scholarly journals Population genomic evidence that human and animal infections in Africa come from the same populations of Dracunculus medinensis

2020 ◽  
Vol 14 (11) ◽  
pp. e0008623
Author(s):  
Caroline Durrant ◽  
Elizabeth A. Thiele ◽  
Nancy Holroyd ◽  
Stephen R. Doyle ◽  
Guillaume Sallé ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Host Species ◽  
Disease Transmission ◽  
Population Bottleneck ◽  
Guinea Worm ◽  
Control Programs ◽  
Population Genomic ◽  
Eradication Campaign ◽  
Almost All ◽  
Shed Light

Background Guinea worm–Dracunculus medinensis–was historically one of the major parasites of humans and has been known since antiquity. Now, Guinea worm is on the brink of eradication, as efforts to interrupt transmission have reduced the annual burden of disease from millions of infections per year in the 1980s to only 54 human cases reported globally in 2019. Despite the enormous success of eradication efforts to date, one complication has arisen. Over the last few years, hundreds of dogs have been found infected with this previously apparently anthroponotic parasite, almost all in Chad. Moreover, the relative numbers of infections in humans and dogs suggests that dogs are currently the principal reservoir on infection and key to maintaining transmission in that country. Principal findings In an effort to shed light on this peculiar epidemiology of Guinea worm in Chad, we have sequenced and compared the genomes of worms from dog, human and other animal infections. Confirming previous work with other molecular markers, we show that all of these worms are D. medinensis, and that the same population of worms are causing both infections, can confirm the suspected transmission between host species and detect signs of a population bottleneck due to the eradication efforts. The diversity of worms in Chad appears to exclude the possibility that there were no, or very few, worms present in the country during a 10-year absence of reported cases. Conclusions This work reinforces the importance of adequate surveillance of both human and dog populations in the Guinea worm eradication campaign and suggests that control programs aiming to interrupt disease transmission should stay aware of the possible emergence of unusual epidemiology as pathogens approach elimination.

scholarly journals Population genomic evidence that human and animal infections in Africa come from the same populations of Dracunculus medinensis

2019 ◽  
Author(s):  
Caroline Durrant ◽  
Elizabeth A. Thiele ◽  
Nancy Holroyd ◽  
Stephen R Doyle ◽  
Guillaume Sallé ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Burden Of Disease ◽  
Host Species ◽  
Population Bottleneck ◽  
Guinea Worm ◽  
Control Programs ◽  
Population Genomic ◽  
Eradication Campaign ◽  
Almost All ◽  
Shed Light

AbstractBackgroundGuinea worm – Dracunculus medinensis – was historically one of the major parasites of humans and has been known since antiquity. Now, Guinea worm is on the brink of eradication, as efforts to interrupt transmission have reduced the annual burden of disease from millions of infections per year in the 1980s to only 30 human cases reported globally last year. Despite the enormous success of eradication efforts to date, one complication has arisen. Over the last few years, hundreds of dogs have been found infected with this previously apparently anthroponotic parasite, almost all in Chad. Moreover, the relative numbers of infections in humans and dogs suggests that dogs may be key in maintaining transmission in that country.ResultsIn an effort to shed light on this peculiar epidemiology of Guinea worm in Chad, we have sequenced and compared the genomes of worms from dog, human and other animal infections. Confirming previous work with other molecular markers, we show that all of these worms are D. medinensis, and that the same population of worms are causing both infections, can confirm the suspected transmission between host species and detect signs of a population bottleneck due to the eradication efforts. The diversity of worms in Chad appears to exclude the possibility that there were no, or very few, worms present in the country during a 10-year absence of reported cases.ConclusionsThis work reinforces the importance of adequate surveillance of both human and dog populations in the Guinea worm eradication campaign and suggests that control programs should stay aware of the possible emergence of unusual epidemiology as they approach elimination.

scholarly journals Understanding mosquito host-choice behaviour: a new and low-cost method of identifying the sex of human hosts from mosquito blood meals

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Fiona Teltscher ◽  
Sophie Bouvaine ◽  
Gabriella Gibson ◽  
Paul Dyer ◽  
Jennifer Guest ◽  
...  
Keyword(s):  
Blood Meal ◽  
Host Species ◽  
Disease Transmission ◽  
Low Cost ◽  
Host Choice ◽  
Epidemiological Models ◽  
Choice Behaviour ◽  
Vector Borne ◽  
Transmission Models ◽  
Blood Meals

Abstract Background Mosquito-borne diseases are a global health problem, causing hundreds of thousands of deaths per year. Pathogens are transmitted by mosquitoes feeding on the blood of an infected host and then feeding on a new host. Monitoring mosquito host-choice behaviour can help in many aspects of vector-borne disease control. Currently, it is possible to determine the host species and an individual human host from the blood meal of a mosquito by using genotyping to match the blood profile of local inhabitants. Epidemiological models generally assume that mosquito biting behaviour is random; however, numerous studies have shown that certain characteristics, e.g. genetic makeup and skin microbiota, make some individuals more attractive to mosquitoes than others. Analysing blood meals and illuminating host-choice behaviour will help re-evaluate and optimise disease transmission models. Methods We describe a new blood meal assay that identifies the sex of the person that a mosquito has bitten. The amelogenin locus (AMEL), a sex marker located on both X and Y chromosomes, was amplified by polymerase chain reaction in DNA extracted from blood-fed Aedes aegypti and Anopheles coluzzii. Results AMEL could be successfully amplified up to 24 h after a blood meal in 100% of An. coluzzii and 96.6% of Ae. aegypti, revealing the sex of humans that were fed on by individual mosquitoes. Conclusions The method described here, developed using mosquitoes fed on volunteers, can be applied to field-caught mosquitoes to determine the host species and the biological sex of human hosts on which they have blood fed. Two important vector species were tested successfully in our laboratory experiments, demonstrating the potential of this technique to improve epidemiological models of vector-borne diseases. This viable and low-cost approach has the capacity to improve our understanding of vector-borne disease transmission, specifically gender differences in exposure and attractiveness to mosquitoes. The data gathered from field studies using our method can be used to shape new transmission models and aid in the implementation of more effective and targeted vector control strategies by enabling a better understanding of the drivers of vector-host interactions.

scholarly journals Coronavirus and Soft Law in Germany: Business as Usual?

2021 ◽  
pp. 1-17
Author(s):  
Matthias Knauff
Keyword(s):  
Legal Order ◽  
Soft Law ◽  
Constitutional Order ◽  
Binding Forms ◽  
Almost All ◽  
Business As Usual ◽  
Shed Light ◽  
Made In

In combating the coronavirus pandemic in Germany, soft law has played an important, albeit not a central, role. Its use basically corresponds to that of under “normal circumstances”. In accordance with the German constitutional order, almost all substantial decisions are made in a legally binding form. However, these are often prepared through or supplemented by soft law. This article shows that soft law has played an important role in fighting the pandemic and its effects in Germany, although there cannot be any doubt that legally binding forms of regulation have prevailed. At the same time, the current pandemic has shed light on the advantages and effects of soft law in the context of the German legal order.

Investigating Male Aedes aegypti (Diptera: Culicidae) Attraction to Different Oviposition Containers Using Various Configurations of the Sound Gravid Aedes Trap

2019 ◽  
Vol 57 (3) ◽  
pp. 957-961
Author(s):  
Kyran M Staunton ◽  
Barukh B Rohde ◽  
Michael Townsend ◽  
Jianyi Liu ◽  
Mark Desnoyer ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Zika Virus ◽  
Disease Transmission ◽  
Urban Landscape ◽  
Mosquito Control ◽  
Transmission Risk ◽  
Northern Australia ◽  
Control Programs ◽  
Male Dispersal ◽  
Olfactory Attractant

Abstract Aedes aegypti (Linnaeus), the primary vectors of the arboviruses dengue virus and Zika virus, continue to expand their global distributions. In efforts to better control such species, several mosquito control programs are investigating the efficacy of rearing and releasing millions of altered male Aedes throughout landscapes to reduce populations and disease transmission risk. Unfortunately, little is known about Ae. aegypti, especially male, dispersal behaviors within urban habitats. We deployed Sound-producing Gravid Aedes Traps (SGATs) in Cairns, northern Australia, to investigate male Ae. aegypti attraction to various oviposition container configurations. The traps were arranged to include: 1) water only, 2) organically infused water, 3) infused water and L3 larvae, 4) infused water and a human-scented lure, and lastly 5) no water or olfactory attractant (dry). Our data suggest that males were more attracted to SGATs representing active larval sites than potential larval sites, but were equally attracted to dry SGATs relative to those containing water and/or infusion. Additionally, we found that female Ae. aegypti were equally attracted to wet SGATs, with or without infusion, but not dry ones. These results suggest that male Ae. aegypti within northern Australia are more attracted to active larval sites and equally attracted to dry containers as wet or infused ones. Additionally, female Ae. aegypti are unlikely to enter dry containers. Such findings contribute to our understanding of potentially attractive features for local and released Ae. aegypti throughout the northern Australian urban landscape.

Mechanism of anteroposterior axis specification in vertebrates. Lessons from the amphibians

Development ◽  
1992 ◽  
Vol 114 (2) ◽  
pp. 285-302 ◽  
Author(s):  
J.M. Slack ◽  
D. Tannahill
Keyword(s):  
Molecular Markers ◽  
Expression Patterns ◽  
Signal Transduction Pathway ◽  
Homeobox Gene ◽  
Neural Induction ◽  
High Sensitivity ◽  
Neural Plate ◽  
Mesoderm Induction ◽  
Inducing Factors ◽  
Almost All

Interest in the problem of anteroposterior specification has quickened because of our near understanding of the mechanism in Drosophila and because of the homology of Antennapedia-like homeobox gene expression patterns in Drosophila and vertebrates. But vertebrates differ from Drosophila because of morphogenetic movements and interactions between tissue layers, both intimately associated with anteroposterior specification. The purpose of this article is to review classical findings and to enquire how far these have been confirmed, refuted or extended by modern work. The “pre-molecular” work suggests that there are several steps to the process: (i) Formation of anteroposterior pattern in mesoderm during gastrulation with posterior dominance. (ii) Regional specific induction of ectoderm to form neural plate. (iii) Reciprocal interactions from neural plate to mesoderm. (iv) Interactions within neural plate with posterior dominance. Unfortunately, almost all the observable markers are in the CNS rather than in the mesoderm where the initial specification is thought to occur. This has meant that the specification of the mesoderm has been assayed indirectly by transplantation methods such as the Einsteckung. New molecular markers now supplement morphological ones but they are still mainly in the CNS and not the mesoderm. A particular interest attaches to the genes of the Antp-like HOX clusters since these may not only be markers but actual coding factors for anteroposterior levels. We have a new understanding of mesoderm induction based on the discovery of activins and fibroblast growth factors (FGFs) as candidate inducing factors. These factors have later consequences for anteroposterior pattern with activin tending to induce anterior, and FGF posterior structures. Recent work on neural induction has implicated cAMP and protein kinase C (PKC) as elements of the signal transduction pathway and has provided new evidence for the importance of tangential neural induction. The regional specificity of neural induction has been reinvestigated using molecular markers and provides conclusions rather similar to the classical work. Defects in the axial pattern may be produced by retinoic acid but it remains unclear whether its effects are truly coordinate ones or are concentrated in certain regions of high sensitivity. In general the molecular studies have supported and reinforced the “pre-molecular ones”. Important questions still remain: (i) How much pattern is there in the mesoderm (how many states?) (ii) How is this pattern generated by the invaginating organizer? (iii) Is there one-to-one transmission of codings to the neural plate? (iv) What is the nature of the interactions within the neural plate? (v) Are the HOX cluster genes really the anteroposterior codings?

scholarly journals Evaluation the Pulmonary Tuberculosis Control Program with Strategy DOTS in Puskesmas Tanah Kalikedinding Surabaya

2014 ◽  
Vol 2 (2) ◽  
pp. 251
Author(s):  
Adistha Eka Noveyani ◽  
Santi Martini
Keyword(s):  
Pulmonary Tuberculosis ◽  
Health Center ◽  
Control Program ◽  
Tuberculosis Patient ◽  
Tuberculosis Control ◽  
Control Programs ◽  
Department Of Health ◽  
Inhibiting Factor ◽  
Rate Evaluation ◽  
Almost All

ABSTRACTStrategy DOTS is the tuberculosis control programs. The program has implemented in Tanah Kalikedinding Health Center and has expected to reach CDR ≥ 70% and SR ≥ 85%, which closely related to the management of health centers. This study aimed to evaluate the implementation of the DOTS program in health center whose the results associated with indicators of tuberculosis. This was a descriptive design study with the population was all pulmonary specialist, tuberculosis officers and laboratory personnel and pulmonary tuberculosis patients. The number of Tuberculosis patient respondents was 32 respondents. Samples were chosen using purposive sampling. Data collected by interview questionnaire and checklist. The variables were the finding case, the TB treatment, the enabling factor and inhibiting factor, recording and reporting, and result of tuberculosis indicators. This study resulted that CDR in 2013 was 112% already reached the national target ≥ 70%. This success related to the finding case almost all patients > 2 weeks of cought and all (100%) patients were examinated sputum and diagnosed according to the steps of tuberculosis diagnosis in Indonesia Department of Health guidelines. While SR in 2013 was 65.5% did not reach the target ≥ 85%. It was caused of there are patients who did not have a taking drug observer (PMO). All (100%) patients ever forgot taking anti tuberculosis drugs. Change in schedule of visit to the continuation phase be 2×/month caused patients to forget taking anti tuberculosis drugs. The enabling factor was counseling routinely by health care workers in health center. Inhibiting factor was distance to health center by majority (65,5%) patients were > 1 km. So they needed vehicle to go to the health center. Recording and reporting using electronic systems and being reported by online. So it is expected all TB patients were expected have a taking drug observer and optimizing the role of the a taking drug observer to increase success rate.Keywords: DOTS strategy, Case Detection Rate, Success Rate, evaluation,                     Tuberculosis

scholarly journals Incursion pathways of the Asian tiger mosquito (Aedes albopictus) into Australia contrast sharply with those of the yellow fever mosquito (Aedes aegypti)

2020 ◽  
Author(s):  
Thomas L Schmidt ◽  
Jessica Chung ◽  
Anthony R. van Rooyen ◽  
Angus Sly ◽  
Andrew R Weeks ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Aedes Albopictus ◽  
Species Differences ◽  
Invasive Disease ◽  
Disease Vectors ◽  
Pacific Region ◽  
Control Methods ◽  
Asian Tiger Mosquito ◽  
Control Programs ◽  
Asian Tiger

AbstractBACKGROUNDUnderstanding pest incursion pathways is critical for preventing new invasions and for stopping the transfer of alleles that reduce the efficacy of local control methods. The mosquitoes Aedes albopictus (Skuse) and Ae. aegypti (Linnaeus) are both highly invasive disease vectors, and through a series of ongoing international incursions are continuing to colonise new regions and spread insecticide resistance alleles among established populations. This study uses high-resolution molecular markers and a set of 241 reference genotypes to trace incursion pathways of Ae. albopictus into mainland Australia, where no successful invasions have yet been observed. We contrast these results with incursion pathways of Ae. aegypti, investigated previously.RESULTSAssignments successful identified China, Japan, Singapore and Taiwan as source locations. Incursion pathways of Ae. albopictus were entirely different to those of Ae. aegypti, despite broad sympatry of these species throughout the Indo-Pacific region. Incursions of Ae. albopictus appeared to have come predominantly along marine routes from key trading locations, while Ae. aegypti was mostly linked to aerial routes from tourism hotspots.CONCLUSIONThese results demonstrate how genomics can help decipher otherwise cryptic incursion pathways. The inclusion of reference genotypes from the Americas may help resolve some unsuccessful assignments. While many congeneric taxa will share common incursion pathways, this study highlights that this is not always the case, and incursion pathways of important taxa should be specifically investigated. Species differences in aerial and marine incursion rates may reflect the efficacy of ongoing control programs such as aircraft disinsection.

scholarly journals The Delay Measurement and Analysis of Unreachable Hosts of Internet

2022 ◽  
Author(s):  
Ali Gezer
Keyword(s):  
Trip Time ◽  
Internet Control ◽  
Delay Measurement ◽  
Measurement Results ◽  
Measurement And Analysis ◽  
Control Message ◽  
Almost All ◽  
Random Behaviour ◽  
Shed Light

Delay related metrics are significant quality of service criteria for the performance evaluation of networks. Almost all delay related measurement and analysis studies take into consideration the reachable sources of Internet. However, unreachable sources might also shed light upon some problems such as worm propagation. In this study, we carry out a delay measurement study of unreachable destinations and analyse the delay dynamics of unreachable nodes. 2. Internet Control Message Protocol (ICMP) destination unreachable Internet Control Message Protocol-Destination Unreachable (ICMP T3) packets are considered for the delay measurement according to their code types which shows network un reach ability, host un reach ability, port un reach ability, etc. Measurement results show that unreachable sources exhibit totally different delay behaviour compared to reachable IP hosts. A significant part of the unreachable hosts experiences extra 3 seconds Round Trip Time (RTT) delay compared to accessible hosts mostly due to host un reach ability. It is also seen that, approximately 79% of destination un reach ability causes from host un reach ability. Obtained Hurst parameter estimation results reveal that unreachable host RTTs show lower Hurst degree compared to reachable hosts which is approximately a random behaviour. Unreachable sources exhibit totally different distributional characteristic compared to accessible ones which is best fitted with Phased Bi-Exponential distribution.

Lessons in French

2021 ◽  
pp. 74-99
Author(s):  
Alison Rice
Keyword(s):  
Women Writers ◽  
French Literature ◽  
Mother Tongue ◽  
Literary Creation ◽  
Initial Exposure ◽  
Conscious Choice ◽  
History Of ◽  
New Form ◽  
Almost All ◽  
Shed Light

None of the writers in my study can call French, without hesitation and qualification, a mother tongue. Some of them didn’t start studying the language until they arrived in Paris in their twenties and grappled with learning a new form of expression at a relatively late age. When they recall their initial exposure to this foreign tongue, they describe a fascinating apprenticeship involving dictionaries and renowned works of French literature, and they often shed light on the distinction between oral and written competence in their experience. It is crucial to note that even those authors who have long been fluent in French underscore their non-native relationship to it. Chapter 3 addresses the approaches of these worldwide women writers to French and examines their inventive literary publications in this tongue. It is sensitive to the history of this language and its inextricable connection to a colonial past that many of these writers experienced or became aware of in their homeland. It also focuses on the reality that, for almost all of these authors, this is not the only tongue with which they are familiar. For multilingual individuals, selecting French as their language of literary creation is often the result of a conscious choice motivated by a particular affinity. What comes through in their reflections is most often a passion for this language and a confirmation of the freedom it affords them, as well as an affirmation of its inimitable music that makes it especially well-suited for creative compositions.

Epidemiology and optimal foraging: modelling the ideal free distribution of insect vectors

Parasitology ◽  
2000 ◽  
Vol 120 (3) ◽  
pp. 319-327 ◽  
Author(s):  
D. W. KELLY ◽  
C. E. THOMPSON
Keyword(s):  
Host Species ◽  
Disease Transmission ◽  
Ideal Free Distribution ◽  
Host Population ◽  
Control Effort ◽  
Susceptible Host ◽  
Vector Density ◽  
Free Distribution ◽  
Blood Sucking ◽  
Ideal Free

Existing models of the basic case reproduction number (R0) for vector-borne diseases assume (i) that the distribution of vectors over the susceptible host species is homogenous and (ii) that the biting preference for the susceptible host species rather than other potential hosts is a constant. Empirical evidence contradicts both assumptions, with important consequences for disease transmission. In this paper we develop an Ideal Free Distribution (IFD) model of host choice by blood-sucking insects, predicated on the argument that vectors must have evolved to choose the least defensive hosts in order to maximize their feeding success. From a re-analysis of existing data, we demonstrate that the interference constant, m, of the IFD can vary between host species. As a result, the predicted distribution of insects over hosts has 2 desirable and intuitively plausible behaviours: that it is heterogeneous both within and between host species; and that the intensity of heterogeneity varies with host and vector density. When the IFD model is incorporated into R0, the relationship with the vector: host ratio becomes non-linear. If correct, the IFD could add considerable realism to models which seek to predict the effect of these ecological parameters on disease transmission as they vary naturally (e.g. through seasonality in vector density or host population movement) or as a consequence of artificial manipulation (e.g. zooprophylaxis, vector control). It raises the possibility of targeting transmission hot spots with greater accuracy and concomitant reduction in control effort. The robustness of the model to simplifying assumptions is discussed.

Sign in / Sign up

Export Citation Format

Share Document