scholarly journals Novel protein candidates for serodiagnosis of African animal trypanosomosis: Evaluation of the diagnostic potential of lysophospholipase and glycerol kinase from Trypanosoma brucei

2021 ◽  
Vol 15 (12) ◽  
pp. e0009985
Author(s):  
Magamba Tounkara ◽  
Alain Boulangé ◽  
Magali Thonnus ◽  
Frédéric Bringaud ◽  
Adrien Marie Gaston Bélem ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Sub Saharan Africa ◽  
Tsetse Flies ◽  
African Countries ◽  
Human Form ◽  
Novel Proteins ◽  
Diagnostic Potential ◽  
Sub Saharan ◽  
Better Than ◽  
Novel Protein

African trypanosomosis, a parasitic disease caused by protozoan parasites transmitted by tsetse flies, affects both humans and animals in sub-Saharan Africa. While the human form (HAT) is now limited to foci, the animal form (AAT) is widespread and affects the majority of sub-Saharan African countries, and constitutes a real obstacle to the development of animal breeding. The control of AAT is hampered by a lack of standardized and easy-to used diagnosis tools. This study aimed to evaluate the diagnostic potential of TbLysoPLA and TbGK proteins from Trypanosoma brucei brucei for AAT serodiagnosis in indirect ELISA using experimental and field sera, individually, in combination, and associated with the BiP C-terminal domain (C25) from T. congolense. These novel proteins were characterized in silico, and their sequence analysis showed strong identities with their orthologs in other trypanosomes (more than 60% for TbLysoPLA and more than 82% for TbGK). TbLysoPLA displays a low homology with cattle (<35%) and Piroplasma (<15%). However, TbGK shares more than 58% with cattle and between 45–55% with Piroplasma. We could identify seven predicted epitopes on TbLysoPLA sequence and 14 potential epitopes on TbGK. Both proteins were recombinantly expressed in Escherichia coli. Their diagnostic potential was evaluated by ELISA with sera from cattle experimentally infected with T. congolense and with T.b. brucei, sera from cattle naturally infected with T. congolense, T. vivax and T.b. brucei. Both proteins used separately had poor diagnostic performance. However, used together with the BiP protein, they showed 60% of sensitivity and between 87–96% of specificity, comparable to reference ELISA tests. In conclusion, we showed that the performance of the protein combinations is much better than the proteins tested individually for the diagnosis of AAT.

Antioxidants promote establishment of trypanosome infections in tsetse

Parasitology ◽  
2007 ◽  
Vol 134 (6) ◽  
pp. 827-831 ◽  
Author(s):  
E. T. MacLEOD ◽  
I. MAUDLIN ◽  
A. C. DARBY ◽  
S. C. WELBURN
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Trypanosoma Brucei ◽  
Sub Saharan Africa ◽  
Tsetse Flies ◽  
Oxygen Species ◽  
Infection Rates ◽  
Trypanosoma Brucei Brucei ◽  
Sub Saharan ◽  
Cyclical Transmission

SUMMARYEfficient, cyclical transmission of trypanosomes through tsetse flies is central to maintenance of human sleeping sickness and nagana across sub-Saharan Africa. Infection rates in tsetse are normally very low as most parasites ingested with the fly bloodmeal die in the fly gut, displaying the characteristics of apoptotic cells. Here we show that a range of antioxidants (glutathione, cysteine, N-acetyl-cysteine, ascorbic acid and uric acid), when added to the insect bloodmeal, can dramatically inhibit cell death of Trypanosoma brucei brucei in tsetse. Both L- and D-cysteine invoked similar effects suggesting that inhibition of trypanosome death is not dependent on protein synthesis. The present work suggests that antioxidants reduce the midgut environment protecting trypanosomes from cell death induced by reactive oxygen species.

scholarly journals Beyond poverty as a proxy: reducing inequality in infant mortality by identifying and targeting higher risk births

2021 ◽  
Author(s):  
Antonio Ramos ◽  
Chad Hazlett ◽  
Stephen Smith
Keyword(s):  
Infant Mortality ◽  
Premature Mortality ◽  
Sub Saharan Africa ◽  
Risk Scores ◽  
African Countries ◽  
Left Behind ◽  
Machine Learning Methods ◽  
Mortality Burden ◽  
Sub Saharan ◽  
Better Than

Infant mortality remains high and uneven in much of sub-Saharan Africa. Given finite resources, reducing premature mortality requires effective tools to identifying left- behind populations at greatest risk. While countries routinely use income- or poverty- based thresholds to target policies, we examine whether models that consider other factors can substantially improve our ability to target policies to higher-risk births. Using machine learning methods, and 25 commonly available variables that can be observed prior to birth, we construct child-level risk scores for births in 22 sub-Saharan African countries. We find that targeting based on poverty, proxied by income, is only slightly better than random targeting, with the poorest 10 percent of the population experiencing approximately 10 percent of total infant mortality burden. By contrast the 10 percent of the population at highest risk according to our model accounts for 15-30% of infants deaths, depending on country. A hypothetical intervention that can be administered to 10% of the population and prevents just 5% of the deaths that would otherwise occur, for example, would save roughly 841,000 lives if targeted to the poorest decile, but over 1.6 million if targeted using our approach.

scholarly journals Positional Dynamics and Glycosomal Recruitment of Developmental Regulators during Trypanosome Differentiation

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Balázs Szöőr ◽  
Dorina V. Simon ◽  
Federico Rojas ◽  
Julie Young ◽  
Derrick R. Robinson ◽  
...  
Keyword(s):  
Life Cycle ◽  
Trypanosoma Brucei ◽  
Tyrosine Phosphatase ◽  
Tsetse Fly ◽  
Sub Saharan Africa ◽  
Metabolic Adaptation ◽  
Tsetse Flies ◽  
Content Type ◽  
African Trypanosomes ◽  
Sub Saharan

ABSTRACT Glycosomes are peroxisome-related organelles that compartmentalize the glycolytic enzymes in kinetoplastid parasites. These organelles are developmentally regulated in their number and composition, allowing metabolic adaptation to the parasite’s needs in the blood of mammalian hosts or within their arthropod vector. A protein phosphatase cascade regulates differentiation between parasite developmental forms, comprising a tyrosine phosphatase, Trypanosoma brucei PTP1 (TbPTP1), which dephosphorylates and inhibits a serine threonine phosphatase, TbPIP39, which promotes differentiation. When TbPTP1 is inactivated, TbPIP39 is activated and during differentiation becomes located in glycosomes. Here we have tracked TbPIP39 recruitment to glycosomes during differentiation from bloodstream “stumpy” forms to procyclic forms. Detailed microscopy and live-cell imaging during the synchronous transition between life cycle stages revealed that in stumpy forms, TbPIP39 is located at a periflagellar pocket site closely associated with TbVAP, which defines the flagellar pocket endoplasmic reticulum. TbPTP1 is also located at the same site in stumpy forms, as is REG9.1, a regulator of stumpy-enriched mRNAs. This site provides a molecular node for the interaction between TbPTP1 and TbPIP39. Within 30 min of the initiation of differentiation, TbPIP39 relocates to glycosomes, whereas TbPTP1 disperses to the cytosol. Overall, the study identifies a “stumpy regulatory nexus” (STuRN) that coordinates the molecular components of life cycle signaling and glycosomal development during transmission of Trypanosoma brucei. IMPORTANCE African trypanosomes are parasites of sub-Saharan Africa responsible for both human and animal disease. The parasites are transmitted by tsetse flies, and completion of their life cycle involves progression through several development steps. The initiation of differentiation between blood and tsetse fly forms is signaled by a phosphatase cascade, ultimately trafficked into peroxisome-related organelles called glycosomes that are unique to this group of organisms. Glycosomes undergo substantial remodeling of their composition and function during the differentiation step, but how this is regulated is not understood. Here we identify a cytological site where the signaling molecules controlling differentiation converge before the dispersal of one of them into glycosomes. In combination, the study provides the first insight into the spatial coordination of signaling pathway components in trypanosomes as they undergo cell-type differentiation.

scholarly journals The population genetics of Trypanosoma brucei and the origin of human infectivity

2001 ◽  
Vol 356 (1411) ◽  
pp. 1035-1044 ◽  
Author(s):  
Annette MacLeod ◽  
Andy Tait ◽  
C. Michel R. Turner
Keyword(s):  
Trypanosoma Brucei ◽  
Genetic Relationships ◽  
Genetic Exchange ◽  
Sub Saharan Africa ◽  
Tsetse Flies ◽  
Implicit Assumption ◽  
Mixed Genotype ◽  
Disease Biology ◽  
Zoonotic Parasite ◽  
Sub Saharan

The African trypanosome, Trypanosoma brucei , is a zoonotic parasite transmitted by tsetse flies. Two of the three subspecies, T. brucei gambiense and T.b. rhodesiense , cause sleeping sickness in humans whereas the third subspecies, T.b. brucei , is not infective to humans. We propose that the key to understanding genetic relationships within this species is the analysis of gene flow to determine the importance of genetic exchange within populations and the relatedness of populations. T.brucei parasites undergo genetic exchange when present in infections of mixed genotypes in tsetse flies in the laboratory, although this is not an obligatory process. Infections of mixed genotype are surprisingly common in field isolates from tsetse flies such that there is opportunity for genetic exchange to occur. Population genetic analyses, taking into account geographical and host species of origin, show that genetic exchange occurs sufficiently frequently in the field to be an important determinant of genetic diversity, except where particular clones have acquired the ability to infect humans. Thus, T. brucei populations have an ‘epidemic’ genetic structure, but the better-characterized human-infective populations have a ‘clonal’ structure. Remarkably, the ability to infect humans appears to have arisen on multiple occasions in different geographical locations in sub-Saharan Africa. Our data indicate that the classical subspecies terminology for T. brucei is genetically inappropriate. It is an implicit assumption in most infectious disease biology that when a zoonotic pathogen acquires the capability to infect humans, it does so once and then spreads through the human population from that single-source event. For at least one major pathogen in tropical medicine, T. brucei , this assumption is invalid.

Crowdsourcing Covid-19 signals in sub-Saharan Africa: Leveraging digital contributor networks for participatory surveillance of Covid-19 symptoms and deaths (Preprint)

2020 ◽  
Author(s):  
Ngozi A Erondu ◽  
Sagal A Ali ◽  
Mohamed Ali ◽  
Schadrac C Agbla
Keyword(s):  
Public Health ◽  
Sub Saharan Africa ◽  
Specific Information ◽  
Surveillance Systems ◽  
Health Seeking ◽  
African Countries ◽  
Cross Sectional Survey ◽  
Local Networks ◽  
The World ◽  
Sub Saharan

BACKGROUND In sub-Saharan Africa, underreporting of cases and deaths has been attributed to various factors including, weak disease surveillance, low health-seeking behaviour of flu like symptoms, and stigma of Covid-19. There is evidence that SARS-CoV-2 spread mimics transmission patterns of other countries across the world. Since the Covid-19 pandemic has changed the way research can be conducted and in light of restrictions on travel and risks to in-person data collection, innovative approaches to collecting data must be considered. Nearly 50% of Africa’s population is a unique mobile subscriber and it is one of the fastest growing smart-phone marketplaces in the world; hence, mobile phone platforms should be considered to monitor Covid-19 trends in the community. OBJECTIVE We demonstrate the use of digital contributor platforms to survey individuals about cases of flu-like symptoms and instances of unexplained deaths in Ethiopia, Kenya, Nigeria, Somalia, and Zimbabwe. METHODS Rapid cross-sectional survey of individuals with severe flu and pneumonia symptoms and unexplained deaths in Ethiopia, Kenya, Nigeria, Somalia and Zimbabwe RESULTS Using a non-health specific information platform, we found COVID-19 signals in five African countries, specifically: •Across countries, nearly half of the respondents (n=739) knew someone who had severe flu or pneumonia symptoms in recent months. •One in three respondents from Somalia and one in five from Zimbabwe respondents said they knew more than five people recently displaying flu and/or pneumonia symptoms. •In Somalia there were signals that a large number of people might be dying outside of health facilities, specifically in their homes or in IDP or refugee camps. CONCLUSIONS Existing digital contributor platforms with local networks are a non-traditional data source that can provide information from the community to supplement traditional government surveillance systems and academic surveys. We demonstrate that using these distributor networks to for community surveys can provide periodic information on rumours but could also be used to capture local sentiment to inform public health decision-making; for example, these insights could be useful to inform strategies to increase confidence in Covid19 vaccine. As Covid-19 continues to spread somewhat silently across sub-Saharan Africa, regional and national public health entities should consider expanding event-based surveillance sources to include these systems.

Managing African Urbanization in the Context of Environmental Change

2014 ◽  
Vol 2 (2) ◽  
Author(s):  
Shuaib Lwasa
Keyword(s):  
Climate Change ◽  
Economic Growth ◽  
Social Services ◽  
Urban Areas ◽  
Urban Governance ◽  
Sub Saharan Africa ◽  
African Countries ◽  
Sub Saharan ◽  
Urbanization Rate ◽  
Development And Management

Africa’s urbanization rate has increased steadily over the past three decades and is reported to be faster than in any other region in the world . It is estimated that by 2030, over half of the African population will be living in urban areas . But the nature of Africa’s urbanization and subsequent form of cities is yet to be critically analyzed in the context of city authorities’ readiness to address the challenges . Evidence is also suggesting that urbanization in African countries is increasingly associated with the high economic growth that has been observed in the last two decades . Both underlying and proximate drivers are responsible for the urbanization, and these include population dynamics, economic growth, legislative designation, increasing densities in rural centers, as well as the growth of mega cities such as Lagos, Cairo and Kinshasa, that are extending to form urban corridors . With the opportunities of urbanization in Sub–Saharan Africa, there are also challenges in the development and management of these cities . Those challenges include provision of social services, sustainable economic development, housing development, urban governance, spatial development guidance and environmental management, climate change adaptation, mitigation and disaster risk reduction . The challenge involves dealing with the development and infrastructure deficit, in addition to required adaption to and mitigation of climate change . This paper examines the current state of urban management in Africa .

Monetary Policy in Sub-Saharan Africa

2018 ◽  
Keyword(s):  
Monetary Policy ◽  
Low Income ◽  
Sub Saharan Africa ◽  
Low Income Countries ◽  
African Countries ◽  
Policy Regimes ◽  
Export Prices ◽  
Policy Work ◽  
Sub Saharan ◽  
Policy Guidance

Having broadly stabilized inflation over the past two decades, many policymakers in sub-Saharan Africa are now asking more of their monetary policy frameworks. They are looking to avoid policy misalignments and respond appropriately to both domestic and external shocks, including swings in fiscal policy and spikes in food and export prices. In many cases they are finding current regimes—often characterized as ‘money targeting’—lacking, with opaque and sometimes inconsistent objectives, inadequate transmission of policy to the economy, and difficulties in responding to supply shocks. At the same time, little existing research on monetary policy is targeted to low-income countries. What do we know about the empirics of monetary transmission in low-income countries? (How) Does monetary policy work in countries characterized by a huge share of food in consumption, underdeveloped financial markets, and opaque policy regimes? (How) Can we use methods largely derived in advanced countries to answer these questions? And (how) can we use the results to guide policymakers? This book draws on years of research and practice at the IMF and in central banks from the region to shed empirical and theoretical light on these questions and to provide practical tools and policy guidance. A key feature of the book is the application of dynamic general equilibrium models, suitably adapted to reflect key features of low-income countries, for the analysis of monetary policy in sub-Saharan African countries.

Financing Energy Access in Africa

2018 ◽  
Author(s):  
Peter Kayode Oniemola ◽  
Jane Ezirigwe
Keyword(s):  
Oil And Gas ◽  
Sub Saharan Africa ◽  
Capital Investments ◽  
Energy Access ◽  
African Countries ◽  
Sustainable Technologies ◽  
Energy Technologies ◽  
Sub Saharan ◽  
Diesel Motors

To achieve universal energy access will attract huge capital investments. If sub-Saharan Africa is to realize anything close to the ambitious goals set for its energy access, then new actors, innovative funding mechanisms and sustainable technologies will have to be attracted. Finance is needed for activities such as rural electrification, clean cooking facilities, diesel motors and generators, other renewable energy technologies, oil and gas infrastructures, etc. Finance is also needed in research and development of suitable technologies and funding options as well as investment in the capacity to formulate and implement sound energy policies. This chapter examines the varied financing options for energy access in sub-Saharan Africa. It argues that with appropriate laws in place and effective mechanism for implementation, African countries can significantly engage private sector financing, international financial institutions and foreign donors. The role of the law here will be in creating an enabling environment for financing.

scholarly journals Positioning for success: building capacity in academic competencies for early-career researchers in sub-Saharan Africa

2019 ◽  
Vol 6 ◽  
Author(s):  
C. Merritt ◽  
H. Jack ◽  
W. Mangezi ◽  
D. Chibanda ◽  
M. Abas
Keyword(s):  
Mental Health ◽  
Capacity Building ◽  
Low Cost ◽  
Early Career ◽  
Sub Saharan Africa ◽  
Training Experience ◽  
African Countries ◽  
Early Career Researchers ◽  
Academic Competencies ◽  
Sub Saharan

Background. Capacity building is essential in low- and middle-income countries (LMICs) to address the gap in skills to conduct and implement research. Capacity building must not only include scientific and technical knowledge, but also broader competencies, such as writing, disseminating research and achieving work–life balance. These skills are thought to promote long-term career success for researchers in high-income countries (HICs) but the availability of such training is limited in LMICs. Methods. This paper presents the contextualisation and implementation of the Academic Competencies Series (ACES). ACES is an early-career researcher development programme adapted from a UK university. Through consultation between HIC and LMIC partners, an innovative series of 10 workshops was designed covering themes of self-development, engagement and writing skills. ACES formed part of the African Mental Health Research Initiative (AMARI), a multi-national LMIC-led consortium to recruit, train, support and network early-career mental health researchers from four sub-Saharan African countries. Results. Of the 10 ACES modules, three were HIC-LMIC co-led, four led by HIC facilitators with LMIC training experience and three led by external consultants from HICs. Six workshops were delivered face to face and four by webinar. Course attendance was over 90% and the delivery cost was approximately US$4500 per researcher trained. Challenges of adaptation, attendance and technical issues are described for the first round of workshops. Conclusions. This paper indicates that a skills development series for early-career researchers can be contextualised and implemented in LMIC settings, and is feasible for co-delivery with local partners at relatively low cost.

scholarly journals Suicidal ideation and associated factors among school-going adolescents in rural Ghana

2021 ◽  
Author(s):  
Emmanuel Nii-Boye Quarshie ◽  
Samuel Kofi Odame
Keyword(s):  
Suicidal Ideation ◽  
Associated Factors ◽  
Attempted Suicide ◽  
Sub Saharan Africa ◽  
Rural Adolescents ◽  
African Countries ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Rural Ghana ◽  
Sub Saharan

AbstractSuicidal ideation is a critical risk for attempted suicide and eventual suicide. Little is known about suicidal ideation among rural adolescents in most sub-Saharan African countries. We aimed to estimate the 12-month prevalence of suicidal ideation and to describe some of the common and gender-specific associated factors among in-school adolescents in rural Ghana. We conducted a cross-sectional survey involving a random sample of 1101 in-school adolescents aged 10–19 years in a rural district in Eastern Ghana. The Suicidal Behavior Questionnaire-Revised was used to assess suicidal ideation. Overall, 25.1% participants (95% CI = 22.5–27.7), representing 28.3% females (95% CI = 24.7–32.2) and 21.5% males (95% CI = 18.0–25.2) reported suicidal ideation during the previous 12 months. Females who experienced personal and interpersonal adversities mainly outside the family context were likely to report suicidal ideation, while suicidal ideation among males was associated with conflict with parents. Regardless of gender, adolescents who reported exposure to a friend’s attempted suicide were about two times more likely to report suicidal ideation. The prevalence of suicidal ideation among adolescents in rural Ghana compares with in-school estimates from other countries within sub-Saharan Africa, but also underscores the need for targeted and universal prevention programmes and intervention efforts to mitigate the potential transition from suicidal ideations to suicidal attempts and eventual deaths by suicide among rural adolescents.

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