scholarly journals Lassa fever: History, causes, effects, and reduction strategies

2020 ◽  
Vol 6 (2) ◽  
pp. 95-98
Author(s):  
Promise Tewogbola ◽  
Norah Aung
Keyword(s):  
Lassa Fever ◽  
Lassa Virus ◽  
Modus Operandi ◽  
The Past ◽  
Reduction Strategies ◽  
Primary Vector ◽  
Multimammate Rat

Lassa fever is a disease that is not well-known worldwide, particularly due to the inability of the multimammate rat, the primary vector of the Lassa virus, to breed in temperate regions. The aim of this review is to provide an overview of the disease and its modus operandi while also providing information about trends in the past decade, as well as proven strategies that have been used to manage its spread.

cccccImmunological screening of Lassa Virus among Health workers and Contacts of patients of Lassa fever in Ondo State

Immunobiology ◽  
2021 ◽  
pp. 152076
Author(s):  
Joseph Ojonugwa Shaibu ◽  
Olumuyiwa Babalola Salu ◽  
Olufemi Samuel Amoo ◽  
Ifeoma Idigbe ◽  
Adesola Zaidat Musa ◽  
...  
Keyword(s):  
Health Workers ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Ondo State

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.

scholarly journals Cognitive load reduction strategies in questionnaire design

2021 ◽  
pp. 147078532098679
Author(s):  
Kylie Brosnan ◽  
Bettina Grün ◽  
Sara Dolnicar
Keyword(s):  
Cognitive Load ◽  
Data Quality ◽  
Survey Data ◽  
Task Difficulty ◽  
Questionnaire Design ◽  
Load Reduction ◽  
The Past ◽  
Load Theory ◽  
Learning Tasks ◽  
Reduction Strategies

Survey data quality suffers when respondents have difficulty completing complex tasks in questionnaires. Cognitive load theory informed the development of strategies for educators to reduce the cognitive load of learning tasks. We investigate whether these cognitive load reduction strategies can be used in questionnaire design to reduce task difficulty and, in so doing, improve survey data quality. We find that this is not the case and conclude that some of the traditional survey answer formats, such as grid questions, which have been criticized in the past lead to equally good data and do not frustrate respondents more than alternative formats.

scholarly journals Individual shareholder activism in South Africa: The case of Theo Botha

2017 ◽  
Vol 9 (2) ◽  
pp. 247-369
Author(s):  
Suzette Viviers
Keyword(s):  
South Africa ◽  
Shareholder Activism ◽  
Document Analysis ◽  
Modus Operandi ◽  
Normative Power ◽  
The Past ◽  
Depth Interview ◽  
Clear Goal

Shareholder activists play a key role in monitoring managerial behaviour. This study was undertaken given the paucity of research on the shareholder activism as practised by individual shareholders. Accordingly, the motives, modus operandi and sources of salience of Mr Theo Botha, a well-known shareholder activist in South Africa, were investigated. Document analysis and an in-depth interview conducted with Botha revealed that he not only has a clear goal, but is also very passionate about achieving his goal. Botha prepares meticulously before engaging companies across the economic spectrum. In addition to possessing normative power, Botha also exhibits individual, pragmatic and societal legitimacy. His assertiveness, persistence and willingness to apply his own resources significantly contribute to his prominence as a corporate watchdog. Shareholder activists who wish to become more salient (irrespective of their size) could learn from Botha’s experiences over the past decade.

scholarly journals Differential pathogenesis of closely related 2018 Nigerian outbreak clade III Lassa virus isolates

2021 ◽  
Vol 17 (10) ◽  
pp. e1009966
Author(s):  
Derek R. Stein ◽  
Bryce M. Warner ◽  
Jonathan Audet ◽  
Geoff Soule ◽  
Vinayakumar Siragam ◽  
...  
Keyword(s):  
Animal Models ◽  
Lassa Fever ◽  
Geographic Region ◽  
World Health ◽  
Limiting Factor ◽  
Lassa Virus ◽  
African Countries ◽  
Animal Models Of Disease ◽  
Medical Countermeasures

Nigeria continues to experience ever increasing annual outbreaks of Lassa fever (LF). The World Health Organization has recently declared Lassa virus (LASV) as a priority pathogen for accelerated research leading to a renewed international effort to develop relevant animal models of disease and effective countermeasures to reduce LF morbidity and mortality in endemic West African countries. A limiting factor in evaluating medical countermeasures against LF is a lack of well characterized animal models outside of those based on infection with LASV strain Josiah originating form Sierra Leone, circa 1976. Here we genetically characterize five recent LASV isolates collected from the 2018 outbreak in Nigeria. Three isolates were further evaluated in vivo and despite being closely related and from the same spatial / geographic region of Nigeria, only one of the three isolates proved lethal in strain 13 guinea pigs and non-human primates (NHP). Additionally, this isolate exhibited atypical pathogenesis characteristics in the NHP model, most notably respiratory failure, not commonly described in hemorrhagic cases of LF. These results suggest that there is considerable phenotypic heterogeneity in LASV infections in Nigeria, which leads to a multitude of pathogenesis characteristics that could account for differences between subclinical and lethal LF infections. Most importantly, the development of disease models using currently circulating LASV strains in West Africa are critical for the evaluation of potential vaccines and medical countermeasures.

Impacts of population growth in relation to changes in aquaculture and fisheries prices

2021 ◽  
Vol 36 (1) ◽  
pp. 83-92
Author(s):  
A.A. Garba
Keyword(s):  
Population Growth ◽  
Lassa Fever ◽  
World Population ◽  
Intensive Culture ◽  
Fish Food ◽  
Civil Strife ◽  
The Past ◽  
The World ◽  
Great Pressure ◽  
Negative Impacts

The paper reviewed the impacts of population growth and the ways it affects aquaculture and fisheries prices. As the world population  continues to grow arithmetically, great pressure is placed on arable lands, water, energy, and biological resources to provide an adequate supply of food while maintaining the integrity of the ecosystem. In 2010, FAO projected the world population to double from 6.2 billion in October, 1999 to 12.5 billion in the year 2050. This had created serious negative impacts on the aquaculture and fisheries prices. At present fertile crop lands had been lost at an alarming rates while some abandoned during the past 50 years because erosions made it unproductive. Other vices such as food crisis, political unrest and war (Mexico, Uzbekistan, Turkistan, Yemen, Iraq, Afghanistan, Syria, Morocco and Sudan), civil strife and multiple years of draught (Niger, Mauritania and Senegal), impacts of HIV/AIDS Ebola, Lassa fever and Coronavirus the world over, clashes between cattle rearers and farmers and boko haram issues (Nigeria) as well as kidnapping and  corruptions have severely affected aquaculture and fisheries production and accompanied prices. Thus, this review was conducted to raise a cry for farmers and citizens to engage and participate in intensive culture and fisheries practices in order to fill the demand - supply gap so as to make fish food products available for the teeming masses.

scholarly journals Attenuated Replication of Lassa Virus Vaccine Candidate ML29 in STAT-1-/- Mice

Pathogens ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 9 ◽  
Author(s):  
Dylan Johnson ◽  
Jenny Jokinen ◽  
Igor Lukashevich
Keyword(s):  
Vaccine Development ◽  
Vaccine Candidate ◽  
Small Animal ◽  
Vero Cells ◽  
Lassa Fever ◽  
Effective Vaccine ◽  
Cell Mediated Immunity ◽  
Lassa Virus ◽  
Cell Responses ◽  
Fold Reduction

Lassa virus (LASV), a highly prevalent mammalian arenavirus endemic in West Africa, can cause Lassa fever (LF), which is responsible for thousands of deaths annually. LASV is transmitted to humans from naturally infected rodents. At present, there is not an effective vaccine nor treatment. The genetic diversity of LASV is the greatest challenge for vaccine development. The reassortant ML29 carrying the L segment from the nonpathogenic Mopeia virus (MOPV) and the S segment from LASV is a vaccine candidate under current development. ML29 demonstrated complete protection in validated animal models against a Nigerian strain from clade II, which was responsible for the worst outbreak on record in 2018. This study demonstrated that ML29 was more attenuated than MOPV in STAT1-/- mice, a small animal model of human LF and its sequelae. ML29 infection of these mice resulted in more than a thousand-fold reduction in viremia and viral load in tissues and strong LASV-specific adaptive T cell responses compared to MOPV-infected mice. Persistent infection of Vero cells with ML29 resulted in generation of interfering particles (IPs), which strongly interfered with the replication of LASV, MOPV and LCMV, the prototype of the Arenaviridae. ML29 IPs induced potent cell-mediated immunity and were fully attenuated in STAT1-/- mice. Formulation of ML29 with IPs will improve the breadth of the host’s immune responses and further contribute to development of a pan-LASV vaccine with full coverage meeting the WHO requirements.

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.

scholarly journals A recombinant vesicular stomatitis-based Lassa fever vaccine elicits rapid and long-term protection from lethal Lassa virus infection in guinea pigs

npj Vaccines ◽  
2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Derek R. Stein ◽  
Bryce M. Warner ◽  
Geoff Soule ◽  
Kevin Tierney ◽  
Kathy L. Frost ◽  
...  
Keyword(s):  
Virus Infection ◽  
Guinea Pigs ◽  
Lassa Fever ◽  
Lassa Virus ◽  
Vesicular Stomatitis

scholarly journals Development of Recombinant Nucleoprotein-Based Diagnostic Systems for Lassa Fever

2007 ◽  
Vol 14 (9) ◽  
pp. 1182-1189 ◽  
Author(s):  
Masayuki Saijo ◽  
Marie-Claude Georges-Courbot ◽  
Philippe Marianneau ◽  
Victor Romanowski ◽  
Shuetsu Fukushi ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Hela Cells ◽  
Recombinant Baculovirus ◽  
Lassa Fever ◽  
Rabbit Serum ◽  
Enzyme Linked Immunosorbent Assay ◽  
Lassa Virus ◽  
Diagnostic Systems ◽  
Serum Samples ◽  
Capture Elisa

ABSTRACT Diagnostic systems for Lassa fever (LF), a viral hemorrhagic fever caused by Lassa virus (LASV), such as enzyme immunoassays for the detection of LASV antibodies and LASV antigens, were developed using the recombinant nucleoprotein (rNP) of LASV (LASV-rNP). The LASV-rNP was expressed in a recombinant baculovirus system. LASV-rNP was used as an antigen in the detection of LASV-antibodies and as an immunogen for the production of monoclonal antibodies. The LASV-rNP was also expressed in HeLa cells by transfection with the expression vector encoding cDNA of the LASV-NP gene. An immunoglobulin G enzyme-linked immunosorbent assay (ELISA) using LASV-rNP and an indirect immunofluorescence assay using LASV-rNP-expressing HeLa cells were confirmed to have high sensitivity and specificity in the detection of LASV-antibodies. A novel monoclonal antibody to LASV-rNP, monoclonal antibody 4A5, was established. A sandwich antigen capture (Ag-capture) ELISA using the monoclonal antibody and an anti-LASV-rNP rabbit serum as capture and detection antibodies, respectively, was then developed. Authentic LASV nucleoprotein in serum samples collected from hamsters experimentally infected with LASV was detected by the Ag-capture ELISA. The Ag-capture ELISA specifically detected LASV-rNP but not the rNPs of lymphocytic choriomeningitis virus or Junin virus. The sensitivity of the Ag-capture ELISA in detecting LASV antigens was comparable to that of reverse transcription-PCR in detecting LASV RNA. These LASV rNP-based diagnostics were confirmed to be useful in the diagnosis of LF even in institutes without a high containment laboratory, since the antigens can be prepared without manipulation of the infectious viruses.

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