Sensitivity and specificity of cryptococcal antigen lateral flow assay for the diagnosis of HIV-associated cryptococcal meningitis in western Kenya

Background: HIV-associated cryptococcal meningitis carries a high case-fatality-rate in sub-Saharan Africa. Diagnostic delays partly contribute to this. Rapid point-of-care tests may facilitate speedy diagnosis. This study aimed to determine the sensitivity and specificity of urine, serum and cerebrospinal fluid (CSF) cryptococcal antigen lateral flow assay for the diagnosis of HIV-associated cryptococcal meningitis compared with the gold standard CSF culture.Methods: A cross-sectional study was conducted in the medical wards of Moi Teaching and Referral Hospital, Eldoret, Kenya. Adult (≥18years) HIV-infected in-patients suspected to have meningitis had paired samples of urine, serum and CSF collected and tested real time using the cryptococcal antigen lateral flow assay (rapid point of care test). CSF cultures were also conducted. Data were analyzed using STATA ® (Statacorp Texas USA®). Descriptive statistics were used to summarize demographic, clinical and laboratory parameters. Sensitivity and specificity of the rapid test were calculated with the CSF culture as the gold standard.Results: Of the 302 participants included 172 (57%) were female, median age 37 years (IQR 30-45). The median CD4+ cell count was 183/ul (IQR 54-333). Among 288 participants with available CSF culture results, 50(17%) had culture-confirmed cryptococcal meningitis. Urine rapid test had a sensitivity and specificity of 86 %( 95% CI 73-94) and 95.7% (95% CI 92-98) respectively. Serum rapid test had a sensitivity and specificity of 92% (95%CI 81-98) and 94.9% (95%CI 91-97) respectively. CSF rapid test had a sensitivity and specificity of 92% (95%CI 81-98%) and 94.5% (95% CI 91-97) respectively. Conclusion: Serum and CSF cryptococcal antigen lateral flow assay are highly sensitive and specific for the diagnosis of HIV-associated cryptococcal meningitis. Urine is relatively sensitive and specific. Serum and CSF cryptococcal antigen lateral flow assay can be used as a less expensive alternative to cryptococcal antigen latex agglutination method. Urine cryptococcal antigen lateral flow assay could be adopted as a rapid point of care diagnostic test in primary care clinics in low income settings without experience in handling CSF or serum, to fast track diagnosis of cryptococcal meningitis

Development and utilization of a decision support tool for the optimization of fertilizer application in smallholder farms in Uganda

This paper presents the development and pilot of the Fertilizer Optimization Tool (FOT), a decision support tool for use by extension agents in  advising smallholder farmers in Uganda in applying optimum (rather than maximum) fertilizer by considering the farmers’ financial abilities. The FOT is made up of three components which includes, the optimizer tool, the nutrient substitution table, and a fertilizer calibration tool. The FOT was developed using field trial data collected on specific agro-ecological zones and mapped using global positioning systems in 13 Sub-Saharan Africa countries. The FOT provides site- and farmer-specific fertilizer recommendations, providing both economic and environmental benefits. Results are based on a survey of 241 households, 57 technical personnel and tracking of 33 FOT users over a 3-season period. Results show a progressive shift in farmers’ attitude towards the value of fertilizer. More FOT users (71%) disagreed with the statement that fertilizers destroy soils, compared with  non-FOT users (52%). Crop yields (tons/ha) were significantly higher for crops receiving fertilizers compared to those not. While it is generally accepted that using fertilizer improves crop response and achieves better yields, the value of FOT was reported in terms of rationalization of investment by farmers. The average seasonal investment was approx. $43, giving a return on investment of over 107%. Given the evidence  generated from Uganda, there is a need for considering out scaling the FOT technology to other countries in Africa, which are faced with the same challenges of low fertilizer use among smallholder farmers. Using the mobile FOT app provides a further cost-effective opportunity to out scale the approach to benefit more smallholder farmers in sub-Saharan Africa. Further development of the FOT is suggested, particularly in the wake of increased focus on multi-nutrient fertilizer blends, and the need to adjust for soil PH, moisture, and long-term impacts of nutrient substitution. Key words: decision support tool, fertilizer optimization tool, precision agriculture, site-specific fertilizer recommendation

Transgenic expression of Arabidopsis ELONGATION FACTOR-TU RECEPTOR (AtEFR) gene in banana enhances resistance to Banana Xanthomonas Wilt disease

Preprint PublicationBanana Xanthomonas wilt (BXW) caused by Xanthomonas campestris pv. musacearum (Xcm) is a severe bacterial disease devastating banana production in East and Central Africa, where banana is cultivated as a staple crop. Classical breeding of banana is challenging because the crop is clonally propagated and has limited genetic diversity. Thus, genetic engineering serves as a viable alternative for banana improvement. Several studies have shown that interfamily transfer of the elongation factor Tu receptor gene (AtEFR) from Arabidopsis thaliana to other plant families can increase broad-spectrum resistance against bacterial diseases. In this study, transgenic events of banana cultivar dwarf Cavendish expressing the AtEFR gene were generated and evaluated for resistance against Xcm under greenhouse conditions. The transgenic banana events were responsive to the EF-Tu-derived elf18 peptide and exhibited enhanced resistance to BXW disease compared to non-transgenic control plants. This study suggests that the functionality of AtEFR is retained in banana with the potential of enhancing resistance to BXW disease under field conditions

Below Ground Benefits of Cactus \u3ci\u3eOpuntia stricta\u3c/i\u3e Under Rangeland Conditions in Laikipia, Kenya

Cactus Opuntia stricta primarily invades arid and semi-arid lands (ASALs), which form more than 80% of Kenya’s landmass. The ability of the plant to tolerate poor soils and accumulate biomass under low precipitation has resulted in studies into its potential use by pastoral communities for biofuel and livestock feed. However, few studies have assessed the below-ground benefits associated with cactus under rangeland conditions. In this study, we evaluated the root contributions of the invasives cactus Opuntia stricta under rangeland conditions in Laikipia, Kenya. The experiment was laid out in a randomized complete block design with ten (10) replicates, each measuring 30 × 30 m. Each block was further subdivided into three plots of 10 x 30m Three clusters were randomly selected from each plot for roots and soil samples starting from the center of the cluster (C) to the outside in a gradient of three radii, R1, R2 and R3. Data was collected for root (dry root biomass, % carbon and % nitrogen) and soil (pH, bulk density, % moisture and % nitrogen) characteristics. Significant differences in total root mass, root carbon, and root nitrogen were observed under varying cluster gradients. Root mass ranged from 4527.0 to 9242.0 kg/ha for the outermost radius (R3) and the cluster’s center, respectively. Similarly, except for the soil nitrogen, statistical differences were observed for soil bulk density, percent soil moisture and percent nitrogen along the different cluster gradients. The soil bulk density ranged from 1.2±0.02 (center) to 1.5±0.01 g cm3 (radius 2). Findings from this study demonstrate the important contribution of the invasive cactus species in sustaining the ecological functions of rangeland soils such as those found in Laikipia, Kenya

Distinctive Kaposi Sarcoma-Associated Herpesvirus Serological Profile during Acute Plasmodium falciparum Malaria Episodes

The seroprevalence of Kaposi sarcoma-associated herpesvirus (KSHV) and the incidence of endemic Kaposi sarcoma (KS) overlap with regions of malaria endemicity in sub-Saharan Africa. Multiple studies have shown an increased risk of KSHV seroconversion in children from high malaria compared to low malaria regions; however, the impact of acute episodes of Plasmodium falciparum (P. falciparum) malaria on KSHV’s biphasic life cycle and lytic reactivation has not been determined. Here, we examined KSHV serological profiles and viral loads in 134 children with acute malaria and 221 healthy children from high malaria regions in Kisumu, as well as 77 healthy children from low malaria regions in Nandi. We assayed KSHV, Epstein–Barr virus (EBV), and P. falciparum malaria antibody responses in these three by multiplexed Luminex assay. We confirmed that KSHV seroprevalence was significantly associated with malaria endemicity (OR = 1.95, 1.18–3.24 95% CI, p = 0.01) with 71–77% seropositivity in high-malaria (Kisumu) compared to 28% in low-malaria (Nandi) regions. Furthermore, KSHV serological profiles during acute malaria episodes were distinct from age-matched non-malaria-infected children from the same region. Paired IgG levels also varied after malaria treatment, with significantly higher anti-ORF59 at day 0 but elevated ORF38, ORF73, and K8.1 at day 3. Acute malaria episodes is characterized by perturbation of KSHV latency in seropositive children, providing further evidence that malaria endemicity contributes to the observed increase in endemic KS incidence in sub-Saharan Africa

TDR Targets: a chemogenomics resource for neglected diseases

The TDR Targets Database (http://tdrtargets.org) has been designed and developed as an online resource to facilitate the rapid identification and prioritization of molecular targets for drug development, focusing on pathogens responsible for neglected human diseases. The database integrates pathogen specific genomic information with functional data (e.g. expression, phylogeny, essentiality) for genes collected from various sources, including literature curation. This information can be browsed and queried using an extensive web interface with functionalities for combining, saving, exporting and sharing the query results. Target genes can be ranked and prioritized using numerical weights assigned to the criteria used for querying. In this report we describe recent updates to the TDR Targets database, including the addition of new genomes (specifically helminths), and integration of chemical structure, property and bioactivity information for biological ligands, drugs and inhibitors and cheminformatic tools for querying and visualizing these chemical data. These changes greatly facilitate exploration of linkages (both known and predicted) between genes and small molecules, yielding insight into whether particular proteins may be druggable, effectively allowing the navigation of chemical space in a genomics context

A Novel Technique to Label Cover Crop Biomass Using Stable Isotopes

Stable isotopes can be used as tracers for carbon and nitrogen pathways being a great tool to track nutrients in integrated systems. The objective of this experiment was to understand the partitioning of 15N and 13C within cover crop plants when they were labeled with stable isotopes, using chambers under field conditions. Cover crops were planted at the University of Florida, North Florida Research and Education Center-Marianna, located in Marianna, FL. Treatments were four cover crops, in which one was considered a typical cover crop system and the other three consisted of an integrated crop-livestock system with or without the inclusion of legume or different nitrogen fertilizer rates grazed every two weeks. All treatments were replicated three times in a randomized complete block design. Two chambers were built and placed in each plot to label the cover crop plants. For the 15N labeling, 15N2-labeled urea (98 atom% 15N) was applied at a rate of 0.5 kg N ha-1 only once. The target amount of 13CO2 (99 atom% 13C) was determined considering a 20% enrichment of the CO2 concentration present inside the chamber’s volume. The 13CO2 labeling was performed for 28 consecutive days. The labeling technique using chambers and stable isotopes to enrich cover crop species worked under field conditions for both, grass and legume species. Moving forward, this labeling technique can be a useful tool to track nutrient pathways, especially litter decomposition in diversified integrated crop and livestock systems under different management practices

Building a Sustainable Comprehensive Multiple Myeloma Program in Western Kenya

Despite improved treatment strategies for multiple myeloma (MM), patient outcomes in low- and middle-income countries remain poor, unlike high-income countries. Scarcity of specialized human resources and diagnostic, treatment, and survivorship infrastructure are some of the barriers that patients with MM, clinicians, and policymakers have to overcome in the former setting. To improve outcomes of patients with MM in Western Kenya, the Academic Model Providing Access to Healthcare (AMPATH) MM Program was set up in 2012. In this article, the program's activities, challenges, and future plans are described distilling important lessons that can be replicated in similar settings. Through the program, training on diagnosis and treatment of MM was offered to healthcare professionals from 35 peripheral health facilities across Western Kenya in 2018 and 2019. Access to antimyeloma drugs including novel agents was secured, and pharmacovigilance systems were developed. Finally, patients were supported to obtain health insurance in addition to receiving peer support through participation in support group meetings. This article provides an implementation blueprint for similar initiatives aimed at increasing access to care for patients with MM in underserved areas

Retrospective Analysis of Presentation, Treatment, and Outcomes of Multiple Myeloma at a Large Public Referral Hospital in Eldoret, Kenya

Purpose: Treatment patterns and survival outcomes of patients with multiple myeloma (MM) in Kenya have not been adequately characterized. The objectives of this study were to describe the clinical, laboratory, and imaging findings at diagnosis, to describe the treatment offered, and to determine the survival outcomes of patients with MM over an 11-year period. Patients and methods: A retrospective chart review was carried out for all patients who were diagnosed and treated for MM at Moi Teaching and Referral Hospital from 2009 to 2019. The Kaplan-Meier method was used to estimate survival. Factors affecting survival were identified using univariate and multivariate analyses. Results: A total of 221 patient charts were analyzed of which 124 belonged to male patients (56.1%). The median age at diagnosis was 61 years. Bone pain was the most common presenting complaint observed in 69.6% of 194 patients assessed. Out of 102 patients who received imaging studies, 60 (58.8%) had lytic lesions, 30 (29.4%) had fractures, whereas 30 (29.4%) had spinal cord compression. Anemia, renal failure, and hypercalcemia were observed in 87/187 (46.5%), 22/161 (13.7%), and 23/42 (54.8%) patients, respectively. Thalidomide and dexamethasone (65.2%); bortezomib, thalidomide, and dexamethasone (14.6%); and melphalan and prednisolone (11.9%) were the most prescribed initial chemotherapy regimens among 219 patients analyzed. Overall survival at 1 and 5 years was 70% and 21%, respectively; median overall survival was 29.0 months. In multivariate analysis, male sex (hazard ratio [HR] 1.9), baseline anemia (HR 1.8), and baseline renal failure (HR 3.2) were associated with significantly shorter survival. Conclusion: Survival outcomes were poor despite increased use of multiagent-based chemotherapy regimens. Greater access to available diagnostics and treatments is required to achieve rational treatment and increased survival

Trypanosoma brucei Glycogen Synthase Kinase-3, A Target for Anti-Trypanosomal Drug Development: A Public-Private Partnership to Identify Novel Leads

Over 60 million people in sub-Saharan Africa are at risk of infection with the parasite Trypanosoma brucei which causes Human African Trypanosomiasis (HAT), also known as sleeping sickness. The disease results in systemic and neurological disability to its victims. At present, only four drugs are available for treatment of HAT. However, these drugs are expensive, limited in efficacy and are severely toxic, hence the need to develop new therapies. Previously, the short TbruGSK-3 short has been validated as a potential target for developing new drugs against HAT. Because this enzyme has also been pursued as a drug target for other diseases, several inhibitors are available for screening against the parasite enzyme. Here we present the results of screening over 16,000 inhibitors of human GSK-3β (HsGSK-3) from the Pfizer compound collection against TbruGSK-3 short. The resulting active compounds were tested for selectivity versus HsGSK-3β and a panel of human kinases, as well as their ability to inhibit proliferation of the parasite in vitro. We have identified attractive compounds that now form potential starting points for drug discovery against HAT. This is an example of how a tripartite partnership involving pharmaceutical industries, academic institutions and non-government organisations such as WHO TDR, can stimulate research for neglected diseases