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| 2. |
- Hagbom, Marie, et al.
(författare)
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Ionizing air affects influenza virus infectivity and prevents airborne-transmission
- 2015
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Ingår i: Scientific Reports. - : Nature Publishing Group: Open Access Journals - Option C / Nature Publishing Group. - 2045-2322. ; 5:11431
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Tidskriftsartikel (refereegranskat)abstract
- By the use of a modified ionizer device we describe effective prevention of airborne transmitted influenza A (strain Panama 99) virus infection between animals and inactivation of virus (greater than 97%). Active ionizer prevented 100% (4/4) of guinea pigs from infection. Moreover, the device effectively captured airborne transmitted calicivirus, rotavirus and influenza virus, with recovery rates up to 21% after 40 min in a 19 m(3) room. The ionizer generates negative ions, rendering airborne particles/aerosol droplets negatively charged and electrostatically attracts them to a positively charged collector plate. Trapped viruses are then identified by reverse transcription quantitative real-time PCR. The device enables unique possibilities for rapid and simple removal of virus from air and offers possibilities to simultaneously identify and prevent airborne transmission of viruses.
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| 3. |
- Hansdotter, Frida I., et al.
(författare)
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The incidence of acute gastrointestinal illness in Sweden
- 2015
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Ingår i: Scandinavian Journal of Public Health. - : SAGE Publications. - 1651-1905 .- 1403-4948. ; 43:5, s. 540-547
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Tidskriftsartikel (refereegranskat)abstract
- Aims: The aim of this study was to estimate the self-reported domestic incidence of acute gastrointestinal illness in the Swedish population irrespective of route of transmission or type of pathogen causing the disease. Previous studies in Sweden have primarily focused on incidence of acute gastrointestinal illness related to consumption of contaminated food and drinking water. Methods: In May 2009, we sent a questionnaire to 4000 randomly selected persons aged 0-85 years, asking about the number of episodes of stomach disease during the last 12 months. To validate the data on symptoms, we compared the study results with anonymous queries submitted to a Swedish medical website. Results: The response rate was 64%. We estimated that a total number of 2744,778 acute gastrointestinal illness episodes (95% confidence intervals 2475,641-3013,915) occurred between 1 May 2008 and 30 April 2009. Comparing the number of reported episodes with web queries indicated that the low number of episodes during the first 6 months was an effect of seasonality rather than recall bias. Further, the result of the recall bias analysis suggested that the survey captured approximately 65% of the true number of episodes among the respondents. Conclusions: The estimated number of Swedish acute gastrointestinal illness cases in this study is about five times higher than previous estimates. This study provides valuable information on the incidence of gastrointestinal symptoms in Sweden, irrespective of route of transmission, indicating a high burden of acute gastrointestinal illness, especially among children, and large societal costs, primarily due to production losses.
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| 4. |
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| 5. |
- Hedlund, Martin, 1987-
(författare)
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Growth and decline in rural Sweden : geographical distribution of employment and population 1960–2010
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis investigates the combination of changes in the population and employment into sectors in rural Sweden for the period 1960-2010. The aim is to describe and analyze the demographic changes together with the labour market changes, and to account for the spatial outcome of these changes by considering the heterogeneity of rural areas. The analysis departs from the framework of rural restructuring, where changes in employment and population in rural Sweden are interpreted as local products of the global processes of technological development, social modernization and globalization. Empirically, the analysis is based on a combination of longitudinal censuses and register data on the Swedish population covering the period 1960-2010.The first part of the aim is achieved by applying a life-course perspective and exploiting the longitudinal nature of the data. The life-course perspective distinguishes between historical time and the age of individuals, making it possible to situate changes in employment and migration on the individual level. The second part of the aim is achieved through developing a typology of rural Sweden by doing a cluster analysis on SAMS-areas.The results show that rural change after 1980 was characterized by de-industrialization and the rise of the urban service sector. The period was also characterized by regional urbanization rather than local urbanization. Peripheral urban and rural areas based on industrial employment found themselves with a declining economic motor, which meant that people had to find their source of income elsewhere. The migration stream in this period was thus increasingly directed towards metropolitan or large city centers, and their rural surroundings within commuting distance. However, the more fine-tuned spatial typology reveals that also a few areas in the rural periphery have experienced growth, these areas are mainly attractive places based on various kinds of tourism. It can thus be concluded that different rural areas have experienced, and will continue to experience, the shift from manufacturing to services differently, where some areas have grown in both demographic and employment terms while others have declined. In this sense the heterogeneity of rural areas are a product of both growth and decline – of old development paths that is reaching their end and of new development paths that will continue into the future.
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| 6. |
- Johansen, Kari, et al.
(författare)
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Norovirus strains belonging to the GII.4 genotype dominate as a cause of nosocomial outbreaks of viral gastroenteritis in Sweden 1997-2005 - Arrival of new variants is associated with large nation-wide epidemics
- 2008
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Ingår i: Journal of Clinical Virology. - : Elsevier BV. - 1386-6532 .- 1873-5967. ; 42:2, s. 129-134
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Tidskriftsartikel (refereegranskat)abstract
- Background: In recent years an increase of the incidence of nosocomial outbreaks caused by noroviruses has been observed throughout Sweden, with high peaks noted in the winter seasons 2002/2003 and 2004/2005, respectively. Objectives: To phylogenetically characterize norovirus strains causing nosocomial outbreaks from 1997 to 2005 and estimate the impact of norovirus-like disease on the Swedish health care system during the peak season 2002/2003 when a new variant of norovirus occurred. Study design: Stool samples from 115 randomly selected nosocomial outbreaks occurring during 1997-2005 throughout Sweden were studied by RT-PCR and sequencing. In addition, to investigate the impact on the health-care system, a questionnaire was distributed to infection control units (n = 90) serving all Swedish hospitals, nursing homes and other health-care institutions during the largest epidemic of nosocomial outbreaks. Results: Sequencing of 279 nucleotides of the norovirus RNA polymerase gene in stools containing norovirus RNA showed that strains belonging to the GII.4 genotype dominated. Each of the two large epidemics was due to a new variant within this cluster. The questionnaire revealed that 30,000-35,000 episodes of nosocomial norovirus-like infections occurred in 80 of 82 major Swedish hospitals affected in 2002/2003. Conclusion: New norovirus variants within the cluster GGII.4 may have a major impact on the health-care system. (c) 2008 Elsevier B.V. All rights reserved.
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| 7. |
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| 8. |
- Johansson, Hugo, et al.
(författare)
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Food-borne outbreak of gastroenteritis associated with genogroup I calicivirus.
- 2002
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Ingår i: Journal of Clinical Microbiology. - 1098-660X. ; 40:3, s. 794-798
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Tidskriftsartikel (refereegranskat)abstract
- An outbreak of gastroenteritis affecting 158 of 219 (72%) guests and employees at a hotel is described. Food served at the hotel restaurant is believed to have been the source of the outbreak and to have been contaminated by sick employees working in the restaurant. A secondary attack rate of 22% was seen involving 43 persons in all. In stool specimens from seven of eight patients, Norwalk-like viruses (NLVs) were detected by electron microscopy. While NLV-specific PCR using primers JV12 and JV13 were negative, all specimens examined with primers NVp69 and NVp110 were positive. The failure of primers JV12 and JV13 was attributed to several mismatches in the JV12 primer. Genotyping and sequence analysis revealed that all samples had identical sequences and clustered with genogroup I, and the most closely related well-characterized genotype is Desert Shield. This is the first described food-borne outbreak associated with genogroup I virus in Sweden.
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| 9. |
- Karlsson, Beatrice, et al.
(författare)
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Quasispecies dynamics and molecular evolution of human norovirus capsid P region during chronic infection
- 2009
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Ingår i: Journal of General Virology. - : Microbiology Society. - 0022-1317 .- 1465-2099. ; 90:2, s. 432-441
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Tidskriftsartikel (refereegranskat)abstract
- In this novel study, we have for the first time identified evolutionarily conserved capsid residues in an individual chronically infected with norovirus (GGII.3). From 2000 to 2003, a total of 147 P1-1 and P2 capsid sequences were sequenced and investigated for evolutionarily conserved and functionally important residues by the evolutionary trace (ET) algorithm. The ET algorithm revealed more absolutely conserved residues (ACR) in the P1-1 domain (47/53, 88 %) as compared with the P2 domain (86/133, 64 %). The capsid P1-1 and P2 domains evolved in time-dependent manner, with a distinct break point observed between autumn/winter of year 2000 (isolates P1, P3 and P5) and spring to autumn of year 2001 (isolates P11, P13 and P15), which presumably coincided with a change of clinical symptoms. Furthermore, the ET analysis revealed a similar receptor-binding pattern as reported for Norwalk and VA387 strains, with the CS-4 and CS-5 patch (Norwalk strain) including residues 329 and 377 and residues 306 and 310, respectively, all being ACR in all partitions. Most interesting was that residues 343, 344, 345, 374, 390 and 391 of the proposed receptor A and B trisaccharide binding site (VA387 strain) within the P2 domain remained ACR in all partitions, presumably because there was no selective advantage to alter the histo blood group antigens (HBGA) receptor binding specificity. In conclusion, this study provides novel insights to the evolutionary process of norovirus during chronic infection.
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| 10. |
- Kylberg, Gustaf, et al.
(författare)
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Segmentation of virus particle candidates in transmission electron microscopy images
- 2012
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Ingår i: Journal of Microscopy. - : Blackwell Publishing. - 0022-2720 .- 1365-2818. ; 245:2, s. 140-147
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present an automatic segmentation method that detects virus particles of various shapes in transmission electron microscopy images. The method is based on a statistical analysis of local neighbourhoods of all the pixels in the image followed by an object width discrimination and finally, for elongated objects, a border refinement step. It requires only one input parameter, the approximate width of the virus particles searched for. The proposed method is evaluated on a large number of viruses. It successfully segments viruses regardless of shape, from polyhedral to highly pleomorphic.
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