Expanded cocirculation of stable subtypes, emerging lineages, and new sporadic reassortants of porcine influenza viruses in swine populations in Northwest Germany.

The emergence of the human 2009 pandemic H1N1 (H1N1pdm) virus from swine populations refocused public and scientific attention on swine as an important source of influenza A viruses bearing zoonotic potential. Widespread and year-round circulation of at least four stable lineages of porcine influenza viruses between 2009 and 2012 in a region of Germany with a high-density swine population is documented here. European avian influenza virus-derived H1N1 (H1N1av) viruses dominated the epidemiology, followed by human-derived subtypes H1N2 and H3N2. H1N1pdm viruses and, in particular, recently emerging reassortants between H1N1pdm and porcine HxN2 viruses (H1pdmN2) were detected in about 8% of cases. Further reassortants between these main lineages were diagnosed sporadically. Ongoing diversification both at the phylogenetic and at the antigenic level was evident for the H1N1av lineage and for some of its reassortants. The H1avN2 reassortant R1931/11 displayed conspicuously distinct genetic and antigenic features and was easily transmitted from pig to pig in an experimental infection. Continuing diverging evolution was also observed in the H1pdmN2 lineage. These viruses carry seven genome segments of the H1N1pdm virus, including a hemagglutinin gene that encodes a markedly antigenically altered protein. The zoonotic potential of this lineage remains to be determined. The results highlight the relevance of surveillance and control of porcine influenza virus infections. This is important for the health status of swine herds. In addition, a more exhaustive tracing of the formation, transmission, and spread of new reassortant influenza A viruses with unknown zoonotic potential is urgently required.

Reliability of operational data from pig herds and performance ratings by veterinarians and pig farmers collected during telephone interviews for the evaluation of a PCV2 piglet vaccination.

BACKGROUND: The aim of the present study was to evaluate the feasibility of using a telephone survey in gaining an understanding of the possible herd and management factors influencing the performance (i.e. safety and efficacy) of a vaccine against porcine circovirus type 2 (PCV2) in a large number of herds and to estimate customers' satisfaction. RESULTS: Datasets from 227 pig herds that currently applied or have applied a PCV2 vaccine were analysed. Since 1-, 2- and 3-site production systems were surveyed, the herds were allocated in one of two subsets, where only applicable variables out of 180 were analysed. Group 1 was comprised of herds with sows, suckling pigs and nursery pigs, whereas herds in Group 2 in all cases kept fattening pigs. Overall 14 variables evaluating the subjective satisfaction with one particular PCV2 vaccine were comingled to an abstract dependent variable for further models, which was characterized by a binary outcome from a cluster analysis: good/excellent satisfaction (green cluster) and moderate satisfaction (red cluster). The other 166 variables comprised information about diagnostics, vaccination, housing, management, were considered as independent variables. In Group 1, herds using the vaccine due to recognised PCV2 related health problems (wasting, mortality or porcine dermatitis and nephropathy syndrome) had a 2.4-fold increased chance (1/OR) of belonging to the green cluster. In the final model for Group 1, the diagnosis of diseases other than PCV2, the reason for vaccine administration being other than PCV2-associated diseases and using a single injection of iron had significant influence on allocating into the green cluster (P < 0.05). In Group 2, only unchanged time or delay of time of vaccination influenced the satisfaction (P < 0.05). CONCLUSION: The methodology and statistical approach used in this study were feasible to scientifically assess "satisfaction", and to determine factors influencing farmers' and vets' opinion about the safety and efficacy of a new vaccine.

Biosecurity measures for the prevention of African swine fever on German pig farms: comparison of farmers' own appraisals and external veterinary experts' evaluations.

BACKGROUND: Since its first introduction into the German wild boar population in 2020, African swine fever (ASF) has been spreading slowly from the eastern border westwards and has been introduced into eight domestic pig farms thus far. The European Food Safety Authority has named deficits in farm biosecurity and increased human activity as major risk factors for the introduction of the ASF virus into pig farms. Studies have shown that pig farms in Germany generally have a high level of biosecurity. However, veterinary practitioners and policy-makers have expressed concerns that not all pig farmers are appropriately prepared to deal with the threat of ASF. This study aimed to evaluate the level of biosecurity on pig farms in Lower Saxony and explore the reasons for deficits in the implementation of biosecurity measures. For this purpose, pig farmers were interviewed in open structured face-to-face interviews about their perception of ASF and biosecurity, and the implemented measures on their farms were assessed with a checklist. In the data analysis, the farmers' answers and the results of the biosecurity check were compared to gain further insights into the factors influencing the implementation of biosecurity measures on the farms. RESULTS: The biosecurity check showed that on most farms, a high level of biosecurity had been implemented. Nevertheless, deficits were found concerning the fences and the delimitation of clean and dirty areas on farm grounds and in the anteroom. Overall, the farmers were well informed about ASF and had a realistic perception of their own biosecurity. They considered the farm layout, financial means and practicality of hygiene measures to be the main barriers to implementing biosecurity measures against ASF. However, the results also suggested that farmers' attitudes and legal regulations were major influencing factors. CONCLUSION: The results indicated a high level of biosecurity against ASF on most pig farms and a realistic perception of their own biosecurity by the farmers. Current knowledge transfer and information should focus on building upon the farmers' own motivation and expertise and supporting them to put existing knowledge into practice.

Foot lesions and forelimb skin abrasions in suckling piglets: development and risk factors.

BACKGROUND: Foot lesions in suckling piglets have been associated with poor flooring in several studies and were recently proposed to be indicative of swine inflammatory and necrosis syndrome. However, identical findings are also the typical outcome of various non-infectious causes; thus, further risk analysis is needed. The objective of this study was to describe the development of heel bruising, coronary band lesions and forelimb skin abrasion in suckling pigs up to 5 days of age. Furthermore, the effects of various intrinsic and extrinsic factors were examined. On each of four commercial piglet-producing farms, piglets from two or three batches of eight sows were studied. The piglets were included within 18 h after birth. Each piglet was individually scored four times. The score for the heels differentiated six (0-5) and for the coronary band and forelimb skin abrasion three stages (0-2). The body weight was measured two times. The effect of the floor was estimated by allocating the sows randomly to farrowing pens equipped with either soft rubber mats covered with litter or fully slatted plastic floors. RESULTS: The final analysis comprised data from 1045 piglets. Foot lesions were not found at birth but started to develop on day 1. On day 5, heel bruising was found in 94%, main claw coronary band lesions in 49% and forelimb skin abrasion in 73% of the piglets. In a multifactorial logistic regression analysis, it was shown that a slatted plastic floor significantly increased the odds of heel bruising and coronary band lesions, while a rubber floor with litter increased the odds of forelimb skin abrasions. CONCLUSION: Foot and forelimb lesions in new-born piglets are mainly induced by the floor. The effect of slatted plastic floors on heel bruising showed an overwhelming OR of 52.89 (CI 26.29-106.43). Notably, coronary band lesions in young suckling piglets occur on slatted as well as non-slatted floors, indicating that the piglets incur these injuries not only from the wedging of their feet into the gaps between slats but also from contact with the floor while suckling. Based on these findings, preventive measures should be redirected to the improvement of the floor in the farrowing pen, particularly in the area under the sow's udder.

Effects of different tooth grinding procedures on the occurrence of tooth injuries, skin lesions, performance and behaviour of suckling piglets.

BACKGROUND: Immediately after birth, newborn piglets fight to establish a teat order. During this process, lesions appear on the piglets' faces and on the sows' teats, which is why tooth resection is carried out on many farms in Germany even though it is known that this procedure is frequently resulting in pulp openings. The opening of a pulp cave is suspected to cause painful tooth alterations and may be an entrance for infectious agents. The purpose of this study was to analyse the effect of tooth resection on skin lesions, development of bodyweight and behaviour in suckling piglets. Four days prepartum, 110 sows in farrow-to-finish production were assigned to one of three treatments. Litters had their teeth left intact (control group, CG), ground with a tea-cup roller head (Tea-cup head grinder group, TCG, Wilofa Diamant, D-56,133 Fachbach, Germany) or ground with a diamond rolling head (rolling head grinder group, RG, IBS/E Company Proxxon GmbH, 54,343 Föhren, Germany). The number of pulp openings in the RG and TCG was examined using a random sample. Piglet body weight and skin lesion scores were recorded within the first 24 h after birth and during each week of the suckling period. Each sow's udder was examined before farrowing, in the second week of lactation and at weaning. The behaviour of the litters from nine sows was video-recorded throughout the suckling period. The aim of this study was to investigate the effects of tooth grinding by a tea-cup head (compared to grinding by a diamond roller head and no grinding [control group]) on the behaviour and average daily gain of piglets as well as on skin lesions on sow udder. RESULTS: The number of dental injuries was significantly greater in the RG than in the TCG (p < 0.01). Head lesions on piglets were significantly more common in the CG than in the RG (p = 0. 02). Compared to CG piglets, TCG piglets had a significantly greater weight at the end of the suckling period (p = 0.02). No significant difference between treatments was found in the sows' udder (parenchyma, skin, or teat) or in the behaviour of the litters. CONCLUSION: As tooth grinding is frequently inducing pulp openings, the necessity of the procedure should be carefully and critically scrutinised. In case tooth resection seems inevitable until the underlying management problems have been solved, the Tea-cup grinding head should be used due to significantly fewer pulp openings.

Effects of Two Different Methods of Teeth Grinding on Dental Injuries, Skin Lesions, Growth and Behaviour of Suckling Piglets Compared to a Non-Treated Control Group.

Teeth grinding in suckling piglets is performed on many farms to protect the piglets' littermates and the sow's udder from injuries caused by the piglets' canines and third incisors. In this study, the effects of two teeth-grinding methods on the piglets' dental health and welfare were investigated. The piglets of a litter were evenly assigned to a treatment: one-third of littermates were ground with a roller grinding head (RG), one-third with a teacup grinding head (TCG), and one-third were not ground at all (CG). A random sample of 100 animals each from the RG and TCG treatment was examined for tooth injuries, i.e., dental pulp openings. Additionally, behavioural analysis was performed (n = 650 piglets), and skin lesions, growth and mortality were determined (n = 1565 piglets). TCG piglets had a lower risk (p < 0.001) of pulp opening than RG piglets (0.08 ± 0.31 vs. 2.67 ± 1.67 opened pulps per piglet). Mortality, growth, skin lesions and behaviour of piglets were not influenced by treatment (p > 0.05). This study showed that both teeth-grinding methods led to pulp openings. If teeth grinding cannot be avoided on a farm, using the teacup grinding head is recommended concerning animal health and welfare.

Reassortment incompetent live attenuated and replicon influenza vaccines provide improved protection against influenza in piglets.

Swine influenza A viruses (swIAV) cause an economically important respiratory disease in modern pig production. Continuous virus transmission and antigenic drift are difficult to control in enzootically infected pig herds. Here, antibody-positive piglets from a herd enzootically infected with swIAV H1N2 (clade 1 A.3.3.2) were immunized using a homologous prime-boost vaccination strategy with novel live attenuated influenza virus (LAIV) based on a reassortment-incompetent bat influenza-swIAV chimera or a vesicular stomatitis virus-based replicon vaccine. Challenge infection of vaccinated piglets by exposure to H1N2 swIAV-infected unvaccinated seeder pigs showed that both LAIV and replicon vaccine markedly reduced virus replication in the upper and lower respiratory tract, respectively, compared to piglets immunized with commercial heterologous or autologous adjuvanted whole-inactivated virus vaccines. Our novel vaccines may aid in interrupting continuous IAV transmission chains in large enzootically infected pig herds, improve the health status of the animals, and reduce the risk of zoonotic swIAV transmission.

Reassortants of pandemic influenza A virus H1N1/2009 and endemic porcine HxN2 viruses emerge in swine populations in Germany.

The incursion of the human pandemic influenza A virus H1N1 (2009) (H1N1 pdm) into pig populations and its ongoing co-circulation with endemic swine influenza viruses (SIVs) has yielded distinct human-porcine reassortant virus lineages. The haemagglutinin (HA) gene of H1N1 pdm was detected in 41 influenza virus-positive samples from seven swine herds in north-west Germany in 2011. Eight of these samples yielded virus that carried SIV-derived neuraminidase N2 of three different porcine lineages in an H1N1 pdm backbone. The HA sequences of these viruses clustered in two distinct groups and were distinguishable from human and other porcine H1 pdm by a unique set of eight non-synonymous mutations. In contrast to the human population, where H1N1 pdm replaced seasonal H1N1, this virus seems to co-circulate and interact more intensely with endemic SIV lineages, giving rise to reassortants with as-yet-unknown biological properties and undetermined risks for public health.

Killing underweighted low viable newborn piglets: Which health parameters are appropriate to make a decision?

BACKGROUND: The aim of this study was to estimate the mortality risk and associated factors within the first days of life for underweight or low-vital neonatal piglets. This risk estimation should start a discussion concerning the preconditions for timely killing of compromised newborn piglets to prevent unnecessary pain and suffering. In an observational study, various clinical and laboratory variables were examined in 529 piglets out of four farms. Body weight, crown-rump-length, rectal temperature, a 4-stage vitality score, an intrauterine-growth-retardation score, glucose, lactate, haemoglobin and immunocrit were assessed on the first day of life. Vitality was scored by three factors: movement, abdominal palpation, and colour of the skin. Afterwards the death of the piglets (by killing or spontaneously) was monitored until day 5 of age. RESULTS: Body weight, rectal temperature and vitality score were significantly associated with probability of death. Piglets with rectal temperatures ≤ 37.5 °C, a body weight < 0.86 kg and impaired vitality scores were found to have the highest probability of death until day 5 of age. CONCLUSION: The clinical findings, identified by this model, allow a first estimation of mortality risk for newborn piglets within the first days of life. In a further step veterinarians, farmers and ethicians now need to clarify what probability of death should justifiy the killing of a newborn piglet.

Reassorted pandemic (H1N1) 2009 influenza A virus discovered from pigs in Germany.

A natural reassortant influenza A virus consisting of seven genome segments from pandemic (H1N1) 2009 virus and a neuraminidase segment from a Eurasian porcine H1N1 influenza A virus was detected in a pig herd in Germany. The obvious reassortment compatibility between the pandemic (H1N1) 2009 and H1N1 viruses of porcine origin raises concern as to whether swine may become a reservoir for further reassortants of pandemic (H1N1) 2009 viruses with unknown implications for human health and swine production.

[Comparison of sample materials for the detection of infection with porcine reproductive and respiratory syndrome virus]. / Vergleich von Probenmaterialien zur Früherkennung einer Infektion mit dem Virus des Porzinen Reproduktiven und Respiratorischen Syndroms.

OBJECTIVE: In breeding farms with a high health status, pigs are frequently sampled using invasive methods (i. e. blood sampling). The aim of the present study was to evaluate less invasive methods concerning their suitability for an early detection of the infection with the porcine reproductive and respiratory syndrome virus (PRRSV). MATERIAL AND METHODS: Blood and saliva swabs, chewing rope derived oral fluids and serum samples were used for PRRSV-1 and PRRSV-2 detection via PCR. 19 gilts were repeatedly sampled following intramuscular or intranasal vaccination with live-attenuated vaccines containing PRRSV-1 or -2. Swabs were either moistened with saliva from the mouth mucosa or with blood from the ear veins following superficial needle puncture. Serum samples were taken via puncture of the V. jugularis externa. Chewing ropes served for a means of oral fluid sampling and were kept hanging in the barn at the pigs' head height for 30 minutes. RESULTS: All animals were negative for PRRSV at the time of vaccination (sampling point 0). In serum samples, the first virus detection was achieved 12 hours following vaccination (p. vacc.). From day 4 p. vacc. on all animals were viremic and from day 10 p. vacc. on the percentage of positive animals decreased. The first detection of PRRSV in GenoTube® blood swabs was possible 36 hours p. vacc. Examination of the eSwab® blood swab resulted in only one positive finding within the entire testing period. In the saliva samples, first detection of PRRSV was possible on day 5 p. vacc. CONCLUSION AND CLINICAL RELEVANCE: This study demonstrates that serum samples taken from the V. jugularis externa may be considered as the gold standard for diagnostic of PRRSV viremia. Detection rates in serum were higher than in the alternative sample types. However, since sample collection procedures and processing of the alternative sample materials offer clear advantages with regard to welfare, practical handling and logistics, further attempts are warranted in order to improve these methods. Based on the presented results, the described method using eSwab® blood sampling does not represent a satisfactory alternative approach for the detection of early PRRSV infection. Future application of this method warrants further improvement of its diagnostic efficacy.

Congenital Myofibroblastic Skin Tumours in a Newborn Piglet Resembling the Multicentric Form of Infantile Myofibromatosis.

A 2-day-old female piglet was submitted with multiple congenital, nodular skin masses located on the head, neck, trunk and legs. Histopathological examination revealed the presence of nodular, cutaneous tumours with a biphasic growth pattern and comprising a population of undifferentiated, oval or slightly polygonal, frequently perivascularly located cells and a population of spindle-shaped, fibroblast-like cells arranged in bundles. Multifocally, tumour cells infiltrated subcutaneous adipose and muscular tissue. Immunohistochemically, the undifferentiated tumour cells expressed vimentin and calponin, whereas the spindle-shaped tumour cells were positive for vimentin, α-smooth muscle actin and calponin. Based on these findings, the diagnosis was myofibroblastic tumours closely resembling the multicentric form of human infantile myofibromatosis.

Health Monitoring of Fattening Pigs - Use of Production Data, Farm Characteristics and On-Farm Examination.

BACKGROUND: The use of processed secondary data for health monitoring of fattening pigs has been established in various areas, such as the use of antibiotics or in the context of meat inspection. Standardized scores were calculated based on several sources of production data and can be used to describe animal health in a large collective of pig units. In the present study, the extent to which these scores are related to different farm characteristics and management decisions were investigated. In addition, slaughter scores were compared with the results of a veterinary examination on the farms. RESULTS: The comparison of the results of the uni- and multifactorial analyses revealed that almost all of the examined factors play a role in at least one of the scores when considered individually. However, when various significant influencing factors were taken into account at any one time, most of the variables lost their statistical significance due to confounding effects. In particular, production data such as production costs or daily feed intake remained in the final models of the scores on mortality, average daily gain and external lesions. Regarding the second part of the investigation, a basic technical correlation between the slaughter scores and the on-farm indicators could be established via principal component analysis. The modelling of the slaughter scores by the on-farm indicators showed that the score on external lesions could be represented by equivalent variables recorded on the farm (e.g., lesions caused by tail or ear biting). CONCLUSIONS: It has been demonstrated that the examined health scores are influenced by various farm and management characteristics. However, when several factors are taken into account, confounding occurs in some cases, which must be considered by consultants. Additionally, it was shown that on-farm examination content is related to the scores based on equivalent findings from slaughter pigs.

Peracute selenium toxicosis followed by sudden death in growing and finishing pigs.

Fattening pigs (n = 751) showed progressive apathy, paralysis, and sudden death after accidental ingestion of excessive concentrations of selenium in mineral feed. Selenium concentrations of 1.09 to 1.32 mg/L in the serum confirmed the diagnosis. Within 3 d all pigs had died spontaneously or were euthanized due to the grave prognosis and on welfare grounds.

Seroprevalence and risk factors associated with seropositivity in sows from 67 herds in north-west Germany infected with Mycoplasma hyopneumoniae.

Risk factors for the spread of Mycoplasma hyopneumoniae in sows have not been studied although vertical transmission from sows to their offspring is considered a significant risk factor in the development of enzootic pneumonia in growers and finishers. Seropositivity for M. hyopneumoniae in sows, as assessed by commercial ELISA, is a possible indicator of infection pressure among sows. The objective of this study was to estimate seroprevalence and associated risk factors of a sow being seropositive for M. hyopneumoniae. A cross-sectional study was carried out in 2578 sows from 67 herds in north-west Germany. Data concerning general herd characteristics, acclimatisation practices, indoor and outside contacts, as well as data describing the immediate local environment were collected during a herd visit via questionnaire. Blood samples were seropositive in 65% of the 2578 sows, and all herds had >/=14% seropositive sows. Data analysis was performed in two steps. First, univariate analysis of predictor variables for the risk of a sow being seropositive for M. hyopneumoniae was performed using chi-square test. Secondly, all variables associated with the risk of a sow being seropositive (P

A comparison of the carcase characteristics of pigs immunized with a 'gonadotrophin-releasing factor (GnRF)' vaccine against boar taint with physically castrated pigs.

Evaluating the effect of using a GnRF vaccine against boar taint on the carcase characteristics of boars, vaccinated pigs were compared with physically castrated. In total, 554 male pigs were randomly assigned to treatment groups. T01 comprised physically castrated pigs in the first week of life, T02 comprised pigs vaccinated twice before slaughtering. There was neither significant difference between the groups in terms of average liveweight nor in the hot carcase weight. The mean dressing percentage was 1.5% higher for T01 than for T02 (P<0.0001). The lean meat percentage was significantly higher in T02 (P<0.0001). Backfat and backmuscle thickness were significantly higher in T01 (P<0.0001 and P=0.0099, respectively). Within the EUROP grading vaccinated pigs were in favour (P=0.0034). There were no significant differences using the AutoFOM system: weights of the boned ham, boned shoulder and loin (P=0.5102, P=0.8881 and P=0.1919, respectively). The weight of the belly was significantly higher (P=0.0042) in T01 while the lean meat percentage of belly was significantly higher (P<0.0001) in T02.

How effective are clinical pre-farrowing risk assessment and the use of soft rubber mats in preventing shoulder ulcers in at-risk sows?

BACKGROUND: Lameness, low BCS and scar tissue in the skin covering the tuber spina scapulae are known as risk factors for shoulder ulcer in sows. In a two-step study, the predictive ability of pre-farrowing clinical examination and the preventive effect of rubber mats on the development of shoulder ulcers in at-risk sows were evaluated. MATERIAL AND METHODS: The study included 659 sows that were clinically examined one week before farrowing to distinguish risk sows from no-risk sows. Sows with a BCS ≤ 2 and/or a locomotion score > 3 and/or scar tissue in the skin covering the tuber spina scapulae were classified as at risk of developing shoulder ulcers. The at-risk sows were randomly assigned to either a prevention group in which sows were stalled in farrowing crates equipped with rubber mats, or a non-prevention group in which sows were stalled in standard crates. The shoulder areas were photographed during the first two weeks of the lactation period. RESULTS: The chance of developing a shoulder ulcer was significantly higher for at-risk sows than for non-at-risk sows (OR 5.55, p < 0.0001). At-risk sows stalled in crates equipped with rubber mats as preventive substrates had a significantly lower chance of developing shoulder ulcers than did those stalled in standard pens (OR 0.54, p = 0.0358). CONCLUSIONS: The development of shoulder ulcers in sows can be predicted by clinical pre-farrowing risk assessment based on BCS, locomotion score and scar tissue scoring. Providing at-risk sows with farrowing crates equipped with rubber mats had a statistically significant protective effect.

Scoring shoulder ulcers in breeding sows - is a distinction between substantial and insubstantial animal welfare-related lesions possible on clinical examination?

BACKGROUND: Shoulder ulcers in breeding sows that are restricted to the superficial skin layers, epidermis and dermis are usually classified as insubstantial animal welfare-related lesions. These less-severe lesions need to be differentiated from more-severe wounds that also involve the subcutis and the underlying bone, commonly evaluated as substantial animal welfare-related lesions. Scoring schemes based on clinical or histopathological findings are available, but the consistency between both types of findings has not been definitively evaluated. The present study was designed to compare clinical findings for various stages of shoulder ulcers with accompanying histopathological evaluation. A validated histopathologic score (Score-H) classifying the tissues involved in the different stages of shoulder ulcers was set as the reference standard. RESULTS: Testing the histopathological scores for associations with various clinical findings resulted in a clinical score (Score-C) that could be segregated into four stages. Stage I is characterised by intact skin without any ulcerative lesions. Stage II, representing ulcerative lesions restricted to the superficial skin layers, can be predicted with a probability of 90% when a scab with diameter less than 1.2 cm is present. Stage III, representing ulcers involving the entire skin and sometimes the underlying bone, can be identified by the diameter of the scab (DOS) and/or proliferation of wound margins (powm) and/or increase of tissue volume (mass). To achieve a probability of 90%, the DOS needs to be 8.3 cm when mass and powm are absent. DOS, when accompanied by powm and mass, needs to be only a minimum of 1.9 cm for a correct classification with a 90% probability. Stage IV represents skin without open wounds but with scar tissue indicative of a former shoulder ulcer. CONCLUSIONS: Based on the association with the histopathological findings as the reference standard a clinical score (Score-C) for the categorisation of shoulder ulcers in sows was developed. This score enables veterinarians and farmers to discriminate shoulder ulcers restricted to the superficial skin layers from ulcers involving all skin layers and sometimes even the underlying bone, which must be assessed as substantial animal welfare-related lesions.

Detection of respiratory pathogens in porcine lung tissue and lavage fluid.

The objective of this study was to compare the detection rate of bacterial agents in bronchoalveolar lavage fluid (BALF), taken without visual control, to that in affected lung tissue obtained from the same pig at necropsy. BALF and affected lung tissue were examined for Mycoplasma hyopneumoniae using PCR, and standard cultural methods were used for Actinobacillus pleuropneumoniae, Bordetella bronchiseptica, Haemophilus parasuis, Pasteurella multocida and Streptococcus suis. All pigs with a history of respiratory symptoms were submitted as live animals for routine diagnostic examination. In each animal the site of lavage, marked by injecting methylene blue, differed from the site of pneumonic lesions. M. hyopneumoniae was detected more frequently in lung tissue than in BALF in cases with moderate or severe lung lesions. The detection rates of M. hyopneumoniae were higher in the BALF of pigs with mild lesions. Cultural examination of BALF was at least as satisfactory as affected lung tissue for detecting B. bronchiseptica, H. parasuis and P. multocida.

Diagnosis of Lawsonia intracellularis infection in pigs after vaccination or antimicrobial treatment.

Diagnosis of infection with Lawsonia (L.) intracellularis, the causative agent of porcine proliferative enteropathy, is routinely based on the detection of L. intracellularis in faeces and/or tissue samples by PCR. Furthermore, infection can be determined by the detection of antibodies in serum samples. The aim of this comparative study was to examine whether results from molecular biology and serological testing are influenced by applying live bacteria vaccine Enterisol Ileitis or antimicrobial treatment to pigs naturally exposed to L. intracellularis. Decreased shedding was detected in tylosin treated pigs only. Thus, the distribution of 345 pigs into groups of 0-, 1- or > or = 2-times positive by PCR was significantly influenced by the treatment (P < 0.0001). A global effect of positive PCR results on average daily weight gain was also highly significant (P < 0.0001). The serological reaction was detected by a blocking ELISA after infection but not after vaccination independent of treatment. The results indicate no influence of vaccination on applied diagnostic tests.