Disease In Pig Production Research Articles

PSV-2 Impact of Diseases in Pig Production on Carcass and Meat Quality

Abstract Several diseases, including Porcine Respiratory and Reproductive Syndrome (PRRS), are present in pig herds. The effects of diseases on growth performance are generally well known, but there is a lack of information on the consequences on carcass and meat quality. The aim of this project was to assess the impact of diseases present in the nursery and finishing on performances, carcass yields and meat quality. The trial was carried out at the Deschambault Swine Evaluation Station, where a project aimed at evaluating disease resilience is being carried out. A total of 480 castrated piglets from 8 different batches entered the nursery barn every 3 weeks. Pigs were observed daily, and a careful examination of the clinical signs was carried out weekly on each animal, to separate pigs showing signs of disease from those in good health. Ultrasound measurements of back fat thickness, muscle depth and intramuscular fat (IMF) level were performed three different times during growth. When the pigs reached a body weight of approximately 120 kg, carcass quality and meat yield measurements were taken 18 to 24 hours after slaughter. The ultimate pH, color, water loss and marbling were measured on the loin. The presence of PRRS and other diseases had a significant impact on the growth performance of pigs in fattening and demonstrates that the presence of the virus in the herd significantly decreases the average daily gain (ADG). This difference has a direct impact on the number of days in fattening. Results for back fat thickness at the end of fattening show significant differences (P < 0.05) between uninfected pigs (14.7 mm), pigs infected in nursery (13.9 mm) and fattening (12.8 mm) only, and pigs that have been ill both in nursery and fattening (12.4 mm). These results indicate that the presence of diseases leads to a decrease in fat deposition in pigs at the end of fattening. However, results for IMF measured at the end of fattening demonstrate that the presence of diseases had no significant impact on the final IMF level (P > 0.10), varying between 2.05% for healthy pigs and 2.13% for animals that have been sick in nursery and fattening. The results obtained in the slaughterhouse have shown that the presence of diseases does not seem to have an impact on the various measures of meat quality (P > 0.05). Only drip loss shows a significant difference (P < 0.05) between healthy and sick animals. However, the low number of sick pigs in the batches evaluated could have limited the observed effects. The work carried out by the CDPQ has made it possible to quantify the impact of diseases by providing a better understanding of their impact on product quality.

Preparation and application of a novel monoclonal antibody specific for the heat shock protein 60 of Lawsonia intracellularis

Porcine proliferative enteropathy (PPE), an important infectious disease in pig production caused by an obligate intracellular bacterium Lawsonia intracellularis, is commonly associated with diarrhea and reduced weight gain in growing pigs widespread. An accurate method for detecting L. intracellularis is particularly important for preventing and controlling PPE. Heat shock protein 60 (Hsp60) is an immunodominant bacterial antigen found in all eukaryotic and prokaryotic organisms. Thus, the purpose of the current investigation was to produce a novel L. intracellularis Hsp60 monoclonal antibody (mAb) useful for immunodiagnostics. Three hybridomas secreted anti-Hsp60 termed 3E5, 4E2, and 9G6 were generated, and the titers of ascitic fluids of 3E5, 4E2, 9G6 were 1:1 024 000, 1:2 048 000 and 1:2 048 000, respectively. The Western blotting analysis demonstrated that recombinant Hsp60 (rHsp60) was recognized by mAbs 3E5, 4E2 and 9G6. Subsequently, analyses of specificity showed all the mAbs were highly specific to L. intracellularis while could not significantly react with other enteric bacteria commonly found in the ileum of pigs, such as Escherichia coli, Salmonella Choleraesuis, Salmonella Typhimurium, and Brachyspira hyodysenteriae. Furthermore, the mAbs were useful for detecting L. intracellularis in the infected monolayer cells and histological sections of the ileum from PPE-affected pigs. Our research will provide a foundation for the development of immunological diagnostic tests.

Impact of diseases in pig production on carcass and meat quality

Impact of diseases in pig production on carcass and meat quality

Pigs as a shortcut to money? Social traps in smallholder pig production in northern Uganda

Recent decades have seen a growing market for pork in Uganda. The government and donors have promoted pig rearing as a potential route out of poverty for poor smallholders. The idea is that upscaling and commercialisation of smallholder pig production can be a successful way out of poverty. Drawing on the concepts of trust and social traps, this article describes how pig production fails as a pathway out of poverty in post-conflict communities in northern Uganda due to tensions created by the focus on individual wealth creation. Results from ethnographic fieldwork reveal that there is a strong moral obligation in the studied communities for individuals who fare better to contribute to the community and share their wealth. Social tensions remaining from the period of conflict are stoked by the focus on individual wealth creation in pig production, resulting in acts of harming, stealing and killing other people's pigs. Locally these acts are said to be caused by “jealousy”, which for many smallholders is a more significant problem than disease in pig production. The findings suggest that poverty reduction measures would be more successful if they focused on distributed approaches aimed at raising the general level of welfare in communities and supporting the collective rather than the individual.

Molecular survey of porcine respiratory disease complex pathogens in Brazilian wild boars

Wild boar (Sus scrofa) is an exotic invasive species in Brazil and may be a reservoir for several pathogens, including those related to the porcine respiratory disease complex (PRDC), a critical infectious disease in pig production. The objective of this study was to investigate viral and bacterial pathogens related to PRDC in free-living wild boars from Brazil. Eighty animals were examined in search of genomes of porcine circovirus 2 (PCV2), Torque teno Sus virus 1a (TTSuV1a) and 1b (TTSuV1b), Influenza A virus (IAV), Actinobacillus pleuropneumoniae, Glaesserella parasuis, Pasteurella multocida, and Mycoplasma hyopneumoniae. The results demonstrated that 57.5% (46/80) of the animals had at least one detected pathogen, and 11.3% of them (9/80) were co-infected. TTSuV1a was the most prevalent genome, for which risk factors were associated with increased contact between wild boars and other animals. The other pathogens were detected at much lower frequencies or not detected (M. hyopneumoniae and IAV). An additional IAV serology search identified H1N1pdm09 antibodies in 35.5% (16/45) of the wild boars, bringing concern related to public health. In conclusion, wild boars are infected with pathogens that cause swine diseases, so their eventual contact with domestic pigs might risk animal production in Brazil.

F4- and F18-Positive Enterotoxigenic Escherichia coli Isolates from Diarrhea of Postweaning Pigs: Genomic Characterization.

This study aimed to characterize in silico enterotoxigenic Escherichia coli F4- and F18-positive isolates (n = 90) causing swine postweaning diarrhea, including pathogenic potential, phylogenetic relationship, antimicrobial and biocide resistance, prophage content, and metal tolerance rates. F4 strains belonged mostly to the O149 and O6 serogroups and ST100 and ST48 sequence types (STs). F18 strains were mainly assigned to the O8 and O147 serogroups and ST10, ST23, and ST42. The highest rates of antimicrobial resistance were found against streptomycin, sulfamethoxazole, tetracycline, trimethoprim, and ampicillin. No resistance was found toward ciprofloxacin, cefotaxime, ceftiofur, and colistin. Genes conferring tolerance to copper (showing the highest diversity), cadmium, silver, and zinc were predicted in all genomes. Enterotoxin genes (ltcA, 100% F4, 62% F18; astA, 100% F4, 38.1% F18; sta, 18.8% F4, 38.1% F18; stb, 100% F4, 76.2% F18) and fimbria-encoding genes typed as F4ac and F18ac were detected in all strains, in addition to up to 16 other virulence genes in individual strains. Phage analysis predicted between 7 and 20 different prophage regions in each strain. A highly diverse variety of plasmids was found; IncFII, IncFIB, and IncFIC were prevalent among F4 isolates, while IncI1 and IncX1 were dominant among F18 strains. Interestingly, F4 isolates from the early 1990s belonged to the same clonal group detected for most of the F4 strains from 2018 to 2019 (ONT:H10-A-ST100-CH27-0). The small number of single-nucleotide polymorphism differences between the oldest and recent F4 ST100 isolates suggests a relatively stable genome. Overall, the isolates analyzed in this study showed remarkably different genetic traits depending on the fimbria type.IMPORTANCE Diarrhea in the postweaning period due to enterotoxigenic E. coli (ETEC) is an economically relevant disease in pig production worldwide. In Denmark, prevention is mainly achieved by zinc oxide administration (to be discontinued by 2022). In addition, a breeding program has been implemented that aims to reduce the prevalence of this illness. Treatment with antimicrobials contributes to the problem of antimicrobial resistance (AMR) development. As a novelty, this study aims to deeply understand the genetic population structure and variation among diarrhea-associated isolates by whole-genome sequencing characterization. ST100-F4ac is the dominant clonal group circulating in Danish herds and showed high similarity to ETEC ST100 isolates from China, the United States, and Spain. High rates of AMR and high diversity of virulence genes were detected. The characterization of diarrhea-related ETEC is important for understanding the disease epidemiology and pathogenesis and for implementation of new strategies aiming to reduce the impact of the disease in pig production.

Use of meat juice and blood serum with a miniaturised protein microarray assay to develop a multi-parameter IgG screening test with high sample throughput potential for slaughtering pigs

BackgroundSerological screening of pig herds at the abattoir is considered a potential tool to improve meat inspection procedures and herd health management. Therefore, we previously reported the feasibility of a miniaturised protein microarray as a new serological IgG screening test for zoonotic agents and production diseases in pigs. The present study investigates whether the protein microarray-based assay is applicable for high sample throughput using either blood serum or meat juice.Material and methodsMicroarrays with 12 different antigens were produced by Abbott (formerly Alere Technologies GmbH) Jena, Germany in a previously offered ‘ArrayTube’ platform and in an ‘ArrayStrip’ platform for large-scale use. A test protocol for the use of meat juice on both microarray platforms was developed. Agreement between serum and meat juice was analysed with 88 paired samples from three German abattoirs. Serum was diluted 1:50 and meat juice 1:2. ELISA results for all tested antigens from a preceding study were used as reference test to perform Receiver Operating Characteristic analysis for both test specimens on both microarray platforms.ResultsHigh area under curve values (AUC > 0.7) were calculated for the analysis of T. gondii (0.87), Y. enterocolitica (0.97), Mycoplasma hyopneumoniae (0.84) and Actinobacillus pleuropneumoniae (0.71) with serum as the test specimen and for T. gondii (0.99), Y. enterocolitica (0.94), PRRSV (0.88), A. pleuropneumoniae (0.78) and Salmonella spp. (0.72) with meat juice as the test specimen on the ArrayStrip platform. Cohens kappa values of 0.92 for T. gondii and 0.82 for Y. enterocolitica were obtained for the comparison between serum and meat juice. When applying the new method in two further laboratories, kappa values between 0.63 and 0.94 were achieved between the laboratories for these two pathogens.ConclusionFurther development of a miniaturised pig-specific IgG protein microarray assay showed that meat juice can be used on microarray platforms. Two out of twelve tested antigens (T. gondii, Y. enterocolitica) showed high test accuracy on the ArrayTube and the ArrayStrip platform with both sample materials.

Early Parenteral Administration of Ceftiofur has Gender-Specific Short- and Long-Term Effects on the Fecal Microbiota and Growth in Pigs from the Suckling to Growing Phase.

Simple SummaryAntibiotics are commonly used in prevention and therapy of bacterial diseases in pig production. Although the main target of antibiotics are the pathogenic bacteria, they often disrupt the commensal gut microbiota as a whole, leading to intestinal disturbances. These detrimental effects have been well established for oral administration of antibiotics, whereas knowledge about potential disturbing effects of single parenteral antibiotic treatments on the gut microbiota development is limited. In this research, the impact of a single antibiotic injection on the first day of life on the maturation of the fecal microbiome and host growth performance was evaluated from the suckling to the growing phase. Results showed that a single antibiotic injection early in life influenced the bacterial community development in the short- and long-term and that this disturbance in the bacterial community was sex-specific. Present results further demonstrated that changes in the bacterial ecosystem of the gut may impair the growth performance of the growing pig. Thus, the results of the present study emphasize the importance of a proper and strict use of antibiotics in swine herds.Using ceftiofur during the first days of life is a common preventative strategy against several bacterial diseases in pig production. This study aimed to evaluate short- and long-term effects of early use of ceftiofur on the fecal microbiota development in suckling and growing pigs. Sixty-four piglets from eight litters were assigned to the antibiotic (AB; n = 32) or control group (control; n = 32). Twelve hours postpartum (day 0) AB piglets received an intramuscular injection of ceftiofur (5.0 mg/kg body weight) or a placebo. DNA was extracted from fecal samples collected on days 0, 12, 28, and 97 for deep-sequencing of the 16S rRNA gene. The AB administration disturbed the maturational changes in the fecal microbiome, whereby effects were sex-specific. Sex-related differences in AB metabolism in females and males may have caused these diverging AB-effects on the fecal microbiota. Especially the loss of bacterial diversity and of certain taxa in female AB pigs may have contributed to the decreased body weight of these females on day 97 of life. Taken together, this study showed that an AB injection with ceftiofur 12 h postpartum markedly affected the successional changes in the fecal microbiota composition in male and female pigs, with long-term consequences for host performance.

Development of a miniaturized protein microarray as a new serological IgG screening test for zoonotic agents and production diseases in pigs.

In order to monitor the occurrence of zoonotic agents in pig herds as well as to improve herd health management, the development of new cost-effective diagnostic methods for pigs is necessary. In this study, a protein microarray-based assay for the simultaneous detection of immunoglobulin G (IgG) antibodies against different zoonotic agents and pathogens causing production diseases in pigs was developed. Therefore, antigens of ten different important swine pathogens (Toxoplasma gondii, Yersinia enterocolitica, Salmonella spp., Trichinella spp., Mycobacterium avium, Hepatitis E virus, Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, the porcine reproductive and respiratory syndrome virus, Influenza A virus) were spotted and covalently immobilized as ‘antigen-spots’ on microarray chips in order to test pig serum for the occurrence of antibodies. Pig serum was sampled at three German abattoirs and ELISA tests for the different pathogens were conducted with the purpose of creating a panel of reference samples for microarray analysis. To evaluate the accuracy of the antigens on the microarray, receiver operating characteristic (ROC) curve analysis using the ELISA test results as reference was performed for the different antigens. High area under curve values were achieved for the antigens of two zoonotic agents: Toxoplasma gondii (0.91), Yersinia enterocolitica (0.97) and for three production diseases: Actinobacillus pleuropneumoniae (0.77), Mycoplasma hyopneumoniae (0.94) and the porcine reproductive and respiratory syndrome virus (0.87). With the help of the newly developed microarray assay, collecting data on the occurrence of antibodies against zoonotic agents and production diseases in pig herds could be minimized to one measurement, resulting in an efficient screening test.

Placebo-controlled study on the effects of oral administration of Allium sativum L in postweaning piglets.

Postweaning diarrhoea (PWD) due to Escherichia coli is an economically important disease in pig production. In this placebo-controlled study performed in Switzerland, the effects of oral supplementation of Allium sativum L. (garlic, AS) on performance (bodyweight (BW) and daily weight gain (DWG)) and health (body condition and clinical score) were investigated in postweaning piglets. Piglets (n=600) were randomly assigned to the treatment groups (placebo, AS or colistin) and observed from birth until three weeks postweaning. The treatments were administered for the first two weeks postweaning. Faecal dry matter (FDM) and coliform bacteria on pen level were measured weekly. Data were analysed using generalised mixed-effect models in R. BW and DWG of the AS group were significantly higher compared with placebo in the third week postweaning. No differences in body condition and FDM were observed. The clinical score of AS-treated animals was significantly better compared with the colistin group. About 33 per cent of the piglets of the AS and the placebo group had to be treated with antibiotics due to the occurrence of severe PWD. The major finding of this study showed that AS supplementation increased growth performance and improved clinical health, but did not reduce the incidence and severity of PWD.

Seasonal patterns and space-time clustering of porcine reproductive and respiratory syndrome (PRRS) cases from 2008 to 2016 in Vietnam.

SummaryPorcine reproductive and respiratory syndrome (PRRS) is an important disease in pig production and is endemic in Vietnam. No nationwide studies have been carried out to understand the spread of PRRS in Vietnam. The main objective of this study was to identify the seasonal patterns and space‐time clusters of PRRS from 2008 to 2016 using national surveillance data in Vietnam. A total of 614,219 cases were reported during the period. There was a seasonal pattern with single peak by region (except North Central Coast, showing double peaks in March and June). The seasonal plots from the Northern regions showed a higher peak between March and April, whereas the four regions from Southern part displayed a higher peak between June and August. Overall, outbreaks from the northern part of Vietnam tended to occur 3–4 months earlier than the southern part. When the spatial window was set at 50%, space‐time cluster analysis found that the first cluster occurred in the Red River Delta (RRD) (radius: 82.17 km; ratios: 5.5; period: Mar–May/2010) and the second (radius: 50.8 km; ratios: 10.61; period: Aug–Oct/2011) in the Mekong River Delta (MRD) region. Four other clusters were observed in the central and Southern parts. Our findings might provide better insight into the distribution of clusters and temporal patterns of PRRS in Vietnam. This study may provide policy makers with valuable information on the hotspot areas and timing of outbreaks. Also, it identifies when and where national control program could be implemented more efficiently by targeting resources for the prevention and control of PRRS.

A systematic literature mapping and meta-analysis of animal-based traits as indicators of production diseases in pigs

The choice of animal-based traits to identify and deal with production diseases is often a challenge for pig farmers, researchers and other related professionals. This systematic review focused on production diseases, that is, the diseases that arise from management practices, affecting the digestive, locomotory and respiratory system of pigs. The aim was to classify all traits that have been measured and conduct a meta-analysis to quantify the impact of diseases on these traits so that these can be used as indicators for intervention. Data were extracted from 67 peer-reviewed publications selected from 2339 records. Traits were classified as productive (performance and carcass composition), behavioural, biochemical and molecular traits. A meta-analysis based on mixed models was performed on traits assessed more than five times across studies, using the package metafor of the R software. A total of 524 unique traits were recorded 1 to 31 times in a variety of sample material including blood, muscle, articular cartilage, bone or at the level of whole animal. No behavioural traits were recorded from the included experiments. Only 14 traits were measured on more than five occasions across studies. Traits within the biochemical, molecular and productive trait groups were reported most frequently in the published literature and were most affected by production diseases; among these were some cytokines (interleukin (IL) 1-β, IL6, IL8 and tumour necrosis factor-α), acute phase proteins (haptoglobin) and daily weight gain. Quantification of the influence of factors relating to animal characteristics or husbandry practices was not possible, due to the low frequency of reporting throughout the literature. To conclude, this study has permitted a holistic assessment of traits measured in the published literature to study production diseases occurring in various stages of the production cycle of pigs. It shows the lack of consensus and common measurements of traits to characterise production diseases within the scientific literature. Specific traits, most of them relating to performance characteristics or immunological response of pigs, are proposed for further study as potential tools for the prognosis and study of production diseases.

Integrating transportation and economic information for the African Swine Fever Virus (ASFV) risk modelling purposes in the Greater Mekong Sub-region (GMS) using online data and grey literature

Integrating transportation and economic information for the African Swine Fever Virus (ASFV) risk modelling purposes in the Greater Mekong Sub-region (GMS) using online data and grey literature

Space-time cluster analysis to improve classical swine fever risk-based surveillance in Ecuador

Space-time cluster analysis to improve classical swine fever risk-based surveillance in Ecuador

Identification of Differentially Expressed Non-coding RNA in Porcine Alveolar Macrophages from Tongcheng and Large White Pigs Responded to PRRSV

Porcine reproductive and respiratory syndrome (PRRS) is one of the most ruinous diseases in pig production. Our previous work showed that Tongcheng pigs (TC) were less susceptible to PRRS virus (PRRSV) than Large White (LW) pigs. To elucidate the difference in PRRSV resistance between the two breeds, small RNA-seq and ribo-zero RNA-seq were used to identify differentially expressed non-coding RNAs (including miRNAs and lincRNAs) responded to PRRSV in porcine alveolar macrophages (PAMs) from TC and LW pigs. Totally, 250 known mature miRNAs were detected. For LW pigs, there were 44 down-regulated and 67 up-regulated miRNAs in infection group; while for TC pigs, 12 down-regulated and 23 up-regulated miRNAs in TC infection group were identified. The target genes of the common differentially expressed miRNAs (DEmiRNAs) in these two breeds were enriched in immune-related processes, including apoptosis process, inflammatory response, T cell receptor signaling pathway and so on. In addition, 5 shared DEmiRNAs (miR-181, miR-1343, miR-296-3p, miR-199a-3p and miR-34c) were predicted to target PRRSV receptors, of which miR-199a-3p was validated to inhibit the expression of CD151. Interestingly, miR-378 and miR-10a-5p, which could inhibit PRRSV replication, displayed higher expression level in TC control group than that in LW control group. Contrarily, miR-145-5p and miR-328, which were specifically down-regulated in LW pigs, could target inhibitory immunoreceptors and may involve in immunosuppression caused by PRRSV. This indicates that DEmiRNAs are involved in the regulation of the immunosuppression and immune escape of the two breeds. Furthermore, we identified 616 lincRNA transcripts, of which 48 and 30 lincRNAs were differentially expressed in LW and TC pigs, respectively. LincRNA TCONS_00125566 may play an important role in the entire regulatory network, and was predicted to regulate the expression of immune-related genes through binding with miR-1343 competitively. In conclusion, this study provides an important resource for further revealing the interaction between host and virus, which will specify a new direction for anti-PRRSV research.

Efficacy of a modified-live virus vaccine in pigs experimentally infected with a highly pathogenic porcine reproductive and respiratory syndrome virus type 1 (HP-PRRSV-1)

PRRS is one of the main viral diseases in pig production, causing huge economic losses to the swine industry worldwide. The virus shows an intrinsic genomic instability and is able to change continuously, with the emergence of new strains, with different pathogenicity patterns. Commercially available vaccines only partially prevent or counteract the disease and the correlated losses. Moreover, the emergence of highly virulent and pathogenetic isolates represents a particular concern for PRRS control and diagnosis. The purpose of this study was to evaluate the efficacy of a modified-live virus (MLV) PRRSV-1 commercial vaccine in reducing the severity of the disease and minimizing losses upon challenge with a highly pathogenic PRRSV-1.1 Italian isolate (PRRSV-1_PR40/2014). Four different groups were compared: C (unvaccinated-uninfected), VAC-C (vaccinated-uninfected), PR40 (unvaccinated-infected) and VAC-PR40 (vaccinated-infected). The tested vaccine provided partial, but statistically significant clinical, virological and pathological protection after challenge under experimental conditions. In particular, vaccinated animals showed reduced viremia in terms of duration and magnitude, reduced respiratory signs and pathological lesions. Vaccination was able to trigger adaptive immunity able to respond efficiently also against the HP PR40 isolate. Vaccinated animals showed higher average daily weight gain, even during the viremic period, compared to non-vaccinated challenged pigs.

Effect of O. porcinus Tick Salivary Gland Extract on the African Swine Fever Virus Infection in Domestic Pig

African swine fever is a haemorrhagic disease in pig production that can have disastrous financial consequences for farming. No vaccines are currently available and animal slaughtering or area zoning to restrict risk-related movements are the only effective measures to prevent the spread of the disease. Ornithodoros soft ticks are known to transmit the African swine fever virus (ASFV) to pigs in farms, following the natural epidemiologic cycle of the virus. Tick saliva has been shown to modulate the host physiological and immunological responses during feeding on skin, thus affecting viral infection. To better understand the interaction between soft tick, ASFV and pig at the bite location and the possible influence of tick saliva on pig infection by ASFV, salivary gland extract (SGE) of Ornithodoros porcinus, co-inoculated or not with ASFV, was used for intradermal auricular inoculation. Our results showed that, after the virus triggered the disease, pigs inoculated with virus and SGE presented greater hyperthermia than pigs inoculated with virus alone. The density of Langerhans cells was modulated at the tick bite or inoculation site, either through recruitment by ASFV or inhibition by SGE. Additionally, SGE and virus induced macrophage recruitment each. This effect was enhanced when they were co-inoculated. Finally, the co-inoculation of SGE and virus delayed the early local spread of virus to the first lymph node on the inoculation side. This study has shown that the effect of SGE was powerful enough to be quantified in pig both on the systemic and local immune response. We believe this model should be developed with infected tick and could improve knowledge of both tick vector competence and tick saliva immunomodulation.

Establishment of serological herd profiles for zoonoses and production diseases in pigs by “meat juice multi-serology”

The most important pork-borne zoonotic diseases in humans such as Salmonelloses and Yersinioses cause only latent infections in pigs. Thus, the infection of pigs does not result in apparent or palpable alterations in the pig carcasses. This is the major reason, why the traditional meat inspection with adspection, palpation and incision is not able to control the food safety risks of today. The objective of this paper is to evaluate a set of serological tests, which provides a classification of pig herds into “zoonoses risk categories” as demanded by EU law and into “herd health risk categories” by using meat juice as diagnostic specimen for ELISA tests. Serological data that were obtained by testing meat juice samples from various pig herds were analyzed as proof of the “meat juice multi-serology” concept. For that, at least 60 meat juice samples from 49 pig herds each were taken between September 2010 and March 2011 and tested for antibodies against zoonotic pathogens (Salmonella spp., Trichinella spp., Yersinia enterocolitica and Toxoplasma gondii) and against pathogens causing production diseases (Mycoplasma hyopneumoniae, influenza A virus subtype H1N1, influenza A virus subtype H3N2 and PRRSV). Apparent and true animal prevalence, herd prevalence values and intra-herd seroprevalence values as well as the predictive values for the herd and the animal prevalence values were calculated for each pathogen and each of the 49 randomly selected herds. The herd seroprevalence values (one seropositive sample per herd determined a “positive herd”) for Y. enterocolitica, Salmonella spp., T. gondii, M. hyopneumoniae and PRRSV were higher than 80%, respectively, for the influenza A viruses between 60% and 14% and for Trichinella spp. 0%. Although all herds were located in the same area in the Northwest of Germany within a radius of 250km, the intra-herd seroprevalence values for all tested pathogens, except for Trichinella spp., varied remarkably from herd to herd. In the case of Y. enterocolitica and T. gondii the intra-herd seroprevalence values varied even from zero to 100%. This shows that a serological risk categorization of pig herds regarding zoonoses and production diseases is meaningful if used for risk-based decisions in the framework of the new meat inspection concept and as part of the herd health management system. Thus, the development of a cost-efficient, time- and labour-saving test system for simultaneously detecting various antibodies should be the next step for an extensive implementation of the meat juice multi-serology concept.

Suscetibilidade a desinfetantes e perfil de resistência a antimicrobianos em isolados de Escherichia coli

A colibacilose, causada por Escherichia coli, é a enfermidade entérica de maior impacto na produção de suínos, podendo levar à morte do animal. Esta bactéria possui grande capacidade de desenvolver resistência a múltiplos antimicrobianos e a desinfetantes. Desta forma, estudos que abordem mecanismos de resistência e perfil de amostras de campo tornam-se necessários. E. coli é amplamente utilizada como modelo de estudos que exploram a resistência intrínseca e extrínseca a multidrogas. Neste trabalho, buscou-se verificar o perfil de sensibilidade de 62 isolados de E. coli de suínos frente a três desinfetantes e a 13 antimicrobianos. Ainda, em 31 destes isolados foi pesquisada a presença de mecanismo de efluxo. Dos três desinfetantes avaliados, o cloreto de alquil dimetil benzil amônio+poliexietilenonilfenileter foi o que se mostrou mais eficaz (100%), seguido do glutaraldeído+cloreto de alquil dimetil benzil amônio (95,2%) e do cloreto de alquil dimetil benzil amônio (88,8%). Dentre os antimicrobianos testados, observou-se maior resistência para a tetraciclina (62,2%) e maior sensibilidade para o florfenicol (88,6%). A alta sensibilidade dos isolados frente aos desinfetantes pode estar relacionada à ausência de mecanismo de efluxo. O índice de resistência múltipla médio aos antimicrobianos foi de 0,52, o que demonstra um perfil multirresistente dos isolados, conduzindo para a necessidade do uso racional destas drogas em suinocultura.

Pyelonephritis in slaughter pigs and sows: Morphological characterization and aspects of pathogenesis and aetiology

BackgroundPyelonephritis is a serious disease in pig production that needs to be further studied. The purpose of this study was to describe the morphology, investigate the pathogenesis, and evaluate the aetiological role of Escherichia coli in pyelonephritis in slaughtered pigs by concurrent bacteriological, gross and histopathological examinations.MethodsFrom Danish abattoirs, kidneys and corresponding lymph nodes from 22 slaughtered finishing pigs and 26 slaughtered sows with pyelonephritis were collected and evaluated by bacteriology and pathology. Based on gross lesions, each kidney (lesion) was grouped as acute, chronic, chronic active, or normal and their histological inflammatory stage was determined as normal (0), acute (1), sub-acute (2), chronic active (3), or chronic (4). Immunohistochemical identification of neutrophils, macrophages, T-lymphocytes, B-lymphocytes, plasma cells, E. coli and Tamm-Horsfall protein (THP) in renal sections was performed. The number of E. coli and the proportion of immunohistochemically visualized leukocytes out of the total number of infiltrating leukocytes were scored semi-quantitatively.ResultsLesions in finishing pigs and sows were similar. Macroscopically, multiple unevenly distributed foci of inflammation mostly affecting the renal poles were observed. Histologically, tubulointerstitial infiltration with neutrophils and mononuclear cells and tubular destruction was the main findings. The significant highest scores of L1 antigen+ neutrophils were in inflammatory stage 1 while the significant highest scores of CD79αcy+ B-lymphocytes, IgG+ and IgA+ plasma cells were in stage 3 or 4. Neutrophils were the dominant leukocytes in stage 1 while CD3ε+ T-lymphocytes dominated in stage 2, 3 and 4. Interstitially THP was seen in 82% and 98% of kidneys with pyelonephritis from finishing pigs and sows, respectively. E. coli was demonstrated in monoculture and/or identified by immunohistochemistry in relation to inflammation in four kidneys from finishing pigs and in 34 kidneys from sows.ConclusionsE. coli played a significant role in the aetiology of pyelonephritis. Neutrophils were involved in the first line of defence. CD3ε+ T-lymphocytes were involved in both the acute and chronic inflammatory response while a humoral immune response was most pronounced in later inflammatory stages. The observed renal lesions correspond with an ascending bacterial infection with presence of intra-renal reflux.