scholarly journals Phylogeography of Lassa Virus in Nigeria

2019 ◽  
Vol 93 (21) ◽  
Author(s):  
Deborah U. Ehichioya ◽  
Simon Dellicour ◽  
Meike Pahlmann ◽  
Toni Rieger ◽  
Lisa Oestereich ◽  
...  
Keyword(s):  
West Africa ◽  
Case Fatality ◽  
Hemorrhagic Fever ◽  
Lassa Fever ◽  
Future Research ◽  
Lassa Virus ◽  
Southeastern Part ◽  
Data Set ◽  
Content Type ◽  
Virus Strains

ABSTRACT Lassa virus is genetically diverse with several lineages circulating in West Africa. This study aimed at describing the sequence variability of Lassa virus across Nigeria and inferring its spatiotemporal evolution. We sequenced and isolated 77 Lassa virus strains from 16 Nigerian states. The final data set, including previous works, comprised metadata and sequences of 219 unique strains sampled between 1969 and 2018 in 22 states. Most of this data originated from Lassa fever patients diagnosed at Irrua Specialist Teaching Hospital, Edo State, Nigeria. The majority of sequences clustered with the main Nigerian lineages II and III, while a few sequences formed a new cluster related to Lassa virus strains from Hylomyscus pamfi. Within lineages II and III, seven and five sublineages, respectively, were distinguishable. Phylogeographic analysis suggests an origin of lineage II in the southeastern part of the country around Ebonyi State and a main vector of dispersal toward the west across the Niger River, through Anambra, Kogi, Delta, and Edo into Ondo State. The frontline of virus dispersal appears to be in Ondo. Minor vectors are directed northeast toward Taraba and Adamawa and south toward Imo and Rivers. Lineage III might have spread from northern Plateau State into Kaduna, Nasarawa, Federal Capital Territory, and Bauchi. One sublineage moved south and crossed the Benue River into Benue State. This study provides a geographic mapping of lineages and phylogenetic clusters in Nigeria at a higher resolution. In addition, we estimated the direction and time frame of virus dispersal in the country. IMPORTANCE Lassa virus is the causative agent of Lassa fever, a viral hemorrhagic fever with a case fatality rate of approximately 30% in Africa. Previous studies disclosed a geographical pattern in the distribution of Lassa virus strains and a westward movement of the virus across West Africa during evolution. Our study provides a deeper understanding of the geography of genetic lineages and sublineages of the virus in Nigeria. In addition, we modeled how the virus spread in the country. This knowledge allows us to predict into which geographical areas the virus might spread in the future and prioritize areas for Lassa fever surveillance. Our study not only aimed to generate Lassa virus sequences from across Nigeria but also to isolate and conserve the respective viruses for future research. Both isolates and sequences are important for the development and evaluation of medical countermeasures to treat and prevent Lassa fever, such as diagnostics, therapeutics, and vaccines.

scholarly journals Predicting the evolution of Lassa Virus endemic area and population at risk over the next decades

2021 ◽  
Author(s):  
Raphaëlle Klitting ◽  
Liana E. Kafetzopoulou ◽  
Wim Thiery ◽  
Gytis Dudas ◽  
Sophie Gryseels ◽  
...  
Keyword(s):  
At Risk ◽  
West Africa ◽  
Endemic Area ◽  
Hemorrhagic Fever ◽  
Lassa Fever ◽  
Environmental Data ◽  
World Health ◽  
Lassa Virus ◽  
Viral Genomes ◽  
Health Organization

AbstractLassa fever is listed among the diseases that pose the greatest risks to public health by the World Health Organization. This severe viral hemorrhagic fever is caused by Lassa virus, a zoonotic pathogen that repeatedly spills over to humans from its rodent reservoirs. It is currently not known how climate change, transformations in land use, and human population growth could affect the endemic area of this virus, currently limited to parts of West Africa. By exploring the environmental data associated with virus occurrence, we show how temperature, precipitation and the presence of pastures determine ecological suitability for virus circulation. We project that regions in Central and East Africa will likely become suitable for Lassa virus over the next decades and estimate that the total population living in areas suitable for Lassa virus may grow from about 100 million to 700 million by 2070. By analysing geotagged viral genomes, we find that in the event of Lassa virus being introduced into a new suitable region, its spread might remain spatially limited over the first decades. Our results highlight how the endemic area of Lassa virus may expand well beyond West Africa in the next decades due to human impact on the environment, putting hundreds of million more people at risk of infection.

scholarly journals Genome Sequence of Lassa Virus Isolated from the First Domestically Acquired Case in Germany

2016 ◽  
Vol 4 (5) ◽  
Author(s):  
Svenja Wolff ◽  
Tilman Schultze ◽  
Sarah Katharina Fehling ◽  
Jan Philipp Mengel ◽  
Gerrit Kann ◽  
...  
Keyword(s):  
West Africa ◽  
Genome Sequence ◽  
Treatment Options ◽  
Specific Treatment ◽  
Hemorrhagic Fever ◽  
Lassa Fever ◽  
Lassa Virus ◽  
First Case

Lassa virus (LASV) is a zoonotic, hemorrhagic fever-causing virus endemic in West Africa, for which no approved vaccines or specific treatment options exist. Here, we report the genome sequence of LASV isolated from the first case of acquired Lassa fever disease outside of Africa.

scholarly journals Lassa Virus Circulation in Small Mammal Populations in Bo District, Sierra Leone

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 28
Author(s):  
Umaru Bangura ◽  
Jacob Buanie ◽  
Joyce Lamin ◽  
Christopher Davis ◽  
Gédéon Ngiala Bongo ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Sierra Leone ◽  
Small Mammal ◽  
Hemorrhagic Fever ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Sierra Leonean ◽  
Bayesian Phylogenetic Analysis ◽  
Prevalent Species ◽  
Lineage Iv

Lassa fever is a viral hemorrhagic fever caused by the Lassa virus LASV, which was first isolated in the rodent Mastomys natalensis in 1974 in Kenema, Sierra Leone. As little is known about the abundance and the presence of LASV in rodents living in the Bo area, we carried out a small mammal longitudinal population survey. A standardized trapping session was performed in various habitats and seasons in six villages over two years (2014–2016) and samples collected were tested for arenavirus IgG and LASV. A Bayesian phylogenetic analysis was performed on sequences identified by PCR. A total of 1490 small mammals were collected, and 16 rodent species were identified, with M. natalensis (355, 24%) found to be the most prevalent species. Forty-one (2.8%) samples were IgG positive, and 31 of these were trapped in homes and 10 in surrounding vegetation. Twenty-nine of 41 seropositive rodents were M. natalensis. We detected four LASV by PCR in two villages, all found in M. natalensis. Phylogenetic analysis showed that the sequences were distributed within the Sierra Leonean clade within lineage IV, distinguishing a Bo sub-clade older than a Kenema sub-clade. Compared to other settings, we found a low abundance of M. natalensis and a low circulation of LASV in rodents in villages around Bo district.

Impact of business model innovations on SME’s innovativeness and performance

2019 ◽  
Vol 14 (4) ◽  
pp. 521-539 ◽  
Author(s):  
Rimantas Gatautis† ◽  
Egle Vaiciukynaite ◽  
Asta Tarute
Keyword(s):  
Business Model ◽  
Structural Equation ◽  
Positive Impact ◽  
Equation Modeling ◽  
Future Research ◽  
Data Set ◽  
Content Type ◽  
Innovation Activities ◽  
Organizational Inertia ◽  
Multiple Characteristics

Purpose Business model innovations (BMIs), their drivers and outcomes are attracting increasing attention in academic literature. However, previous studies have mainly focused on large companies, while knowledge of BMI in small-to-medium-sized enterprises (SMEs) is limited. Therefore, the purpose of this paper is to add new insights into how related BMI drivers, practices and outcomes are in relation to SMEs. Design/methodology/approach An extensive review of the existing literature was performed. Consequently, the relationships between BMI drivers, BMI practices and outcomes of BMI were developed as a conceptual framework. An empirical study was carried out. A structural equation modeling (SEM) procedure was used to empirically test the model using a quantitative data set of Lithuanian SMEs (n=73). Findings The study provides insights into the relations between BMI drivers, BMI practices and outcomes of BMI in SMEs. The findings of SEM, four drivers (innovation activities, strategic orientation, market and technology turbulence, respectively) are indicated to contribute to BMI of SMEs. In addition, the results proved that the implementation of BMI practices leads to strategic and architectural changes in firms and has a positive impact on SMEs performance and innovativeness. Research limitations/implications Empirical research is focused on a limited number of internal and external BMI drivers, which have an influence on BMI in SMEs from one geographical region. Consequently, there are many external and internal BMI drivers which also may have an influence on BMI in SMEs, such as industry life cycle, organizational inertia and leadership. Meanwhile, SMEs possess multiple characteristics, i.e. a phase of maturity, gender of CEO, firm size and industry; therefore, the aforesaid aspects are considered to be significant limitations. In addition, the importance of SMEs characteristics as mediators for the effects on a firm’s performance and innovativeness should be considered in future research avenues. Practical implications Findings of this research can be used by SME managers to better understand how firms might actively engage in BMI practices, what drivers lead to BMI and, in turn, affect their firm’s performance and innovativeness. SME managers should be encouraged to pay attention to strategic and architectural changes of BM that can contribute to enterprise performance and innovativeness. Originality/value This paper adds to the stream of BMI research by empirically exploring drivers and outcomes of BMI in SMEs. In addition, this paper fulfills research gaps proposed by Bouwman et al. (2018), Foss and Saebi (2017), Heikkilä, Bouwman and Heikkilä (2018) and Lambert and Davidson (2013), and enhances the current overall understanding of BMIs.

scholarly journals Determining Ancestry between Rodent- and Human-Derived Virus Sequences in Endemic Foci: Towards a More Integral Molecular Epidemiology of Lassa Fever within West Africa

Biology ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 26 ◽  
Author(s):  
Ayodeji Olayemi ◽  
Adetunji Samuel Adesina ◽  
Thomas Strecker ◽  
N’Faly Magassouba ◽  
Elisabeth Fichet-Calvet
Keyword(s):  
West Africa ◽  
Sierra Leone ◽  
Evolutionary History ◽  
Epidemiological Studies ◽  
Lassa Fever ◽  
Clinical Samples ◽  
Ecological Studies ◽  
Emergence Patterns ◽  
Genetic Sequences ◽  
Virus Strains

Lassa fever is a viral hemorrhagic illness responsible for thousands of human deaths in West Africa yearly. Rodents are known as natural reservoirs of the causative Lassa mammarenavirus (LASV) while humans are regarded as incidental, spill-over hosts. Analysis of genetic sequences continues to add to our understanding of the evolutionary history, emergence patterns, and the epidemiology of LASV. Hitherto, the source of data in such investigations has mainly comprised human clinical samples. Presently, a rise in the quantity of virus strains accessed through ecological studies over the last 15 years now allows us to explore how LASV sequences obtained from rodents might affect phylogenetic patterns. In this study, we phylogenetically compared LASV sequences obtained from both rodents and humans across West Africa, including those from two localities highly endemic for the disease: Ekpoma in Nigeria and Kenema in Sierra Leone. We performed a time-calibrated phylogeny, using a Bayesian analysis on 198 taxa, including 102 sequences from rodents and 96 from humans. Contrary to expectation, our results show that LASV strains detected in humans within these localities, even those sampled recently, are consistently ancient to those circulating in rodents in the same area. We discuss the possibilities connected to this preliminary outcome. We also propose modalities to guide more comprehensive comparisons of human and rodent data in LASV molecular epidemiological studies.

Audit roles and the review process: workpaper preparers’ and reviewers’ differing perspectives

2019 ◽  
Vol 34 (4) ◽  
pp. 438-461 ◽  
Author(s):  
Brandon Ater ◽  
Christine Gimbar ◽  
J. Gregory Jenkins ◽  
Gabriel Saucedo ◽  
Nicole S. Wright
Keyword(s):  
Review Process ◽  
Future Research ◽  
Senior Managers ◽  
Data Set ◽  
Accounting Firms ◽  
Content Type ◽  
Face To Face ◽  
Process Characteristics ◽  
Workpaper Review ◽  
The Face

Purpose This paper aims to examine the perceptions of auditor roles on the workpaper review process in current audit practice. Specifically, the paper investigates how an auditor’s defined role leads to perceived differences in what initiates the workpaper review process, the preferred methods for performing reviews and the stylization or framing of communicated review comments. Design/methodology/approach A survey was administered in which practicing auditors were asked about workpaper review process prompts, methods and preferences. The survey was completed by 215 auditors from each of the Big 4 accounting firms and one additional international firm. The final data set consists of quantitative and qualitative responses from 25 audit partners, 33 senior managers, 30 managers, 75 in-charge auditors/seniors and 52 staff auditors. Findings Findings indicate reviewers and preparers differ in their perceptions of the review process based on their defined roles. First, reviewers and preparers differ in their perspectives on which factors initiate the review process. Second, the majority of reviewers and preparers prefer face-to-face communication when discussing review notes. Reviewers, however, are more likely to believe the face-to-face method is an effective way to discuss review notes and to facilitate learning, whereas preparers prefer the method primarily because it reduces back-and-forth communication. Finally, reviewers believe they predominantly provide conclusion-based review notes, whereas preparers perceive review notes as having both conclusion- and documentation-based messages. Research limitations/implications This paper advances the academic literature by providing a unique perspective on the review process. Instead of investigating a single staff level, it examines the workpaper review process on a broader scale. By obtaining views from professionals across all levels, this work intends to inspire future research directed at reconciling differences and filling gaps in the review process literature. The finding that reviewers and preparers engage in role conformity that leads to incongruent perceptions of the review process should encourage the consideration of mechanisms, with the potential to be tested experimentally, by which to reconcile the incongruities. Practical implications Results support recent regulator concerns that there are breakdowns in the workpaper review process, and the findings provide some insight into why these breakdowns are occurring. Incongruent perceptions of review process characteristics may be the drivers of these identified regulatory concerns. Originality/value This is the first study to examine current workpaper review processes at the largest accounting firms from the perspective of both preparers and reviewers. From this unique data set, one key interpretation of the findings is that workpaper preparers do not appear to recognize a primary goal of the review process: to ensure that subordinates receive appropriate coaching, learning and development. However, workpaper reviewers do, in fact, attempt to support preparers and work to create a supportive team environment.

scholarly journals Tax increment financing and major league venues

2020 ◽  
Vol 10 (4) ◽  
pp. 495-517
Author(s):  
Robert Sroka
Keyword(s):  
Real Estate ◽  
Future Research ◽  
Real Estate Development ◽  
Tax Increment Financing ◽  
General Reference ◽  
Data Set ◽  
Content Type ◽  
Capital Costs ◽  
Major League ◽  
Sports Venues

PurposeThis article intends to shine a light on venue-related tax increment financing (TIF) through the first comprehensive inventory of its use at the major league level.Design/methodology/approachFor each 2018 venue in the five North American major leagues, data was collected on TIF contributions to direct venue capital costs as well as to projects using TIF to enable real estate development ancillary to a venue. Neighborhoods surrounding a venue were also assessed for the presence of a TIF district. With both the direct and ancillary elements, data was collected from government, industry, academic, mapping and media sources. A review of this data set and findings are followed by a discussion of implications and directions for future work.FindingsOver one-third of the TIF eligible permanent stadiums and arenas studied in the five major leagues have a direct or strong TIF connection. Direct TIF contributions to sports venues, as well as TIF use intended to generate real estate development around these venues, are most frequent and financially significant in arenas and soccer-specific stadiums. Additionally, arena and stadium projects using TIF often accompany ancillary real estate development.Originality/valueA primary purpose of this article is to provide a previously missing general reference resource to governments and citizens of jurisdictions considering facility TIF use on the scope, nature, extent and identity of TIF projects related to major league sports venues. More generally, the inventory and assessment of TIF use in professional sports venues offered by this article sets the stage for future research on associative relationships between TIF contributions and facility finance outcomes as well as the normative value of venue-related TIF.

Spatial analysis of Twitter sentiment and district-level housing prices

2019 ◽  
Vol 12 (2) ◽  
pp. 173-189
Author(s):  
Christopher Hannum ◽  
Kerem Yavuz Arslanli ◽  
Ali Furkan Kalay
Keyword(s):  
News Media ◽  
Housing Prices ◽  
District Level ◽  
Future Research ◽  
Scoring Method ◽  
Cross Sectional ◽  
Data Set ◽  
Content Type ◽  
Property Prices ◽  
Price Appreciation

Purpose Studies have shown a correlation and predictive impact of sentiment on asset prices, including Twitter sentiment on markets and individual stocks. This paper aims to determine whether there exists such a correlation between Twitter sentiment and property prices. Design/methodology/approach The authors construct district-level sentiment indices for every district of Istanbul using a dictionary-based polarity scoring method applied to a data set of 1.7 million original tweets that mention one or more of those districts. The authors apply a spatial lag model to estimate the relationship between Twitter sentiment regarding a district and housing prices or housing price appreciation in that district. Findings The findings indicate a significant but negative correlation between Twitter sentiment and property prices and price appreciation. However, the percentage of check-in tweets is found to be positively correlated with prices and price appreciation. Research limitations/implications The analysis is cross-sectional, and therefore, unable to answer the question of whether Twitter can Granger-cause changes in housing markets. Future research should focus on creation of a property-focused lexicon and panel analysis over a longer time horizon. Practical implications The findings suggest a role for Twitter-derived sentiment in predictive models for local variation in property prices as it can be observed in real time. Originality/value This is the first study to analyze the link between sentiment measures derived from Twitter, rather than surveys or news media, on property prices.

scholarly journals Differential Immune Responses to Hemorrhagic Fever-Causing Arenaviruses

Vaccines ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 138 ◽  
Author(s):  
Mantlo ◽  
Paessler ◽  
Huang
Keyword(s):  
Clinical Importance ◽  
Hemorrhagic Fever ◽  
Lassa Fever ◽  
Innate Immune ◽  
Host Immune System ◽  
Lassa Virus ◽  
Type I ◽  
Highly Pathogenic ◽  
The Family ◽  
Pro Inflammatory Cytokines

The family Arenaviridae contains several pathogens of major clinical importance. The Old World (OW) arenavirus Lassa virus is endemic in West Africa and is estimated to cause up to 300,000 infections each year. The New World (NW) arenaviruses Junín and Machupo periodically cause hemorrhagic fever outbreaks in South America. While these arenaviruses are highly pathogenic in humans, recent evidence indicates that pathogenic OW and NW arenaviruses interact with the host immune system differently, which may have differential impacts on viral pathogenesis. Severe Lassa fever cases are characterized by profound immunosuppression. In contrast, pathogenic NW arenavirus infections are accompanied by elevated levels of Type I interferon and pro-inflammatory cytokines. This review aims to summarize recent findings about interactions of these pathogenic arenaviruses with the innate immune machinery and the subsequent effects on adaptive immunity, which may inform the development of vaccines and therapeutics against arenavirus infections.

Skills and knowledge management in higher education: how service learning can contribute to social entrepreneurial competence development

2019 ◽  
Vol 23 (10) ◽  
pp. 1925-1948 ◽  
Author(s):  
Jantje Halberstadt ◽  
Jana-Michaela Timm ◽  
Sascha Kraus ◽  
Katherine Gundolf
Keyword(s):  
Service Learning ◽  
Social Entrepreneurship ◽  
Qualitative Content Analysis ◽  
Educational Practice ◽  
Future Research ◽  
Small Data ◽  
Learning Approaches ◽  
Structured Interviews ◽  
Data Set ◽  
Content Type

Purpose The purpose of this paper is to elaborate on how service learning approaches are able to foster social entrepreneurship competences. The aim of the paper is to formulate a framework of key competences for social entrepreneurship and to give first insights in how service learning actually has an impact on change in students’ set of competences. Design/methodology/approach This paper uses a mixed-methods approach combining qualitative data collectionmethods of learning diaries of the students and semi-structured interviews, including 40 master’s students studying at a German university in interdisciplinary learning settings and five instructors from the same universities. Analysis was carried out by means of qualitative content analysis. Findings This paper provides empirical insights about the competences that are being fostered by service learning. From these, a framework for social entrepreneurship competences is being derived. Research limitations/implications The set of competences should be further investigated, as it was derived out of a small data set. Therefore, researchers are encouraged to use the set of competences for social entrepreneurship as a basis for future research and on a longer-term perspective, which lead to substantial implications for educational practice. Practical implications This paper includes implications for new perspectives on service learning in the light of the development of a relevant framework for social entrepreneurship competence, having significant implications for educational practice in social entrepreneurship education. Originality/value With this paper, the authors fulfill the need of a framework of social entrepreneurship competences that serves as a foundation for educational practice and further research in the context of service learning and beyond.

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