Stensvold C.R.,Statens Serum Institute |
Lebbad M.,Swedish Institute for Infectious Disease Control |
Clark C.G.,London School of Hygiene and Tropical Medicine
Molecular Biology and Evolution | Year: 2012
Iodamoeba is the last genus of obligately parasitic human protist whose phylogenetic position is unknown. Iodamoeba small subunit ribosomal DNA sequences were obtained using samples from three host species, and phylogenetic analyses convincingly placed Iodamoeba as a sister taxon to Endolimax. This clade in turn branches among free-living amoeboflagellates of the genus Mastigamoeba. Two Iodamoeba ribosomal lineages (RL1 and RL2) were detected whose sequences differ by 31%, each of which is found in both human and nonhuman hosts. © The Author 2011.
Levin L.I.,U.S. Army |
Munger K.L.,Harvard University |
O'Reilly E.J.,Harvard University |
Falk K.I.,Swedish Institute for Infectious Disease Control |
And 2 more authors.
Annals of Neurology | Year: 2010
To determine whether multiple sclerosis (MS) risk increases following primary infection with the Epstein-Barr virus (EBV), we conducted a nested case-control study including 305 individuals who developed MS and 610 matched controls selected among the >8 million active-duty military personnel whose serum has been stored in the Department of Defense Serum Repository. Time of EBV infection was determined by measuring antibody titers in serial serum samples collected before MS onset among cases, and on matched dates among controls. Ten (3.3%) cases and 32 (5.2%) controls were initially EBV negative. All of the 10 EBV-negative cases became EBV positive before MS onset; in contrast, only 35.7% (n = 10) of the 28 controls with follow-up samples seroconverted (exact p value = 0.0008). We conclude that MS risk is extremely low among individuals not infected with EBV, but it increases sharply in the same individuals following EBV infection. © 2010 American Neurological Association.
Ramqvist T.,Karolinska Institutet |
Dalianis T.,Karolinska Institutet |
Dalianis T.,Swedish Institute for Infectious Disease Control
Emerging Infectious Diseases | Year: 2010
A growing body of research shows that human papillomavirus(HPV) is a common and increasing cause of oropharyngeal squamous cell carcinoma (OSCC). Thus, the International Agency for Research against Cancer has acknowledged HPV as a risk factor for OSCC, in addition to smoking and alcohol consumption. Recently, in Finland, the United Kingdom, the Netherlands, the United States, and Sweden, incidence of OSCC has increased, and an increase in the proportion of HPV-positive tumors was noted. On the basis of these data and reports indicating that patients with HPV-positive cancer have their first sexual experience at a young age and have multiple partners, we postulate that increase dincidence of OSCC in the United States and some countries in northern Europe is because of a new, primarily sexually transmitted HPV epidemic. We also suggest that individualized treatment modalities and preventive vaccination should be further explored.
Stoltz M.,Karolinska Institutet |
Stoltz M.,Swedish Institute for Infectious Disease Control |
Klingstrom J.,Karolinska Institutet |
Klingstrom J.,Swedish Institute for Infectious Disease Control
Journal of Virology | Year: 2010
Type III interferons ([IFNs]IFN-λ and interleukin-28 and -29 [IL-28/29]) are recently recognized cytokines with innate antiviral effects similar to those of type I IFNs (IFN-α/β). Like IFN-α/β, IFN-λ-expression can be induced by viruses, and it is believed that type I and III IFNs are regulated in the same manner. Hantaviruses are weak IFN-α/β inducers and have surprisingly been shown to activate IFN-α/β-independent IFN-stimulated gene (ISG) expression. Here, we show that in Hantaan virus (HTNV)-infected human epithelial A549 cells, induction of IFN-λ1 preceded induction of MxA and IFN-β by 12 and 24 h, respectively, and IFN-α was not induced at all. Furthermore, induction of IFN-λ1 and MxA was observed in HTNV-infected African green monkey epithelial Vero E6 cells, a cell line that cannot produce type I IFNs, clearly showing that HTNV can induce IFN-λ1 and ISGs in the complete absence of IFN-α/β. In HTNV-infected human fibroblast MRC-5 cells, which lack the IFN-λ receptor, induction of MxA coincided in time with IFN-β-induction. UV-inactivated HTNV did not induce any IFNs or MxA in any cell line, showing that activation of IFN-λ1 is dependent on replicating virus. Induction of both IFN-β and IFN-λ1 in A549 cells after poly(I:C)-stimulation was strongly inhibited in HTNV-infected cells, suggesting that HTNV can inhibit signaling pathways used to simultaneously activate types I and III IFNs. In conclusion, we show that HTNV can cause type I IFN-independent IFN-λ1 induction and IFN-λ1-specific ISG induction. Importantly, the results suggest the existence of specific signaling pathways that induce IFN-λ1 without simultaneous type I IFN induction during virus infection. Copyright © 2010, American Society for Microbiology. All Rights Reserved.
Andersson A.F.,Uppsala University |
Andersson A.F.,Swedish Institute for Infectious Disease Control |
Riemann L.,Linnaeus University |
Bertilsson S.,Uppsala University
ISME Journal | Year: 2010
Variation in traits causes bacterial populations to respond in contrasting ways to environmental drivers. Learning about this will help us understand the ecology of individual populations in complex ecosystems. We used 454 pyrosequencing of the hypervariable region V6 of the 16S rRNA gene to study seasonal dynamics in Baltic Sea bacterioplankton communities, and link community and population changes to biological and chemical factors. Surface samples were collected from May to October 2003 and in May 2004 at the Landsort Deep in the central Baltic Sea Proper. The analysis rendered, on average, 20 200 sequence reads for each of the eight samples analyzed, providing the first detailed description of Baltic Sea bacterial communities. Community composition varied dramatically over time, supporting the idea of strong temporal shifts in bacterioplankton assemblages, and clustered according to season (including two May samples from consecutive years), suggesting repeatable seasonal succession. Overall, community change was most highly correlated with change in phosphorus concentration and temperature. Individual bacterial populations were also identified that tightly co-varied with different Cyanobacteria populations. Comparing the abundance profiles of operational taxonomic units at different phylogenetic distances revealed a weak but significant negative correlation between abundance profile similarity and genetic distance, potentially reflecting habitat filtering of evolutionarily conserved functional traits in the studied bacterioplankton.
Noren T.,Örebro University |
Alriksson I.,Örebro University |
Andersson J.,Örebro University |
Akerlund T.,Swedish Institute for Infectious Disease Control |
Unemo M.,Örebro University
Journal of Clinical Microbiology | Year: 2011
Compared to the composite gold standard cytotoxin B assay and toxigenic culture, the loop-mediated isothermal amplification (LAMP) test for Clostridium difficile had a sensitivity and specificity of 98%, positive predictive value of 92%, and negative predictive value of >99%. A one-hour turnaround time for the LAMP test provides rapid diagnosis and cost savings. Copyright © 2011, American Society for Microbiology. All Rights Reserved.
Lundstrom J.,Swedish Institute for Infectious Disease Control
PLoS neglected tropical diseases | Year: 2010
Neurocysticercosis is a disease caused by the oral ingestion of eggs from the human parasitic worm Taenia solium. Although drugs are available they are controversial because of the side effects and poor efficiency. An expressed sequence tag (EST) library is a method used to describe the gene expression profile and sequence of mRNA from a specific organism and stage. Such information can be used in order to find new targets for the development of drugs and to get a better understanding of the parasite biology. Here an EST library consisting of 5760 sequences from the pig cysticerca stage has been constructed. In the library 1650 unique sequences were found and of these, 845 sequences (52%) were novel to T. solium and not identified within other EST libraries. Furthermore, 918 sequences (55%) were of unknown function. Amongst the 25 most frequently expressed sequences 6 had no relevant similarity to other sequences found in the Genbank NR DNA database. A prediction of putative signal peptides was also performed and 4 among the 25 were found to be predicted with a signal peptide. Proposed vaccine and diagnostic targets T24, Tsol18/HP6 and Tso31d could also be identified among the 25 most frequently expressed. An EST library has been produced from pig cysticerca and analyzed. More than half of the different ESTs sequenced contained a sequence with no suggested function and 845 novel EST sequences have been identified. The library increases the knowledge about what genes are expressed and to what level. It can also be used to study different areas of research such as drug and diagnostic development together with parasite fitness via e.g. immune modulation.
Hulth A.,Swedish Institute for Infectious Disease Control
Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin | Year: 2010
This paper discusses computer-supported outbreak detection using routine surveillance data, as implemented at six institutes for infectious disease control in five European countries. We give an overview of the systems used at the Statens Serum Institut (Denmark), Health Protection Agency (England, Wales and Northern Ireland), Robert Koch Institute (Germany), Governmental Institute of Public Health of Lower Saxony (Germany), National Institute for Public Health and the Environment (the Netherlands) and Swedish Institute for Infectious Disease Control (Sweden). Despite the usefulness of the algorithms or the outbreak detection procedure itself, all institutes have experienced certain limitations of the systems. The paper therefore concludes with a list of recommendations for institutes planning to introduce computer-supported outbreak detection, based on experiences on the practical usage of the systems. This list--which concerns usability, standard operating procedures and evaluation--might also inspire improvements of systems in use today.
Hulth A.,Swedish Institute for Infectious Disease Control |
Rydevik G.,Swedish Institute for Infectious Disease Control
BMC Public Health | Year: 2011
Background: The assumption behind the presented work is that the information people search for on the internet reflects the disease status in society. By having access to this source of information, epidemiologists can get a valuable complement to the traditional surveillance and potentially get new and timely epidemiological insights. For this purpose, the Swedish Institute for Infectious Disease Control collaborates with a medical web site in Sweden. Methods. We built an application consisting of two conceptual parts. One part allows for trends, based on user specified requests, to be extracted from anonymous web query data from a Swedish medical web site. The second conceptual part permits tailored analyses of particular diseases, where more complex statistical methods are applied to the data. To evaluate the epidemiological relevance of the output, we compared Google search data and search data from the medical web site. Results: In the paper, we give concrete examples of the output from the web query-based system. We also present results from the comparison between data from the search engine Google and search data from the national medical web site. Conclusions: The application is in regular use at the Swedish Institute for Infectious Disease Control. A system based on web queries is flexible in that it can be adapted to any disease; we get information on other individuals than those who seek medical care; and the data do not suffer from reporting delays. Although Google data are based on a substantially larger search volume, search patterns obtained from the medical web site may still convey more information from an epidemiological perspective. Furthermore we can see advantages with having full access to the raw data. © 2011 Hulth and Rydevik; licensee BioMed Central Ltd.
Akerlund T.,Swedish Institute for Infectious Disease Control
Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin | Year: 2011
We report the results of two nationwide surveillance studies of Clostridium difficile infection conducted during 2008 and 2009 in Sweden. The first study aimed to identify and quantify the proportion of C. difficile isolates with decreased susceptibility to moxifloxacin, particularly those of PCR-ribotype 027. From December 2007 to September 2008, 20 of 28 regional laboratories sent 585 isolates to the Swedish Institute for Infectious Disease Control for typing. A majority of the isolates (454 of 585; 78%) belonged to four PCR ribotypes (012, SE37, 017 and 046), all clustered in geographical regions. Only two type 027 isolates were found, both from the same patient. In the second study, involving all 28 regional laboratories, all consecutive C. difficile isolates collected during two time periods in 2009 (n=364) were typed and tested for susceptibility to clindamycin, erythromycin, moxifloxacin, metronidazole and vancomycin. The three most common PCR ribotypes were SE21, 001 and 020 (22% of all isolates). Types 012, 017, and 046 were geographically clustered and associated with decreased susceptibility to moxifloxacin, clindamycin and erythromcin. The extent of moxifloxacin prescription was highly variable among counties, indicating a need for careful monitoring of prescription rates to follow its role in C. difficile epidemiology.