasuis include virulent and non-virulent strains and confirmation of virulence in H. parasuis is still dependent on experimental reproduction of the disease. Since the variability in virulence is supported by serotyping and genotyping (particularly, multilocus sequence typing [MLST]), we examined the relationship between the classification of 8 field strains by these methods and their capacity to cause disease in snatch-farrowed, colostrum-deprived piglets. The severity of clinical signs and lesions produced by the different strains correlated with the quantity of H. parasuis recovered from the lesions. However, the virulence of the strains in the animal model did not show a total correlation with their serovar or their classification by MLST. More studies are needed to identify a virulence marker that could substitute animal experimentation in H. parasuis. In addition, we reproduced disease in domestic pigs with a strain isolated from the nasal cavity of wild boars. This result indicates the existence of virulent strains of H. parasuis in wild suids, which could produce disease under appropriate circumstances, and suggests a possible source of infection for domestic pigs.

The present study describes the effects of a commercially available genetically engineered chimeric vaccine against porcine circovirus type 2 (PCV2) on clinical, pathological and virological features in three multi-site farms suffering from postweaning multisystemic wasting syndrome (PMWS). The vaccine product was able to reduce clinical signs, PCV2 viral load in lymphoid organs and/or sera, and overall mortality in nurseries and fattening units. This is the first time in which is shown that a PCV2 vaccine is able to decrease specifically PMWS-associated mortality. Another novelty of this study is the assessment of PMWS-like histological lesions in a large number of vaccinated and non-vaccinated pigs under field conditions.

The immunogenicity and efficacy generated by one dose of a PCV2 sub-unit vaccine (Porcilis PCV) were evaluated in 3-week-old conventional piglets. Vaccination induced both humoral and cell-mediated responses against PCV2, which were increased after the challenge with a PCV2 genotype "b" isolate. High levels of maternally derived antibodies (IPMA >or= 10 log(2)) at the time of vaccination were found to interfere with the active seroconversion, whereas titres below 8 log(2) allowed the development of a proper antibody response. Nevertheless, the immunity induced by one dose of the product was partly protective against PCV2 infection, since viremia, shedding and viral load in tissues were significantly reduced in vaccinated pigs compared to controls.

Mycoplasma hyopneumoniae is the principal aetiological agent of enzootic pneumonia (EP), a chronic respiratory disease that affects mainly finishing pigs. Although major efforts to control M. hyopneumoniae infection and its detrimental effects have been made, significant economic losses in pig production worldwide due to EP continue. M. hyopneumoniae is typically introduced into pig herds by the purchase of subclinically infected animals or, less frequently, through airborne transmission over short distances. Once in the herd, M. hyopneumoniae may be transmitted by direct contact from infected sows to their offspring or between pen mates. The 'gold standard' technique used to diagnose M. hyopneumoniae infection, bacteriological culture, is laborious and is seldom used routinely. Enzyme-linked immunosorbent assay and polymerase chain reaction detection methods, in addition to post-mortem inspection in the form of abattoir surveillance or field necropsy, are the techniques most frequently used to investigate the potential involvement of M. hyopneumoniae in porcine respiratory disease. Such techniques have been used to monitor the incidence of M. hyopneumoniae infection in herds both clinically and subclinically affected by EP, in vaccinated and non-vaccinated herds and under different production and management conditions. Differences in the clinical course of EP at farm level and in the efficacy of M. hyopneumoniae vaccination suggest that the transmission and virulence characteristics of different field isolates of M. hyopneumoniae may vary. This paper reviews the current state of knowledge of the epidemiology of M. hyopneumoniae infection including its transmission, infection and seroconversion dynamics and also compares the various epidemiological tools used to monitor EP.

The objectives of the present study were to compare Mycoplasma hyopneumoniae (Mh) colonization and serologic status on Mh vaccinated and non-vaccinated sows and to assess the effect of sow vaccination on colonization and serologic status of their piglets at weaning as well as presence of enzootic pneumonia (EP) lung lesions at slaughter. Fifty sows (25 vaccinated and 25 unvaccinated) as well as five of their piglets were included in the study. Blood samples and nasal swabs from sows at 7 weeks pre-farrowing and 1 week post-farrowing and from piglets at 3-4 weeks of age were taken. Nasal swabs and sera were tested by a nested polymerase chain reaction (nPCR) to detect Mh DNA and by an enzyme-linked immunosorbent assay (ELISA) test to detect antibodies to the pathogen, respectively. Finally, at 23 weeks of age, pigs were sent to the slaughter where the extension of EP-compatible gross lesions was assessed. Vaccination with two doses of Mh vaccine resulted in a significantly higher (p0.05) percentage of seropositive sows than in the non-vaccinated group at 1 week post-farrowing. On the contrary, no statistical significant differences were found in the number of nasal nPCR positive sows among different treatments (p0.05). At 3-4 weeks of age, a significantly higher percentage (p0.001) of seropositive piglets came from vaccinated than from non-vaccinated sows. Although the number of Mh infected piglets coming from non-vaccinated sows was higher than the one from vaccinated sows, the difference was not statistically significant (p0.05). Overall, piglets from vaccinated sows had a significant lower (p0.05) mean of EP-compatible lung lesions (1.83+/-2.8) than piglets from non-vaccinated sows (3.02+/-3.6). Under the conditions described in this study, sow vaccination did not affect sow or piglet colonization but increased the percentage of seropositive sows and piglets at weaning and reduced significantly the mean EP-compatible lung lesion scoring at slaughter.

The notion that postweaning multisystemic wasting syndrome (PMWS)-affected pigs develop an impaired humoral response against porcine circovirus type 2 (PCV2) has been reported in several studies. However, little information is available regarding the presence of neutralizing antibodies (NA) in PCV2-infected pigs and their role in the pathogenesis of the disease. The aim of the present work was to further characterize the humoral response, and in particular the production of NA, in pigs with different PCV2-infection status. Seventy-two conventional pigs from different farms were classified into three groups based on PCV2 infection and clinico-pathological status, namely: PCV2-negative, non-PMWS PCV2-positive and PMWS-affected animals. In addition, 9-week old pigs from an experimental infection (6 controls and 14 PCV2-inoculated pigs) were also studied. NA and total PCV2 antibodies (TA) as well as viral load in serum were determined and correlated with the clinico-pathological status of pigs. Results indicated that PMWS-affected pigs had lower NA titres, if any, than healthy animals. NA titres were also inversely correlated with PCV2 load in serum. NA and TA titres were positively correlated; however, correlation differed among infection status, being lower in PCV2-positive pigs. Also, the diagnostic performance of each test was evaluated, indicating that the combination of viral neutralization and quantitative PCR in serum was useful to discard PMWS (specificity 92%). In experimentally infected animals, the evolution of NA paralleled the course TA, although a slight delay in NA production was seen in some animals. The increase of NA coincided with the drop in viral load. Results from this work further support that PMWS-affected pigs show an impaired humoral immune response and, particularly, an inefficient NA response against PCV2.

A field trial was conducted to study Mycoplasma hyopneumoniae (Mh) infection dynamics by nested polymerase chain reaction (nPCR) and serology in pigs of a farm affected by enzootic pneumonia (EP). Moreover, correlation of Mh detection at different respiratory tract sites with presence of EP gross and microscopic lung lesions was assessed. These parameters were studied and compared between vaccinated (two doses at 1 and 3 weeks of age versus one dose at 6 weeks of age) and non-vaccinated pigs. Animals were monitored from birth to slaughter by nPCR from nasal swabs and by serology. From 3 to 22 weeks of age, an average of three pigs per treatment and per batch were necropsied (n = 302). The remaining pigs were sent to the slaughter (n = 103). Nasal, bronchial and tonsillar swabs were taken from the necropsied/slaughtered pigs; gross and microscopic EP-suggestive lung lesions were also assessed. Single and double vaccination resulted in earlier seroconversion and higher percentage of Mh seropositive pigs compared to control group. At slaughter, double vaccinated pigs showed lower percentage of EP-compatible gross lung lesions and lower Mh prevalence at upper respiratory tract sites (nasal cavity and tonsil) than control pigs.

Mycoplasma hyopneumoniae is the primary aetiological agent of swine enzootic pneumonia (EP) and one of the major contributors to the porcine respiratory disease complex (PRDC). Gross lung lesions in pigs affected by EP consist of cranioventral pulmonary consolidation (CVPC), usually distributed bilaterally in the apical, intermediate, accessory and cranial parts of the diaphragmatic lobes. Several lung scoring methods are currently in place for the evaluation of CVPC. The aims of this study were (1) to review the lung lesion scoring systems used to assess pneumonia associated with M. hyopneumoniae infection, and (2) to evaluate eight of these scoring systems by applying them to the lungs of 76 pigs with experimentally-induced M. hyopneumoniae pneumonia. A significant correlation between all lung lesion scoring systems was observed and the coefficients of determination in a regression analysis were very high between each pair-wise comparison, except for a unique scoring system based on image analysis. A formula of equivalence between lung scoring methods was developed in order to compare the results obtained with these methods. The present review provides a basis for comparison (even retrospectively) of lesions evaluated using different lung scoring systems.

The present study represents the first survey of Torque teno virus (TTV) prevalence in European wild boar (Sus scrofa). The prevalence of two distinct TTV genogroups in 178 Spanish wild boar sera from different geographic regions, management conditions, gender and age was determined by a nested PCR method. The overall prevalence of TTV genogroups was 84% (58% for genogroup 1 and 66% for genogroup 2), and differences between genogroup prevalence were observed depending on the geographical region analysed. Significantly higher prevalence for TTV genogroup 2 was found in fenced managed wild boar, juvenile animals and females. No other significant differences in TTV genogroup prevalence were observed. The phylogenetic analysis of nucleotide sequences obtained from the untranslated region of selected samples revealed that the same TTV genogroups are infecting wild boar and domestic pig. The results indicate that TTV is apparently ubiquitous in European wild boar populations., This work was partly funded by the Project no. 513928 from the Sixth Framework Programme of the European Commission, and by OAPN-MMA and SDGSA-MAPA, as well as Ministerio de Educación, Plan Nacional de I + D, grant AGL2005-07401-GAN. Francisco Ruiz-Fons is an FPU-MEC grantee.

Four swine facilities located in Northern Luzon, in the Philippines, showed lesions and clinical signs similar to those described in post weaning multisystemic wasting syndrome (PMWS). Post-mortem and histopathological examination revealed the presence of typical lymphoid lesions caused by porcine circovirus type 2 (PCV2). An in situ hybridization (ISH) technique allowed the detection of PCV2 nucleic acid associated with the lesions in target tissues. PCV2 DNA from paraffin embedded tissues was extracted, purified and sequenced. The phylogenetic analysis of the sequences obtained confirmed their identity, and grouped them into a PCV2 subgroup, together with some Canadian, French and Dutch isolates. This report is the first description of the presence of PMWS in the Philippines.

International audience; Porcine circovirus type 2 (PCV2) is the essential infectious agent for PCV2-systemic disease (PCV2-SD, formerly known as postweaning multisystemic wasting syndrome) and other pathological conditions. Recent studies indicated antigenic variability amongst different PCV2 isolates and suggested that single amino acid changes within the capsid protein determine differences in the level of neutralization by specific monoclonal antibodies. The objective of the present study was to examine the cross-reactivity of PCV2 antibodies induced in the context of a natural infection against different PCV2 isolates belonging to genotypes PCV2a and PCV2b. Sera taken from several farms from animals of varying health status (PCV2-SD and age-matched healthy pigs and a set of slaughter-aged animals) were assayed for neutralizing activity against four PCV2 isolates from both predominant genotypes (PCV2a and PCV2b) and of differing geographic origins (Europe and North-America). Results showed that most of studied pigs (79 out of 82) contained neutralizing antibodies (NA) able to neutralize all four studied viral strains. Overall, pigs had significantly higher NA titres against PCV2a than against PCV2b (P

The objective of this study was to investigate the presence of porcine circovirus type 2 (PCV2) DNA and antibody to the virus in the serum and colostrum of sows vaccinated prior to mating and in their offspring. Seventy-seven sows were randomly distributed into vaccinated (V, n = 36) and non-vaccinated (NV, n = 41) groups. One week before mating, sows were given a PCV2 vaccine (V group) or PBS (NV group) IM. Blood samples were taken from the sows at fixed time-points and colostrum samples were taken at farrowing. Blood samples were also taken from the piglets of the sows at 4 weeks of age. The results indicated that vaccination prior to mating elicited a strong, homogeneous humoral response and, in consequence, more homogeneous colostral PCV2 antibody concentrations.

This study investigated the development of cellular immunity to Porcine circovirus type 2 (PCV2) Cap and Rep proteins in pigs vaccinated with a commercial PCV2 genotype a (PCV2a) based sub-unit vaccine, before and after a heterologous challenge with a PCV2b isolate. At three weeks of age, 20 pigs were inoculated intramuscularly with either the vaccine product (V group, n = 9) or phosphate buffered saline solution (PBS) (NV group, n = 11). Three weeks after vaccination, pigs were challenged intranasally with PCV2b (V-C and NV-C groups) or PBS (V-NC and NV-NC groups). None of the pigs developed clinical signs during the whole experiment, but all NV-C and 3/5 V-C pigs developed viraemia. Vaccination induced the development IFN-γ-secreting cells in response to the Cap protein of PCV2, which appeared three weeks post-vaccination and increased after challenge. By that time, no significant differences were detected on PCV2 antibody titres between vaccinated and non-vaccinated pigs, although there were significant differences on day 7 post-challenge. PCV2-inoculation induced a cellular response against the Rep protein. Such response was significantly reduced or even absent in PCV2-inoculated pigs that were previously vaccinated (V-C group), presumably as a result of a lower PCV2 replication in vaccinated animals compared to non-vaccinated ones.

The present study describes the effects of sow and/or piglet porcine circovirus type 2 (PCV2) vaccination on viraemia, antibody response and production parameters (average daily weight gain [ADWG] and mortality) of piglets from a PCV2 subclinically infected farm. Four hundred seventy-six piglets born from vaccinated (V) or non-vaccinated (NV) sows were further subdivided in a total of four groups: NV sows-NV pigs (NV-NV, n=134), NV sows-V pigs (NV-V, n=135);V sows-NV pigs (V-NV, n=104) and V sows-V pigs (V-V, n=103). A single vaccination of sows before mating was able to confer significantly higher antibody titres to their piglets at 4 weeks of age and a different PCV2 dynamics infection compared to piglets coming from NV sows. Piglet vaccination (independently of sow treatment) caused an earlier seroconversion and lower percentages of PCV2 infected pigs compared to the NV ones throughout their life. The double PCV2 vaccination strategy was able to reduce PCV2 infection but apparently caused some interference in piglet humoral response development. PCV2 vaccination was able to overcome this interference since the ADWG was improved in both groups of vaccinated piglets, independently of the sow treatment, being the highest ones obtained in the double vaccination group.

Two prospective longitudinal studies in 13 postweaning multisystemic wasting syndrome (PMWS)-affected farms from Spain ( n = 3) and Denmark ( n = 10) were performed. Blood samples from pigs were longitudinally collected from 1st week until the occurrence of the PMWS outbreak. Wasted and healthy age-matched pigs were euthanized, necropsied and histopathologically characterised. PMWS diagnosis was confirmed by means of lymphoid lesions and detection of porcine circovirus type 2 (PCV2) in these tissues by in situ hybridization or immunohistochemistry. Serological analyses were performed in longitudinally collected serum samples to detect antibodies against, PCV2, porcine reproductive and respiratory syndrome virus (PRRSV), porcine parvovirus (PPV), swine influenza virus (SIV) and Lawsonia intracellularis (law), Mycoplasma hyopneumoniae , Aujeszky’s disease virus (ADV) and Salmonella spp. A Cox proportional hazards model was used to investigate the simultaneous effects of seroconversion and maternal immunity against the studied pathogens. Results showed that high levels of maternal immunity against PCV2 had a protecting effect in farms from both countries. Moreover, for the Danish dataset, seroconversion against law had an overall protecting effect, but for animals with very low levels of maternal antibody levels against this pathogen, the effect appeared neutral or aggravating. Otherwise, for the Spanish dataset, maternal immunity against PPV and PRRSV gave protective and aggravating effects, respectively. In conclusion, the present study reflects the complex interaction among different pathogens and their effects in order to trigger PMWS in PCV2 infected pigs.

International audience; Genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) has been based on ORF5/GP5 and ORF7/N protein variations. Complete viral genome studies are limited and focused on a single or a few set of strains. Moreover, there is a general tendency to extrapolate results obtained from a single isolate to the overall PRRSV population. In the present study, six genotype-I isolates of PRRSV were sequenced from ORF1a to ORF7. Phylogenetic comparisons and the variability degree of known linear B-epitopes were done considering other available full-length genotype-I sequences. Cytokine induction of all strains was also evaluated in different cellular systems. Non structural protein 2 (nsp2) was the most variable part of the virus with 2 out of 6 strains harboring a 74 aa deletion. Deletions were also found in ORF3 and ORF4. Phylogenetic analyses showed that isolates could be grouped differently depending on the ORF examined and the highest similarity with the full genome cluster was found for the nsp9. Interestingly, most of predicted linear B-epitopes in the literature, particularly in nsp2 and GP4 regions, were found deleted or varied in some of our isolates. Moreover, 4 strains, those with deletions in nsp2, induced TNF-α and 3 induced IL-10. These results underline the high genetic diversity of PRRSV mainly in nsp1, nsp2 and ORFs 3 and 4. This variability also affects most of the known linear B-epitopes of the virus. Accordingly, different PRRSV strains might have substantially different immunobiological properties. These data can contribute to the understanding of PRRSV complexity.

Porcine circovirus type 2 (PCV2) vaccination has been recently included as a measure to control postweaning multisystemic wasting syndrome (PMWS) in the field. Aiming to obtain a more affordable vaccine to be extensively implemented in the field, a highly efficient non-fermentative expression platform based on Trichoplusia ni (T. ni) larvae was used to produce a baculovirus-derived recombinant PCV2 Cap protein (rCap) for vaccine purposes. Vaccination of pigs with rCap induced solid protection against PCV2 experimental infection, inhibiting both the viremia and the viral shedding very efficiently. The protection afforded by the rCap vaccine strongly correlated with the induction of specific humoral immune responses, even in the presence of PCV2-specific maternal immunity, although cellular responses also seemed to play a partial role. In summary, we have shown that rCap expressed in T. ni larvae could be a cost-effective PCV2 vaccine candidate to be tested under field conditions. © 2009 Elsevier Ltd.

There are evidences that wild boar and domestic pig populations share the vulnerability to certain pathogens and, in consequence, the risk of pathogen transmission. Based on serological evidences, it is known that Mycoplasma hyopneumoniae (Mhyo) is able to infect the wild boar. However, if this infection causes lesions and disease in this species is still unknown. The objectives of the present study were to assess the seroprevalence to Mhyo, as well as the rates of detection of Mhyo (by nested polymerase chain reaction, nPCR) in upper and lower respiratory tract of the wild boar. Moreover, presence of enzootic pneumonia (EP)-like gross and microscopic lesions in these animals was also assessed. Antibodies against Mhyo were detected in 92 out of 428 (21%) serum samples tested. Moreover, Mhyo DNA was detected by nPCR in 17 out of 85 (20%) nasal swabs and in 12 out of 156 (8%) lung samples. No gross EP-like lesions were observed in any of the studied pigs. Besides, presence of EP-like microscopic lung lesions was observed in 18 out of 63 (29%) animals. Mhyo DNA was detected at lung level in 2 out of these 18 (11%) animals. Presence of EP-like microscopic lesions was significantly related (p0.05) with its detection in lung samples; such lesions were also linked (p

A longitudinal study was performed to analyze the dynamics of Toxoplasma gondii antibodies in naturally infected piglets from 1 to 25 weeks of age. Seventy-three piglets from 20 seronegative sows (modified agglutination test, MAT1:25) and 20 naturally infected T. gondii seropositive sows (MATor=1:25) were analyzed at 1, 3, 6, 9, 12, 15, 18, 22 and 25 weeks of age. Twenty-six of the 73 piglets analyzed (35.6%; CI 95%: 25.5-45.7) were seropositive at some point during the study. Seroprevalence in piglets at 1 and 3 weeks of age was significantly higher in animals born from seropositive sows (P0.001 and P=0.02, respectively) as an indication of maternally derived antibodies. The longest persistence (up to 6 weeks of age) was observed in piglets whose dam had high T. gondii antibody level (MATor=1:500), while persistence of maternally derived antibodies in the piglets born from sows with low antibody titers (maximum 1:50) was shorter and lasted only up to 3 weeks of age, when the piglets were weaned. The risk of horizontal transmission in piglets increased with age and was higher in piglets during the finishing period. The present results indicate that the decline of T. gondii maternally derived antibodies in naturally infected piglets is associated with the titers of their dams.

Torque teno virus (TTV) is a non-enveloped, single-stranded DNA (ssDNA) virus infecting human and non-primate species. Two genogroups of TTV (TTV1 and TTV2) have been described in swine so far. In the present study, TTV1 and TTV2 prevalences in serum, and nasal as well as rectal swabs of 55 randomly selected piglets from seven Spanish multi-site farms, were monitored from 1 to 15 weeks of age. Also, blood from their dams (n=41) were taken at 1 week post-farrowing. Samples were tested by means of two TTV genogroup specific PCRs. Although prevalence of TTV1 and TTV2 in sows was relatively high (54% and 32%, respectively), it was not directly associated to their prevalence in the offspring. Percentage of viremic pigs for both TTV genogroups followed similar dynamics, increasing progressively over time, with the highest rate of detection at 11 weeks of age for TTV1 and at 15 weeks for TTV2. Forty-two (76%) and 33 (60%) of the 55 studied pigs were TTV1 and TTV2 PCR positive in serum, respectively, in more than one sampling time. TTV1 and TTV2 viremia lasted in a number of animals up to 15 and 8 weeks, respectively. Co-infection with both TTV genogroups in serum was detected at all sampling points, but at 1 week of age. On the contrary, there were animals PCR negative to both genogroups in serum at all sampling times but at 15 weeks of age. During the study period, TTV1 and TTV2 nasal shedding increased also over time and faecal excretion was intermittent and of low percentage (20%). In conclusion, the present study describes for the first time the infection dynamics of TTV1 and TTV2 as well as the nasal and faecal excretion throughout the life of pigs from conventional, multi-site farms. Moreover, results indicate that both swine TTV genogroups are able to establish persistent infections in a number of pigs.

International audience; Haemophilus parasuis is a colonizer of the upper respiratory tract of healthy pigs, but virulent strains can cause a systemic infection characterized by fibrinous polyserositis, commonly known as Glässer's disease. The variability in virulence that is observed among H. parasuis strains is not completely understood, since the virulence mechanisms of H. parasuis are largely unknown. In the course of infection, H. parasuis has to survive the host pulmonary defences, which include alveolar macrophages, to produce disease. Using strains from different clinical backgrounds, we were able to detect clear differences in susceptibility to phagocytosis. Strains isolated from the nose of healthy animals were efficiently phagocytosed by porcine alveolar macrophages (PAM), while strains isolated from systemic lesions were resistant to this interaction. Phagocytosis of susceptible strains proceeded through mechanisms independent of a specific receptor, which involved actin filaments and microtubules. In all the systemic strains tested in this study, we observed a distinct capsule after interaction with PAM, indicating a role of this surface structure in phagocytosis resistance. However, additional mechanisms of resistance to phagocytosis should be explored, since we detected different effects of microtubule inhibition among systemic strains.