Cognitive mechanisms and resilience in UK-based general practitioners: cross-sectional findings.

BACKGROUND: Being a general practitioner (GP) is a stressful occupation, and the strain GPs are under can have negative effects on their psychological well-being, as well as on the patients' experience of healthcare. Resilience can help buffer against this and is a dynamic process by which one can cope with adversity and stress. AIMS: This study aimed to identify modifiable cognitive mechanisms related to resilience in GPs, specifically interpretation bias and cognitive reappraisal. METHODS: One hundred and fourteen GPs completed an online cross-sectional correlational study. This comprised questionnaires assessing resilience, emotional distress, work environment and cognitive mechanisms (emotion regulation), as well as a task assessing interpretation bias. RESULTS: Resilience of GPs was negatively correlated with measures of emotional distress. Furthermore, resilience was positively correlated with positive interpretation bias (r = 0.60, ρ = 0.60, P < 0.01) and cognitive reappraisal (r = 0.39, ρ = 0.40, P < 0.01). In a hierarchical regression, positive interpretation bias (B = 0.25, SE B = 0.06, ß = 0.39, P < 0.01) was a significant independent predictor of resilience when controlling for depression, anxiety and stress. CONCLUSIONS: This is the first study to establish an association between resilience and positive interpretation bias and cognitive reappraisal in GPs. Future research should use longitudinal designs to determine if they have a causal role in promoting resilience, and importantly whether interventions focusing on these processes may foster resilience in less resilient GPs.

Early Mortality after Radical Radiotherapy in Head and Neck Cancer - A Nationwide Analysis from the Danish Head and Neck Cancer Group (DAHANCA) Database.

AIMS: Curative-intent radiotherapy (RT) or chemoradiation (CRT) of squamous cell carcinoma of the head and neck (HNSCC) produces high survival rates, but is associated with substantial toxicity. However, there are no commonly accepted quality metrics for early mortality in radiation oncology. To assess the applicability of early mortality as a clinical quality indicator, this study investigated the temporal distribution, risk factors and trends of 90- and 180-day overall and non-cancer mortality in a nationwide cohort of HNSCC patients treated with RT/CRT. MATERIALS AND METHODS: Information on all HNSCC patients treated with curative-intent RT/CRT in Denmark between 2000 and 2017 was obtained from the national Danish Head and Neck Cancer Group clinical database. Deaths in patients with residual or recurrent disease after RT/CRT were classified as cancer-related. Possible risk factors were investigated using logistic regression analysis. RESULTS: Data from 11 419 patients were extracted. In total, 90- and 180-day mortality risks were 3.1% and 7.1%, respectively. There was a uniform temporal distribution of 180-day mortality. In multivariable analysis, increasing age, stage, performance status, earlier treatment year and hypopharyngeal cancer were significantly associated with an increased risk (P < 0.05). Risk factor estimates were comparable for 90- versus 180-day mortality as well as for overall versus non-cancer mortality. Between 2000 and 2017 there was a significant decrease in 180-day mortality, which was driven by a reduction in cancer-related events. CONCLUSION: The distribution of 180-day overall and non-cancer mortality did not indicate a well-defined early high-risk period. Moreover, risk factor estimates were highly similar across risk periods and groups. Taken together, our findings question the applicability of early mortality as a standard metric for treatment-associated toxicity.

Accuracy and sensitivity of three-dimensional echocardiography to detect changes in right ventricular volumes: comparison study with cardiac magnetic resonance.

We aimed to investigate the ability of three-dimensional transthoracic echocardiography (3DE) to detect changes in RV volumes compared to cardiac magnetic resonance (CMR). Eighty-five subjects including 45 with no known cardiac disease and 40 patients with a variety of cardiac diseases were included. Two- and three-dimensional echocardiography as well as CMR of the RV was performed before and after infusion of on average two litres of saline. Examinations were analysed with estimation of RV dimensions, volumes and ejection fraction (RVEF). Intra- and inter-examiner variability was evaluated in 25 patients randomly selected from the cohort. Three-dimensional echocardiography underestimated volumes and RVEF compared to CMR with mean differences and 95% limits of agreement of 110.3 ± 59 mL for RV end-diastolic volume (RVEDV), 43.3 ± 32 mL for RV end-systolic volume (RVESV) and 3.5 ± 10.7% for RVEF. CMR was more reproducible than 3DE, with intra-observer coefficient of variation (CV) of 4% vs. 14.2% for RVEDV, 9.7% vs. 16.7% for RVESV and 6.3% vs. 8.6% for RVEF. The RVEDV, RVESV and RV stroke volume (RVSV) by CMR significantly increased after saline infusion by 15.3 ± 16.2 mL, 3.5 ± 14.2 mL and 11.8 ± 12.6 mL, respectively, as well as RVEF by 1.5 ± 4.6% (p < 0.05). However, 3DE was not able to detect any of these changes in RV volumes (p ≥ 0.05). Compared to CMR imaging of the RV, three-dimensional echocardiography appears unable and unreliable in detecting RV volume changes of less than 15%, highlighting the need for cautious utility of 3DE in these circumstances.

Exploring the limits of prolonged apnoea with high-flow nasal oxygen: an observational study.

High-flow nasal oxygen is increasingly used for oxygenation during apnoea. Extending apnoea duration using this technique has mainly been investigated during minor laryngeal surgery, but it is unclear how long it can be administered for before it should be discontinued due to acidosis. We aimed to describe the dynamics of arterial blood gases during apnoeic oxygenation with high-flow nasal oxygen with jaw thrust only, to explore the limits of this technique. We included adult orthopaedic patients scheduled for general anaesthesia. After pre-oxygenation, anaesthesia with neuromuscular blockade was induced and high-flow nasal oxygen (70 l.min-1 ) was continued with jaw thrust as the only means of airway management, with monitoring of vital signs and arterial blood gas sampling every 5 minutes. Apnoeic oxygenation with high-flow nasal oxygen was discontinued when arterial carbon dioxide tension (PaCO2 ) exceeded 12 kPa or pH fell to 7.15. This technique was used in 35 patients and median (IQR [range]) apnoea time was 25 (20-30 [20-45]) min and was discontinued in all patients when pH fell to 7.15. The mean (SD) PaCO2 increase was 0.25 (0.06) kPa.min-1 but it varied substantially (range 0.13-0.35 kPa.min-1 ). Mean (SD) arterial oxygen tension was 48.6 (11.8) kPa when high-flow nasal oxygen was stopped. Patients with apnoea time > 25 minutes were significantly older (p = 0.025). We conclude that apnoeic oxygenation with high-flow nasal oxygen resulted in a significant respiratory acidosis that varies substantially on the individual level, but oxygenation was maintained.

Production losses five months after outbreak with a recombinant of two PRRSV vaccine strains in 13 Danish sow herds.

BACKGROUND: In July 2019, a PRRSV-negative boar station was infected with a recombinant of two PRRSV vaccine strains, which subsequently spread to at least 36 herds that had received semen from the boar station. In the following months, all the infected herds reported reduced productivity. The aim of the present study was to evaluate the impact of the PRRS outbreak. RESULTS: Production data were collected from 13 of the herds. The average levels of farrowings/week, liveborns/litter, stillborns/litter, pre-weaning mortality and weaned pigs/litter were compared for the five-month period after infection and the preceding 7 months before infection with the new variant of PRRSV-1. Twelve herds experienced a decrease in farrowings/week (0.1-10.8% fewer farrowings/week), and all herds experienced fewer liveborns (0.8-4.8 fewer liveborns/litter) and more stillborns (0.6-2.6 more stillborns/litter). Pre-weaning mortality nearly doubled in half of the herds. Overall, the 13 herds were missing 2.4-6.5 pigs/litter at weaning during the 5 months after infection compared to the seven preceding months before infection. CONCLUSION: In this study, the impact of this new PRRSV-1 variant on productivity exceeded that typically seen in Danish herds infected with PRRSV-1.

Migrations, trauma and mental health: A literature update on psychological assessment.

INTRODUCTION: Migrants and refugees often face potentially traumatic events and post-migratory stressors. Upon arrival in the host country, they can be referred to mental health services to assess the impact of their previous experiences. These cross-cultural clinical encounters may raise questions, particularly regarding the assessment of mental health using models based on Western conceptions of psychopathology. OBJECTIVES AND METHOD: The objective of the present non-systematic review of the literature is to discuss the psychological evaluation of post-traumatic reactions in migrants and refugees. More specifically, we present current research on psychopathology, resilience and post-traumatic development (PTG) among the migrant and refugee population. We also examine the cross-cultural validity of concepts such as Post-Traumatic Stress Disorder, resilience and PTG. Finally, we describe the most frequently used tools in cross-cultural psychological assessment and briefly reflect on the question of cultural sensitivity of mental health professionals. A bibliographic search was carried out using the databases: PILOTS, Pubmed, APA PsycNET, and Google Scholar using the following keywords: "migrants", "refugees", "posttraumatic stress disorder", "mental health", "Psychopathology", "risk factors", "protection factors", "posttraumatic growth" and "resilience". We have also reviewed the reference lists of articles encountered from database searches. RESULTS: Responses to a potentially traumatic situation are multiple. Regarding the migrant and refugee population, the reviewed articles studied different post-traumatic reactions such as resilience, post-traumatic development, and psychopathologies. The most studied psychopathological responses were depression, anxiety and Post-traumatic Stress Disorder. After reviewing these studies, we asked the following question: considering the complexity of the migration process, what are the factors associated with the development of these different post-traumatic responses? Indeed, several individual and social factors before, during and after migration influence the mental health of individuals in a migration situation. Among the most cited risk factors identified were: to be a victim of or witness to violence in the country of origin and, after migration, to face post-migration difficulties such as asylum denial, to be in a precarious situation with regard to housing and work, as well as the difficulties linked to adaptation to the new culture. We have also described protective factors for the mental health of this population, such as: social support, psychological support, and a good quality of life in the host country. The reviewed articles also describe an important influence of cultural aspects on mental health, such as the perception of an event as traumatic. Although the authors of the reviewed articles accept this influence of culture on post-traumatic responses, most of the tools used to assess the mental health of migrants and refugees were created in a Western context. Studies show a growing concern with these cultural aspects, and certain tools that allow a more culturally sensitive evaluation, such as the "Cultural Formulation Interview", are being developed. DISCUSSION AND CONCLUSION: Even if the concern with the sensitivity of the tools used in cross-cultural assessment seems to be more present in the international literature, researchers seem to encounter difficulties in better understanding the effects of culture on the mental health of individuals. With increasingly diverse societies, new research should not be based on participants' geographic or ethnic origins, but rather try to "unpack" culture with, for example, the exploration of the relationships between certain values or orientations and the different expressions of psychological distress. Finally, given the still lacking development in the field of cross-cultural research, certain practices, such as the participation of interpreters, the supervision of cultural mediators or the use of culturally sensitive tools, can help the clinician to maintain good practices with patients from different cultures in the diagnostic and psychotherapeutical processes.

NTCP model validation method for DAHANCA patient selection of protons versus photons in head and neck cancer radiotherapy.

Introduction: Prediction models using logistic regression may perform poorly in external patient cohorts. However, there is a need to standardize and validate models for clinical use. The purpose of this project was to describe a method for validation of external NTCP models used for patient selection in the randomized trial of protons versus photons in head and neck cancer radiotherapy, DAHANCA 35. Material and methods: Organs at risk of 588 patients treated primarily with IMRT in the randomized controlled DAHANCA19 trial were retrospectively contoured according to recent international recommendations. Dose metrics were extracted using MatLab and all clinical parameters were retrieved from the DAHANCA database. The model proposed by Christianen et al. to predict physician-rated dysphagia was validated through the closed testing, where change of the model intercept, slope and individual beta's were tested for significant prediction improvements. Results: Six months prevalence of dysphagia in the validation cohort was 33%. The closed testing procedure for physician-rated dysphagia showed that the Christianen et al. model needed an intercept refitting for the best match for the Danish patients. The intercept update increased the risk of dysphagia for the validation cohort by 7.9 ± 2.5% point. For the raw model performance, the Brier score (mean squared residual) was 0.467, which improved significantly with a new intercept to 0.415. Conclusions: The previously published Dutch dysphagia model needed an intercept update to match the Danish patient cohort. The implementation of a closed testing procedure on the current validation cohort allows quick and efficient validation of external NTCP models for patient selection in the future.

Prognostic factors for survival after salvage total laryngectomy following radiotherapy or chemoradiation failure: a 10-year retrospective longitudinal study in eastern Denmark.

OBJECTIVE: The primary aims were to determine the rates of and prognostic factors for overall survival, disease-specific survival and disease-free survival following salvage total laryngectomy. DESIGN: Retrospective longitudinal study. SETTING: Tertiary medical centres. PARTICIPANTS: A total of 142 patients in eastern Denmark undergoing salvage total laryngectomy for squamous cell carcinoma of the larynx or hypopharynx. MAIN OUTCOME MEASURES: 5-year overall survival, 5-year disease-specific survival, 5-year disease-free survival and prognostic factors for these outcomes. RESULTS: 5-year overall survival, disease-specific survival and disease-free survival were 37.7%, 54.9% and 55.3%, respectively. N classification at primary diagnosis, lymph node excision and postoperative complications within 1 year after salvage total laryngectomy were prognostic factors for shorter overall survival, disease-specific survival and disease-free survival. Residual tumour/recurrence was negatively associated with overall survival, close or involved resection margins with disease-specific survival, and second primary cancer was associated with longer disease-specific survival and disease-free survival. Nine per cent of all patients had residual tumour and 33.8% developed a recurrence. CONCLUSION: Our overall survival, disease-specific survival and disease-free survival findings are in accordance with previous studies. With the purpose of identifying recurrent tumour, we suggest extra attention being given to patients with higher N classification and need for lymph node excision during salvage total laryngectomy along with use of frozen sections. The high number of patients with recurrence within 1 year after salvage total laryngectomy occurred although thorough and regular follow-up visits were performed.

Reações pós-traumáticas em crianças: como, por que e quais aspectos avaliar? / Post-traumatic reactions in children: how, why and which aspects evaluate?

A vivência de eventos traumáticos nos primeiros anos de vida impacta o desenvolvimento infanto-juvenilem diferentes níveis, com repercussões psicológicas, neurobiológicas e sociais. Este artigo discutiu aavaliação clínica das reações pós-traumáticas em crianças e adolescentes, incluindo questões relacionadasà manifestação dos sintomas, às consequências a longo prazo e aos instrumentos de avaliaçãodisponíveis. Foi apresentado um modelo ilustrativo dos fatores de risco para o Transtorno de EstressePós-Traumático em crianças. Concluiu-se que a avaliação precoce é fundamental para a detecção defatores de risco e indicação de diferentes intervenções, servindo como fonte de prevenção secundária(AU)

Risk factors for postoperative complications after total laryngectomy following radiotherapy or chemoradiation: a 10-year retrospective longitudinal study in Eastern Denmark.

OBJECTIVES: To determine the rates of and risk factors for postoperative complications following total laryngectomy in patients treated with radiotherapy or chemoradiation. DESIGN: Retrospective longitudinal study. SETTING: Tertiary medical centres. PARTICIPANTS: A total of 143 patients undergoing total laryngectomy for squamous cell carcinoma of the larynx or hypopharynx. MAIN OUTCOME MEASURES: Overall postoperative complications and fistula formation. RESULTS: Overall postoperative complications, fistula formation, wound infection, bleeding and wound necrosis within one year after total laryngectomy occurred in 56.6%, 42.3%, 31.0%, 11.3% and 9.2% of patients, respectively. Stenosis of the pharynx/oesophagus and stoma shrinkage within five years after surgery were each seen in 18.2% of cases. In 66.7% of cases, conservative treatment of the fistulas was chosen. Rehospitalisations within five years occurred for 44.8% with a median rate of 1.5 (range 1-11). Smoking status (P = 0.005 and 0.013) and chronic obstructive pulmonary disease (COPD) (P = 0.013 and 0.011) were significant risk factors for both overall postoperative complications and fistula formation in uni- and multivariate analysis. Tumour localisation in the hypopharynx was associated with overall postoperative complications (P = 0.036). Residual tumour or cancer recurrence was associated with late-onset fistulas (P < 0.001). CONCLUSION: The frequencies of postoperative complications after total laryngectomy were comparable with similar international studies, although fistula formation rate is increasing in Denmark. We suggest optimising treatment of COPD and to further encourage to smoking cessation. We propose that development of fistulas >2 months after surgery prompts immediate biopsies. Additionally, we suggest standardised registration of surgical techniques to identify variables affecting the frequency of postoperative complications.

Experimental airborne transmission of porcine postweaning multisystemic wasting syndrome.

The objective of these studies was to investigate if porcine postweaning multisystemic wasting syndrome (PMWS) could be induced in healthy pigs following contact with air from pigs with clinical signs of PMWS. The pigs were housed in different units. Either 31 (study I) or 25 (study II) pigs with clinical symptoms of PMWS from a PMWS-affected herd and 25 healthy pigs from a PMWS-free, but PCV2-positive, herd were housed in unit A. Fifty pigs from a PMWS-free herd were housed in unit B, which were connected by pipes to unit A. In unit C, 30 pigs from a PMWS-free herd were housed as controls. In study II, the pigs in units A and B from the PMWS-free herd developed clinical signs of PMWS 2-3 weeks after arrival. PMWS was confirmed at necropsy and the diseased pigs had increased PCV2 load and increased antibody titers against PCV2 in serum that coincided with the development of clinical signs typical of PMWS. Sequence analysis revealed that the PCV2 isolate belonged to genotype 2b. In conclusion, the present study showed that PMWS can be induced in pigs from a PMWS-free herd by airborne contact with pigs from a PMWS-affected herd.

Waiting times for diagnosis and treatment of head and neck cancer in Denmark in 2010 compared to 1992 and 2002.

BACKGROUND AND AIM: Significant tumour progression was observed during waiting time for treatment of head and neck cancer. To reduce waiting times, a Danish national policy of fast track accelerated clinical pathways was introduced in 2007. This study describes changes in waiting time and the potential influence of fast track by comparing waiting times in 2010 to 2002 and 1992. METHODS: Charts of all new patients diagnosed with squamous cell carcinoma of the oral cavity, pharynx and larynx at the five Danish head and neck oncology centres from January to April 2010 (n=253) were reviewed and compared to similar data from 2002 (n=211) and 1992 (n=168). RESULTS: The median time to diagnosis was 13 days (2010) versus 17 days (2002; p<0.001) and 20 days (1992; p<0.001). Median days from diagnosis to treatment start were 25 (2010) versus 47 (2002; p<0.001) and 31 (1992; p<0.001). Total pre-treatment time was median 41 days in 2010 versus 69 days (2002) (p<0.001) and 50 days (1992; p<0.001). Significantly more diagnostic imaging was done in 2010 compared to 2002 and 1992. When compared to current fast track standards the adherence to diagnosis improved slightly from 47% (1992) to 51% (2002) and 64% (2010); waiting time for radiotherapy was within standards for 7%, 1% and 22% of cases, respectively; waiting time for surgery was within standards for 17%, 22% and 48%, respectively. CONCLUSION: The study showed a significant reduction in delay of diagnosis and treatment of head and neck cancer in 2010, but still less than half of all patients start treatment within the current standards.

Executive functions rehabilitation for schizophrenia: a critical systematic review.

BACKGROUND: Consistent evidences suggest that poor functional outcomes in schizophrenia are associated with deficits in executive functions (EF). As result cognitive training, remediation and/or rehabilitation (CR) programs have been developed and many theories, methods and approaches have emerged in support of them. This article presents a systematic review of randomized controlled trials (RCT), including EF rehabilitation interventions, with a focus on methodological issues and evidences of EF improvements. METHOD: Electronic databases (Medline, Web of Science, PsycINFO and Embase) were searched for articles on schizophrenia, EF and cognitive rehabilitation terms. The methodological quality of each article was measured by 5-point JADAD scale. RESULTS: A total of 184 articles were initially identified, but after exclusion criteria, 30 RCT remained in this review. A proportion of 23% of studies scored higher than 4 points in JADAD scale, 40% scored 3 points, 33% scored 2 points and one study scored only 1 point. The average length of interventions was approximately 80 h distributed around 3.42 h/week. CONCLUSION: The reviewed articles corroborate the literature pointing that CR could be a promising therapeutic option for cognitive deficits in schizophrenia. In general, CR could improve cognitive domains and social adjustment either using computerized or paper-and-pencil programs. Additionally, CR combined with cognitive behavioral therapy and/or group sessions is particularly effective. In this paper, we also speculated and discussed optimal doses of treatment and the differences regarding modalities and approaches.

Short communication: within-day variation in fatty acid composition of milk from cows in an automatic milking system.

Milk fatty acid composition is influenced by a range of conditions such as breed, feeding, and stage of lactation. Knowledge of milk fatty acid composition of individual cows would make it possible to sort milk at farm level according to certain fatty acid specifications. In the present study, 225 milk samples were taken from 84 cows in a herd equipped with an automatic milking system. Milk fat content varied depending on yield and time since last milking, whereas the milk fatty acid composition did not vary significantly within cow. It was concluded that random milk samples may be used for analysis of fatty acid composition.

Methods for estimating the site of origin of locoregional recurrence in head and neck squamous cell carcinoma.

PURPOSE: Methods to estimate the likely origin of recurrences after radiation therapy for head and neck squamous cell carcinoma are compared. METHODS AND MATERIALS: A total of 25 patients meeting the following inclusion criteria were randomly selected: curatively intended intensity-modulated radiotherapy planned on a positron emission tomography-computed tomography (PET/CT) scan during the period 2005-2009; squamous cell carcinoma in the oral cavity, pharynx or larynx; complete clinical response followed by locoregional recurrence; and a CT scan at recurrence before any salvage therapy. Exclusion criteria were previous cancer in the area, surgery prior to radiotherapy, or a synchronous cancer. Three methods of estimating focal points of recurrence origin and two volume overlap methods assigning the recurrences to the most central target volumes encompassing at least 50% or 95% of the recurrence volumes were tested. Treatment planning and recurrence scans were rigid and deformable co-registered in order to transfer focal points to the treatment planning scan. Double determinations of all volumes, points, and co-registrations were made. RESULTS: The volume overlap methods assigned the recurrences to significantly more peripheral target volumes than focal methods (p < 0.0001 for all comparisons of 95% overlap vs. focal methods, p < 0.028 for all comparisons of 50% overlap vs. focal methods). Repeated registrations of the same point had higher reproducibility with deformable registration than with rigid registration (median distance 0.31 vs. 0.35 cm, p = 0.015). No significant differences were observed among the focal methods. CONCLUSION: Significant differences between methods were found which may affect strategies to improve radiotherapy based on pattern of failure analyses.

Porcine circovirus diseases: a review of PMWS.

This article is a review on post-weaning multisystemic wasting syndrome (PMWS), the first described disease among the porcine circovirus diseases (PCVD). Post-weaning multisystemic wasting syndrome has, since its appearance in Canada in 1991, been seen in all major pig producing countries. To diagnose PMWS at herd level typical clinical appearance consisting of wasting and increased mortality must be combined with finding at autopsy of diseased pigs, where typical microscopic findings in the lymphatic tissue must be present. Post-weaning multisystemic wasting syndrome significantly increases the mortality and reduces the daily weight gain in weaner pig and/or in finishing pigs. Post-weaning multisystemic wasting syndrome can be transmitted by pig-to-pig contact and some studies point at airborne transmission as a possibility. Studies in Europe have shown several risk factors that either increase or decrease the risk for a pig herd to be affected by PMWS. At the pig level, studies have shown the importance of maternal immunity as protection for subsequent development of PMWS. To control PMWS, good production management and control of other diseases are crucial. Since 2004, commercial vaccines against Porcine Circo Virus type 2 have been coming on the market and many studies have shown great benefits of these to control PMWS. Today, sow vaccines as well as piglet vaccines are available in most countries. An extensive meta-analysis of many of the vaccines has shown a comparable good efficacy of the vaccines in significantly reducing mortality and increasing weight gain of the pigs.

Lexicon of disease spread modelling terms.

Over the past decade there has been a notable increase in the magnitude and variety of modelling work in the realm of animal health. Similarly, there has been an increase in the extent to which modelling is used as a component in the development of animal health policy. The increased dependency on modelling creates a need to enhance understanding and linkages between policy-makers (those that pose the policy or scientific questions, commission modelling work and use model outputs in the development of policy), intermediaries (those that are responsible for working with modellers and communicating model results to policy-makers), and modellers. Development of a lexicon of disease spread modelling terms can help support clear communication and collaboration between all players.

Transmission of different variants of PCV2 and viral dynamics in a research facility with pigs mingled from PMWS-affected herds and non-affected herds.

Post-weaning Multisystemic Wasting Syndrome (PMWS) has been identified in most swine-producing countries worldwide. The disease has resulted in significant health challenges and economic damage to the swine industry. The aim of this study was to determine horizontal transmission of porcine circovirus type 2 (PCV2) and to examine viral dynamics in pigs in a controlled PMWS transmission study. In the study pigs from PMWS-affected herds and non-affected herds were permitted to have close contact (same pen), nose-to-nose contact (to pigs in neighbouring pens) or no physical contact (pen across the aisle and pens in other compartments). By DNA sequence analysis, eight variants of genotype PCV-2b were identified in the research facility. From the spread of these PCV2-variants it was concluded that PCV2 primarily infects through close contact and nose-to-nose contact. PCV2 genome sequences were obtained from selected pigs at arrival to the research facility and again when the same pigs developed PMWS. This analysis showed that pigs from PMWS-affected herds developed PMWS caused by the same variant of PCV2 as they carried when entering the research facility. In contrast, pigs from non-affected herds developed PMWS with PCV2-variants identified in pigs from PMWS-affected herds. This was probably connected to at least 10(3) higher mean serum-titer of PCV2 in pigs from PMWS-affected herds as compared to pigs from non-affected herds at the beginning of the transmission study. The study further showed that pigs able to control the PCV2 infection, as measured by the PCV2-titer in serum, recovered clinically (pigs from PMWS-affected herds) or stayed healthy (pigs from non-affected herds). Like this, pigs with a PCV2 titer below 5x10(8) copies/ml serum during the study period had a chance of recover from the PCV2 infection whereas pigs with PCV2 titers above 5x10(8) copies/ml serum at any time point generally died from PMWS.