Discovery of a single male Aedes aegypti (L.) in Merseyside, England

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Skeeter Buster: A Stochastic, Spatially Explicit Modeling Tool for Studying Aedes aegypti Population Replacement and Population Suppression Strategies

Dengue is a viral disease that affects approximately 50 million people annually, and is estimated to result in 12,500 fatalities. Dengue viruses are vectored by mosquitoes, predominantly by the species Aedes aegypti. Because there is currently no vaccine or specific treatment, the only available strategy to reduce dengue transmission is to control the populations of these mosquitoes. This can be achieved by traditional approaches such as insecticides, or by recently developed genetic methods that propose the release of mosquitoes genetically engineered to be unable to transmit dengue viruses. The expected outcome of different control strategies can be compared by simulating the population dynamics and genetics of mosquitoes at a given location. Development of optimal control strategies can then be guided by the modeling approach. To that end, we introduce a new modeling tool called Skeeter Buster. This model describes the dynamics and the genetics of Ae. aegypti populations at a very fine scale, simulating the contents of individual houses, and even the individual water-holding containers in which mosquito larvae reside. Skeeter Buster can be used to compare the predicted outcomes of multiple control strategies, traditional or genetic, making it an important tool in the fight against dengue

Changes over time in the effect of marital status on cancer survival

<p>Abstract</p> <p>Background</p> <p>Rates of all-cause and cause-specific mortality are higher among unmarried than married individuals. Cancer survival is also poorer in the unmarried population. Recently, some studies have found that the excess all-cause mortality of the unmarried has increased over time, and the same pattern has been shown for some specific causes of death. The objective of this study was to investigate whether there has been a similar change over time in marital status differences in cancer survival.</p> <p>Methods</p> <p>Discrete-time hazard regression models for cancer deaths among more than 440 000 women and men diagnosed with cancer 1970-2007 at age 30-89 were estimated, using register data encompassing the entire Norwegian population. More than 200 000 cancer deaths during over 2 million person-years of exposure were analyzed.</p> <p>Results</p> <p>The excess mortality of the never-married compared to the married has increased steadily for men, in particular the elderly. Among elderly women, the excess mortality of the never-married compared to the married has increased, and there are indications of an increasing excess mortality of the widowed. The excess mortality of divorced men and women, however, has been stable.</p> <p>Conclusions</p> <p>There is no obvious explanation for the increasing disadvantage among the never-married. It could be due to a relatively poorer general health at time of diagnosis, either because of a more protective effect of partnership in a society that may have become less cohesive or because of more positive selection into marriage. Alternatively, it could be related to increasing differentials with respect to treatment. Today's complex cancer therapy regimens may be more difficult for never-married to follow, and health care interventions directed and adapted more specifically to the broad subgroup of never-married patients might be warranted.</p

HLA Class I Restriction as a Possible Driving Force for Chikungunya Evolution

After two decades of quiescence, epidemic resurgence of Chikungunya fever (CHIKF) was reported in Africa, several islands in the Indian Ocean, South-East Asia and the Pacific causing unprecedented morbidity with some cases of fatality. Early phylogenetic analyses based on partial sequences of Chikungunya virus (CHIKV) have led to speculation that the virus behind recent epidemics may result in greater pathogenicity. To understand the reasons for these new epidemics, we first performed extensive analyses of existing CHIKV sequences from its introduction in 1952 to 2009. Our results revealed the existence of a continuous genotypic lineage, suggesting selective pressure is active in CHIKV evolution. We further showed that CHIKV is undergoing mild positive selection, and that site-specific mutations may be driven by cell-mediated immune pressure, with occasional changes that resulted in the loss of human leukocyte antigen (HLA) class I-restricting elements. These findings provide a basis to understand Chikungunya virus evolution and reveal the power of post-genomic analyses to understand CHIKV and other viral epidemiology. Such an approach is useful for studying the impact of host immunity on pathogen evolution, and may help identify appropriate antigens suitable for subunit vaccine formulations

New perspectives on evolutionary medicine: the relevance of microevolution for human health and disease

Evolutionary medicine (EM) is a growing field focusing on the evolutionary basis of human diseases and their changes through time. To date, the majority of EM studies have used pure theories of hominin macroevolution to explain the present-day state of human health. Here, we propose a different approach by addressing more empirical and health-oriented research concerning past, current and future microevolutionary changes of human structure, functions and pathologies. Studying generation-to-generation changes of human morphology that occurred in historical times, and still occur in present-day populations under the forces of evolution, helps to explain medical conditions and warns clinicians that their current practices may influence future humans. Also, analyzing historic tissue specimens such as mummies is crucial in order to address the molecular evolution of pathogens, of the human genome, and their coadaptations.Frank Jakobus Rühli and Maciej Henneber

Replication and active partition of integrative and conjugative elements (ICEs) of the SXT/R391 family : the line between ICEs and conjugative plasmids is getting thinner

Integrative and Conjugative Elements (ICEs) of the SXT/R391 family disseminate multidrug resistance among pathogenic Gammaproteobacteria such as Vibrio cholerae. SXT/R391 ICEs are mobile genetic elements that reside in the chromosome of their host and eventually self-transfer to other bacteria by conjugation. Conjugative transfer of SXT/R391 ICEs involves a transient extrachromosomal circular plasmid-like form that is thought to be the substrate for single-stranded DNA translocation to the recipient cell through the mating pore. This plasmid-like form is thought to be non-replicative and is consequently expected to be highly unstable. We report here that the ICE R391 of Providencia rettgeri is impervious to loss upon cell division. We have investigated the genetic determinants contributing to R391 stability. First, we found that a hipAB-like toxin/antitoxin system improves R391 stability as its deletion resulted in a tenfold increase of R391 loss. Because hipAB is not a conserved feature of SXT/R391 ICEs, we sought for alternative and conserved stabilization mechanisms. We found that conjugation itself does not stabilize R391 as deletion of traG, which abolishes conjugative transfer, did not influence the frequency of loss. However, deletion of either the relaxase-encoding gene traI or the origin of transfer (oriT) led to a dramatic increase of R391 loss correlated with a copy number decrease of its plasmid-like form. This observation suggests that replication initiated at oriT by TraI is essential not only for conjugative transfer but also for stabilization of SXT/R391 ICEs. Finally, we uncovered srpMRC, a conserved locus coding for two proteins distantly related to the type II (actin-type ATPase) parMRC partitioning system of plasmid R1. R391 and plasmid stabilization assays demonstrate that srpMRC is active and contributes to reducing R391 loss. While partitioning systems usually stabilizes low-copy plasmids, srpMRC is the first to be reported that stabilizes a family of ICEs

Sense of Coherence and Gambling: Exploring the Relationship Between Sense of Coherence, Gambling Behaviour and Gambling-Related Harm

Understanding why some people experience problems with gambling whilst others are able to restrict gambling to recreational levels is still largely unexplained. One potential explanation is through salutogenesis, which is a health promotion approach of understanding factors which move people towards health rather than disease. An important aspect of salutogenesis is sense of coherence. Individuals with stronger sense of coherence perceive their environment as comprehensible, manageable and meaningful. The present study examined the relationship of individuals’ sense of coherence on their gambling behaviour and experience of gambling related harm. This exploratory study utilised an archival dataset (n = 1236) from an online, cross sectional survey of people who had experienced negative consequences from gambling. In general, a stronger sense of coherence was related to lower problem gambling severity. When gambling behaviour was controlled for, sense of coherence was significantly related to the experience of individual gambling harms. A strong sense of coherence can be seen as a protective factor against problematic gambling behaviour, and subsequent gambling related harms. These findings support the value of both primary and tertiary prevention strategies that strengthen sense of coherence as a harm minimisation strategy. The present study demonstrates the potential value of, and provides clear direction for, considering sense of coherence in order to understand gambling-related issues.This study was funded by the Victorian Responsible Gambling Foundation, Grant VRGF1-13