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BACKGROUND: Infection with porcine reproductive and respiratory syndrome virus (PRRSV) leads to significant economic losses worldwide. One of the initial measures following an outbreak is to stabilise the herd and to prevent vertical transmission of PRRSV. The objective of this study was to detect PRRSV in different sampling material, both in an experimental model and on a commercial piglet producing farm, with a focus on evaluating the suitability of tongue fluid samples. RESULTS: In the experimental model, PRRSV negative pregnant gilts were infected with PRRSV-1 AUT15-33 on gestation day 85 and necropsy of gilts and foetuses was performed three weeks later. 38.3% of individual foetal serum and 39.4% of individual foetal thymus samples were considered PRRSV RT-qPCR positive. Tongue fluids from individual foetuses showed a 33.0% positivity rate. PRRSV RNA was detected in all but one sample of litter-wise pooled processing fluids and tongue fluids. In the field study, the investigated farm remained PRRSV positive and unstable for five consecutive farrowing groups after the start of the sampling process. Tongue fluid samples pooled by litter in the first investigated farrowing group had a 54.5% positivity rate, with the overall highest viral load obtained in the field study. In this farrowing group, 33.3% of investigated litter-wise pooled processing fluid samples and all investigated serum samples (pools of 4-6 individuals, two piglets per litter) were considered positive. Across all investigated farrowing groups, tongue fluid samples consistently showed the highest viral load. Moreover, tongue fluid samples contained the virus in moderate amounts for the longest time compared to the other investigated sampling material. CONCLUSION: It can be concluded that the viral load in individual foetuses is higher in serum or thymus compared to tongue fluid samples. However, litter-wise pooled tongue fluid samples are well-suited for detecting vertical transmission within the herd, even when the suspected prevalence of vertical transmission events is low.
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Introduction: The cognitive map is an internal representation of the environment and allows us to navigate through familiar environments. It preserves the distances and directions between landmarks which help us orient ourselves in our surroundings. The aim of our task was to understand the role played by theta waves in the cognitive map and especially how the cognitive map is recalled and how the manipulation of distances and directions occurs within the cognitive map. Method: In order to investigate the neural correlates of the cognitive map, we used the Cognitive Map Recall Test, in which 33 participants had to estimate distances and directions between familiar landmarks tailored to their own knowledge. We examined the role of theta waves in the cognitive map, as well as the brain regions that generated them. To that aim, we performed electroencephalographic source imaging while focusing on frequency spectral analysis. Results: We observed increases of theta amplitude in the frontal, temporal, parahippocampal gyri and temporal poles during the recall of the cognitive map. We also found increases of theta amplitude in the temporal pole and retrosplenial cortex during manipulation of directions. Overall, direction processing induces higher theta amplitude than distance processing, especially in the temporal lobe, and higher theta amplitude during recall compared to manipulation, except in the retrosplenial cortex where this pattern was reversed. Discussion: We reveal the role of theta waves as a marker of directional processing in the retrosplenial cortex and the temporal poles during the manipulation of spatial information. Increases in theta waves in frontal, parahippocampal, temporal and temporal pole regions appear to be markers of working memory and cognitive map recall. Therefore, our Cognitive Map Recall Test could be useful for testing directional difficulties in patients. Our work also shows that there are two distinct parts to the cognitive map test: recall and manipulation of spatial information. This is often considered as two similar processes in the literature, but our work demonstrates that these processes could be different, with theta waves from different brain regions contributing to either recall or manipulation; this should be considered in future studies.
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INTRODUCTION: Chronic diseases in older adults are one of the major epidemiological challenges of current times and leading cause of disability, poor quality of life, high healthcare costs and death. Self-management of chronic diseases is essential to improve health behaviours and health outcomes. Technology-assisted interventions have shown to improve self-management of chronic diseases. Virtual avatars can be a key factor for the acceptance of these technologies. Addison Care is a home-based telecare solution equipped with a virtual avatar named Addison, connecting older persons with their caregivers via an easy-to-use technology. A central advantage is that Addison Care provides access to self-management support for an up-to-now highly under-represented population-older persons with chronic disease(s), which enables them to profit from e-health in everyday life. METHODS AND ANALYSIS: A pragmatic, non-randomised, one-arm pilot study applying an embedded mixed-methods approach will be conducted to examine user experience, usability and user engagement of the virtual avatar Addison. Participants will be at least 65 years and will be recruited between September 2022 and November 2022 from hospitals during the discharge process to home care. Standardised instruments, such as the User Experience Questionnaire, System Usability Scale, Instrumental Activities of Daily Living scale, Short-Form-8-Questionnaire, UCLA Loneliness Scale, Geriatric Depression Scale, Stendal Adherence with Medication Score and Self-Efficacy for Managing Chronic Diseases Scale, as well as survey-based assessments, semistructured interviews and think-aloud protocols, will be used. The study seeks to enrol 20 patients that meet the criteria. ETHICS AND DISSEMINATION: The study protocol has been approved by the ethic committee of the German Society for Nursing Science (21-037). The results are intended to be published in peer-reviewed journals and disseminated through conference papers. TRIAL REGISTRATION NUMBER: DRKS00025992.
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Autogestão , Telemedicina , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Doença Crônica , Humanos , Projetos Piloto , Qualidade de Vida , Autogestão/métodos , TecnologiaRESUMO
We report the clinical case of AB, a right-handed 19-year-old woman who presents severe developmental topographical disorientation, a relatively rare syndrome, leading to difficulties in navigating in familiar (and novel) environments. This symptomatology appears without acquired cerebral damage (MRI described as normal) nor more global cognitive disability (high degree of education achieved). An extensive assessment of spatial cognition with different aspects of underlying cognitive processes is first presented. Second, the patient's preserved cognitive abilities and her major difficulties in calculation, as well as her attention deficit, as seen in a detailed neuropsychological assessment, are reported. For the first time to our knowledge, we show that developmental topographical disorientation can be associated with other developmental cognitive disorders affecting number processing (dyscalculia) and attention (Attention Deficit-Hyperactivity Disorder (ADHD)). We discuss the links between these different cognitive processes in relation to visuo-spatial working memory and magnitude representation, which could represent common denominators for all these syndromes. This case report highlights the importance of thoroughly assessing potentially associated neurocognitive disorders in developmental topographical disorientation. In addition, it highlights the necessity to keep in mind the prevalence of spatial difficulties in the assessment of children and adolescents with other neurodevelopmental syndromes. Finally, this case study raises a new question about the nosology of developmental disorders affecting the visuo-spatial and spatial domains.
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Transtorno do Deficit de Atenção com Hiperatividade , Discalculia , Adolescente , Adulto , Transtorno do Deficit de Atenção com Hiperatividade/complicações , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico por imagem , Criança , Confusão/etiologia , Deficiências do Desenvolvimento/complicações , Deficiências do Desenvolvimento/diagnóstico por imagem , Discalculia/complicações , Discalculia/diagnóstico por imagem , Feminino , Humanos , Testes Neuropsicológicos , Síndrome , Adulto JovemRESUMO
Vertical transmission is a consistently discussed pathway of porcine circovirus type 2 (PCV2) and porcine circovirus type 3 (PCV3) transmission in pigs. To evaluate the presence of PCV2 and PCV3 in piglets, we collected tissue samples from 185 piglets that were crushed within the first week of life from 16 farms located in Germany and Austria. Pooled samples consisting of thymus, inguinal lymph node, myocardium, lung and spleen were examined for PCV2 and PCV3 by qPCR. Furthermore, oral fluid samples (OFS) from grow−finish pigs were collected and examined the same way. In piglets, PCV2 was highly prevalent (litters: 69.4%; piglets: 61.6%), whereas PCV3 prevalence was low (litters: 13.4%; piglets: 13.0%). In total, 72.6% and 67.2% of all collected OFS were PCV2 or PCV3 positive, respectively. Sow vaccination against PCV2 was identified as a protective factor concerning PCV2 in piglets (OR: 0.279; CI: 0.134−0.578; p < 0.001), whereas the porcine reproductive and respiratory syndrome virus (PRRSV) vaccination of sows was identified as a protective factor concerning PCV3 in piglets (OR: 0.252 CI: 0.104−0.610; p = 0.002). Our results show that PCV2, but not PCV3, is ubiquitous in suckling piglets and that early PCV3 infections might be modulated by PRRSV−PCV3 interaction. However, the ubiquitous nature of both viruses in older pigs could be confirmed.
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BACKGROUND: A cross-sectional study was carried out to assess the prevalence of Mycoplasma hyopneumoniae infections before vaccination in 3-week-old piglets and to gain information about infection dynamics. METHODS: In 13 German and three Austrian farms with a known history of enzootic pneumonia, 790 piglets and 158 sows were sampled (blood samples, tracheobronchial swabs [TBS] [piglets], laryngeal swabs [LS] [sows]), and 525 pen-based oral fluids (OFs) were collected in growing and fattening pigs. Laboratory diagnostics included enzyme-linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (PCR) analyses. RESULTS: Antibodies to M. hyopneumoniae were present in 87.5 per cent of all herds. Seroprevalence ranged from 0.0 to 100.0 per cent and 0.0 to 88.0 per cent in sows and piglets, respectively. M. hyopneumoniae-deoxyribonucleic acid (DNA) was present in 3.8 and 0.4 per cent of LS and TBS, respectively. Gilts had a 10.9 times higher chance being M. hyopneumoniae PCR-positive than older sows. In 75.0 per cent of all farms, M. hyopneumoniae-DNA was present in OFs. Detection rate was significantly higher in OFs of 20-week-old than in younger pigs (p < 0.001). CONCLUSION: Results indicate that M. hyopneumoniae infections of the lower respiratory tract in piglets are rare but highlight the role of gilts in maintaining infection in the herd. Collecting OFs seems promising for surveillance, if coughing occurs simultaneously.
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Infecções por Mycoplasma , Mycoplasma hyopneumoniae , Pneumonia Suína Micoplasmática , Doenças dos Suínos , Animais , Estudos Transversais , DNA , Feminino , Infecções por Mycoplasma/veterinária , Pneumonia Suína Micoplasmática/epidemiologia , Prevalência , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Estudos Soroepidemiológicos , Suínos , Doenças dos Suínos/epidemiologiaRESUMO
PURPOSE: Depression is a highly prevalent mental health condition with substantial individual, societal and economic consequences. This study focussed on the association of depressive symptom severity with absenteeism duration and employer labour costs. METHODS: Using cross-sectional data from the German Health Update 2014/2015, multivariable zero-inflated Poisson regression (ZIP) models explored the association of depressive symptom severity (8-item depression patient health questionnaire-PHQ-8), with absenteeism weeks during 12 months in men and women working full- or part-time. The predicted sick leave weeks were multiplied by mean average labour costs. RESULTS: The sample consisted of 12,405 persons with an average sick leave of 1.89 weeks (SD 4.26). Fifty-four % were women and 57% were between 40 and 59 years of age. In men and women, mild, moderate, moderately severe and severe depressive symptoms were associated with a significant factor increase in sick leave weeks compared to persons with no or minimal symptoms. Labour costs increased with increasing symptom severity from 1468.22 for men with no or minimal depressive symptoms to 7190.25 for men with severe depressive symptoms and from 1045.82 to 4306.30 in women, respectively. CONCLUSION: The present results indicate that increasing depressive symptom severity is associated with increasing absenteeism and employer costs. They emphasize the need for implementation, realignment or extension of professional work-site health promotion programmes aiming at the improvement and maintenance of employee health and the reduction of labour costs associated with depression-related sick leave.
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Absenteísmo , Depressão , Custos e Análise de Custo , Estudos Transversais , Depressão/epidemiologia , Feminino , Humanos , Masculino , Licença MédicaRESUMO
The service utilisation of persons with dementia (PwD) and their caregivers is subject to lively debate. The reasons for non-utilisation are manifold and heterogeneous. Conceptual models and explanatory frameworks may help identify predictors of the usage of health services. Literature examining the utilisation of home care services for PwD is scarce. This study explored predictors of home care nursing utilisation of PwD and their informal caregivers in a rural setting, according to the Andersen Behavioural Model of Health Care Use. A mixed-methods study was conducted in a rural area of Austria. In using non-random multistage sampling, anonymous questionnaires were distributed to collect data on family caregivers of PwD. Data were analysed using sequential binary logistic regression to characterise home care service users. To reflect the complexity of the Andersen model, a regression tree model was used. In total, 107 family caregivers completed the survey. Predisposing factors for home care nursing utilisation were higher age of the caregiver, female gender of PwD and kinship of the PwD and caregiver. Disruptive behaviour and independence in activities of daily living of PwD were associated with need factors for service use. According to the Andersen model, the predisposing and need factors contributed most to the explanation of home care nursing utilisation. The enabling factors employment, education and income tend to predict service use. Our findings indicate that higher age of the family caregiver and female gender of PwD are the main predictors for utilisation of home care nursing in a rural setting. To improve utilisation, the advantages of professional care services should be promoted, and the awareness about the variety of services available should be increased. To ensure a better understanding of the barriers to accessing home care, PwD should more often be included in healthcare service research.
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Demência , Serviços de Assistência Domiciliar , Atividades Cotidianas , Áustria , Cuidadores , Feminino , HumanosRESUMO
Dementia is a progressive disease that puts substantial strain on caregivers. Many persons with dementia (PwDs) receive care from a relative. Since male and female caregivers experience different issues related to stress, it is important to meet their different needs to prevent the early nursing home placement of PwDs. This study investigated the multifactorial aspects of caregiver burden and explored gender differences in caregiver burden in a rural setting. This was a cross sectional study that administered anonymous questionnaires to family caregivers of PwDs. Caregiver burden was assessed using the Burden Scale for Family Caregivers-short version. A path model was used to determine the multivariate associations between the variables. To reflect the multifaceted aspects of caregiver burden, we used Pearlin's model with its four dimensions. A total of 113 family caregivers responded to our survey. The overall burden of caregivers was moderate. According to the path model, gender differences were predictors of caregiver burden. The behaviour of the person with dementia and cohabitation had direct effects on caregiver burden. Our results suggest that the experiences of men and women caring for a PwD are different and highlight the need for tailored support in dementia care.
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Navigating toward a goal and mentally comparing distances and directions to landmarks are processes requiring reading information off the memorized representation of the environment, that is, the cognitive map. Brain structures in the medial temporal lobe, in particular, are known to be involved in the learning, storage, and retrieval of cognitive map information, which is generally assumed to be in allocentric form, whereby pure spatial relations (i.e., distance and direction) connect locations with each other. The authors recorded functional magnetic resonance imaging activity, while participants were submitted to a variant of a neuropsychological test (the Cognitive Map Reading Test; CMRT) originally developed to evaluate the performance of brain-lesioned patients and in which participants have to compare distances and directions in their mental map of their hometown. Our main results indicated posterior parahippocampal, but not hippocampal, activity, consistent with a task involving spatial memory of places learned a long time ago; left parietal and left frontal activity, consistent with the distributed processing of navigational representations; and, unexpectedly, cerebellar activity, possibly related to the role of the cerebellum in the processing of (here, imaginary) self-motion cues. In addition, direction, but not distance, comparisons elicited significant activation in the posterior parahippocampal gyrus.
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BACKGROUND: Persons with dementia (PwD) need support to remain in their own homes as long as possible. Family caregivers, homecare nurses and general practitioners (GPs) play an important role in providing this support, particularly in rural settings. Assessing caregiver burden is important to prevent adverse health effects among this population. This study analysed perceived burden and needs of family caregivers of PwD in rural areas from the perspectives of healthcare professionals and family caregivers. METHODS: This was a sequential explanatory mixed methods study that used both questionnaires and semi-structured interviews. Questionnaires measuring caregiver burden, quality of life and nursing needs were distributed to the caregivers; health professionals received questionnaires with adjusted items for each group. Additionally, in-depth qualitative interviews were carried out with eight family caregivers. RESULTS: The cross-sectional survey population included GPs (n = 50), homecare nurses (n = 140) and family caregivers (n = 113). Healthcare professionals similarly assessed the psychosocial burden and stress caused by behavioural disturbances as most relevant. Psychological stress, social burden and disruptive behaviour (in that order) were regarded as the most important factors from the caregivers' perspective. It was found that 31% of caregivers reported permanent or frequent caregiver overload. Eight themes related to caregiver burden emerged from the subsequent interviews with caregivers. CONCLUSIONS: Professional support at home on an hourly basis was found to be highly relevant to prevent social isolation and compensate for lack of leisure among caregivers of PwD. Improvement of interprofessional dementia-related education is needed to ensure high-quality primary care.
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Sobrecarga do Cuidador/diagnóstico , Cuidadores/psicologia , Demência/terapia , Pessoal de Saúde/psicologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Sobrecarga do Cuidador/psicologia , Cuidadores/estatística & dados numéricos , Estudos Transversais , Feminino , Pessoal de Saúde/estatística & dados numéricos , Necessidades e Demandas de Serviços de Saúde , Humanos , Entrevistas como Assunto , Masculino , Pessoa de Meia-Idade , Avaliação das Necessidades , Qualidade de Vida/psicologia , População Rural/estatística & dados numéricos , Inquéritos e QuestionáriosRESUMO
Difficulty in navigating in a well-known environment (i.e., topographical disorientation) is an incapacitating syndrome. Despite the relatively high frequency after a right cerebral lesion, there is currently a dearth of neuropsychological tests to assess it. We propose a completely new test, the third in a battery of three, which assesses perspective taking, a crucial process in spatial orientation. In this test, inspired from Piaget and Inhelder Three Mountains, the subject must imagine a change in perspective in two conditions: after a rotational or a linear displacement. This task was proposed to 63 patients with a right cerebral lesion and a control group (N = 112). Results show that a right cerebral lesion impairs perspective taking, more specifically when rotation is involved. In addition, the pattern of responses in patients indicates that they have a general deficit in the ability of decentering. Furthermore, we established preliminary normative data taking into account the effect of age and education (there was no effect of gender) on performance. These data indicate that this new test is a good tool in clinical practice for assessing spatial orientation and determining more precisely the symptoms underlying topographical disorientation.
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Encefalopatias/fisiopatologia , Disfunção Cognitiva/diagnóstico , Lateralidade Funcional/fisiologia , Imaginação/fisiologia , Testes Neuropsicológicos/estatística & dados numéricos , Orientação Espacial/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Espacial/fisiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Encefalopatias/complicações , Disfunção Cognitiva/etiologia , Escolaridade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos/normas , Valores de Referência , Adulto JovemRESUMO
Topographical disorientation, the inability to orient in a well-known environment, is a very incapacitating syndrome. Despite its relatively high frequency after a right cerebral lesion, there is currently no specific neuropsychological test to assess it. We propose a completely new test, with preliminary normative data, assessing the subjects' ability to recall allocentric spatial information from their cognitive map. The subjects are asked to mentally compare distances and directions between landmarks in their familiar environment. This necessitates creating an individual version of the test tailored to every participant's knowledge. This task was proposed to 53 patients with a right lesion and a control group (N = 133). We evaluated performance at comparing distances and directions, and the impact of sociodemographic variables (age, gender, and education). Results show that a right cerebral lesion leads to difficulties in evoking and comparing allocentric spatial information, and more specifically in judging directions. Furthermore, the results show an impact of age, but not gender nor education, on recalling information from a cognitive map. Although there are some intrinsic difficulties (for example in creating patient-specific versions of the test), preliminary normative data indicate that this original test is workable and provides important information in assessing topographical disorientation in clinical practice.
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Neoplasias Encefálicas/complicações , Testes de Navegação Mental , Orientação/fisiologia , Transtornos da Percepção/diagnóstico , Transtornos da Percepção/fisiopatologia , Percepção Espacial/fisiologia , Memória Espacial/fisiologia , Acidente Vascular Cerebral/complicações , Adulto , Fatores Etários , Idoso , Neoplasias Encefálicas/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Transtornos da Percepção/diagnóstico por imagem , Transtornos da Percepção/etiologia , Acidente Vascular Cerebral/diagnóstico por imagemRESUMO
There is currently no specific neuropsychological test assessing spatial orientation abilities, despite the fact that navigational deficits are heavily incapacitating in daily life. This lack of a specific test is probably due to theoretical vagueness of concepts in this field and important interindividual differences in spatial cognition. Here we propose a new standardized test assessing a fundamental component of spatial orientation-namely, mental imagery: Adequate mental visualization of the environment is indeed a necessary step in finding one's way. Two conditions of mental imagery were proposed to a group of 58 patients with a right cerebral lesion and to a control group (N = 117). The 1st condition assessed global, categorical imagery; the 2nd evaluated precise, metric imagery. We evaluated performance of the 2 groups in the 2 conditions and the impact of sociodemographic variables (age, gender, education). Results show that the right-lesioned patients presented difficulties in mental imagery, especially in the metric condition. Moreover, the data indicate a global impact of age and a milder effect of education on mental imagery abilities. Although sample sizes are sometimes small, preliminary normative data are given; already in the present form, they are usable and informative in assessing mental imagery, and more generally, spatial orientation, in a clinical practice.
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Envelhecimento/psicologia , Confusão/diagnóstico , Imaginação , Testes Neuropsicológicos , Percepção Espacial , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Córtex Cerebral/patologia , Confusão/psicologia , Escolaridade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valores de Referência , Adulto JovemRESUMO
A right posterior cerebral lesion can lead to an inability to orient and can consequently interfere with daily-life autonomy. Despite the wide literature about navigation abilities, it is still difficult to assess topographical disorientation (TD) because of the interindividual specificity of spatial knowledge and the diversity of symptoms. We describe here a set of new tests evaluating spatial cognition in a patient with TD presenting difficulties in navigating inside the hospital and in his hometown more than 3 years after his diffuse ischemic right Sylvian stroke. These tests assess mental imagery (global and specifically spatial imagery), perspective change, and the ability to recall spatial relations in familiar environments. The evaluation revealed difficulties with all the tests (but not in global mental imagery) in this patient when compared with matched controls. Hence, these new tests seem specific and affected by a right hemispheric lesion. The observed deficits can explain, at least partially, the spatial orientation difficulties experienced by this patient in the hospital and familiar environments. In conclusion, these tests could be appropriate tools for the assessment of visuospatial and spatial processes.
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Confusão/diagnóstico , Testes Neuropsicológicos , Orientação/fisiologia , Memória Espacial/fisiologia , Navegação Espacial/fisiologia , Acidente Vascular Cerebral/fisiopatologia , Isquemia Encefálica/fisiopatologia , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
A cDNA clone of the classical swine fever virus (CSFV) strain Alfort/187 [Ruggli N, Tratschin JD, Mittelholzer C, Hofmann MA. Nucleotide sequence of classical swine fever virus strain Alfort/187 and transcription of infectious RNA from stably cloned full-length cDNA. J Virol 1996;70(6):3478-87] was used to construct two E2 deletion mutants lacking either the complete E2 gene or, alternatively, a stretch of 204 nucleotides encoding 68 amino acids located in the C-terminal region of the E2 glycoprotein. The respective in vitro synthesized mutant RNAs replicated in SK-6 cells but no infectious virus was generated. Both replicons could be packaged into virus particles in SK-6 cells constitutively expressing E2 of CSFV. For the resulting CSF virus replicon particles (CSF-VRP) A187-E2del373 and A187-E2del68 titers of 10(6) and 10(7) TCID(50)/ml, respectively, were obtained. Oronasal vaccination with 10(7) TCID(50) of either of the two CSF-VRP protected pigs against a challenge with a lethal dose of CSFV strain Eystrup. In contrast, after intradermal vaccination VRP A187-E2del68 but not VRP A187-E2del373 lacking the complete E2 gene induced a protective immune response. We conclude that E2-complemented CSF-VRP have the potential to be used as live-attenuated non-transmissible oral vaccines for pigs. In addition, our data suggest that E2 of CSFV is dispensable for the induction of mucosal but not of parenteral immunity.
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Vírus da Febre Suína Clássica/imunologia , Peste Suína Clássica/imunologia , Peste Suína Clássica/prevenção & controle , Proteínas do Envelope Viral/genética , Vacinas Virais/imunologia , Administração Intranasal , Administração Oral , Animais , Células Cultivadas , Deleção de Genes , Injeções Intradérmicas , RNA Viral/análise , RNA Viral/biossíntese , Suínos , Vacinas Sintéticas/imunologiaRESUMO
During short excursions away from home, some mammals are known to update their position with respect to their point of departure through path integration (dead reckoning) by processing internal (idiothetic) signals generated by rotations and translations. Path integration (PI) is a continuously ongoing process in which errors accumulate. To remain functional over longer excursions, PI needs to be reset through position information from stable external references. We tested the homing behaviour of golden hamsters (Mesocricetus auratus W.) during hoarding excursions following a rotation of the arena and nest. In continuous darkness, the hamsters returned to their point of departure at the rotated nest, and therefore depended on PI only. In other trials, the animals were briefly presented with visual room cues during or at the end of the outward trip, visual cues being pitted by 67 degrees or 98 degrees against the animal's current self-generated position vector. After a fix, the animals headed for the usual (unrotated) nest location, as defined by room cues, independent of the timing of the fix. These results were obtained in two different geometrical settings and showed that, after the fix, the animals update their position, and not merely their head direction or internal compass, in a new reference frame. Thus, episodic fixes on familiar external references reset the PI and therefore greatly enhance the functional signification of navigation that is based on feedback information from locomotion.
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Sinais (Psicologia) , Comportamento de Retorno ao Território Vital/fisiologia , Mesocricetus/fisiologia , Orientação/fisiologia , Percepção Espacial/fisiologia , Comportamento Espacial/fisiologia , Animais , Cricetinae , Escuridão , Feminino , RotaçãoRESUMO
In this study we show that social voles (Microtus socialis guentheri) preserve the same level of activity and spatio-temporal organization of behavior whether exploring a small (1 x 1 m) or a large (2 x 2 m) open field. In each open field, a vole established a home base from which it set on to round-trips of exploration; taking fewer but longer trips in the large open field, compared with more frequent but shorter trips in the small open field. Each trip comprised bouts of progression (locomotion) interrupted by stops. The number of stops per trip was the same for both large open field (longer trips) and small open field (shorter trips), and achieved by scaling the distance between stops according to the size of the open field. Voles traveled more along the walls in the large compared with the small open field. These adjustments in locomotor behavior to open field size were observed immediately after the voles were introduced into the arena, indicating that the perceived distances available for locomotion were identified by the voles immediately at the beginning of exploration. It is suggested that these properties of spontaneous exploration are an expression of navigation using visual landmarks and path integration.