Showing papers by "University of Zimbabwe published in 2017"

Synthesis, characterisation and methyl orange adsorption capacity of ferric oxide–biochar nano-composites derived from pulp and paper sludge

Abstract: A Fe2O3–biochar nano-composite (Fe2O3–BC) was prepared from FeCl3-impregnated pulp and paper sludge (PPS) by pyrolysis at 750 °C. The characteristics and methyl orange (MO) adsorption capacity of Fe2O3–BC were compared to that of unactivated biochar (BC). X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the composite material was nano-sized. Fourier transform infrared (FTIR) spectroscopy revealed the presence of hydroxyl and aromatic groups on BC and on Fe2O3–BC, but Brunauer–Emmett–Teller (BET) surface area and Barrett–Joyner–Halenda (BJH) porosity were lower for Fe2O3–BC than BC. Despite the lower BET surface area and porosity of Fe2O3–BC, its MO adsorption capacity was 52.79 % higher than that of BC. The equilibrium adsorption data were best represented by the Freundlich model with a maximum adsorption capacity of 20.53 mg g−1 at pH 8 and 30 min contact time. MO adsorption obeyed pseudo-second-order kinetics for both BC and Fe2O3–BC with R 2 values of 0.996 and 0.999, respectively. Higher MO adsorption capacity for Fe2O3–BC was attributed to the hybrid nature of the nano-composites; adsorption occurred on both biochar matrix and Fe2O3 nanocrystals. Gibbs free energy calculations confirmed the adsorption is energetically favourable and spontaneous with a high preference for adsorption on both adsorbents. The nano-composite can be used for the efficient removal of MO (>97 %) from contaminated wastewater.

Enhanced prophylaxis plus antiretroviral therapy for advanced HIV infection in Africa.

Abstract: BackgroundIn sub-Saharan Africa, among patients with advanced human immunodeficiency virus (HIV) infection, the rate of death from infection (including tuberculosis and cryptococcus) shortly after the initiation of antiretroviral therapy (ART) is approximately 10%. MethodsIn this factorial open-label trial conducted in Uganda, Zimbabwe, Malawi, and Kenya, we enrolled HIV-infected adults and children 5 years of age or older who had not received previous ART and were starting ART with a CD4+ count of fewer than 100 cells per cubic millimeter. They underwent simultaneous randomization to receive enhanced antimicrobial prophylaxis or standard prophylaxis, adjunctive raltegravir or no raltegravir, and supplementary food or no supplementary food. Here, we report on the effects of enhanced antimicrobial prophylaxis, which consisted of continuous trimethoprim–sulfamethoxazole plus at least 12 weeks of isoniazid–pyridoxine (coformulated with trimethoprim–sulfamethoxazole in a single fixed-dose combination tablet),...

Importance of resolving fungal nomenclature: The case of multiple pathogenic species in the Cryptococcus genus

Abstract: Cryptococcosis is a major fungal disease caused by members of the Cryptococcus gattii and Cryptococcus neoformans species complexes. After more than 15 years of molecular genetic and phenotypic studies and much debate, a proposal for a taxonomic revision was made. The two varieties within C. neoformans were raised to species level, and the same was done for five genotypes within C. gattii. In a recent perspective (K. J. Kwon-Chung et al., mSphere 2:e00357-16, 2017, https://doi.org/10.1128/mSphere.00357-16), it was argued that this taxonomic proposal was premature and without consensus in the community. Although the authors of the perspective recognized the existence of genetic diversity, they preferred the use of the informal nomenclature "C. neoformans species complex" and "C. gattii species complex." Here we highlight the advantage of recognizing these seven species, as ignoring these species will impede deciphering further biologically and clinically relevant differences between them, which may in turn delay future clinical advances.

Social Contact Structures and Time Use Patterns in the Manicaland Province of Zimbabwe.

Abstract: Background Patterns of person-to-person contacts relevant for infectious diseases transmission are still poorly quantified in Sub-Saharan Africa (SSA), where socio-demographic structures and behavioral attitudes are expected to be different from those of more developed countries. Methods and Findings We conducted a diary-based survey on daily contacts and time-use of individuals of different ages in one rural and one peri-urban site of Manicaland, Zimbabwe. A total of 2,490 diaries were collected and used to derive age-structured contact matrices, to analyze time spent by individuals in different settings, and to identify the key determinants of individuals’ mixing patterns. Overall 10.8 contacts per person/day were reported, with a significant difference between the peri-urban and the rural site (11.6 versus 10.2). A strong age-assortativeness characterized contacts of school-aged children, whereas the high proportion of extended families and the young population age-structure led to a significant intergenerational mixing at older ages. Individuals spent on average 67% of daytime at home, 2% at work, and 9% at school. Active participation in school and work resulted the key drivers of the number of contacts and, similarly, household size, class size, and time spent at work influenced the number of home, school, and work contacts, respectively. We found that the heterogeneous nature of home contacts is critical for an epidemic transmission chain. In particular, our results suggest that, during the initial phase of an epidemic, about 50% of infections are expected to occur among individuals younger than 12 years and less than 20% among individuals older than 35 years. Conclusions With the current work, we have gathered data and information on the ways through which individuals in SSA interact, and on the factors that mostly facilitate this interaction. Monitoring these processes is critical to realistically predict the effects of interventions on infectious diseases dynamics.

Prevention of HIV-1 Transmission Through Breastfeeding: Efficacy and Safety of Maternal Antiretroviral Therapy Versus Infant Nevirapine Prophylaxis for Duration of Breastfeeding in HIV-1-Infected Women With High CD4 Cell Count (IMPAACT PROMISE): A Randomized, Open-Label, Clinical Trial.

Abstract: Background:No randomized trial has directly compared the efficacy of prolonged infant antiretroviral prophylaxis versus maternal antiretroviral therapy (mART) for prevention of mother-to-child transmission throughout the breastfeeding period.Setting:Fourteen sites in Sub-Saharan Africa and India.Met

Hard-to-cook phenomenon in bambara groundnut (Vigna subterranea (L.) Verdc.) processing: Options to improve its role in providing food security

Abstract: Indigenous legume crops are pivotal in providing proteins and food security to sub-Saharan African rural communities, but most of these crops are underutilized because of the so-called hard-to-cook (HTC) phenomenon in combination with inadequate processing techniques. This review studies the case of bambara groundnut, which is third in importance after groundnut and cowpea and especially adapted to semi-arid areas. Published data on the HTC phenomenon implicate microstructural and compositional changes as factors leading to its development. Useful and sustainable techniques to process HTC legumes in developing countries include cooking with alkaline salts, milling, roasting, fermentation, and malting. Improvement of these processing techniques in relation to nutrient bioaccessibility, safety, and consumer acceptance of the products is urgently needed. Recommendations are to lessen the problems of food security in sub-Saharan African countries through, amongst other means, the optimization of bamba...

Etiology of Severe Acute Watery Diarrhea in Children in the Global Rotavirus Surveillance Network Using Quantitative Polymerase Chain Reaction

Abstract: Background The etiology of acute watery diarrhea remains poorly characterized, particularly after rotavirus vaccine introduction. Methods We performed quantitative polymerase chain reaction for multiple enteropathogens on 878 acute watery diarrheal stools sampled from 14643 episodes captured by surveillance of children <5 years of age during 2013-2014 from 16 countries. We used previously developed models of the association between pathogen quantity and diarrhea to calculate pathogen-specific weighted attributable fractions (AFs). Results Rotavirus remained the leading etiology (overall weighted AF, 40.3% [95% confidence interval {CI}, 37.6%-44.3%]), though the AF was substantially lower in the Americas (AF, 12.2 [95% CI, 8.9-15.6]), based on samples from a country with universal rotavirus vaccination. Norovirus GII (AF, 6.2 [95% CI, 2.8-9.2]), Cryptosporidium (AF, 5.8 [95% CI, 4.0-7.6]), Shigella (AF, 4.7 [95% CI, 2.8-6.9]), heat-stable enterotoxin-producing Escherichia coli (ST-ETEC) (AF, 4.2 [95% CI, 2.0-6.1]), and adenovirus 40/41 (AF, 4.2 [95% CI, 2.9-5.5]) were also important. In the Africa Region, the rotavirus AF declined from 54.8% (95% CI, 48.3%-61.5%) in rotavirus vaccine age-ineligible children to 20.0% (95% CI, 12.4%-30.4%) in age-eligible children. Conclusions Rotavirus remained the leading etiology of acute watery diarrhea despite a clear impact of rotavirus vaccine introduction. Norovirus GII, Cryptosporidium, Shigella, ST-ETEC, and adenovirus 40/41 were also important. Prospective surveillance can help identify priorities for further reducing the burden of diarrhea.

Challenges facing young African scientists in their research careers: A qualitative exploratory study.

Abstract: Background: Africa accounts for 14% of world’s population, and the economies of most African countries are considered to be growing, but this is not reflected in the amount of research published by Africans. This study aimed at identifying the challenges that young African scientists face in their career development. Methods: This was a qualitative exploratory study involving young researchers who attended the Teaching and Research in Natural Sciences for Development (TReND) in Africa scientific writing and communication workshop, which was held in Malawi in September 2015. A semi-structured questionnaire was sent to all workshop participants who consented to taking part in the survey. In total, 28 questionnaires were sent via email and 15 were returned, representing a response rate of 53.6%. Data were analysed using thematic analysis. Results: Young Africans develop their research interests various ways. The most common career-promoting factors identified by the study participants included formal classroom learning, aspirations to attain academic qualifications, work satisfaction, and the desire to fulfill parents’ dreams. Challenges cited by survey respondents included a lack of mentorship, funds, and research and writing skills. Lack of interest in research by policymakers, lack of motivation by peers, and heavy workload (leaving little time for research) were also reported as challenges. Respondents suggested that grants specifically targeting young scientists would be beneficial. Participants also urged for the establishment of mentorship programmes, increasing motivation for research, and more frequent training opportunities. Conclusions: There is need for improved funding for institutional and research network strengthening in Africa, with particular attention given to expanding opportunities for young researchers.

Treatment as Prevention: Characterization of Partner Infections in the HIV Prevention Trials Network 052 Trial.

Abstract: HIV Prevention Trials Network 052 demonstrated that antiretroviral therapy (ART) prevents HIV transmission in serodiscordant couples. HIV from index–partner pairs was analyzed to determine the genetic linkage status of partner infections. Forty-six infections were classified as linked, indicating that the index was the likely source of the partner’s infection. Lack of viral suppression and higher index viral load were associated with linked infection. Eight linked infections were diagnosed after the index started ART: 4 near the time of ART initiation and 4 after ART failure. Linked infections were not observed when the index participant was stably suppressed on ART.

Ungauged runoff simulation in Upper Manyame Catchment, Zimbabwe: Application of the HEC-HMS model

Abstract: The Hydrologic Engineering Center Hydrologic Modelling System (HEC-HMS) model was applied to simulate runoff in the ten gauged and ungauged Upper Manyame subcatchments in Zimbabwe. Remote sensing and Geographic Information System techniques were used to determine the geometric and hydrologic parameters required for estimating model parameters. The Snyder Unit Hydrograph method was used for ungauged subcatchment simulations based on parameter transfer from gauged subcatchments. The Marimba and Mukuvisi subcatchments were considered as the gauged subcatchments based on data completeness for the simulation period (2004–2010). Before extrapolating the calibrated model setup to eight ungauged subcatchments, the feasibility of model parameter transferability was tested, using the proxy – catchment approach and evaluated using the Nash Sutcliffe (NSE) and Relative Volume Error (RVE) criterion. Results showed that the model successfully predicted gauged catchment runoff and peakflows for the calibration (Marimba NSE = 68%, RVE = 5.8%; Mukuvisi NSE = 64%, RVE = −8.9%) and validation (Marimba NSE = 61%, RVE = 8.1%; Mukuvisi NSE = 57%, RVE = 9.9%) periods. The study demonstrates the suitability of HEC-HMS for continuous runoff simulation in a complex watershed with numerous subcatchments and channel reaches. The ungauged subcatchments contribute to 51% of Upper Manyame Catchment's runoff. Ruwa and Lake Chivero subcatchments had the highest ungauged subcatchment contribution to Upper Manyame Catchment runoff (19% and 15% respectively). This work will have a significant contribution for the future development of water resources programs in Upper Manyame Catchment in particular and in other data-scarce catchments.

The impact of adoption of conservation agriculture on smallholder farmers’ food security in semi-arid zones of southern Africa

Abstract: In southern Africa, conservation agriculture (CA) has received a lot of research and promotional support from various organizations in the past decades. Conservation agriculture is largely promoted as one of the few win–win technologies affordable to farmers, in the sense that potentially it improves farmers’ yields (in the long term) at the same time conserving the environment. This is because conservation agriculture reduces nitrogen loss in the soil, promotes water and soil conservation and improves agronomic use efficiency of applied nutrients. However, some concerns have been raised over the feasibility of conservation agriculture on smallholder farms given constraints imposed by the biophysical and institutional realities under which smallholder farmers operate. The main aim of this study is to answer the question whether conservation agriculture is resulting in tangible livelihood outcomes to smallholder farmers. The counterfactual outcome approach was used to estimate ex post impact of conservation agriculture adoption on one of the key livelihood outcomes—food security. The study that utilized a data set covering 1623 households in Zimbabwe, Malawi and Mozambique found no significant impact of conservation agriculture adoption on Food Consumption Score of farmers in Zimbabwe and Malawi. Possible reasons for the insignificant of CA impact on food security in Zimbabwe and Malawi could include the small land areas currently devoted to CA, and the failure to implement the full complement of practices necessary to set off the biophysical process that are expected to drive yield increases. In Mozambique, conservation agriculture significantly improved the Food Consumption Score for farmers exposed to the technology. A possible reason for effectiveness of CA in Mozambique could be due to the fact that often CA is being promoted together with other better cropping management practices such as timely weeding and improved seed varieties, which are poorly practiced by the generality of farmers in a country just emerging from a war period. This paper provides one of the few ex post assessments of the impact of conservation agriculture adoption on household livelihood outcomes—food security. Given the mixed findings, the study suggests that conservation agriculture farmers in the three countries need to be supported to adopt a value chain approach to conservation agriculture. This entails the introduction of commercial or high-value crops in the conservation agriculture programmes, value addition on farmers produce, access to the necessary support services such as markets for seed, fertilizer, herbicides and equipment as well as reliable extension. We believe that under such circumstances conservation agriculture can effectively reduce food insecurity and poverty in the medium to long term.

Pathways to transformational change in the face of climate impacts: an analytical framework

Abstract: Unprecedented impacts of climate change and climate variability in the twenty-first century are likely to require transformational social, organizational and human responses. Yet, little existing empirical work examines how decision-makers can facilitate such responses. This paper suggests that in order to assess whether responses to climate risks and threats are transformational, it is necessary to move away from a focus only on outcomes and scale and towards the multiple dimensions of social responses and the processes through which transformational changes are realized. In so doing, the paper seeks to move the discussion on transformational change towards the processes and sustainability of adaptation interventions, and the changes they trigger. Drawing on the literature on transformational change in organizational theory and social–ecological systems, the paper first develops a framework with which to examine and assess development and adaptation interventions. The framework is then applied to eight i...

Neuropsychological performance in African children with HIV enrolled in a multisite antiretroviral clinical trial

Abstract: Objective and design Children with HIV infection (HIV+) are at neuropsychological risk, but few studies have evaluated this at multiple sites in low-income and middle-income countries. We compared neuropsychological outcomes at enrollment (>5 years age) among HIV+, HIV perinatally exposed uninfected (HEU), and HIV unexposed uninfected (HUU) children from four sub-Saharan countries. Methods IMPAACT P1060 compared nevirapine versus lopinavir/ritonavir-based antiretroviral treatment (ART) in HIV-infected children 6-35 months of age. The present study (P1104s) enrolled P1060 children at 5-11 years of age and evaluated their neuropsychological performance over 2 years using the Kaufman Assessment Battery for Children, 2nd edition (KABC-II), Tests of Variables of Attention (TOVA), Bruininks-Oseretsky Test, 2nd edition (BOT-2), and parent-reported Behavior Rating Inventory of Executive Function (BRIEF). Cohorts were compared using generalized estimating equations least-squares means adjusted for site, child age and sex, and personal and social characteristics for child and caregiver. Results Six hundred and eleven (246 HIV+, 183 HEU, 182 HUU) of the 615 enrolled at six sites [South Africa (three), Zimbabwe, Malawi, Uganda] were available for analysis. Mean age was 7.2 years, 48% male, 69% in school. Unadjusted and adjusted comparisons were consistent. HIV+ children performed significantly worse than HEU and HUU cohorts on all KABC-II cognitive performance domains and on BOT-2 total motor proficiency (P Conclusion Significant cognitive deficits were documented among HIV+ children at school age, even when started on ART at an early age. Earlier HIV treatment, neuropsychological monitoring, and rehabilitative interventions are all needed. Subsequent testing for 2 more years will help further evaluate how HIV infection and exposure affect the developmental trajectory.

Benefits and Risks of Antiretroviral Therapy for Perinatal HIV Prevention

Abstract: BackgroundRandomized-trial data on the risks and benefits of antiretroviral therapy (ART) as compared with zidovudine and single-dose nevirapine to prevent transmission of the human immunodeficiency virus (HIV) in HIV-infected pregnant women with high CD4 counts are lacking. MethodsWe randomly assigned HIV-infected women at 14 or more weeks of gestation with CD4 counts of at least 350 cells per cubic millimeter to zidovudine and single-dose nevirapine plus a 1-to-2-week postpartum “tail” of tenofovir and emtricitabine (zidovudine alone); zidovudine, lamivudine, and lopinavir–ritonavir (zidovudine-based ART); or tenofovir, emtricitabine, and lopinavir–ritonavir (tenofovir-based ART). The primary outcomes were HIV transmission at 1 week of age in the infant and maternal and infant safety. ResultsThe median CD4 count was 530 cells per cubic millimeter among 3490 primarily black African HIV-infected women enrolled at a median of 26 weeks of gestation (interquartile range, 21 to 30). The rate of transmission w...

Decentralized domestic wastewater systems in developing countries: the case study of Harare (Zimbabwe)

Abstract: Until recently there has been little, if any, concern over revamping let alone improving wastewater management system in Zimbabwe’s urban areas given the dominance and institutionalised water-borne system. Yet, the current constraints in this system and the immensity of urbanisation in the country begs and compels planners, engineers and systems thinkers to rethink what best can work as a sustainable wastewater system. With particular reference to the ever-expanding Harare metropolitan region, this article provides an evaluative analysis on the potentiality, risks and strategies that can be adopted by Harare and its satellites in addressing the problems of the conventional wastewater management system. The suggested framework of operation is a decentralised domestic wastewater collection and treatment system which however has its own multifarious risks. Using systems dynamics conceptualisation of the potentiality, opportunities, risks and strategies, the paper seeks to model the path and outcomes of this decentralised domestic wastewater collection and treatment system and also suggests a number of policy measures and strategies that the city of Harare and its satellites can adopt.

The role of gender norms in access to agricultural training in Chikwawa and Phalombe, Malawi

Abstract: Based on qualitative research conducted in Chikwawa and Phalombe in Malawi, this article discusses how gender relations shape men and women’s access to and participation in agricultural training. I...

How do health workers experience and cope with shocks? Learning from four fragile and conflict-affected health systems in Uganda, Sierra Leone, Zimbabwe and Cambodia.

Abstract: This article is grounded in a research programme which set out to understand how to rebuild health systems post-conflict. Four countries were studied-Uganda, Sierra Leone, Zimbabwe and Cambodia-which were at different distances from conflict and crisis, as well as having unique conflict stories. During the research process, the Ebola epidemic broke out in West Africa. Zimbabwe has continued to face a profound economic crisis. Within our research on health worker incentives, we captured insights from 128 life histories and in-depth interviews with a variety of staff that had remained in service. This article aims to draw together lessons from these contexts which can provide lessons for enhancing staff and therefore health system resilience in future, especially in similarly fragile and conflict-affected contexts. We examine the reported effects, both personal and professional, of the three different types of shock (conflicts, epidemics and prolonged political-economic crises), and how staff coped. We find that the impact of shocks and coping strategies are similar between conflict/post-conflict and epidemic contexts-particularly in relation to physical threats and psychosocial threats-while all three contexts create challenges and staff responses for working conditions and remuneration. Health staff showed considerable inventiveness and resilience, and also benefited from external assistance of various kinds, but there are important gaps which point to ways in which they should be better protected and supported in the future. Health systems are increasingly fragile and conflict-prone, and shocks are often prolonged or repeated. Resilience should not be taken for granted or used as an excuse for abandoning frontline health staff. Strategies should be in place at local, national and international levels to prepare for predictable crises of various sorts, rather than waiting for them to occur and responding belatedly, or relying on personal sacrifices by staff to keep services functioning.

Structural drivers of vulnerability to zoonotic disease in Africa.

Abstract: This paper argues that addressing the underlying structural drivers of disease vulnerability is essential for a ‘One Health’ approach to tackling zoonotic diseases in Africa. Through three case stu...

Sorptive removal of methylene blue from simulated wastewater using biochars derived from pulp and paper sludge

Abstract: Biochar (BC) and Fe 2 O 3 –biochar nanocomposite (NC) derived from pulp and paper sludge (PPS) were used to remove methylene blue (MB) dye from synthetic wastewater. Morphology characterization indicated heterogeneous adsorbent surfaces, and textural measurements showed BC and NC possessed pore size in the range 1.7–300 nm. Both these characteristics endowed the adsorbents with good sorption properties for MB. The maximum adsorption capacity of NC (50 mg/g) was higher than of BC (33 mg/g). This was attributed to the hybrid nature of NC where adsorption occurs both on the biochar matrix and Fe 2 O 3 nanoparticles. MB adsorption data on BC and NC followed pseudo-second order ( r 2 = 0 . 958 ) and pseudo-first order kinetics ( r 2 = 1 . 000 ) , respectively. Isotherm data for BC and NC followed the Freundlich ( r 2 = 0 . 801 ) and Langmuir ( r 2 = 0 . 948 ) isotherm models, respectively. Despite having lower adsorption capacities compared to other adsorbents reported in literature, the use of BC and NC for wastewater remediation is an ingenious way of reducing environmental and health risks associated with the current disposal of PPS while providing remediation of water contaminated with industrial dye effluents.

Benefits and Risks of Antiretroviral Therapy for Perinatal HIV Prevention

Abstract: BackgroundRandomized-trial data on the risks and benefits of antiretroviral therapy (ART) as compared with zidovudine and single-dose nevirapine to prevent transmission of the human immunodeficiency virus (HIV) in HIV-infected pregnant women with high CD4 counts are lacking. MethodsWe randomly assigned HIV-infected women at 14 or more weeks of gestation with CD4 counts of at least 350 cells per cubic millimeter to zidovudine and single-dose nevirapine plus a 1-to-2-week postpartum “tail” of tenofovir and emtricitabine (zidovudine alone); zidovudine, lamivudine, and lopinavir–ritonavir (zidovudine-based ART); or tenofovir, emtricitabine, and lopinavir–ritonavir (tenofovir-based ART). The primary outcomes were HIV transmission at 1 week of age in the infant and maternal and infant safety. ResultsThe median CD4 count was 530 cells per cubic millimeter among 3490 primarily black African HIV-infected women enrolled at a median of 26 weeks of gestation (interquartile range, 21 to 30). The rate of transmission w...

Local processing and nutritional composition of indigenous fruits : The case of monkey orange (Strychnos spp.) from Southern Africa

Abstract: Monkey orange (Strychnos spp.) is a widely distributed fruit species in Southern Africa commonly consumed by the local population. It has potential to improve the nutritional status of rural populations, being a precious food source in areas with periodic shortages, since it is rich in vitamin C, zinc, and iron. To improve the availability of this food outside its production season, processing and preservation techniques used at household level need upgrading as they are unreliable and their effects on nutritional quality are unknown. Based on this review, we recommend better indigenous fruit production as a sustainable solution to malnutrition in rural areas in transition countries.