| 1. |
- Gherasim, A., et al.
(författare)
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Two geographically separated food-borne outbreaks in Sweden linked by an unusual Cryptosporidium parvum subtype, October 2010
- 2012
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Ingår i: EUROSURVEILLANCE. - 1560-7917. ; 17:46, s. 29-36
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Tidskriftsartikel (refereegranskat)abstract
- The number of sporadic cases of Cryptosporidium identified in the Stockholm county area increased above the expected limit during October 2010. Additionally, two food-borne outbreaks of cryptosporidiosis occurred in two other Swedish cities: Umea (4 October) and Orebro (9 October). The outbreak investigations did not reveal any responsible food item, however fresh herbs were suspected. Thirty stool samples, originating from all three events, tested positive for Cryptosporidium oocysts. Polymerase chain reaction (PCR) and subsequent restriction fragment length polymorphism (RFLP) revealed that 27 individuals were infected with C. parvum, two with C. hominis, and one with C. felis. Using sequence analysis of the GP60 glycoprotein gene, a polymorphic marker with high intra-species diversity, we identified the same C. parvum subtype IIdA24G1 in samples from both the Umea outbreak and the Stockholm area cases, thus indicating a possible outbreak in the Stockholm area and establishing a link between these two events. C. parvum IIdA24G1 has not previously been described in connection with a food-borne outbreak. For the outbreak in Orebro, another subtype was identified: C. parvum IIdA20G1e. These findings demonstrate that subtyping C. parvum isolates using GP60 gene amplification can be used to link cases in an outbreak investigation and we recommend its use in future similar events.
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| 2. |
- Rehn, M., et al.
(författare)
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Unusual increase of psittacosis in southern Sweden linked to wild bird exposure, January to April 2013
- 2013
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Ingår i: Eurosurveillance. - 1025-496X .- 1560-7917. ; 18:19, s. 13-20
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Tidskriftsartikel (refereegranskat)abstract
- Free-living wild birds worldwide act as reservoir for Chlamydia psittaci, but the risk of transmission to humans through contact with wild birds has not been widely documented. From 12 January to April 9 2013, a total of 25 cases of psittacosis were detected in southern Sweden, about a threefold increase compared with the mean of the previous 10 years. A matched case-control study investigating both domestic and wild bird exposure showed that cases were more likely than controls to have cleaned wild bird feeders or been exposed to wild bird droppings in other ways (OR: 10.1; 95% CI: 2.1-47.9). We recommend precautionary measures such as wetting bird feeders before cleaning them, to reduce the risk of transmission of C. psittaci when in contact with bird droppings. Furthermore, C. psittaci should be considered for inclusion in laboratory diagnostic routines when analysing samples from patients with atypical pneumonia, since our findings suggest that psittacosis is underdiagnosed.
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| 3. |
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| 4. |
- Desvars-Larrive, Amélie, et al.
(författare)
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High-risk regions and outbreak modelling of tularemia in humans
- 2017
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Ingår i: Epidemiology and Infection. - : CAMBRIDGE UNIV PRESS. - 0950-2688 .- 1469-4409. ; 145:3, s. 482-490
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Tidskriftsartikel (refereegranskat)abstract
- Sweden reports large and variable numbers of human tularemia cases, but the high-risk regions are anecdotally defined and factors explaining annual variations are poorly understood. Here, high-risk regions were identified by spatial cluster analysis on disease surveillance data for 1984-2012. Negative binomial regression with five previously validated predictors (including predicted mosquito abundance and predictors based on local weather data) was used to model the annual number of tularemia cases within the high-risk regions. Seven high-risk regions were identified with annual incidences of 3.8-44 cases/100 000 inhabitants, accounting for 56.4% of the tularemia cases but only 9.3% of Sweden's population. For all high-risk regions, most cases occurred between July and September. The regression models explained the annual variation of tularemia cases within most high-risk regions and discriminated between years with and without outbreaks. In conclusion, tularemia in Sweden is concentrated in a few high-risk regions and shows high annual and seasonal variations. We present reproducible methods for identifying tularemia high-risk regions and modelling tularemia cases within these regions. The results may help health authorities to target populations at risk and lay the foundation for developing an early warning system for outbreaks.
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| 5. |
- Jaenson, Thomas G.T. 1948-, et al.
(författare)
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The importance of wildlife in the ecology and epidemiology of the TBE virus in Sweden: incidence of human TBE correlates with abundance of deer and hares
- 2018
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Ingår i: Parasites & Vectors. - : Springer Science and Business Media LLC. - 1756-3305. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background: Tick-borne encephalitis (TBE) is one tick-transmitted disease where the human incidence has increased in some European regions during the last two decades. We aim to find the most important factors causing the increasing incidence of human TBE in Sweden. Based on a review of published data we presume that certain temperature-related variables and the population densities of transmission hosts, i.e. small mammals, and of primary tick maintenance hosts, i.e. cervids and lagomorphs, of the TBE virus vector Ixodes ricinus, are among the potentially most important factors affecting the TBE incidence. Therefore, we compare hunting data of the major tick maintenance hosts and two of their important predators, and four climatic variables with the annual numbers of human cases of neuroinvasive TBE. Data for six Swedish regions where human TBE incidence is high or has recently increased are examined by a time-series analysis. Results from the six regions are combined using a meta-analytical method.Results: With a one-year time lag, the roe deer (Capreolus capreolus), red deer (Cervus elaphus), mountain hare (Lepus timidus) and European hare (Lepus europaeus) showed positive covariance; the Eurasian elk (moose, Alces alces) and fallow deer (Dama dama) negative covariance; whereas the wild boar (Sus scrofa), lynx (Lynx lynx), red fox (Vulpes vulpes) and the four climate parameters showed no significant covariance with TBE incidence. All game species combined showed positive covariance.Conclusions: The epidemiology of TBE varies with time and geography and depends on numerous factors, i.a. climate, virus genotypes, and densities of vectors, tick maintenance hosts and transmission hosts. This study suggests that the increased availability of deer to I. ricinus over large areas of potential tick habitats in southern Sweden increased the density and range of I. ricinus and created new TBEV foci, which resulted in increased incidence of human TBE. New foci may be established by TBE virus-infected birds, or by birds or migrating mammals infested with TBEV-infected ticks. Generally, persistence of TBE virus foci appears to require presence of transmission-competent small mammals, especially mice (Apodemus spp.) or bank voles (Myodes glareolus).
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| 6. |
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| 7. |
- Lundkvist, Åke, et al.
(författare)
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Tick-borne encephalitis increasing in Sweden, 2011
- 2011
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Ingår i: Eurosurveillance. - 1025-496X .- 1560-7917. ; 16:39, s. 4-6
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Tidskriftsartikel (refereegranskat)abstract
- Until August, 161 cases of tick-borne encephalitis (TBE) were recorded in Sweden for 2011, leading to an incidence of 1.7 per 100,000 population. Fifty to 59 year-olds (24%) were most affected, 55% of the cases were males. An increase in TBE in Sweden has occurred in the last decade and might be explained by enlarged tick populations, more contact between TBE virus infected ticks and man, and also by growing awareness of the disease. Climatic conditions may have contributed to the increase. Until 25 September 2011, two hundred and four patients have been diagnosed as tick-borne encephalitis (TBE) cases, indicating that 2011 may be a record year for the number of TBE cases in Sweden.
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| 8. |
- Olsson, Gert, et al.
(författare)
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Predicting High Risk for Human Hantavirus Infections, Sweden
- 2009
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Ingår i: Emerging Infectious Diseases. - : Centers for Disease Control and Prevention (CDC). - 1080-6040 .- 1080-6059. ; 15:1, s. 104-106
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Tidskriftsartikel (refereegranskat)abstract
- An increased risk for hemorrhagic fever with renal syndrome caused by Puumala hantavirus was forecast for Sweden in 2007. The forecast was based on a predicted increase in the number of Myodes glareolus rodents (reservoir hosts). Despite raised awareness and preparedness, the number of human cases during July 2007-June 2008 was 1,483, a new high.
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| 9. |
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| 10. |
- Sartz, Lisa, et al.
(författare)
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An outbreak of Escherichia coli O157:H7 infection in southern Sweden associated with consumption of fermented sausage; aspects of sausage production that increase the risk of contamination.
- 2008
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Ingår i: Epidemiology and Infection. - 0950-2688. ; 136:3, s. 370-380
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Tidskriftsartikel (refereegranskat)abstract
- A large outbreak of enterohaemorrhagic Escherichia coli (EHEC) infections occured in southern Sweden during autumn 2002. A matched case-control study was performed and indicated an association between consumption of fermented sausage and EHEC infection (odds ratio 5.4, P<0.002). Pulsed-field gel electrophoresis analysis identified a strain of E. coli O157:H7 in clinical faecal isolates which was identical to a strain isolated from sausage samples obtained from households of infected individuals. A combination of microbiological and epidemiological results established a link between sausage consumption and the outbreak in 30 out of a total of 39 investigated cases. Contaminated beef was suspected to be the source of infection. Delayed start of fermentation, lack of heat-treatment and a short curing period in cold temperature were identified as the main factors enabling EHEC survival. EHEC can survive thorughout the entire production process of fermented sausage if curing conditions are inadequate.
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