BIOCHEMICAL FACTORS ASSOCIATED WITH CASSAVA RESISTANCE TO WHITEFLY INFESTATION

Cassava ( Manihot esculenta Crantz) an important food security crop, is inflicted by whitefly ( Bemisia tabaci ) worldwide, causing direct damage of up to 80% of yield loss. Although resistance to the pest has been associated with antibiosis, changes that occur in metabolite activity, and their effect on the pest have not been fully elucidated. A study was carried out to evaluate changes in peroxidase, tannin and flavonoid activity in cassava genotypes attacked by B. tabaci in order to contribute to knowledge on whitefly resistance in cassava. Five genotypes showing resistance, and three susceptible, were selected based on whitefly count and leaf damage scores, and assayed for peroxidase, tannin and flavonoid activity. There were significant differences among genotypes for leaf damage (P < 0.01) of three to six months plants. Genotypes CS1-144, UG 120133 and NAM 130 showed low damage scores (< 2.00); but a high damage score (> 2.5) was incurred by UG 130068. All genotypes showed significant (P < 0.05) differences for peroxidase activity, with CS1-144 having a high activity rate three months after planting. The lowest activity was observed in UG 120170, a susceptible genotype. A significant (P < 0.01) negative correlation (r = -0.84) was observed between peroxidase activity and cassava leaf damage scores, as well as between tannin and damage (r = -0.57), indicating that peroxidase and tannin play a part in cassava resistance to B. tabaci.Le manioc ( Manihot esculenta Crantz) qui est une importante culture de s\ue9curit\ue9 alimentaire, est influenc\ue9e par la mouche blanche ( Bemisia tabaci ) sur le plan mondial, \ue0 travers des dommages directs allant jusqu\u2019\ue0 80% de perte du rendement. Par ailleurs, la r\ue9sistance \ue0 la peste a \ue9t\ue9 associ\ue9e \ue0 l\u2019antibiose, des changements qui apparaissent dans l\u2019activit\ue9 m\ue9tabolique, et leur effet sur la peste n\u2019ont pas encore \ue9t\ue9 compl\ue8tement \ue9lucid\ue9s. Une \ue9tude a \ue9t\ue9 entreprise pour \ue9valuer les changements d\u2019activit\ue9 en peroxydase, tannin et flavono\uefde dans les g\ue9notypes du manioc attaqu\ue9s par B. tabaci dans le but de contribuer au savoir sur la r\ue9sistance du\ua0manioc. Cinq g\ue9notypes, montrant r\ue9sistance, et trois susceptibles, \ue9taient s\ue9lectionn\ue9s sur la base du nombre de la mouche blanche et les sores de dommages et analys\ue9s pour l\u2019activit\ue9 en peroxydase, tannin and flavono\uefdes. Il y avait de diff\ue9rences significatives entre les g\ue9notypes pour les dommages caus\ue9s sur les feuilles (P< 0,01) des plantes de trois \ue0 six mois. Les g\ue9notypes CS1-144, UG 120133 et NAM 130 ont montr\ue9 de faibles scores de dommage (< 2,00); mais un score \ue9lev\ue9 de dommage (> 2,5) \ue9tait re\ue7u par UG 130068. Tous les g\ue9notypes ont montr\ue9 de diff\ue9rences significatives (P < 0,05) pour l\u2019activit\ue9 de peroxydase, avec CS1-144 ayant un taux d\u2019activit\ue9 \ue9lev\ue9 trois mois apr\ue8s la plantation. La faible activit\ue9 \ue9tait observ\ue9e sur UG 120170, un g\ue9notype susceptible. Une corr\ue9lation significative (P < 0,01) et n\ue9gative (r = -0,84) \ue9tait observ\ue9e entre l\u2019activit\ue9 de peroxydase et les scores de dommages sur les feuilles de manioc, ainsi que entre tannin et dommage (r = -0,57), indiquant que peroxydase et tannin jouent une part de r\uf4le dans la r\ue9sistance du manioc au B. tabaci

Experiences of Justice-Involved People Transitioning to HIV Care in the Community After Prison Release in Lusaka, Zambia: A Qualitative Study

Introduction: In sub-Saharan Africa (SSA), incarcerated people experience a higher HIV burden than the general population. While access to HIV care and treatment for incarcerated people living with HIV (PLHIV) in SSA has improved in some cases, little is known about their transition to and post-release experience with care in the community. To address this gap, we conducted a qualitative study to describe factors that may influence post-release HIV care continuity in Zambia. Methods: In March-December 2018, we recruited study participants from a larger prospective cohort study following incarcerated and newly released PLHIV at 5 correctional facilities in 2 provinces in Zambia. We interviewed 50 participants immediately before release; 27 (54%) participated in a second interview approximately 6 months post-release. Demographic and psychosocial data were collected through a structured survey. Results: The pre-release setting was strongly influenced by the highly structured prison environment and assumptions about life post-release. Participants reported accessible HIV services, a destigmatizing environment, and strong informal social supports built through comradery among people facing the same trying detention conditions. Contrary to their pre-release expectations, during the immediate post-release period, participants struggled to negotiate the health system while dealing with unexpected stressors. Long-term engagement in HIV care was possible for participants with strong family support and a high level of self-efficacy. Conclusion: Our study highlights that recently released PLHIV in Zambia face acute challenges in meeting their basic subsistence needs, as well as social isolation, which can derail linkage to and retention in community HIV care. Releasees are unprepared to face these challenges due to a lack of community support services. To improve HIV care continuity in this population, new transitional care models are needed that develop client self-efficacy, facilitate health system navigation, and pragmatically address structural and psychosocial barriers like poverty, gender inequality, and substance use

The burden and natural history of cardiac pathology at TB diagnosis in a high-HIV prevalence district in Zambia: protocol for the TB-Heart study.

BACKGROUND: Tuberculosis (TB) continues to be a major cause of death across sub-Saharan Africa (SSA). In parallel, non-communicable disease and especially cardiovascular disease (CVD) burden has increased substantially in the region. Cardiac manifestations of TB are well-recognised but the extent to which they co-exist with pulmonary TB (PTB) has not been systematically evaluated. The aim of this study is to improve understanding of the burden of cardiac pathology in PTB in those living with and without HIV in a high-burden setting. METHODS: This is a cross-sectional and natural history study to evaluate the burden and natural history of cardiac pathology in participants with PTB in Lusaka, Zambia, a high burden setting for TB and HIV. Participants with PTB, with and without HIV will be consecutively recruited alongside age- and sex-matched TB-uninfected comparators on a 2:1 basis. Participants will undergo baseline assessments to collect clinical, socio-demographic, functional, laboratory and TB disease impact data followed by point-of-care and standard echocardiography. Participants with PTB will undergo further repeat clinical and functional examination at two- and six months follow-up. Those with cardiac pathology at baseline will undergo repeat echocardiography at six months. DISCUSSION: The outcomes of the study are to a) determine the burden of cardiac pathology at TB diagnosis, b) describe its association with patient-defining risk factors and biochemical markers of cardiac injury and stretch and c) describe the natural history of cardiac pathology during the course of TB treatment

Universal combination antiretroviral regimens to prevent mother-to-child transmission of HIV in rural Zambia: a two-round cross-sectional study

To evaluate if a pilot programme to prevent mother-to-child transmission (PMTCT) of the human immunodeficiency virus (HIV) was associated with changes in early childhood survival at the population level in rural Zambia

Mitigating the effects of COVID-19 on HIV treatment and care in Lusaka, Zambia: A before-after cohort study using mixed effects regression

Introduction The Zambian Ministry of Health (MoH) issued COVID-19 mitigation guidance for HIV care immediately after the first COVID-19 case was confirmed in Zambia on 18 March 2020. The Centre for Infectious Disease Research in Zambia implemented MoH guidance by: 1) extending antiretroviral therapy (ART) refill duration to 6 multi-month dispensation (6MMD) and 2) task-shifting communication and mobilisation of those in HIV care to collect their next ART refill early. We assessed the impact of COVID-19 mitigation guidance on HIV care 3 months before and after guidance implementation. Methods We reviewed all ART pharmacy visit data in the national HIV medical record for PLHIV in care having ≥1 visit between 1 January - 30 June 2020 at 59 HIV care facilities in Lusaka Province, Zambia. We undertook a before-after evaluation using mixed-effects Poisson regression to examine predictors and marginal probability of early clinic return (pharmacy visit >7 days before next appointment), proportion of late visit (>7 days late for next appointment) and probability of receiving a 6MMD ART refill. Results A total of 101 371 individuals (64% female, median age 39) with 130 486 pharmacy visits were included in the analysis. We observed a significant increase in the adjusted prevalence ratio (4.63; 95% CI 4.45 to 4.82) of early return before compared with after guidance implementation. Receipt of 6MMD increased from a weekly mean of 47.9% (95% CI 46.6% to 49.2%) before to 73.4% (95% CI 72.0% to 74.9%) after guidance implementation. The proportion of late visits (8-89 days late) was significantly higher before (18.8%, 95% CI17.2%to20.2%) compared with after (15.1%, 95% CI13.8%to16.4%) guidance implementation. Conclusions Timely issuance and implementation of COVID-19 mitigation guidance involving task-shifted patient communication and mobilisation alongside 6MMD significantly increased early return to ART clinic, potentially reducing interruptions in HIV care during a global public health emergency

Origin and Global Expansion of Mycobacterium tuberculosis Complex Lineage 3

Tuberculosis still causes 1.5 million deaths annually and is mainly caused by Mycobacterium tuberculosis complex strains belonging to three evolutionary modern lineages (Lineages 2–4). While Lineage 2 and Lineage 4 virtually conquered the world, Lineage 3 is particularly successful in Northern and Eastern Africa, as well as in Southern Asia, the suspected evolutionary origin of these strains. Here, we sought to understand how Lineage 3 strains came to the African continent. To this end, we performed routine genotyping to characterize over 2500 clinical isolates from 38 countries. We then selected a representative collection of 373 isolates for a whole-genome analysis and a modeling approach to infer the geographic origin of different sublineages. In fact, the origin of Lineage 3 could be located in India, and we found evidence for independent introductions of four distinct sublineages into North/East Africa, in line with known ancient exchanges and migrations between both world regions. Our study illustrates that the evolutionary history of humans and their pathogens are closely connected and further provides a systematic understanding of the genomic diversity of Lineage 3, which could be important for the development of new tuberculosis vaccines or new therapeutics.Mycobacterium tuberculosis complex (MTBC) Lineage 3 (L3) strains are abundant in world regions with the highest tuberculosis burden. To investigate the population structure and the global diversity of this major lineage, we analyzed a dataset comprising 2682 L3 strains from 38 countries over 5 continents, by employing 24-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats genotyping (MIRU-VNTR) and drug susceptibility testing. We further combined whole-genome sequencing (WGS) and phylogeographic analysis for 373 strains representing the global L3 genetic diversity. Ancestral state reconstruction confirmed that the origin of L3 strains is located in Southern Asia and further revealed multiple independent introduction events into North-East and East Africa. This study provides a systematic understanding of the global diversity of L3 strains and reports phylogenetic variations that could inform clinical trials which evaluate the effectivity of new drugs/regimens or vaccine candidates.Peer Reviewe

Response to the Novel Corona Virus (COVID-19) Pandemic Across Africa: Successes, Challenges, and Implications for the Future

Background: The COVID-19 pandemic has already claimed considerable lives. There are major concerns in Africa due to existing high prevalence rates for both infectious and non-infectious diseases and limited resources in terms of personnel, beds and equipment. Alongside this, concerns that lockdown and other measures will have on prevention and management of other infectious diseases and non-communicable diseases (NCDs). NCDs are an increasing issue with rising morbidity and mortality rates. The World Health Organization (WHO) warns that a lack of nets and treatment could result in up to 18 million additional cases of malaria and up to 30,000 additional deaths in sub-Saharan Africa. Objective: Document current prevalence and mortality rates from COVID-19 alongside economic and other measures to reduce its spread and impact across Africa. In addition, suggested ways forward among all key stakeholder groups. Our Approach: Contextualise the findings from a wide range of publications including internet-based publications coupled with input from senior-level personnel. Ongoing Activities: Prevalence and mortality rates are currently lower in Africa than among several Western countries and the USA. This could be due to a number of factors including early instigation of lockdown and border closures, the younger age of the population, lack of robust reporting systems and as yet unidentified genetic and other factors. Innovation is accelerating to address concerns with available equipment. There are ongoing steps to address the level of misinformation and its consequences including fines. There are also ongoing initiatives across Africa to start addressing the unintended consequences of COVID-19 activities including lockdown measures and their impact on NCDs including the likely rise in mental health disorders, exacerbated by increasing stigma associated with COVID-19. Strategies include extending prescription lengths, telemedicine and encouraging vaccination. However, these need to be accelerated to prevent increased morbidity and mortality. Conclusion: There are multiple activities across Africa to reduce the spread of COVID-19 and address misinformation, which can have catastrophic consequences, assisted by the WHO and others, which appear to be working in a number of countries. Research is ongoing to clarify the unintended consequences given ongoing concerns to guide future activities. Countries are learning from each other

Track E Implementation Science, Health Systems and Economics

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138412/1/jia218443.pd

Early Diagnosis of HIV Infection in Infants - One Caribbean and Six Sub-Saharan African Countries, 2011-2015.

Pediatric human immunodeficiency virus (HIV) infection remains an important public health issue in resource-limited settings. In 2015, 1.4 million children aged 50% decline. The most common challenges for access to testing for early infant diagnosis included difficulties in specimen transport, long turnaround time between specimen collection and receipt of results, and limitations in supply chain management. Further reductions in HIV mortality in children can be achieved through continued expansion and improvement of services for early infant diagnosis in PEPFAR-supported countries, including initiatives targeted to reach HIV-exposed infants, ensure access to programs for early infant diagnosis of HIV, and facilitate prompt linkage to treatment for children diagnosed with HIV infection