Francisella tularansis holarctica : en bakteries underliga vatten- och myggassociation i Sverige

Francisella tularensis, the causative agent of the zoonotic disease tularaemia, is highly contagious and potentially fatal for a wide range of wildlife species of the northern hemisphere, also humans. Although recognized as a pathogen for over 100 years, much still remains to be elucidated concerning the ecology and transmission of the bacterium, hence this literature overview aims at compiling data regarding the aquatic association and the role of mosquitoes in transmission of Francisella tularensis subspecies holartica, the sole subspecies in Sweden. While a linkage between the bacterium and natural waters stands beyond dispute, there is no consensus in the literature concerning its potential as a reservoir. However, two prevailing theories can be distinguished; one proposes the water association being mammaldependent and thus merely the result of contamination from semi-aquatic mammals living in close vicinity to the water source. The other, quite contrary, suggests mammal-independence and hence that water, possibly in association with protozoa, serves as an environmental reservoir for the bacterium. Regarding transmission of the infection in Sweden, it is assumed to be mediated by mosquitoes, yet their precise role and acquisition of bacteria is not well characterized. Again, two possibilities prevail. On the one hand, mosquitoes have been proposed to acquire the bacterium while feeding on infected animals and, on the other hand, already at their larval stages. Although no agreement is reached in literature, the involvement of larvae would inevitably bridge the gap between the aquatic and terrestrial cycle of the bacterium, especially when considering that mosquito invariably feed on protozoa as larvae in floodwater. Future determination of the natural reservoir of Francisella tularensis subspecies holarctica, as well as its relationship with mosquitoes, will shed new light upon its complex life cycle and thus significantly aid in prediction and prevention of new outbreaks.Francisella tularensis, en zoonotisk bakterie spridd över norra halvklotet, ger upphov till den smittsamma och potentiellt dödliga pestsjukdomen tularemi. Bakterien upptäcktes för över 100 år sedan, men trots detta kvarstår flertalet kunskapsluckor angående dess komplexa livscykel, vilken involverar såväl land- och vattenlevande djur som flertalet vektorer. Syftet med denna litteraturöversikt är att undersöka möjligheten till en eventuell vattenassocierad reservoar för Francisella tularensis holarctica, den enda existerande underarten i Sverige, samt myggors roll som smittspridare. Att bakterien är starkt korrelerad till vattenmiljöer är sedan länge känt, dock råder idag ingen konsensus angående vattnets potential som reservoar för bakterien, istället tycks två huvudsakliga teorier föreligga: Bakteriens förekomst i vattendrag förklaras, å ena sidan, vara en följd av kontamination och således helt beroende av frekvent tillförsel från akvatiska däggdjur, medan den, å andra sidan, tycks indikera en självständig reservoar, oberoende av däggdjur men möjligtvis kopplad till protozoer. Båda teorierna har såväl styrkor som svagheter gällande att förklara Francisella tularensis holarcticas epidemiologi och ekologi, och det verkar därmed rimligt att anta att de båda är av vikt i naturen men under olika förutsättningar. Angående myggors betydelse för spridning av tularemi är de sedan länge ansedda de viktigaste vektorerna i Sverige, dock råder delade meningar om hur de infekteras. Traditionellt antas de uppta bakterien vid födosök hos smittade värddjur medan ny forskning pekar på möjlighet till infektion redan som mygglarver. En sådan inkorporering av bakterien i myggans tidiga vattenlevande livsstadier innebär onekligen en önskvärd sammanlänkning av patogenens akvatiska livscykel med dess terrestriska värddjur. Ett fastställande av Francisella tularensis holarcticas naturliga reservoar, eller reservoarer, samt en ökad förståelse för myggors roll som bärare och spridare av bakterien är av största vikt för att förutsäga och förhindra framtida epidemier och epizootier

Bacillus anthracis hemliga liv

Bacillus anthracis is the causative agent of anthrax, a serious and globally distributed zoonosis affecting a wide range of wild and domestic animals, invariably also humans. However, although known to humans since biblical times, much remains to be elucidated concerning the ecology and transmission of this bacterium. Of particular interest is the Bacillus anthracis spore, the uptake of which is the predominant way to contract anthrax and which is legendary for its resilience in the environment and thus crucial for persistence and spread of the disease. Hence, the aim of this study is to review the natural transmission of Bacillus anthracis and investigate potential means by which soil persisting Bacillus anthracis spores reach concentrations sufficient to infect susceptible hosts. When reviewing the literature, three different theories can be distinguished. Firstly, “the incubator area” hypothesis suggests that favourable soil factors, possibly in association with amoebas, may constitute an environment supporting repeated spore-bacterium-spore cycling, thus increasing the local amount of spores. Secondly, water runoff from heavy rains or flooding has been proposed to collect spores and dispose them in closely restricted sites, thus creating “concentrator areas” with locally high amounts of spores. Lastly, the outermost layer of the spore, the exosporium, is proposed to tie spores to the environment where they were first shed and hence maintain infectious spore concentrations at a particular site. Considering that these theories all have their agreements and disagreements with the ecology and epidemiology of anthrax, it is reasonable to assume that all three exert an impact on spore concentrations, possibly at different degrees at various sites and regions. Howsoever, the ecology of Bacillus anthracis requires further research to fully understand the mechanism responsible for transmission and spread of anthrax. Only then can efficient methods for eradication of the disease from contaminated fields, and hence reducing the risk of future epidemics, be developed.Bacillus anthracis är en zoonotisk bakterie som orsakar den allvarliga och globalt förekommande sjukdomen anthrax, eller mjältbrand. Trots att både agens och sjukdom är välbekanta sedan antikens dagar och har varit i fokus för gedigen forskning i över 150 år, kvarstår häpnadsväckande många frågetecken. Av särskilt intresse är Bacillus anthracis alternerande livscykel mellan vegetativ, replikerande cell och metaboliskt vilande, men fortfarande infektiös, spor. Då sporerna har en närmast legendarisk motståndskraft mot yttre omgivningsfaktorer kan de kvarstå i miljön under mycket lång tid, och således upprätthålla ett infektiöst fokus av Bacillus anthracis i jordmånen, från vilket nya mottagliga individer kan infekteras. Då anthrax är en sjukdom som huvudsakligen smittar via sporer och har en hög infektionsdos är syftet med denna litteraturöversikt följaktligen att utröna hur infektiösa nivåer av sporer bildas och bibehållas i omgivningen, samt undersöka möjliga spridningsvägar för nämnda sporer. I litteraturen framträder tre huvudsakliga teorier angående hur sporer koncentreras: För det första, i den så kallade ”incubator area”-hypotesen föreslås Bacillus anthracis sporer uppnå höga antal genom att självständigt, eller möjligtvis via amöbor, germinera, replikera och re-sporulera i miljön, dvs. utanför ett värddjur, under förutsättning att yttre faktorer är gynnsamma. Ett ytterligare alternativ förs fram i ”concentrator area”-teorin där Bacillus anthracis sporer tros följa med avrinningsvatten efter skyfall eller översvämningar för att ackumuleras i låglänta områden där höga lokala sporkoncentrationer således upprättas. Slutligen framförs möjligheten att Bacillus anthracis sporernas yttersta hölje, exosporium, binder sporerna till jordpartiklar och följaktligen kvarhålls de på det ställe där de först hamnar efter bildning. Under beaktande att alla tre teorier uppvisar både enigheter och motstridigheter med Bacillus anthracis epidemiologi och ekologi, är det rimligt att anta att de alla, var och en på sitt sätt, bidrar till att etablera och bibehålla infektiösa spormängder, troligtvis av varierande grad i olika miljöer och regioner. Dock kvarstår mycket forskning för att fullt kunna kartlägga Bacillus anthracis komplexa ekologi och därmed möjliggöra utvecklingen av effektiva metoder för sanering av sporkontaminerade områden och således förebygga framtida anthrax epidemier

Lower treatment intensity and poorer survival in metastatic colorectal cancer patients who live alone

BACKGROUND: Socioeconomic status (SES) and social support influences cancer survival. If SES and social support affects cancer treatment has not been thoroughly explored. METHODS: A cohort consisting of all patients who were initially diagnosed with or who developed metastatic colorectal cancer (mCRC, n=781) in three Scandinavian university hospitals from October 2003 to August 2006 was set up. Clinical and socioeconomic data were registered prospectively. RESULTS: Patients living alone more often had synchronous metastases at presentation and were less often treated with combination chemotherapy than those cohabitating (HR 0.19, 95% CI 0.04–0.85, P=0.03). Surgical removal of metastases was less common in patients living alone (HR 0.29, 95% CI 0.10–0.86, P=0.02) but more common among university-educated patients (HR 2.22, 95% CI 1.10–4.49, P=0.02). Smoking, being married and having children did not influence treatment or survival. Median survival was 7.7 months in patients living alone and 11.7 months in patients living with someone (P<0.001). Living alone remained a prognostic factor for survival after correction for age and comorbidity. CONCLUSION: Patients living alone received less combination chemotherapy and less secondary surgery. Living alone is a strong independent risk factor for poor survival in mCRC

Genetic structure, behaviour and invasion history of the Argentine ant supercolony in Australia

Biological invasions have significant ecological, evolutionary and economic consequences. Ants are exemplary invaders and their invasion success is frequently attributed to a shift in social structure between native and introduced populations. Here, we use a multidisciplinary approach to determine the social structure, origin and expansion of the invasive Argentine ant, Linepithema humile, in Australia by linking behavioural and genetic studies with indicators of dispersal pathways and propagule pressure. Behavioural assays revealed a complete absence of aggression within and between three cities – Melbourne, Adelaide and Perth – spanning 2700 km across Australia. Microsatellite analyses showed intracity genetic homogeneity and limited but significant intercity genetic differentiation. Exceptions were two Perth nests that likely represent independent translocations from Adelaide. These patterns suggest efficient local gene flow with more limited jump dispersal via transport corridors between cities. Microsatellite analyses of L. humile from potential source regions, combined with data from port interceptions, trade pathways and the timeline of spread within Australia, implicate the main European supercolony as the source of L. humile in Melbourne. Such an introduction probably then redistributed across Australia and spread to New Zealand to form an expansive Australasian supercolony

Factors Influencing Selection of Treatment for Colorectal Cancer Patients

In Sweden and elsewhere there is evidence of poorer cancer survival for patients of low socioeconomic status (SES), and in some settings differences in treatment by SES have been shown. The aim of this thesis was to explore factors which influence cancer treatment decisions, such as knowledge reaped from clinical trials, patient-related factors, and physician-related factors. In a register study of colorectal cancer, all stages, patients were stratified for SES-factors. Differences were seen with regards to clinical investigation, surgical and oncological treatment and survival, with the highly educated group being favored. Survival was better for highly educated patients in stages I, II and III but not in stage IV. In a Scandinavian cohort of newly metastasized colorectal cancer patients, recruitment to clinical trials was studied. Patients entering clinical trials had better performance status and fewer cancer symptoms than those who were treated with chemotherapy outside of a clinical trial. Median survival was 21.3 months for trial-patients and 15.2 months for those treated with chemotherapy outside a  trial. Those not treated with chemotherapy had a median survival of just 2.1 months. Patients in clinical trials are highly selected and conclusions drawn from studies cannot be applied to all patients. In the same cohort, treatment and survival were stratified for education, smoking and indicators of social structure. Highly educated patients did not have a survival advantage. Patients who lived alone were offered less combination chemotherapy and surgery of metastases than other patients and had 4 months shorter survival than those who lived with a spouse or child. In a fourth study, 20 Swedish gastrointestinal oncologists were interviewed on which factors they considered when deciding on oncological treatment. Oncologists feared chemotherapy complications due to lack of social support, and ordered less combination chemotherapy for patients living alone. Highly educated patients were seen as well-read and demanding, and giving in to these patients’ requests for treatment was regarded as a way of pleasing patients and relatives and of avoiding conflict

Challenges at Basic Military Training in relation to adult education : from an officer perspective

Den 1 juli 2010 avskaffades värnplikten i förmån för ett yrkesförsvar, varpå premisserna för utbildningen av soldater förändrades. Idag har män och kvinnor från 18 år möjlighet att genomföra s.k. Grundläggande Militär Utbildning (GMU) under tre månader på frivillig basis. De nya premisserna kan m.h.t. frivilligheten ställas i paritet med civil vuxenutbildning, där båda upplever exempelvis avhopp till följd av motivationsbrist. Syftet med studien är delvis att identifiera officerarnas upplevda utmaningar på GMU avseende rekryternas tidigare erfarenheter, motivation samt lärarrollen. Därtill syftar studien till att undersöka om de är desamma för civil vuxenutbildning. Intervjuer av åtta officerare har genomförts för att identifiera de utmaningar som föreligger på GMU, samt en komparativ analys mellan dessa utmaningar och bland annat Knowles andragogikteori, som i den här studien representerar utmaningarna för den civila vuxenutbildningen. Resultatet visar att det föreligger utmaningar på GMU som är desamma för civil vuxenutbildning, särskilt tydligt vad gäller elevens/rekrytens motivation, men å andra sidan visar resultatet på att det föreligger utmaningar på GMU som inte förekommer i samma omfattning som i vuxenutbildning, och vice versa.In July 2010 Sweden abolished conscription in favor of an all-volunteer military force, whereupon the prerequisites for the recruitment and training of soldiers changed. Today, men and women from the age of 18 can sign up for a so-called Basic Military Training (GMU) for three months on a voluntary basis. The new prerequisites can, with regard to voluntariness, be on par with civilian adult education, both of which are, e.g., experiencing drop-outs as a result of lack of motivation. The purpose of the study is partly to identify the officers’ perceived challenges at GMU regarding recruits earlier experience, motivation and the teacher’s role. In addition, the study aims to examine whether these challenges are the same as for the civilian adult education. Interviews of eight officers have been conducted to distinguish the challenges that exist at GMU, as well as a comparative analysis between these challenges and theory of adult learning, including Knowles’s andragogy model, which in this study represents challenges for the civilian adult education. The result shows that there are challenges at GMU that are the same as for the civilian adult education, particularly evident in terms of the motivation of the pupil/recruit, but on the other hand, the result shows that there are challenges at GMU that do not occur in the same extent as in adult education, and vice versa

Factors Influencing Selection of Treatment for Colorectal Cancer Patients

In Sweden and elsewhere there is evidence of poorer cancer survival for patients of low socioeconomic status (SES), and in some settings differences in treatment by SES have been shown. The aim of this thesis was to explore factors which influence cancer treatment decisions, such as knowledge reaped from clinical trials, patient-related factors, and physician-related factors. In a register study of colorectal cancer, all stages, patients were stratified for SES-factors. Differences were seen with regards to clinical investigation, surgical and oncological treatment and survival, with the highly educated group being favored. Survival was better for highly educated patients in stages I, II and III but not in stage IV. In a Scandinavian cohort of newly metastasized colorectal cancer patients, recruitment to clinical trials was studied. Patients entering clinical trials had better performance status and fewer cancer symptoms than those who were treated with chemotherapy outside of a clinical trial. Median survival was 21.3 months for trial-patients and 15.2 months for those treated with chemotherapy outside a  trial. Those not treated with chemotherapy had a median survival of just 2.1 months. Patients in clinical trials are highly selected and conclusions drawn from studies cannot be applied to all patients. In the same cohort, treatment and survival were stratified for education, smoking and indicators of social structure. Highly educated patients did not have a survival advantage. Patients who lived alone were offered less combination chemotherapy and surgery of metastases than other patients and had 4 months shorter survival than those who lived with a spouse or child. In a fourth study, 20 Swedish gastrointestinal oncologists were interviewed on which factors they considered when deciding on oncological treatment. Oncologists feared chemotherapy complications due to lack of social support, and ordered less combination chemotherapy for patients living alone. Highly educated patients were seen as well-read and demanding, and giving in to these patients’ requests for treatment was regarded as a way of pleasing patients and relatives and of avoiding conflict

Challenges at Basic Military Training in relation to adult education : from an officer perspective

Den 1 juli 2010 avskaffades värnplikten i förmån för ett yrkesförsvar, varpå premisserna för utbildningen av soldater förändrades. Idag har män och kvinnor från 18 år möjlighet att genomföra s.k. Grundläggande Militär Utbildning (GMU) under tre månader på frivillig basis. De nya premisserna kan m.h.t. frivilligheten ställas i paritet med civil vuxenutbildning, där båda upplever exempelvis avhopp till följd av motivationsbrist. Syftet med studien är delvis att identifiera officerarnas upplevda utmaningar på GMU avseende rekryternas tidigare erfarenheter, motivation samt lärarrollen. Därtill syftar studien till att undersöka om de är desamma för civil vuxenutbildning. Intervjuer av åtta officerare har genomförts för att identifiera de utmaningar som föreligger på GMU, samt en komparativ analys mellan dessa utmaningar och bland annat Knowles andragogikteori, som i den här studien representerar utmaningarna för den civila vuxenutbildningen. Resultatet visar att det föreligger utmaningar på GMU som är desamma för civil vuxenutbildning, särskilt tydligt vad gäller elevens/rekrytens motivation, men å andra sidan visar resultatet på att det föreligger utmaningar på GMU som inte förekommer i samma omfattning som i vuxenutbildning, och vice versa.In July 2010 Sweden abolished conscription in favor of an all-volunteer military force, whereupon the prerequisites for the recruitment and training of soldiers changed. Today, men and women from the age of 18 can sign up for a so-called Basic Military Training (GMU) for three months on a voluntary basis. The new prerequisites can, with regard to voluntariness, be on par with civilian adult education, both of which are, e.g., experiencing drop-outs as a result of lack of motivation. The purpose of the study is partly to identify the officers’ perceived challenges at GMU regarding recruits earlier experience, motivation and the teacher’s role. In addition, the study aims to examine whether these challenges are the same as for the civilian adult education. Interviews of eight officers have been conducted to distinguish the challenges that exist at GMU, as well as a comparative analysis between these challenges and theory of adult learning, including Knowles’s andragogy model, which in this study represents challenges for the civilian adult education. The result shows that there are challenges at GMU that are the same as for the civilian adult education, particularly evident in terms of the motivation of the pupil/recruit, but on the other hand, the result shows that there are challenges at GMU that do not occur in the same extent as in adult education, and vice versa