| 1. |
- Andersson, Eva M., 1968, et al.
(författare)
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Predictions by early indicators of the time and height of the peaks of yearly influenza outbreaks in Sweden
- 2008
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Ingår i: Scandinavian Journal of Public Health. - : SAGE Publications. - 1403-4948 .- 1651-1905. ; 36:5, s. 475-482
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Methods for prediction of the peak of the influenza from early observations are suggested. These predictions can be used for planning purposes. Methods: In this study, new robust methods are described and applied to weekly Swedish data on influenza-like illness (ILI) and weekly laboratory diagnoses of influenza (LDI). Both simple and advanced rules for how to predict the time and height of the peak of LDI are suggested. The predictions are made using covariates calculated from data in early LDI reports. The simple rules are based on the observed LDI values, while the advanced ones are based on smoothing by unimodal regression. The suggested predictors were evaluated by cross-validation and by application to the observed seasons. Results: The relationship between ILI and LDI was investigated, and it was found that the ILI variable is not a good proxy for the LDI variable. The advanced prediction rule regarding the time of the peak of LDI had a median error of 0.9 weeks, and the advanced prediction rule for the height of the peak had a median deviation of 28%. Conclusions: The statistical methods for predictions have practical usefulness.
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| 2. |
- Andersson, Eva M., 1968, et al.
(författare)
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Predictions by early indicators of the time and height of yearly influenza outbreaks in Sweden
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Aims: Methods for prediction of the peak of the influenza from early observations are suggested. These predictions can be used for planning purposes. Methods: In this study, new robust methods are described and applied on weekly Swedish data on influenza-like illness (ILI) and weekly laboratory diagnoses of influenza (LDI). Both simple and advanced rules for how to predict the time and height of the peak of LDI are suggested. The predictions are made using covariates calculated from data in early LDI reports. The simple rules are based on the observed LDI values while the advanced ones are based on smoothing by unimodal regression. The suggested predictors were evaluated by cross-validation and by application to the observed seasons. Results: The relation between ILI and LDI was investigated and it was found that the ILI variable is not a good proxy for the LDI variable. The advanced prediction rule regarding the time of the peak of LDI had a median error of 0.9 weeks, and the advanced prediction rule for the height of the peak had a median deviation of 28%. Conclusions: The statistical methods for predictions have practical usefulness.
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| 3. |
- Beser, Jessica, et al.
(författare)
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Seroprevalence of SARS-CoV-2 in Sweden, April 26 to May 9, 2021
- 2022
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- A national point seroprevalence study of SARS-CoV-2 was conducted in Sweden in April–May 2021. In total, 2860 individuals 3 to 90 years old from a probability-based web panel were included. Results showed that an estimated 32.6% of the population in Sweden had detectable levels of antibodies, and among non-vaccinated 20.1% had detectable levels of antibodies. We tested for differences in seroprevalence between age groups and by sex and estimated seroprevalence among previously infected participants by time since reporting.
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| 4. |
- Enkirch, Theresa, et al.
(författare)
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Molecular epidemiology of community- and hospital-associated Clostridioides difficile infections in Jönköping, Sweden, October 2017-March 2018
- 2022
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 130:11, s. 661-670
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Tidskriftsartikel (refereegranskat)abstract
- Clostridioides difficile infections (CDIs) in Sweden are mostly hospital-associated (HA) with limited knowledge regarding community-associated (CA) infections. Here, we investigated the molecular epidemiology of clinical isolates of CA-CDI and HA-CDI in a Swedish county. Data and isolates (n = 156) of CDI patients (n = 122) from Jonkoping county, October 2017-March 2018, were collected and classified as CA (without previous hospital care or onset <= 2 days after admission or >12 weeks after discharge from hospital) or HA (onset >3 days after hospital admission or within 4 weeks after discharge). Molecular characterization of isolates included PCR ribotyping (n = 156 isolates) and whole genome sequencing with single nucleotide polymorphisms (SNP) analysis (n = 53 isolates). We classified 47 patients (39%) as CA-CDI and 75 (61%) as HA-CDI. Between CA-CDI and HA-CDI patients, we observed no statistically significant differences regarding gender, age, 30-day mortality or recurrence. Ribotype 005 (RR 3.1; 95% CI: 1.79-5.24) and 020 (RR 2.5; 95% CI: 1.31-4.63) were significantly associated with CA-CDI. SNP analysis identified seven clusters (0-2 SNP difference) involving 17/53 isolates of both CA-CDI and HA-CDI. Molecular epidemiology differed between CA-CDI and HA-CDI and WGS analysis suggests transmission of CDI within and between hospitals and communities.
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| 5. |
- Fischerström, Karolina, et al.
(författare)
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Outbreak of Salmonella Typhimurium linked to Swedish pre-washed rocket salad, Sweden, September to November 2022
- 2024
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Ingår i: Eurosurveillance. - : European Centre for Disease Prevention and Control. - 1025-496X .- 1560-7917. ; 29:10
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Tidskriftsartikel (refereegranskat)abstract
- In September 2022, the Public Health Agency of Sweden observed an increase in domestic Salmonella Typhimurium cases through the Swedish electronic notification system, and an outbreak strain was identified with whole genome sequencing. Overall, 109 cases with symptom onset between 17 September and 24 November 2022 were reported from 20 of 21 Swedish regions. The median age of cases was 52 years (range 4-87 years) and 62% were female. A case-control study found cases to be associated with consumption of rocket salad (adjusted odds ratio (aOR) = 4.9; 95% confidence interval (CI): 2.4-10, p value < 0.001) and bagged mixed salad (aOR = 4.0; 95% CI: 1.9-8.1, p value < 0.001). Trace-back, supported by Finnish authorities who identified the Swedish outbreak strain in a Finnish cluster during the same time period, identified rocket salad, cultivated, pre-washed and pre-packed in Sweden as the likely source of the outbreak. No microbiological analyses of rocket salad were performed. Our investigation indicates that bagged leafy greens such as rocket salad, regardless of pre-washing procedures in the production chain, may contain Salmonella and cause outbreaks, posing a health risk to consumers. We emphasise the need for primary producers of leafy greens to identify possible contamination points to prevent outbreaks.
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| 6. |
- Gherasim, Alin, et al.
(författare)
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Risk factors and potential preventive measures for nephropatia epidemica in Sweden 2011-2012 : a case-control study
- 2015
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Ingår i: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686 .- 2000-8686. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Nephropatia epidemica (NE), a relatively mild form of hemorrhagic fever with renal syndrome caused by the Puumala virus (PUUV), is endemic in northern Sweden. We aim to study the risk factors associated with NE in this region.METHODS: We conducted a matched case-control study between June 2011 and July 2012. We compared confirmed NE cases with randomly selected controls, matched by age, sex, and place of infection or residence. We analyzed the association between NE and several occupational, environmental, and behavioral exposures using conditional logistic regression.RESULTS: We included in the final analysis 114 cases and 300 controls, forming 246 case-control pairs. Living in a house with an open space beneath, making house repairs, living less than 50 m from the forest, seeing rodents, and smoking were significantly associated with NE.CONCLUSION: Our results could orient public health policies targeting these risk factors and subsequently reduce the NE burden in the region.
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| 7. |
- 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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| 8. |
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| 9. |
- Kühlmann-Berenzon, Sharon, 1971, et al.
(författare)
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An additive edge correction for the influence potential of trees
- 2005
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Ingår i: Biometrical Journal. - : Wiley. - 1521-4036 .- 0323-3847. ; 47:4, s. 517-526
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Tidskriftsartikel (refereegranskat)abstract
- The influence potential on a quadrat (IPQ) is an index for measuring the ecological effect that trees have on understory vegetation observed in a quadrat of a plot. IPQ is defined as the sum of the effect of every trees in the plot, where the effect depends on the size of the tree and the distance between the tree and the quadrat. Since only the trees in the plot have been observed and not the trees outside the plot, the true IPQ may be underestimated. Existing edge corrections are not appropriate for this case. We propose a correction that consists of adding the expected IPQ due to effects of trees outside the plot to the observed IPQ. The expectation is obtained by applying the Campbell theorem for stationary marked point processes. Data from the 1985-86 National Forest Inventory of Finland was used to calculate IPQ for six quadrats systematically allocated to each of 1240 plots. The implementation of the correction for this data is described. The distributions of IPQ with and without the correction proved the existence of edge effects and the effectiveness of the correction to eliminate the bias. This method has the potential to be applied to other additive functions. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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| 10. |
- Kühlmann-Berenzon, Sharon, 1971
(författare)
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Edge correction and regression models for quantifying single-tree influence on understory vegetation
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The understory is the layer of vegetation in the forest situated under the canopies of the trees. Some species of understory vegetation benefit from the surrounding trees, e.g by the provided nutrients, while others are restricted, e.g. by the limited amount of light. In this thesis, statistical methods have been developed that allow the quantification of the effect of the trees on the vegetation. This is of importance for understanding ecological dynamics as well as for decisions regarding biodiversity and forest management. The effect of the trees was calculated with an index called influence potential on a quadrat (IPQ), which uses the size of the trees and their spatial distribution. The abundance of the understory was assessed by the proportion of ground covered. The Finnish Forest Research Institute provided the data consisting of observations on trees and vegetation from more than 3000 plots distributed over Finland. In Paper I, an edge correction for IPQ was developed using tools from spatial point processes. The correction eliminates the bias that originates when trees outside the plot are ignored in the calculations. Paper II suggests a logistic model for studying the absence and presence of a plant species, but conditioned on a sufficient statistic for the large-scale effects. These effects are present throughout the data and are due to factors such as climate and latitude. By conditioning, the effects are accounted for but do not require to be estimated. Paper III develops regression models for proportions assuming that the errors are Beta distributed. It uses an alternative parameterization that is more flexible and allows estimation methods not possible with the standard form. Paper IV is an exploratory study of the relationship between IPQ and the abundance of 12 species of understory vegetation.
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