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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.

The aim of this exploratory work was to use a microarray-based approach to study the global transcriptome profile of caesarean-derived, colostrum-deprived (CDCD) piglets experimentally infected with porcine circovirus type 2 (PCV2). PCV2-inoculated piglets developed a subclinical infection, as confirmed by serology, in situ hybridization and quantitative PCR. Total RNA from mesenteric lymph nodes and lungs was obtained by duplicate from 2 control and 2 PCV2-inoculated piglets and was hybridized to Affymetrix Porcine GeneChip. Among the 24,123 probesets studied, 25 and 33 were found to be significantly differentially expressed (DE) between control and PCV2 groups for mesenteric lymph node and lung, respectively. Most up-regulated genes in PCV2 group were closely related to the immune response, such as cytokines (CCL4L, CXCL9, CXCL11), MHC binding molecules (TCRalpha, CD8alpha), immunoglubulins (IgG) and T cell activation (LCK, KLRK1, RASSF2, GBP2). Quantitative real-time PCR was performed to verify the microarray results. Therefore, from a transcriptional point of view, PCV2-inoculated pigs were apparently able to activate a cell-mediated response and develop PCV2-specific antibodies, which probably led to a subclinical infection. The results from this study indicate that a microarray based approach is a helpful tool in order to better understand the pathogenesis of PCV2 infection.

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.

The aim of the present longitudinal study was to assess the evolution of two acute phase proteins (APPs), pig-major acute phase protein (pig-MAP) and haptoglobin (HPT), in serum from pigs that developed postweaning multisystemic wasting syndrome (PMWS) in comparison to healthy and wasted non-PMWS affected pigs. In addition, evidence of infection with other pathogens and its relation with variations in APPs concentrations was also assessed. Fourteen independent batches of 100–154 pigs were monitored from birth to PMWS outbreak occurrence in 11 PMWS affected farms. Pigs displaying PMWS-like signs and age-matched healthy controls were euthanized during the clinical outbreak. PMWS was diagnosed according to internationally accepted criteria and pigs were classified as: (i) PMWS cases, (ii) wasted non-PMWS cases and (iii) healthy pigs. At the moment of PMWS occurrence, pig-MAP and HPT concentration in PMWS affected pigs were higher than in healthy ones (p < 0.0001). No differences in APPs serum concentrations between subclinically PCV2-infected pigs and healthy non-PCV2-infected pigs (based on quantitative PCR on serum results) were detected. Results showed a significant correlation between PCV2 loads and both pig-MAP (R = 0.487–0.602, p < 0.0001) and HPT (R = 0.326–0.550, p < 0.05–0.0001) concentrations in serum of PMWS affected pigs, indicating that the acute phase response in PMWS affected pigs occurred concomitantly to PCV2 viremia. No other pathogen, apart from PCV2, was consistently related with variations in APPs concentrations. A ROC analysis, made to determine the capacity of discrimination of both APPs between PMWS affected and non-affected pigs, showed higher sensitivity and specificity values using pig-MAP compared to HPT. These results suggest that pig-MAP might be a better indicator of PMWS status than HPT. Moreover, the fact that APR occurred some weeks before the start of clinical signs suggests that APPs could provide valuable prognostic information for PMWS development.

Torque teno virus (TTV) is a single-stranded DNA virus that has been detected in serum of primate and non-primate species including swine. Little information on swine TTV infection and transmission dynamics is nowadays available. The goal of this study was to gain insight into the potential role of the sow in transmitting TTV to piglets and the infection dynamics of both swine TTV genogroups (TTV1 and TTV2) during the lactation period. Serum samples from 44 sows at 1-week post-farrowing and 215 piglets at 1 and 3 weeks of age were tested using TTV1 and TTV2 PCR methods. Sow parity distribution and the number of delivered piglets (liveborn, stillborn and mummified) per each studied sow were recorded. TTV1 was detected in higher percentages than TTV2 in both sows (75% vs. 43%, respectively) and piglets at 1 (17% vs. 7%, respectively) and 3 (32% vs. 12%, respectively) weeks of age. TTV1 and TTV2 co-infections were observed in higher percentages in sows (34%) than in piglets (2% and 4% at 1 and 3 weeks of age, respectively). Detection of swine TTV genogroups in sows was not associated with their detection in piglets. Moreover, there were piglets infected at 1 week of age with a swine TTV genogroup different from the one detected in their dam. The number of sows delivering stillborns and the mean number of stillborns per sow tended to be higher in the TTV2 infected sows; this value was significantly higher when co-infected sows (TTV1 and TTV2) were compared with non-co-infected ones. Old parity sows had a higher percentage of TTV1 infected 1-week-old piglets. Results of the present study showed that the TTV infection occurs early in the production system and that these viruses may be transmitted from sow-to-piglet but also from piglet-to-piglet in farrowing facilities.

The interaction between porcine circovirus type 2 (PCV2) and the pig immune system has been suggested to be a determinant event for the pathogenesis of postweaning multisystemic wasting syndrome (PMWS). To gain insight into the host immune mechanisms developed upon PCV2 infection, early innate and adaptive immune responses were examined in 1-week-old, caesarean-derived, colostrum-deprived piglets using a subclinical infection model of PCV2 in combination with lipopolysaccharide (LPS) as a potential immunostimulation factor. The use of LPS did not show any significant effect on the course of PCV2 infection, nor did in the evolution of the immunological parameters evaluated. Ex vivo responses were detected as early as 1 day post-infection (PI) and consisted of an elevation of the plasmatic levels of interleukin (IL)-8 in PCV2-inoculated pigs followed by an increase on plasmatic IFN-alpha at day 5 PI. Regarding IL-10, only one PCV2-inoculated pig was positive (day 7 PI); this pig was the only one in which viremia persisted until the end of the study. In vitro cytokine determination showed that, regardless of the treatment administrated to the pigs, an IL-10 release was observed when peripheral blood mononuclear cells (PBMC) cultures were stimulated with PCV2. Seroconvertion to PCV2 measured by an immunoperoxidase monolayer assay (IPMA) occurred between 7 and 14 days PI, whereas neutralizing antibodies (NA) did not appear until day 29 PI. PCV2 DNA was first detected in serum at day 7 PI, reaching the peak of viremia between days 14 and 21 PI, followed by a drop in viral load that was found coincident with the appearance of PCV2-specific IFN-gamma-secreting cells (PCV2-IFN-gamma-SC) and NA. Results from the present work suggest that viral clearance might be mediated by the development of PCV2-IFN-gamma-SC in contribution to the PCV2-specific NA.

Longitudinal case-control studies were performed in post-weaning multisystemic wasting syndrome (PMWS) affected farms from Denmark and Spain using similar designs. Fourteen independent batches of 100-154 pigs per batch were monitored from birth to PMWS outbreak occurrence. Pigs displaying PMWS-like signs and matched healthy cohorts were euthanized during the clinical outbreak. PMWS was diagnosed according to internationally accepted criteria and pigs were classified as: (i) PMWS cases, (ii) wasted non-PMWS cases and (iii) healthy pigs. Porcine circovirus type 2 (PCV2) quantitative PCR (qPCR) and serology techniques were applied to analyse longitudinally collected sera and/or nasal and rectal swabs. Results showed that PCV2 load increased in parallel to waning maternal antibody levels, reaching the maximum viral load concurrent with development of clinical signs. PMWS affected pigs had higher PCV2 prevalence and/or viral load than healthy pigs in all collected samples at necropsy (p

A retrospective study to detect evidence of swine Torque teno virus (TTV) genogroups 1 and 2 infection in sera of pigs from the Spanish livestock between years 1985 and 2005 was carried out by means of PCR. Also, the molecular evolution of TTV genogroups 1 and 2 during the 20-year period studied using a 250-base sequence of the non-coding region of the viral genome was assessed. Both TTV genogroup genomes were found in pig sera from the first year of study. Taking into account the whole study period, 113 out of 162 animals (69.8%) were infected with one or the other genogroup, while 38 out of 162 pigs (23.5%) were co-infected with both genogroups. Moreover, TTV genogroup 2 (90 out of 162, 55.6%) was significantly more prevalent than genogroup 1 (54 out of 162, 33.3%). The non-coding region of swine TTV genome sequenced showed its adequacy as a molecular marker in swine TTV. This study represents the earliest evidence of TTV infection in pigs to date, 14 years before the initial description of this virus. Moreover, this is also the earliest evidence of TTV infection in any species.

Several real-time PCR assays for quantification of PCV2 DNA (qPCR) have been described in the literature, and different in-house assays are being used by laboratories around the world. A general threshold of 10(7) copies of PCV2 per millilitre serum for postweaning multisystemic wasting syndrome (PMWS) diagnosis has been suggested. However, neither inter-laboratory nor inter-assay comparisons have been published so far. In the present study, two different qPCR probe assays used routinely in two laboratories were compared on DNA extracted from serum, nasal and rectal swabs. Results showed a significant linear association between the assays (p0.0001), and a systematic difference of 1.4 log10 copies of PCV2 per millilitre of sample (p0.0001). This difference indicated that the assay from laboratory 1 yielded a higher output than the one from laboratory 2. Results also showed that there was no linear association between the amount of PCV2 DNA and the amount of total DNA, neither in nasal (p=0.86) nor in rectal (p=0.78) swabs, suggesting that normalizing of PCV2 DNA load in swab samples to total DNA concentration is not suitable. The present exploratory study highlights the need for the performance of ring trials on qPCV2 protocols between laboratories. Meanwhile, the proposed thresholds for PMWS diagnosis should only be considered reliable for each particular laboratory and each particular assay.

Porcine circovirus type 2 (PCV2) is the causative agent of postweaning multisystemic wasting syndrome (PMWS). The presence of immunostimulating factors or concurrent infections seems to be crucial for PMWS development. Lipopolysaccharide (LPS) is a potent immunological activator and has recently been suggested to enhance PCV2 replication in vitro. This study was designed to evaluate the effects of different LPS products on PCV2 in vitro replication of pulmonary macrophages (PMs), and on the potential ability to trigger PMWS in cesarean-derived, colostrum-deprived (CDCD) PCV2-inoculated piglets. In vitro studies using two different PCV2 isolates (Stoon-1010 and 1452/3) showed the presence of PCV2 antigen within the cytoplasm to a variable degree; PCV2 Stoon-1010 was barely detectable (1% of stained cells), and PCV2 1452/3 was seen in the cytoplasm of more than 85% of PMs. However, no differences were found in intracytoplasmic PCV2 signals among different LPS treatments, or between the LPS-treated and non-treated PMs. Moreover, almost no intranuclear signals for PCV2 antigen were detected in PMs. The in vivo experiment included twenty 7-day-old CDCD piglets divided into four groups: control (n = 4), control/LPS (n = 4), PCV2 (n = 6), and PCV2/LPS (n = 6). The control and control/LPS groups were inoculated intranasally with a cell culture medium (MEM), and the PCV2 and PCV2/LPS groups were inoculated with a Spanish isolate of PCV2 (Burgos). The control/LPS and PCV2/LPS groups were inoculated intraperitoneally with LPS on PCV2 inoculation day. All pigs remained clinically healthy during the entire experimental period (29 days). Animals inoculated with LPS had significant hyperthermia within the first 24 hours post-inoculation. No differences in gross or histological findings were observed among the PCV2 and PCV2/LPS inoculated pigs. All PCV2-infected piglets developed a subclinical infection with the virus. Our results showed that LPS did not increase in vitro viral replication and did not trigger PMWS in PCV2-inoculated pigs.

The efficacy of recently developed porcine circovirus type 2 (PCV2) vaccines has not been tested yet against PCV2 isolates of the two proposed genotypes. In the present work, the efficacy of a subunit vaccine containing PCV2 capsid protein was evaluated by using a challenge model with four different PCV2 isolates of different genotype and geographic origin. The vaccine prevented the development of viremia in all cases as well as significantly decreased nasal and faecal shedding of the virus. Also, the vaccine elicited PCV2-specific neutralizing antibodies to PCV2 even in the presence of maternally derived immunity.

Porcine circovirus type 2 (PCV2) is the essential infectious agent of postweaning multisystemic wasting syndrome (PMWS). Despite first sequencing studies did not find any association between PCV2 sequences and PMWS occurrence, recent works have suggested the opposite. In the present study, 87 open reading frame 2 (ORF2) sequences obtained from pigs with different clinical conditions and coming from farms with different PMWS status were analyzed. Results further confirmed the existence of two genogroups and the definition of two PCV2 genotypes (1 and 2) is proposed. All sequences included in genotype 1 came from pigs from PMWS affected farms, while all sequences obtained from non-PMWS affected farms corresponded to genotype 2. Moreover, infection of single pigs from PMWS affected farms harbouring both genotypes is described. Present results suggest that PCV2 genotype 1 may potentially be more pathogenic than PCV2 genotype 2.

Mycoplasma hyopneumoniae, the primary pathogen of enzootic pneumonia, occurs worldwide and causes major economic losses to the pig industry. The organism adheres to and damages the ciliated epithelium of the respiratory tract. Affected pigs show chronic coughing, are more susceptible to other respiratory infections and have a reduced performance. Control of the disease can be accomplished in a number of ways. First, management practices and housing conditions in the herd should be optimized. These include all-in/all-out production, limiting factors that may destabilize herd immunity, maintaining optimal stocking densities, prevention of other respiratory diseases, and optimal housing and climatic conditions. Strategic medication with antimicrobials active against M. hyopneumoniae and, preferably, also against major secondary bacteria may be useful during periods when the pigs are at risk for respiratory disease. Finally, commercial bacterins are widely used to control M. hyopneumoniae infections. The main effects of vaccination include less clinical symptoms, lung lesions and medication use, and improved performance. However, bacterins provide only partial protection and do not prevent colonization of the organism. Different vaccination strategies (timing of vaccination, vaccination of sows, vaccination combined with antimicrobial medication) can be used, depending on the type of herd, the production system and management practices, the infection pattern and the preferences of the pig producer. Research on new vaccines is actively occurring, including aerosol and feed-based vaccines as well as subunit and DNA vaccines. Eradication of the infection at herd level based on age-segregation and medication is possible, but there is a permanent risk for re-infections.

The present study focused on Mycoplasma hyopneumoniae (M. hyopneumoniae) detection by nPCR in nasal swabs of 507 suckling pigs. These animals came from 69 sows (from 1 to 8 parity number) of a farrow-to-finish herd with Enzootic Pneumonia (EP) problems at finishing stages. At 1 and 3 weeks of age (still in the farrowing units), nasal swabs and blood samples were taken from all piglets. Moreover, from these 507 animals, 37 randomly selected pigs were necropsied at 3 weeks of age. From those necropsied pigs, M. hyopneumoniae presence was tested in bronchial and tonsillar swabs. At 1 week post-farrowing, blood samples from sows were collected and used to detect M. hyopneumoniae antibodies. From the 69 analysed sows, 19 (27.5%) were seropositive. Global percentage of pigs with M. hyopneumoniae detection in nasal swabs at 1 and 3 weeks of age was 1.5% (8 out of 507) and 3.8% (19 out of 507), respectively. From these nPCR positive pigs, 89% (24 out of 27) were seronegative and 11% were seropositive. From necropsied animals, the pathogen DNA was detected in two pigs at bronchus level and in another pig at tonsil. In this study, sow parity was not statistically related with sow seropositivity and piglet colonization. These results confirm that M. hyopneumoniae infection may be detected not only in nasal cavities of naturally infected suckling piglets but also at their low respiratory tract airways. Our results suggest that M. hyopneumoniae detection in lower and upper respiratory tract could be an indicator that respiratory problems associated to EP may start relatively early in the production system. In consequence, sow-to-piglet and/or piglet-to piglet transmission in farrowing barns should not be underestimated.

The present study focused on PCV2 quantification by TaqMan PCR in nasal ( n = 99), tonsillar ( n = 108), tracheo-bronchial ( n = 72), urinary ( n = 91) and faecal ( n = 42) swabs, as well as in serum ( n = 57), from a total of 146 pigs received at the Pathological Diagnostic Service at the Veterinary School of Barcelona (Spain). Animals were classified into three categories based on histopathological and in situ hybridisation (ISH) results: PMWS affected pigs (Group A, n = 42), PCV2 subclinically infected pigs (Group B, n = 29), and non-PMWS with PCV2 ISH negative pigs (Group C, n = 75). Overall, tracheo-bronchial swabs had the higher PCV2 load followed by serum, tonsillar, nasal, faecal and, finally, urinary swabs. PCV2 genome was also detected in different proportions in all three categories of pigs; in all tested sites, viral load means were significantly higher ( P ≤ 0.02) in animals with PMWS (Group A pigs) than in animals without PMWS (Group B and C pigs). Therefore, the more severe the lesions, the higher amounts of viral genome by ISH, and the higher PCV2 load in serum and swab specimens. Except for the tracheo-bronchial swab, no significant differences ( p > 0.05) were observed among tested specimens when age-groups (pigs younger than 1.5 months, and equal or older than 1.5 months of age) were compared. In summary, PCV2 is presumably excreted through respiratory (nasal and tracheo-bronchial) and oral (tonsillar) secretions, urine and faeces of both PMWS and non-PMWS affected pigs, with higher viral loads being associated with the presence of PMWS lesions.

This study had 2 objectives: 1) to determine the involvement of Mycoplasma hyopneumoniae in respiratory outbreaks in herds of pigs, with the use of a nested polymerase chain reaction (nPCR) and an enzyme-linked immunosorbent assay (ELISA); and 2) to determine if the dynamics of M. hyopneumoniae infection differ between 3-site versus 1- or 2-site production systems (in which at least farrowing/gestation and nursery pigs are on the same site). Animals of different ages from 12 Spanish farms with respiratory problems were randomly sampled. Blood samples and nasal swabs were collected in a single farm visit, and ELISA and nPCR tests, respectively, were performed. All the farms demonstrated M. hyopneumoniae. According to the proportions of infected animals and the appearance of clinical signs in the different age groups, the farms were divided into 2 groups: farms in which M. hyopneumoniae probably played an important role in the observed respiratory outbreak and farms in which M. hyopneumoniae was not the main agent involved in the outbreak. Although seroconversion occurred in most herds in the finishing units, the number of seropositive pigs in the first group of farms was greater than the number in the second group. Statistically significant differences (P < 0.0001) between farms with a 1- or 2-site production system versus those with a 3-site production system were detected in nPCR results but not in rates of seroconversion. The farm effect also had a great influence on both controlled parameters: the pathogen’s DNA and antibody detection. Thus, although M. hyopneumoniae was present in all the studied farms, there were significant differences in the infection dynamics and clinical implications according to the type of production system, and M. hyopneumoniae colonization and seroconversion were greatly influenced by the effect of the individual farm.

Objective—To determine whether correlations exist between viremia with porcine circovirus type 2 (PCV2) and serum antibody profiles and between detection of PCV2 in nasal cavities and viremia of pigs from farms with and without postweaning multisystemic wasting syndrome (PMWS). Animals—495 pigs, ranging from the late nursery stage to the early grower-finisher stage of production. Procedure—Serum antibodies to PCV2 were studied with an ELISA that detects the ORF2 viral protein. Nasal swab specimens and serum samples were tested with a PCV2-specific PCR assay. Results—PCV2 DNA and serum antibodies to PCV2 were detected in pigs from all farms, although in different proportions. Overall, PCV2 DNA was detected in greater percentages in serum samples and nasal swab specimens of pigs from farms with PMWS. Although viral DNA was detected in both serum samples and nasal swab specimens, PCV2 detection in nasal swab specimens was higher than in serum samples of pigs from all farms. Serum antibodies to PCV2 were detected in a greater percentage of pigs from farms with PMWS, compared with farms without PMWS. Conclusions and Clinical Relevance—A high prevalence of PCV2 infection was found in pigs from farms with and without PMWS. Besides the presence of PCV2, unknown additional factors may be necessary to induce the full expression of PMWS. ( Am J Vet Res 2004;65:88–92)

International audience; - The objective of this study was to evaluate the effect of a commercial vaccine adjuvant on the clinical and pathological outcome of PCV2 experimentally infected 8 to 9-week-old conventional pigs. Forty-four pigs were divided into four groups: non-infected control pigs, pigs that received a vaccine adjuvant, pigs inoculated with PCV2, and pigs inoculated with PCV2 together with the vaccine adjuvant. Infection was monitored until 69 days post-inoculation (PI). Some PCV2 inoculated pigs had hyperthermia, but no other clinical signs were recorded. No characteristic PMWS gross or microscopic lesions were observed in any of the pigs. PCV2 DNA was detected in lymphoid tissues by in situ hybridisation in 6 PCV2 inoculated pigs on day 69 PI. All PCV2 inoculated pigs seroconverted between days 21 and 49 PI, shortly after viremia detection. Moreover, viremia was detected between days 7 and 69 PI using PCR. A peak of the virus load was detected by real-time quantitative PCR between days 14 and 21 PI. There were no significant differences in the proportion of PCV2 positive serum and in the viral load between PCV2 and PCV2 + adjuvant inoculated pigs. Although PMWS was not reproduced in neither PCV2 nor PCV2 + adjuvant inoculated pigs, viremia detection and seroconversion indicated that all PCV2 inoculated pigs developed a chronic long-term asymptomatic infection. An increase of PCV2 replication was not observed in pigs inoculated with the adjuvant. These results indicate that the principle of immunostimulation may not be applicable under the experimental conditions used, suggesting that not all adjuvants used in commercial vaccines are capable of triggering mechanisms for PMWS development.

Background: In this study, four lung lesion scoring methods (Slaughterhouse Pleurisy Evaluation System [SPES], Consolidation Lung Lesion Score [LLS], Image analyses [IA] and Ratio of lung weight/body weight [LW/BW]) were compared for the assessment of the different pathological outcomes derived from an Actinobacillus pleuropneumoniae (App) experimental infection model. Moreover, pathological data was coupled with clinical (fever, inappetence and clinical score), production (average daily weigh gain [ADWG]) and diagnostic (PCR, ELISA and bacterial isolation) parameters within the four infection outcomes (peracute, acute, subclinically infected and non-infected). Results: From the 61 inoculated animals, 9 were classified as peracute (presence of severe App-like clinical signs and lesions and sudden death or euthanasia shortly after inoculation), 31 as acutely affected (presence of App-like clinical signs and lesions and survival until the end of the experiment), 12 as subclinically infected (very mild or no clinical signs but App infection confirmed) and 9 as non-infected animals (lack of App-like clinical signs and lack of evidence of App infection). A significant correlation between all lung lesion scoring systems was found with the exception of SPES score versus LW/BW. SPES showed a statistically significant association with all clinical, production and diagnostic (with the exception of PCR detection of App in the tonsil) variables assessed. LLS and IA showed similar statistically significant associations as SPES, with the exception of seroconversion against App at necropsy. In contrast, LW/BW was statistically associated only with App isolation in lungs, presence of App-like lesions and ELISA OD values at necropsy. Conclusions: In conclusion, SPES, LLS and IA are economic, fast and easy-to-perform lung scoring methods that, in combination with different clinical and diagnostic parameters, allow the characterization of different outcomes after App infection.

L. Grau-Roma *, E. Crisci , M. Sibila , S. Lopez-Soria , M. Nofrarias , M. Cortey , L. Fraile , A. Olvera , J. Segales a,b Centre de Recerca en Sanitat animal (CReSa), Esfera Universitat Autonoma de Barcelona (UAB), Bellaterra 08193, Spain Department de Sanitat i d’Anatomia Animals, Faculita de Veterinaria, Universitat Autonoma de Barcelona (UAB), Bellaterra 08193, Spain Bofill i Codina 14, Calella de P, Girona 17210, Spain

The aim of this study was to compare and correlate antibody titres against porcine circovirus type 2 (PCV2) in porcine sera (n = 1270) obtained by immunoperoxidase monolayer assay (IPMA) with the results of three commercial ELISAs (designated E1, E2 and E3). The correlation between IPMA and ELISA results was excellent (r(2) ≥ 0.90). Compared to IPMA, E2 had the highest sensitivity (93.0%), followed by E3 (90.1%) and E1 (85.0%); the specificity was 100% for all tests. All three commercial ELISAs had predictive values similar to those of IPMA and could be used to monitor antibody responses against PCV2 infection and/or vaccination.

An experiment was conducted to determine whether spray-dried porcine plasma containing 2.47 x 10(5) dna copies of porcine circovirus type 2 (pcv-2) could infect weanling pigs when fed to them. Five specific pathogen-free (spf) weanling pigs were fed ad libitum for 45 days a control diet and six pigs were fed a test diet containing 8 kg sdpp per 100 kg feed. The two groups were housed in separate biosecurity level-3 rooms. None of the pigs in either group developed any clinical signs or became pcv-2 viraemic or seroconverted.

Anelloviruses are small, non-enveloped viruses with circular single stranded DNA, which infect a number of animal species as well as humans. In pigs, two distinct Torque teno sus virus (TTSuV) species have been described so far, being one of them linked to disease occurrence. Specifically, TTSuV2 loads in serum have been found increased in pigs suffering from postweaning multisystemic wasting syndrome (PMWS). Since this pathological condition is able to be controlled by means of porcine circovirus type 2 (PCV2) vaccination, it was hypothesized the possibility that such vaccination would have an impact on TTSuV2 prevalence and loads. A total of 150 pigs were divided in two study groups. Half of them received a PCV2 commercial vaccine, while the other half remained as non-vaccinated controls. PCV2 infection was monitored at 3–4, 8, 12, 16 and 21 weeks of age by means of an standard PCR, while TTSuV2 loads were determined at 8, 16 and 21 weeks of age by a quantitative PCR. No obvious PMWS clinical signs were observed among studied animals, although PCV2 infection was confirmed in both groups of pigs. Almost all pigs got TTSuV2 infection throughout the study period, independently of the PCV2 vaccination status of animals. Moreover, TTSuV2 load did not show significant differences between different pig groups at each sampling time, but mean viral load increased with age. Taking into account that previous results suggest that TTSuV2 load in serum is increased in the background of PMWS, the present study suggests that this is not the case in a PCV2 subclinical infection scenario. Therefore, vaccination of PCV2 subclinically infected pigs did not modify the outcome of TTSuV2 infection.