Assessment of trace elements (Cu, Fe, and Zn) in Limnothrissa miodon from Lake Kariba, Zambia: implications for ecological and human health

This study examined Copper (Cu), Iron (Fe), and Zinc (Zn) levels in Limnothrissa miodon fish from Lake Kariba in Zambia and their potential impact on human health. Two-gram samples from each stratum underwent a 12-hour digestion, and concentrations were determined using Microwave Plasma Atomic Emission Spectrometer. Results indicated that Cu, Fe, and Zn concentrations fell within Food and Agricultural Organization and World Health Organization safety limits. Estimated Daily Intake (EDI) and Hazard Quotient (THQ) values for males and females remained under recommended thresholds, suggesting minimal health risks from consumption. Element concentrations followed the order Fe > Zn > Cu, all below Recommended Daily Allowances (RDAs). THQ values, with Zn posing the highest potential risk followed by Fe and Cu, were under one. Overall, the Hazard Index (HI) was 0.02, signifying a low non-carcinogenic risk from fish consumption. Despite safety, ongoing monitoring of heavy metal accumulation in the ecosystem is advisable for long-term safety. In conclusion, trace element levels in Limnothrissa miodon from Lake Kariba are safe for human consumption with low associated health risks. Nonetheless, continued monitoring of heavy metal levels is vital

Efficacy of sodium bicarbonate (Baking soda) and clove powder (Syzygium aromaticum) as anaesthetic agents for Nile tilapia (Oreochromis niloticus, linnaeus 1758) juveniles

Anaesthetics in aquaculture serve as a stress avoidance mechanism, mitigating stress-related impacts during fish handling and transportation. This study assessed the efficacy of sodium bicarbonate and clove stem powder as anaesthetic agents for Nile Tilapia juveniles. Four hundred and twenty uniform O. niloticus juveniles (5 ± 0.5 g, 74 ± 5 mm) were exposed to varying concentrations of sodium bicarbonate (10, 15, 20, 25, 30, 35, 40 g/L) and clove stem powder (0, 1, 3, 5, 7, 10, 15 g/L) in 20 L transparent plastic tanks. The results showed an inverse relationship between anaesthetic concentration and induction time, a direct relationship with recovery time, and an inverse correlation between induction and recovery times for both agents (P < 0.001). The Appropriate concentrations were determined as 25 g/L for sodium bicarbonate and 10 g/L for clove stem powder. At these levels, induction and recovery times met ideal criteria (3-5 min induction, 5-10 min recovery), with fish exhibiting normal behavior and 100% survival after a week of monitoring

Sustainability of agriculture extension services in the face of COVID-19: a study on gender-specific market systems

In the fourth industrial revolution, achieving sustainable agricultural development while feeding a growing world population and maintaining a balanced interrelationship between the economy, society, and the environment has been a significant challenge. However, COVID-19 disrupted agricultural extension and advisory systems, affecting all market participants. The complexity of the pandemic has impacted the private sector, public sector, extension staff, donor funding, education, and research systems, subsequently affecting human nutrition. This paper aims to expertly review COVID-19’s effects on the sustainability of gender-specific agricultural extension service systems. Demand and supply market stakeholders in the extension system are thematically discussed. The findings reveal various consequences of COVID-19 for market actors on both the demand and supply sides of the extension system. Private-sector players often support expansion directly or indirectly, with multi-sectorial support and funding strategies existing for sustainability. In many developing nations, the comprehensive extension system was disrupted by COVID-19, impacting household incomes and nutrition. The pandemic accelerated the adoption of digital technologies in many developing nations, transitioning from a centralized to a decentralized and pluralistic extension model. Multi-sector coordination and execution, especially from health and other sectors, are crucial in managing complex crises that disrupt the market system

Development and validation of quantitative PCR assays for HIV-associated cryptococcal meningitis in sub-Saharan Africa: a diagnostic accuracy study

Background: HIV-associated cryptococcal meningitis is the second leading cause of AIDS-related deaths, with a 10-week mortality rate of 25–30%. Fungal load assessed by colony-forming unit (CFU) counts is used as a prognostic marker and to monitor response to treatment in research studies. PCR-based assessment of fungal load could be quicker and less labour-intensive. We sought to design, optimise, and validate quantitative PCR (qPCR) assays for the detection, identification, and quantification of Cryptococcus infections in patients with cryptococcal meningitis in sub-Saharan Africa. Methods: We developed and validated species-specific qPCR assays based on DNA amplification of QSP1 (QSP1A specific to Cryptococcus neoformans, QSP1B/C specific to Cryptococcus deneoformans, and QSP1D specific to Cryptococcus gattii species) and a pan-Cryptococcus assay based on a multicopy 28S rRNA gene. This was a longitudinal study that validated the designed assays on cerebrospinal fluid (CSF) of 209 patients with cryptococcal meningitis at baseline (day 0) and during anti-fungal therapy (day 7 and day 14), from the AMBITION-cm trial in Botswana and Malawi (2018–21). Eligible patients were aged 18 years or older and presenting with a first case of cryptococcal meningitis. Findings: When compared with quantitative cryptococcal culture as the reference, the sensitivity of the 28S rRNA was 98·2% (95% CI 95·1–99·5) and of the QSP1 assay was 90·4% (85·2–94·0) in CSF at day 0. Quantification of the fungal load with QSP1 and 28S rRNA qPCR correlated with quantitative cryptococcal culture (R2=0·73 and R2=0·78, respectively). Both Botswana and Malawi had a predominant C neoformans prevalence of 67% (95% CI 55–75) and 68% (57–73), respectively, and lower C gattii rates of 21% (14–31) and 8% (4–14), respectively. We identified ten patients that, after 14 days of treatment, harboured viable but non-culturable yeasts based on QSP1 RNA detection (without any positive CFU in CSF culture). Interpretation: QSP1 and 28S rRNA assays are useful in identifying Cryptococcus species. qPCR results correlate well with baseline quantitative cryptococcal culture and show a similar decline in fungal load during induction therapy. These assays could be a faster alternative to quantitative cryptococcal culture to determine fungal load clearance. The clinical implications of the possible detection of viable but non-culturable cells in CSF during induction therapy remain unclear. Funding: European and Developing Countries Clinical Trials Partnership; Swedish International Development Cooperation Agency; Wellcome Trust/UK Medical Research Council/UKAID Joint Global Health Trials; and UK National Institute for Health Research

Improving ART initiation among men who use HIV self-testing in Malawi: a qualitative study

INTRODUCTION: HIV self‐testing (HIVST) increases HIV testing uptake among men; however, the linkage to antiretroviral therapy (ART) among HIVST users is low. Innovative strategies for ART initiation are needed, yet little is known about the unique barriers to care experienced by male HIVST users, and what ART‐related interventions men desire. METHODS: We conducted semi‐structured in‐depth interviews with cisgender men (≥15 years) in Malawi who tested HIV positive using HIVST between 2018 and 2020, as well as interviews with their female partners (≥15 years) who distributed the HIVST kits. Medical records from seven facilities were used to identify respondents. We included men who received HIVST from a health facility (primary distribution) and from sexual partners (secondary distribution). Interview guides focused on unique barriers to ART initiation following HIVST and desired interventions to improve linkage and initiation. Interviews were audio recorded, translated and transcribed to English, and analysed using constant comparison methods in Atlas.ti v.8.4. Themes were compared by HIVST distribution strategy. Data were collected between 2019 and 2020. RESULTS: Twenty‐seven respondents were interviewed: eight male/female dyads (16 respondents), eight men without a female partner and three women who represented men who did not participate in the study. Among the 19 men represented (16 men interviewed in person, three represented by secondary report from female partners), seven received HIVST through primary distribution, 12 through secondary distribution. Six men never initiated ART (all secondary HIVST distribution). Barriers to ART initiation centred on the absence of healthcare workers at the time of diagnosis and included lack of external motivation for linkage to care (men had to motivate themselves) and lack of counselling before and after testing (leaving ART‐related fears and misconceptions unaddressed)––the latter was especially true for secondary HIVST distribution. Desired interventions were similar across distribution strategies and included ongoing peer mentorship for normalizing treatment adherence, counselling messages tailored to men, outside‐facility services for convenience and privacy, and facility navigation to help men understand how to navigate ART clinics. CONCLUSIONS: Male HIVST users face unique challenges to ART initiation, especially those receiving HIVST through secondary distribution. Male‐tailored interventions are desired by men and may help overcome barriers to care

Application of anaesthetics in fish hatcheries to promote broodstock and fish seed welfare in Zambia

AbstractThis study investigated the application of anaesthetics in 23 private and government-owned hatcheries in 10 provinces of Zambia. The study employed both qualitative and quantitative research designs and used a structured questionnaire to collect data from the respondents. The results showed that most hatcheries (65%) were not using anaesthetics in handling fish and all (100%) that were using anaesthetics (35%) used clove powder as the only type. Most respondents (61%) were not sure or did not have information about the availability of the anaesthetic substances in their localities while only 26% reported wider availability but 13% had a divergent claim. The mortality rate for fingerlings in hatcheries that applied anaesthetics ranged between 15–30% with consistently high demand while those that did not use anaesthetics reported mortality rates of more than 50% and had low demand. The majority of the respondents (53%) had received training up to certificate level, followed by those who had attained up to a diploma qualification (27%) while those that attained up to a degree (13%) and general skills (7%) levels were in the minority. Furthermore, most respondents (35%) did not know the importance of fish anaesthetics. We conclude that the use of fish anaesthetics in Zambian hatcheries is very low and could partly be the cause of high fingerling mortalities, and there is an urgent need to address the situation

Sustainability of agriculture extension services in the face of COVID-19: A study on gender-specific market systems

In the fourth industrial revolution, achieving sustainable agricultural development while feeding a growing world population and maintaining a balanced interrelationship between the economy, society, and the environment has been a significant challenge. However, COVID-19 disrupted agricultural extension and advisory systems, affecting all market participants. The complexity of the pandemic has impacted the private sector, public sector, extension staff, donor funding, education, and research systems, subsequently affecting human nutrition. This paper aims to expertly review COVID-19’s effects on the sustainability of gender-specific agricultural extension service systems. Demand and supply market stakeholders in the extension system are thematically discussed. The findings reveal various consequences of COVID-19 for market actors on both the demand and supply sides of the extension system. Private-sector players often support expansion directly or indirectly, with multi-sectorial support and funding strategies existing for sustainability. In many developing nations, the comprehensive extension system was disrupted by COVID-19, impacting household incomes and nutrition. The pandemic accelerated the adoption of digital technologies in many developing nations, transitioning from a centralized to a decentralized and pluralistic extension model. Multi-sector coordination and execution, especially from health and other sectors, are crucial in managing complex crises that disrupt the market system.</p

Prioritizing plant parasitic nematode and mollusca species likely to be introduced and threaten agriculture, forestry, and biodiversity in Zambia: A horizon scanning approach

Introduction of invasive alien species (quarantine pests) through intentional or unintentional human-mediated activities has caused enormous economic and environmental impacts necessitating forward planning to identify, prioritise, and prevent their introduction. Using CABI’s Horizon Scanning Tool, 26 mollusca and 199 plant parasitic nematode (PPN) species not reported as present in Zambia were identified. The list was refined to focus on species affecting Zambia’s important value chains resulting in final lists of 130 PPN and 20 mollusca species that were subjected to risk assessment using agreed guidelines. The possible highest and lowest overall risk scores expected were 250 and 2 respectively. The highest overall score was 140 obtained for Arion hortensis, Cornu aspersum, and Deroceras reticulatumi (mollusca) and Pratylenchus penetrans, P. thornei, and Rotylenchulus reniformis (PPN) and the lowest for mollusca was 10, recorded for Arion ater and for PPN, three, recorded by for Peltamigratus luci. Nine (45%; N=20) and 58 (45%; N=130) of the assessed mollusca and PPN species respectively, attained a suggested minimum overall risk score of 54 necessary for instituting phytosanitary measures that limit pest introduction. All assessed mollusca species were likely be introduced through the contaminant and stowaway pathways. The majority (54%; n=70; N=130) of the PPN species were likely to be introduced via contaminant or stowaway pathways, 7 (5%) and 53 (41%) solely as contaminants and stowaways, respectively. Eleven of the PPN are known vectors of pathogenic organisms. Five of the vectored viruses recorded overall risk scores above 54 and included Tomato ringspot virus (105), Tobacco rattle virus (90), Pea early-browning virus (72), Tomato black ring virus (70), and Arabis mosaic virus (60). The assessed PPN were also vectored by insects (order Coleoptera and families, Cerambycidae, Curculionidae, and Dryophthoridae), three of which recorded overall risk scores above the suggested minimum, Monochamus galloprovincialis (60) Orthotomicus erosus (100), and Rhynchophorus palmarum (72). Actions to limit introduction were also suggested for pathogenic organism vectored by PPN and vectors of PPN. The information from this assessment will guide a number of interventions aimed at developing strategies that prevent introduction and spread of assessed mollusca and PPN specie

Rapid risk assessment of plant pathogenic bacteria and protists likely to threaten agriculture, biodiversity and forestry in Zambia

A prioritisation study was conducted to address the lack of adequate information about potential pests likely to be introduced in Zambia and become invasive. The study was conducted by subject matter experts from relevant institutions in and outside Zambia. Although this study focused on major pest categories, this paper only addresses bacteria and Protista. A list of 306 bacterial and 10 Protista species adjudged to affect plants was generated using CABI’s Horizon Scanning Tool. The 316 (total) pest species were refined to focus on pests that affect value chains important to Zambia’s economy. This resulted in a final list of 133 bacteria and eight Protista. Four additional bacteria species considered of phytosanitary interest were added and all 137 bacteria and eight Protista species were subjected to a rapid risk assessment using agreed guidelines. Vectors reported to transmit any of the pathogenic organisms were also subjected to a risk assessment. A proportion of 53% (n = 77 of 145) comprising 73 bacteria and four Protista species were reported as present in Africa. Of these, 42 (57%, n = 73) bacterial species and two (n=4) Protista species were reported in neighbouring countries. Considering a cut-off of 54, the highest scoring pests were 40 bacteria (highest score of 140) and three Protista (highest score of 125). Three actions were suggested for high-scoring pests, a detection surveillance, a pest-initiated pest risk analysis (PRA) or a detection surveillance followed by pest-initiated PRA. A “no action” was suggested where the risk was very low although, for some pathogenic organisms, a “no action” was followed by periodic monitoring. This information will contribute towards proactive prevention and management of biological invasions

Rapid Risk Assessment of plant pathogenic bacteria and protists likely to threaten agriculture, biodiversity and forestry in Zambia

A prioritisation study was conducted to address the lack of adequate information about potential pests likely to be introduced in Zambia and become invasive. The study was conducted by subject matter experts from relevant institutions in and outside Zambia. Although this study focussed on major pest categories, this paper only addresses bacteria and Protista. A list of 306 bacterial and 10 Protista species adjudged to affect plants was generated using CABI’s Horizon Scanning Tool. The 316 (total) pest species were refined to focus on pests that affect value chains important to Zambia’s economy. This resulted in a final list of 133 bacteria and 8 Protista. Four additional bacteria species considered of phytosanitary interest were added and all 137 bacteria and 8 Protista species were subjected to a rapid risk assessment using agreed guidelines. Vectors reported to transmit any of the pathogenic organisms were also subjected to a risk assessment. A proportion of 53% (n=77 of 145) comprising 73 bacteria and 4 Protista species were reported as present in Africa. Of these, 42 (57%, n=73) bacterial species and 2 (n=4) Protista species were reported in neighbouring countries. Considering a cut-off of 54, the highest scoring pests were 40 bacteria (highest score of 140) and three Protista (highest score of 125). Three actions were suggested for high-scoring pests, a detection surveillance, a pest-initiated pest risk analysis (PRA) or a detection surveillance followed by pest-initiated PRA. A “no action” was suggested where the risk was very low although for some pathogenic organisms, a “no action” was followed by periodic monitoring. This information will contribute towards proactive prevention and management of biological invasions