The population structure of Borrelia lusitaniae Is reflected by a population division of its Ixodes Vector

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).Populations of vector-borne pathogens are shaped by the distribution and movement of vector and reservoir hosts. To study what impact host and vector association have on tick-borne pathogens, we investigated the population structure of Borrelia lusitaniae using multilocus sequence typing (MLST). Novel sequences were acquired from questing ticks collected in multiple North African and European locations and were supplemented by publicly available sequences at the Borrelia Pubmlst database (accessed on 11 February 2020). Population structure of B. lusitaniae was inferred using clustering and network analyses. Maximum likelihood phylogenies for two molecular tick markers (the mitochondrial 16S rRNA locus and a nuclear locus, Tick-receptor of outer surface protein A, trospA) were used to confirm the morphological species identification of collected ticks. Our results confirmed that B. lusitaniae does indeed form two distinguishable populations: one containing mostly European samples and the other mostly Portuguese and North African samples. Of interest, Portuguese samples clustered largely based on being from north (European) or south (North African) of the river Targus. As two different Ixodes species (i.e., I. ricinus and I. inopinatus) may vector Borrelia in these regions, reference samples were included for I. inopinatus but did not form monophyletic clades in either tree, suggesting some misidentification. Even so, the trospA phylogeny showed a monophyletic clade containing tick samples from Northern Africa and Portugal south of the river Tagus suggesting a population division in Ixodes on this locus. The pattern mirrored the clustering of B. lusitaniae samples, suggesting a potential co-evolution between tick and Borrelia populations that deserve further investigation.This research was financially supported by the Slovak Research and Development Agency (grant number APVV-16-0463), by the Fundação para a Ciência e a Tecnologia by the transitory norm contract DL57/2016/CP1370/CT89 to Ana Cláudia Norte and MARE (MARE-UID/MAR/04292/2020), and by the National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal. The National Reference Center for Borrelia was supported by the Robert-Koch Institute, Berlin, Germany.info:eu-repo/semantics/publishedVersio

Additional evidence on serological correlates of protection against measles: An observational cohort study among once vaccinated children exposed to measles

To assess correlates of protection against measles and against subclinical measles virus (MV) infection, we recruited once-vaccinated children from geographic regions associated with increased MV circulation and/or at schools with low vaccination coverage in the Netherlands. Paired blood samples were collected shortly after onset of the measles outbreak and after the outbreak. A questionnaire was used to document the likelihood of exposure to MV and occurrence of measles-like symptoms. All blood samples were tested for MV-specific antibodies with five different assays. Correlates of protection were assessed by considering the lowest neutralizing antibody levels in children without MV infection, and by ROC analyses. Among 91 participants, two seronegative children (2%) developed measles, and an additional 19 (23%) experienced subclinical MV infection. The correlate of protection against measles was lower than 0.345 IU/mL. We observed a decreasing attack rate of subclinical MV infection with increasing levels of specific antibodies until 2.1 IU/mL, above which no subclinical MV infections were detected. The ROC analyses found a correlate of protection of 1.71 IU/mL (95% CI 1.01–2.11) for subclinical MV infection. Our correlates of protection were consistent with previous estimates. This information supports the analyses of serosurveys to detect immunity gaps that require targeted intervention strategies

Comparison of circulation patterns of mumps virus in the Netherlands and Spain (2015–2020)

BackgroundMumps is a viral infection mainly characterized by inflammation of the parotid glands. Despite of vaccination programs, infections among fully vaccinated populations were reported. The World Health Organization (WHO) recommends molecular surveillance of mumps based on sequencing of the small hydrophobic (SH) gene. The use of hypervariable non-coding regions (NCR) as additional molecular markers was proposed in multiple studies. Circulation of mumps virus (MuV) genotypes and variants in different European countries were described in the literature. From 2010 to 2020, mumps outbreaks caused by genotype G were described. However, this issue has not been analyzed from a wider geographical perspective. In the present study, sequence data from MuV detected in Spain and in The Netherlands during a period of 5  years (2015- March 2020) were analyzed to gain insights in the spatiotemporal spread of MuV at a larger geographical scale than in previous local studies.MethodsA total of 1,121 SH and 262 NCR between the Matrix and Fusion protein genes (MF-NCR) sequences from both countries were included in this study. Analysis of SH revealed 106 different haplotypes (set of identical sequences).ResultsOf them, seven showing extensive circulation were considered variants. All seven were detected in both countries in coincident temporal periods. A single MF-NCR haplotype was detected in 156 sequences (59.3% of total), and was shared by five of the seven SH variants, as well as three minor MF-NCR haplotypes. All SH variants and MF-NCR haplotypes shared by both countries were detected first in Spain.DiscussionOur results suggest a transmission way from south to north Europe. The higher incidence rate of mumps in Spain in spite of similar immunization coverage in both countries, could be associated with higher risk of MuV exportation. In conclusion, the present study provided novel insights into the circulation of MuV variants and haplotypes beyond the borders of single countries. In fact, the use of MF-NCR molecular tool allowed to reveal MuV transmission flows between The Netherlands and Spain. Similar studies including other (European) countries are needed to provide a broader view of the data presented in this study

The 2013-2014 measles outbreak in The Netherlands: New evidence on measles epidemiology and control

In Chapter 2, we described the measles outbreak of 2013/14 that occurred in The Netherlands. The outbreak took mainly place within the orthodox Protestant community. In total, 2700 measles cases, 181 hospitalisations and 1 death were reported. In Chapter 3, we assessed the actual burden of the 2013/14 measles outbreak by assessing the completeness of reporting. Given that 9% of cases were reported, the estimated total size of the 2013/14 outbreak approximated 31,400 measles cases. In Chapter 4, we assessed the severity and contagiousness of 2539 unvaccinated (94%), 121 once vaccinated (5%) and 16 (1%) at least twice-vaccinated measles cases. Compared with unvaccinated and once-vaccinated cases, twice-vaccinated cases were less severe and less infectious. Our findings support the recommendation of the WHO of a two-dose MMR vaccination schedule. In Chapters 5, 6, and 7, we discussed the uptake, effectiveness, and tolerability of an early MMR vaccination offered to infants between 6 and 14 months of age. The national vaccination register is individual-based and is therefore suitable for tailored interventions such as the administration of an early MMR to infants between 6-14 months of age who live in municipalities with low vaccination coverage (<90%). The vaccine uptake of invited infants was 57% (5800 out of 10,097 infants). The crude estimate of the early MMR vaccine effectiveness was estimated to be 94% (95%CI 79%-98%). However, when we, in contrary to previous studies, took into account of the different levels in exposure between the vaccinated and unvaccinated infants, the effectiveness decreased to 71% (95%CI -72%-95%). Administering the vaccine to infants of six months old was considered well-tolerated. Adverse events were similar or fewer than observed among 14 month-olds infants. In Chapter 8, we assessed the correlate of protection against measles and subclinical (asymptomatic) measles among once vaccinated children. The correlate of protection against measles was estimated to be below 0.345 IU/ml, and the correlate against subclinical measles was found to be 2.1 IU/ml. In Chapter 9, we reassessed the seroprevalence of cohort 1972-1990 using the plaque reduction neutralisation test (PRNT). The PRNT tests for measles-specific antibodies that can neutralise measles virus, in contrast to the MIA, which tests for the presence of measles-specific antibodies. Based on PRNT and MIA results, protective antibody levels of birth cohort 1972-1990 were 99% and 94%, respectively. We revealed that the vast majority of the remaining susceptible individuals was unvaccinated. In Chapter 10, we assessed the economic burden of the measles epidemic with a societal perspective. We estimated that the measles outbreak caused an economic burden of ≈€3.9 million. In Chapter 11, we estimated a reduction of 53% (95% credible interval: 45%, 60%) of the contact rate during school vacation using a transmission model. There was a shift from mainly local transmission during school term to mainly cross-regional transmission during school vacations. Despite a reduced contact rate during the school vacation, measles transmission was not stopped, which makes it unlikely that school closure is a possible effective control measure

Additional Evidence on Serological Correlates of Protection against Measles: An Observational Cohort Study among Once Vaccinated Children Exposed to Measles

To assess correlates of protection against measles and against subclinical measles virus (MV) infection, we recruited once-vaccinated children from geographic regions associated with increased MV circulation and/or at schools with low vaccination coverage in the Netherlands. Paired blood samples were collected shortly after onset of the measles outbreak and after the outbreak. A questionnaire was used to document the likelihood of exposure to MV and occurrence of measles-like symptoms. All blood samples were tested for MV-specific antibodies with five different assays. Correlates of protection were assessed by considering the lowest neutralizing antibody levels in children without MV infection, and by ROC analyses. Among 91 participants, two seronegative children (2%) developed measles, and an additional 19 (23%) experienced subclinical MV infection. The correlate of protection against measles was lower than 0.345 IU/mL. We observed a decreasing attack rate of subclinical MV infection with increasing levels of specific antibodies until 2.1 IU/mL, above which no subclinical MV infections were detected. The ROC analyses found a correlate of protection of 1.71 IU/mL (95% CI 1.01&ndash;2.11) for subclinical MV infection. Our correlates of protection were consistent with previous estimates. This information supports the analyses of serosurveys to detect immunity gaps that require targeted intervention strategies

Invloedslijnen voor platen: Ingenieurstool op basis van het balkjesmodel

In het vakgebied van mechanica vormen invloedslijnen een tool waarmee gemakkelijk maat-gevende krachten, momenten en verplaatsingen kunnen worden gevonden. Echter, deze invloedslijnen zijn alleen toepasbaar op balken (één-dimensionaal). Binnen de civiele sector zijn naast balken, ook platen een veelgebruikte constructievorm (twee-dimensionaal). Voor platen is echter geen equivalente methode beschikbaar als invloedslijnen die makkelijk en snel inzicht geeft in een constructie. Dit rapport focust op het ontwikkelen van een ingenieurstool waarmee gemakkelijk invloeds-lijnen voor platen kunnen worden bepaald. Er is een verbeterings- en ontwikkelingsslag gemaakt op het bachelor eindwerk van eerdere studenten die een model hebben ontwikkeld waarbij de plaat wordt geschematiseerd als een groot aantal verbonden balkjes. Dit model is verbeterd en getoetst aan de hand van modellen voor platen. Vervolgens is dit basismodel toegepast in vier modellen voor invloedslijnen. De modellen berekenen de invloedslijnen voor verplaatsingen, krachtsgrootheden volgens de brute kracht methode, krachtsgrootheden volgens de methode dummybelasting en de oplegreacties uit. Het model met de dummybelasting is de verbeterde versie van het model volgens de brute kracht methode, waarbij gebruikt wordt gemaakt van de methode van Muller-Breslau om snel de oplossing te bepalen. Deze invloedslijnen zijn getoetst aan de hand van oplossingen van Guyon &amp; Massonnet en Pucher. Er is een breed inzetbaar, snel en betrouwbare ingenieurstool gemaakt waarmee het gedrag van platen wordt benaderd en invloedslijnen kunnen worden bepaald. Het basismodel voldoet aan alle toetsen, echter ontstaan er fouten rond de randen in de oplossingen voor buigmomenten en dwarskracht door de modellering volgens het balkjesmodel. Het model voor invloedslijnen voldoet aan de meeste toetsen. Alleen bij de dwarskrachten zit er een fout in de oplossing, waardoor deze een factor twee tot vier afwijkt van de oplossing van Pucher. Doordat de plaat als een balkjesmodel wordt benaderd, ontstaat er een grillig effect dat voor fouten in de vergelijking met het plaatmodel zorgt. Dit effect kan nog beter bekeken worden om inzicht te krijgen in hoe het balkjesmodel de plaat het beste kan benaderen. Ook zal onderzocht moeten worden hoe het model het daadwerkelijk gedrag rond de belasting het beste kan benaderen. Er ontstaan in dit punt nu nog grote pieken, die afhankelijk zijn van de detaillering van het model. Als deze punten goed zijn uitgewerkt kan dit model worden gebruikt als basis voor een programma met een makkelijke interface waarmee studenten en/of ingenieurs in de dagelijkse praktijk snel inzicht kunnen krijgen in het gedrag van platen.Civil Engineerin

Buildable Design in Optimisation of Steel Skeletal Structures: A Comparison of Existing and New Methods for Finding the Best Solution with Low Diversity

In the design of steel structures, optimisation methods promise cheap, light and sustainable structures. However, the resulting designs tend to have a high diversity of profiles, making them unbuildable. Furthermore, the optimisation problem is mathematically complex, leading to a long and potentially unsolvable optimisation process. Grouping methods solve both issues by finding the optimum solution, for which the number of distinct profiles is limited. Multiple grouping methods exist in literature, and it is not known which is the best: the methods have not been applied on the same problems, and the computational effort has not been compared. This gap in literature leads to the following question: “Which method for grouping can find the lightest and cheapest steel structure with minimal computational effort?” To answer this question, a comparison of the existing grouping methods is made on their theoretical and numerical performance. The theoretical comparison comprises the size and properties of the search space, and the number of additional calculations. The numerical comparison consists of weight optimisation of eight benchmark problems. For each structure and method, the weight of the solution and corresponding computational effort is evaluated. Manually grouping of members, which is the most popular grouping method, relies on the engineer’s expertise and rules of thumb. This method requires no additional calculations but in general fails to find the optimum grouping for a light or cheap structure. Other existing methods include the geometry, axial force distribution or an ungrouped result in their grouping process, or adapt the optimisation problem. Of these methods, only the cardinality constraints method is guaranteed to potentially find the lightest grouped design, while reducing the search space for a small number of groups. However, it creates many local optima, which increases the complexity of the search space. In the aim of finding a grouping method which creates a simple and small search space and has low computational effort, the fully stressed combinatorial search method is proposed. In this method, the grouping is found by a combinatorial search, which evaluates the estimated weight or costs of a restricted set of groupings based on the weight per unit length of the members of a fully stressed design. Then, optimisation of a small and simple search space finds the corresponding optimum profiles. These steps are repeated, in which the fully stressed design uses the result of the previous optimisation as its reference design. The loop repeats until the grouping is unchanged, or the result diverges. In all numerical experiments, the new method gave results with a low weight, while it kept the computational effort to an acceptable level. It gave the lightest design for four out of eight problems and showed high certainty for converging to the lightest design in two problems. For the other two problems it performed second best. Conclusively, this method is the best available grouping method for steel structural optimisation. In case of cost optimisation, the new grouping method can efficiently find the optimum design including the optimum number of groups; the new method converges to cheaper design with less computations than in the case no grouping is applied. For a real-life case-study, the costs of a design were reduced with 7.3% compared to a manually grouped design and with 19.6% compared to the conventional design process. I suggest that further research focusses on further development of the new grouping method as proposed improvements can be made on the initial design, and the number of computations in the combinatorial search and fully stressed design. Moreover, the effectiveness of a suggested simplification of the new method should be investigated. This would allow application for engineers who are not able to apply a mathematical optimisation method. For practical application, incorporation of building codes and cost functions with a well-defined scope are desired. Finally, utilisation of the grouping methods in other applications is possible, but the performance of the methods should be evaluated per application.Related dataset 4TU.ResearchData http://doi.org/10.4121/uuid:4e32b29f-6647-4a36-9ea1-8931c88f886

Testwijzer voor professionals: leidraad testkeuze en testgebruik voor adviseurs in HRM, onderwijs en loopbaanbegeleiding.

Tests kunnen een waardevol hulpmiddel zijn bij loopbaanontwikkeling en carrièreplanning. Zij bieden de persoon zelfkennis en een confrontatie met de realiteit. Tests kunnen helpen bij het maken van goede, gefundeerde keuzen. Tests worden bij loopbaanbegeleiding echter verre van optimaal als hulpmiddel ingezet. Het komt voor dat een matige test wordt gebruikt, terwijl er betere beschikbaar zijn. Soms maakt men in het geheel geen gebruik van tests, omdat de professional de weg niet kent in de doolhof van (pseudo-)tests en testaanbieders. In de Testwijzer voor professionals worden 57 tests op het gebied van capaciteiten, interesses, persoonlijkheid, waarden en motivatie op praktische wijze beschreven. Per test is onder meer informatie opgenomen over doel, doelgroep, afnameduur, kosten, kwaliteit, wijze van afnemen en vereiste training of bevoegdheid. Loopbaanadviseurs, HRM-medewerkers, re-integratiecoaches, decanen en studieloopbaanbegeleiders kunnen zich op deze manier snel een beeld vormen van de tests die geschikt zouden kunnen zijn voor een bepaalde cliënt of loopbaanvraag

The reduction of measles transmission during school vacations.

Historically, measles incidence has shown clear seasonal patterns driven by the school calendar, but since the start of mass vaccination in developed countries there are only occasional outbreaks, which may have changed the effect of school vacations on transmission. In 2013-2014 a large measles epidemic took place in a low vaccination coverage area in The Netherlands, allowing us to quantify current-day measles transmission and the effect of school vacations

The reduction of measles transmission during school vacations.

Historically, measles incidence has shown clear seasonal patterns driven by the school calendar, but since the start of mass vaccination in developed countries there are only occasional outbreaks, which may have changed the effect of school vacations on transmission. In 2013-2014 a large measles epidemic took place in a low vaccination coverage area in The Netherlands, allowing us to quantify current-day measles transmission and the effect of school vacations