Showing papers by "University of Zimbabwe published in 2021"

Four-Month Rifapentine Regimens with or without Moxifloxacin for Tuberculosis.

Abstract: Background Rifapentine-based regimens have potent antimycobacterial activity that may allow for a shorter course in patients with drug-susceptible pulmonary tuberculosis. Methods In an ope...

Can N2O emissions offset the benefits from soil organic carbon storage

Abstract: To respect the Paris agreement targeting a limitation of global warming below 2°C by 2100, and possibly below 1.5°C, drastic reductions of greenhouse gas emissions are mandatory but not sufficient. Large-scale deployment of other climate mitigation strategies is also necessary. Among these, increasing soil organic carbon (SOC) stocks is an important lever because carbon in soils can be stored for long periods and land management options to achieve this already exist and have been widely tested. However, agricultural soils are also an important source of nitrous oxide (N2 O), a powerful greenhouse gas, and increasing SOC may influence N2 O emissions, likely causing an increase in many cases, thus tending to offset the climate change benefit from increased SOC storage. Here we review the main agricultural management options for increasing SOC stocks. We evaluate the amount of SOC that can be stored as well as resulting changes in N2 O emissions to better estimate the climate benefits of these management options. Based on quantitative data obtained from published meta-analyses and from our current level of understanding, we conclude that the climate mitigation induced by increased SOC storage is generally overestimated if associated N2 O emissions are not considered but, with the exception of reduced tillage, is never fully offset. Some options (e.g. biochar or non-pyrogenic C amendment application) may even decrease N2 O emissions.

The future of farming: Who will produce our food?

Abstract: Achieving SDG2 (zero hunger) in a situation of rapid global population growth requires a continued focus on food production. Farming not merely needs to sustainably produce nutritious diets, but should also provide livelihoods for farmers, while retaining natural ecosystems and services. Rather than focusing on production principles, this article explores the interrelations between farms and farming systems in the global food system. Evaluating farming systems around the world, we reveal a bewildering diversity. While family farms predominate, these range in size from less than 0.1 ha to more than 10,000 ha, and from hand hoe use to machine-based cultivation, enabling one person to plant more than 500 ha in a day. Yet, farming in different parts of the world is highly interdependent, not least because prices paid for farm produce are largely determined by global markets. Furthermore, the economic viability of farming is a problem, globally. We highlight trends in major regions of the world and explore possible trajectories for the future and ask: Who are the farmers of the future? Changing patterns of land ownership, rental and exchange mean that the concept of ‘what is a farm’ becomes increasingly fluid. Next to declining employment and rural depopulation, we also foresee more environmentally-friendly, less external input dependent, regionalised production systems. This may require the reversal of a global trend towards increasing specialisation to a recoupling of arable and livestock farming, not least for the resilience it provides. It might also require a slow-down or reversal of the widespread trend of scale enlargement in agriculture. Next to this trend of scale enlargement, small farms persist in Asia: consolidation of farms proceeds at a snail’s pace in South-east Asia and 70% of farms in India are ‘ultra-small’ – less than 0.05 ha. Also in Africa, where we find smallholder farms are much smaller than often assumed (< 1 ha), farming households are often food insecure. A raft of pro-poor policies and investments are needed to stimulate small-scale agriculture as part of a broader focus on rural development to address persistent poverty and hunger. Smallholder farms will remain an important source of food and income, and a social safety net in absence of alternative livelihood security. But with limited possibilities for smallholders to ‘step-up’, the agricultural engine of growth appears to be broken. Smallholder agriculture cannot deliver the rate of economic growth currently assumed by many policy initiatives in Africa.

The Conundrum of Low COVID-19 Mortality Burden in sub-Saharan Africa: Myth or Reality?

Abstract: The demographic age structure of sub-Saharan Africa contributes significantly to the low morbidity and mortality of COVID-19 compared to other regions in the world. Key Messages Evidence suggests the demographic age structure of sub-Saharan Africa is the leading factor of the low morbidity and mortality of COVID-19 compared to other regions of the world. Widespread social mitigation strategies, such as lockdowns, have resulted in severe economic and societal consequences in terms of food security, adolescent pregnancy, gender-based violence, and disruptions in treating other diseases. It is imperative to weigh the risks and benefits of social mitigation strategies for future waves.

A systematic and meta-analysis review on the diagnostic accuracy of antibodies in the serological diagnosis of COVID-19.

Abstract: Serological testing based on different antibody types are an alternative method being used to diagnose SARS-CoV-2 and has the potential of having higher diagnostic accuracy compared to the current gold standard rRT-PCR. Therefore, the objective of this review was to evaluate the diagnostic accuracy of IgG and IgM based point-of-care (POC) lateral flow immunoassay (LFIA), chemiluminescence enzyme immunoassay (CLIA), fluorescence enzyme-linked immunoassay (FIA) and ELISA systems that detect SARS-CoV-2 antigens. A systematic literature search was carried out in PubMed, Medline complete and MedRxiv. Studies evaluating the diagnostic accuracy of serological assays for SARS-CoV-2 were eligible. Study selection and data-extraction were performed by two authors independently. QUADAS-2 checklist tool was used to assess the quality of the studies. The bivariate model and the hierarchical summary receiver operating characteristic curve model were performed to evaluate the diagnostic accuracy of the serological tests. Subgroup meta-analysis was performed to explore the heterogeneity. The pooled sensitivity for IgG (n = 17), IgM (n = 16) and IgG-IgM (n = 24) based LFIA tests were 0.5856, 0.4637 and 0.6886, respectively compared to rRT-PCR method. The pooled sensitivity for IgG (n = 9) and IgM (n = 10) based CLIA tests were 0.9311 and 0.8516, respectively compared to rRT-PCR. The pooled sensitivity the IgG (n = 10), IgM (n = 11) and IgG-IgM (n = 5) based ELISA tests were 0.8292, 0.8388 and 0.8531 respectively compared to rRT-PCR. All tests displayed high specificities ranging from 0.9693 to 0.9991. Amongst the evaluated tests, IgG based CLIA expressed the highest sensitivity signifying its accurate detection of the largest proportion of infections identified by rRT-PCR. ELISA and CLIA tests performed better in terms of sensitivity compared to LFIA. IgG based tests performed better compared to IgM except for the ELISA. We report that IgG-IgM based ELISA tests have the best overall diagnostic test accuracy. Moreover, irrespective of the method, a combined IgG/IgM test seems to be a better choice in terms of sensitivity than measuring either antibody type independently. Given the poor performances of the current LFIA devices, there is a need for more research on the development of highly sensitivity and specific POC LFIA that are adequate for most individual patient applications and attractive for large sero-prevalence studies. PROSPERO CRD42020179112

Small farms and development in sub-Saharan Africa: Farming for food, for income or for lack of better options?

Abstract: Most food in sub-Saharan Africa is produced on small farms. Using large datasets from household surveys conducted across many countries, we find that the majority of farms are less than 1 ha, much smaller than previous estimates. Farms are larger in farming systems in drier climates. Through a detailed analysis of food self-sufficiency, food and nutrition security, and income among households from divergent farming systems in Ethiopia, Ghana, Mali, Malawi, Tanzania and Uganda, we reveal marked contrasts in food security and household incomes. In the south of Mali, where cotton is an important cash crop, almost all households are food secure, and almost half earn a living income. Yet, in a similar agroecological environment in northern Ghana, only 10% of households are food secure and none earn a living income. Surprisingly, the extent of food insecurity and poverty is almost as great in densely-populated locations in the Ethiopian and Tanzanian highlands that are characterised by much better soils and two cropping seasons a year. Where populations are less dense, such as in South-west Uganda, a larger proportion of the households are food self-sufficient and poverty is less prevalent. In densely-populated Central Malawi, a combination of a single cropping season a year and small farms results in a strong incidence of food insecurity and poverty. These examples reveal a strong interplay between population density, farm size, market access, and agroecological potential on food security and household incomes. Within each location, farm size is a major determinant of food self-sufficiency and a household’s ability to rise above the living income threshold. Closing yield gaps strongly increases the proportion of households that are food self-sufficient. Yet in four of the locations (Ethiopia, Tanzania, Ghana and Malawi), land is so constraining that only 42–53% of households achieve food self-sufficiency, and even when yield gaps are closed only a small proportion of households can achieve a living income. While farming remains of central importance to household food security and income, our results help to explain why off-farm employment is a must for many. We discuss these results in relation to sub-Saharan Africa’s increasing population, likely agricultural expansion, and agriculture’s role in future economic development.

Community perspectives on the COVID-19 response, Zimbabwe.

Abstract: Objective: To investigate community and health-care workers' perspectives on the coronavirus disease 2019 (COVID-19) pandemic and on early pandemic responses during the first 2 weeks of national lockdown in Zimbabwe. Methods: Rapid qualitative research was carried out between March and April 2020 via phone interviews with one representative from each of four community-based organizations and 16 health-care workers involved in a trial of community-based services for young people. In addition, information on COVID-19 was collected from social media platforms, news outlets and government announcements. Data were analysed thematically. Findings: Four themes emerged: (i) individuals were overloaded with information but lacked trusted sources, which resulted in widespread fear and unanswered questions; (ii) communities had limited ability to comply with prevention measures, such as social distancing, because access to long-term food supplies and water at home was limited and because income had to be earned daily; (iii) health-care workers perceived themselves to be vulnerable and undervalued because of a shortage of personal protective equipment and inadequate pay; and (iv) other health conditions were sidelined because resources were redirected, with potentially wide-reaching implications. Conclusion: It is important that prevention measures against COVID-19 are appropriate for the local context. In Zimbabwe, communities require support with basic needs and access to reliable information to enable them to follow prevention measures. In addition, health-care workers urgently need personal protective equipment and adequate salaries. Essential health-care services and medications for conditions other than COVID-19 must also continue to be provided to help reduce excess mortality and morbidity.

Exploring Perceived Barriers and Facilitators of PrEP Uptake among Young People in Uganda, Zimbabwe, and South Africa

Abstract: Pre-exposure prophylaxis (PrEP) is an effective HIV prevention strategy. Few studies have explored adolescents and young people’s perspectives toward PrEP. We conducted 24 group discussions and 60 in-depth interviews with males and females aged 13–24 years in Uganda, Zimbabwe, and South Africa between September 2018 and February 2019. We used the framework approach to generate themes and key concepts for analysis following the social ecological model. Young people expressed a willingness to use PrEP and identified potential barriers and facilitators of PrEP uptake. Barriers included factors at individual (fear of HIV, fear of side effects, and PrEP characteristics), interpersonal (parental influence, absence of a sexual partner), community (peer influence, social stigma), institutional (long waiting times at clinics, attitudes of health workers), and structural (cost of PrEP and mode of administration, accessibility concerns) levels. Facilitators included factors at individual (high HIV risk perception and preventing HIV/desire to remain HIV negative), interpersonal (peer influence, social support and care for PrEP uptake), community (adequate PrEP information and sensitization, evidence of PrEP efficacy and safety), institutional (convenient and responsive services, provision of appropriate and sufficiently resourced services), and structural (access and availability of PrEP, cost of PrEP) levels. The findings indicated that PrEP is an acceptable HIV prevention method. PrEP uptake is linked to personal and environmental factors that need to be considered for successful PrEP roll-out. Multi-level interventions needed to promote PrEP uptake should consider the social and structural drivers and focus on ways that can inspire PrEP uptake and limit the barriers.

Multinutrient biofortification of maize (Zea mays L.) in Africa: current status, opportunities and limitations

Abstract: Macro and micronutrient deficiencies pose serious health challenges globally, with the largest impact in developing regions such as subSaharan Africa (SSA), Latin America and South Asia. Maize is a good source of calories but contains low concentrations of essential nutrients. Major limiting nutrients in maize-based diets are essential amino acids such as lysine and tryptophan, and micronutrients such as vitamin A, zinc (Zn) and iron (Fe). Responding to these challenges, separate maize biofortification programs have been designed worldwide, resulting in several cultivars with high levels of provitamin A, lysine, tryptophan, Zn and Fe being commercialized. This strategy of developing single-nutrient biofortified cultivars does not address the nutrient deficiency challenges in SSA in an integrated manner. Hence, development of maize with multinutritional attributes can be a sustainable and cost-effective strategy for addressing the problem of nutrient deficiencies in SSA. This review provides a synopsis of the health challenges associated with Zn, provitamin A and tryptophan deficiencies and link these to vulnerable societies; a synthesis of past and present intervention measures for addressing nutrient deficiencies in SSA; and a discussion on the possibility of developing maize with multinutritional quality attributes, but also with adaptation to stress conditions in SSA.

Global variations in the prevalence, treatment, and impact of atrial fibrillation in a multi-national cohort of 153,152 middle-aged individuals

Abstract: AIMS To compare the prevalence of electrocardiogram (ECG)-documented atrial fibrillation (or flutter) (AF) across eight regions of the world, and to examine antithrombotic use and clinical outcomes. METHODS AND RESULTS Baseline ECGs were collected in 153 152 middle-aged participants (ages 35-70 years) to document AF in two community-based studies, spanning 20 countries. Medication use and clinical outcome data (mean follow-up of 7.4 years) were available in one cohort. Cross-sectional analyses were performed to document the prevalence of AF and medication use, and associations between AF and clinical events were examined prospectively. Mean age of participants was 52.1 years, and 57.7% were female. Age and sex-standardized prevalence of AF varied 12-fold between regions; with the highest in North America, Europe, China, and Southeast Asia (270-360 cases per 100 000 persons); and lowest in the Middle East, Africa, and South Asia (30-60 cases per 100 000 persons) (P < 0.001). Compared with low-income countries (LICs), AF prevalence was 7-fold higher in middle-income countries (MICs) and 11-fold higher in high-income countries (HICs) (P < 0.001). Differences in AF prevalence remained significant after adjusting for traditional AF risk factors. In LICs/MICs, 24% of participants with AF and a CHADS2 score ≥1 received antithrombotic therapy, compared with 85% in HICs. AF was associated with an increased risk of stroke [hazard ratio (HR) 2.29; 95% confidence interval (CI) 1.49-3.52] and death (HR 2.97; 95% CI 2.25-3.93); with similar rates in different countries grouped by income level. CONCLUSIONS Large variations in AF prevalence occur in different regions and countries grouped by income level, but this is only partially explained by traditional AF risk factors. Antithrombotic therapy is infrequently used in poorer countries despite the high risk of stroke associated with AF.

Insects, Rodents, and Pets as Reservoirs, Vectors, and Sentinels of Antimicrobial Resistance.

Abstract: This paper reviews the occurrence of antimicrobial resistance (AMR) in insects, rodents, and pets. Insects (e.g., houseflies, cockroaches), rodents (rats, mice), and pets (dogs, cats) act as reservoirs of AMR for first-line and last-resort antimicrobial agents. AMR proliferates in insects, rodents, and pets, and their skin and gut systems. Subsequently, insects, rodents, and pets act as vectors that disseminate AMR to humans via direct contact, human food contamination, and horizontal gene transfer. Thus, insects, rodents, and pets might act as sentinels or bioindicators of AMR. Human health risks are discussed, including those unique to low-income countries. Current evidence on human health risks is largely inferential and based on qualitative data, but comprehensive statistics based on quantitative microbial risk assessment (QMRA) are still lacking. Hence, tracing human health risks of AMR to insects, rodents, and pets, remains a challenge. To safeguard human health, mitigation measures are proposed, based on the one-health approach. Future research should include human health risk analysis using QMRA, and the application of in-silico techniques, genomics, network analysis, and 'big data' analytical tools to understand the role of household insects, rodents, and pets in the persistence, circulation, and health risks of AMR.

Tenofovir diphosphate concentrations in dried blood spots from pregnant and postpartum adolescent and young women receiving daily observed pre-exposure prophylaxis in sub-Saharan Africa

Abstract: Background Intracellular tenofovir diphosphate (TFV-DP) concentration measured in dried blood spots (DBS) is used to monitor cumulative adherence to pre-exposure prophylaxis (PrEP). We evaluated TFV-DP in DBS following daily oral PrEP (emtricitabine 200mg/tenofovir diphosphate 300mg) among pregnant and postpartum adolescent girls and young women (AGYW). Methods Directly observed PrEP was administered for 12 weeks in a pregnancy group (14-24 weeks gestation, n=20) and a postpartum group (6-12 weeks postpartum, n=20) of AGYW aged 16-24 years in sub-Saharan Africa. Weekly DBS TFV-DP was measured by validated liquid chromatography-tandem mass spectrometry assay. Week 12 TFV-DP distributions were compared between groups with the Wilcoxon test. Population pharmacokinetic models were fit to estimate steady-state concentrations and create benchmarks for adherence categories. Baseline correlates of TFV-DP were evaluated. Results Participant median age was 20 years (IQR:19,22). Of 3360 doses, 3352 (>99%) were directly observed. TFV-DP median half-life was ten days (IQR:7, 12) in pregnancy and 17 days (IQR:14, 21) postpartum, with steady-state achieved by five and eight weeks, respectively. Observed median steady-state TFV-DP was 965 fmol/punch (IQR:691, 1166) in pregnancy vs 1406 fmol/punch (IQR:1053, 1859) postpartum (p=0.006). Modelled median steady-state TFV-DP was 881 fmol/punch (IQR: 667,1105) in pregnancy vs 1438 fmol/punch (IQR: 1178,1919) postpartum. In pooled analysis, baseline creatinine clearance was associated with observed TFV-DP concentrations. Conclusion TFV-DP in African AGYW was approximately one-third lower in pregnancy than postpartum. Population-specific benchmarks provided by this study can be used to guide PrEP adherence support in pregnant/postpartum African women.

The impact and implications of COVID-19: Reflections on the Zimbabwean society.

Abstract: The article is an attempt to provide a kaleidoscopic interpretation of how social science scholarship views the socio-cultural terrain of Zimbabwe during and after the global health crisis, and the societal and business haemorrhage induced by the coronavirus (COVID-19). Built through a multi-perspective and triangulation involving a modified Delphic approach that engages archival methods involving document and literature review, content analysis and expert interpretation; the article unveils the various effects of COVID-19 on Zimbabwe. It is concluded that COVID-19 by its nature is disruptive to everyday life, restrictive to human-social relations and is an instigator to tradition, spirituality and intellectuality in the country. The challenge of the virus brings to society a deliberate consciousness that global processes and events are converging (borders are porous) while local embeddedness is being entrenched through practices like lockdowns and confinement.

The effect of non-AIDS-defining cancers on people living with HIV.

Abstract: Non-AIDS-defining cancers are a growing source of morbidity for people with HIV globally. Although people living with HIV have a disproportionately increased risk of developing virally mediated cancers, cancer burden for common non-AIDS-defining cancers that are not virally associated and are linked to ageing, such as prostate cancer, is becoming higher than for virally mediated cancers. Ageing, behavioural, and HIV-specific factors drive the incidence and affect the outcomes of non-AIDS-defining cancers, presenting different challenges for addressing global morbidity and mortality from non-AIDS-defining cancer. Although large population-based studies have shown that people living with HIV with non-AIDS-defining cancers have poorer cancer outcomes than do people without HIV, current guidelines emphasise that people living with HIV with non-AIDS-defining cancers should receive standard, guideline-based treatment, and infectious disease and oncology providers should work closely to address potential drug interactions between antiretroviral therapy and antineoplastic treatment. Most trials target preventive measures focusing on non-AIDS-defining cancers. However, treatment trials for the optimal management of people living with HIV and non-AIDS-defining cancer, including interventions such as immunotherapies, are needed to improve non-AIDS-defining cancer outcomes.

A Phase 2b Study to Evaluate the Safety and Efficacy of VRC01 Broadly Neutralizing Monoclonal Antibody in Reducing Acquisition of HIV-1 Infection in Women in Sub-Saharan Africa: Baseline Findings.

Abstract: Background HIV Vaccine Trials Network 703/HIV Prevention Trials Network 081 is a phase 2b randomized, double-blind, placebo-controlled trial to assess the safety and efficacy of passively infused monoclonal antibody VRC01 in preventing HIV acquisition in heterosexual women between the ages of 18 and 50 years at risk of HIV. Participants were enrolled at 20 sites in Botswana, Kenya, Malawi, Mozambique, South Africa, Tanzania, and Zimbabwe. It is one of the 2 Antibody Mediated Prevention efficacy trials, with HIV Vaccine Trials Network 704/HIV Prevention Trials Network 085, evaluating VRC01 for HIV prevention. Methods Intense community engagement was used to optimize participant recruitment and retention. Participants were randomly assigned to receive intravenous VRC01 10 mg/kg, VRC01 30 mg/kg, or placebo in a 1:1:1 ratio. Infusions were given every 8 weeks with a total of 10 infusions and 104 weeks of follow-up after the first infusion. Results Between May 2016 and September 2018, 1924 women from sub-Saharan Africa were enrolled. The median age was 26 years (interquartile range: 22-30), and 98.9% were Black. Sexually transmitted infection prevalence at enrollment included chlamydia (16.9%), trichomonas (7.2%), gonorrhea (5.7%), and syphilis (2.2%). External condoms (83.2%) and injectable contraceptives (61.1%) were the methods of contraception most frequently used by participants. In total, through April 3, 2020, 38,490 clinic visits were completed with a retention rate of 96% and 16,807 infusions administered with an adherence rate of 98%. Conclusions This proof-of-concept, large-scale monoclonal antibody study demonstrates the feasibility of conducting complex trials involving intravenous infusions in high incidence populations in sub-Saharan Africa.

Prediction of anti-tuberculosis treatment duration based on a 22-gene transcriptomic model.

Abstract: Background The World Health Organization recommends standardised treatment durations for patients with tuberculosis (TB). We identified and validated a host-RNA signature as a biomarker for individualised therapy durations for patients with drug-susceptible (DS)- and multidrug-resistant (MDR)-TB. Methods Adult patients with pulmonary TB were prospectively enrolled into five independent cohorts in Germany and Romania. Clinical and microbiological data and whole blood for RNA transcriptomic analysis were collected at pre-defined time points throughout therapy. Treatment outcomes were ascertained by TBnet criteria (6-month culture status/1-year follow-up). A whole-blood RNA therapy-end model was developed in a multistep process involving a machine-learning algorithm to identify hypothetical individual end-of-treatment time points. Results 50 patients with DS-TB and 30 patients with MDR-TB were recruited in the German identification cohorts (DS-GIC and MDR-GIC, respectively); 28 patients with DS-TB and 32 patients with MDR-TB in the German validation cohorts (DS-GVC and MDR-GVC, respectively); and 52 patients with MDR-TB in the Romanian validation cohort (MDR-RVC). A 22-gene RNA model (TB22) that defined cure-associated end-of-therapy time points was derived from the DS- and MDR-GIC data. The TB22 model was superior to other published signatures to accurately predict clinical outcomes for patients in the DS-GVC (area under the curve 0.94, 95% CI 0.9–0.98) and suggests that cure may be achieved with shorter treatment durations for TB patients in the MDR-GIC (mean reduction 218.0 days, 34.2%; p Conclusion Biomarker-guided management may substantially shorten the duration of therapy for many patients with MDR-TB.

Insects in food and feed systems in sub-Saharan Africa: the untapped potentials

Abstract: Insects as food and feed have the potential to alleviate food, feed and nutrition insecurity in sub-Saharan Africa (SSA) against a backdrop of climate change. Such use has gained unprecedented attention in the past decade and the trend will probably continue due to the species diversity, new discoveries in the nutritional, neutraceutical and medicinal potentials of edible insect species. In order to meet the increasing demand for insects as food and feed, insect farming should complement sustainable wild insect harvesting. The ecological impact of insect farming, economics, species biological and processing aspects deserve empirical investigation. This is crucial in order to effectively guide potential insect producers and processors. Besides the use of insects in folk medicine, several industrial products including polyunsaturated and monosaturated fatty acids, peptides, enzymes, and antimicrobial compounds can be obtained from edible insects. With the teaming world population, value addition via product fortification is a practical strategy to enhance the acceptance of edible insects for human food and nutrition security. The future of insects as food and feed will witness the development of international trade and SSA governments should be ready to comply with product standardization and legislation requirements to penetrate external markets. Despite the diversity of edible insects in SSA and some commonalities there-in, not all consumers are well-informed on the inherent risks of allergens, toxicants and antinutritional compounds occurring in some edible species. Further research needs and future strategies to exploit the untapped potential of insects as food and feed in SSA are mapped out.