Project description:Nucleic-acid detection is crucial for basic research as well as for applications in medicine such as diagnostics. In resource-limited settings, however, most DNA-detection diagnostic schemes are inapplicable since they rely on expensive machinery, electricity, and trained personnel. Here, we present an isothermal DNA detection scheme for the diagnosis of pathogenic DNA in resource-limited settings. DNA was extracted from urine and blood samples using two different instrument-free methods, and amplified using Recombinase Polymerase Amplification with a sensitivity of <10 copies of DNA within 15 minutes. Target DNA was bound by dCas9/sgRNA that was labelled with a DNA oligomer to subsequently induce Rolling Circle Amplification. This second amplification step produced many copies of a G-quadruplex DNA structure that facilitates a colorimetric readout that is visible to the naked eye. This isothermal DNA-detection scheme can be performed at temperatures between 20-45 °C. As an example of the applicability of the approach, we isothermally (23 °C) detected DNA from a parasite causing visceral leishmaniasis that was spiked into buffer and resulted in a sensitivity of at least 1 zeptomole. For proof of principle, DNA spiked into blood was coupled to the CRISPR-dCas9-based detection scheme yielding a colorimetric readout visible to the naked eye. Given the versatility of the guide-RNA programmability of targets, we envision that this DNA detection scheme can be adapted to detect any DNA with minimal means, which facilitates applications such as point-of-care diagnostics in resource-limited settings.
Project description:BACKGROUND:Checklists can standardize patient care, reduce errors, and improve health outcomes. For meningitis in resource-limited settings, with high patient loads and limited financial resources, central nervous system diagnostic algorithms may be useful to guide diagnosis and treatment. However, the cost effectiveness of such algorithms is unknown. METHODS:We used decision analysis methodology to evaluate the costs, diagnostic yield, and cost effectiveness of diagnostic strategies for adults with suspected meningitis in resource-limited settings with moderate/high HIV prevalence. We considered 3 strategies: (1) comprehensive "shotgun" approach of utilizing all routine tests; (2) "stepwise" strategy with tests performed in a specific order with additional tuberculosis (TB) diagnostics; (3) "minimalist" strategy of sequential ordering of high-yield tests only. Each strategy resulted in 1 of 4 meningitis diagnoses: bacterial (4%), cryptococcal (59%), TB (8%), or other (aseptic) meningitis (29%). In model development, we utilized prevalence data from 2 Ugandan sites and published data on test performance. We validated the strategies with data from Malawi, South Africa, and Zimbabwe. RESULTS:The current comprehensive testing strategy resulted in 93.3% correct meningitis diagnoses costing $32.00 per patient. A stepwise strategy had 93.8% correct diagnoses costing an average of $9.72 per patient, and a minimalist strategy had 91.1% correct diagnoses costing an average of $6.17 per patient. The incremental cost-effectiveness ratio was $133 per additional correct diagnosis for the stepwise over minimalist strategy. CONCLUSIONS:Through strategically choosing the order and type of testing coupled with disease prevalence rates, algorithms can deliver more care more efficiently. The algorithms presented herein are generalizable to East Africa and Southern Africa.
Project description:BACKGROUND:Current World Health Organization (WHO) guidelines for treatment of HIV in resource-limited settings call for 2 antiretroviral regimens. The effectiveness and cost-effectiveness of increasing the number of antiretroviral regimens is unknown. METHODS:Using a simulation model, we compared the survival and costs of current WHO regimens with two 3-regimen strategies: an initial regimen of 3 nucleoside reverse transcriptase inhibitors followed by the WHO regimens and the WHO regimens followed by a regimen with a second-generation boosted protease inhibitor (2bPI). We evaluated monitoring with CD4 counts only and with both CD4 counts and viral load. We used cost and effectiveness data from Cape Town and tested all assumptions in sensitivity analyses. RESULTS:Over the lifetime of the cohort, 25.6% of individuals failed both WHO regimens by virologic criteria. However, when patients were monitored using CD4 counts alone, only 6.5% were prescribed additional highly active antiretroviral therapy due to missed and delayed detection of failure. The life expectancy gain for individuals who took a 2bPI was 6.7-8.9 months, depending on the monitoring strategy. When CD4 alone was available, adding a regimen with a 2bPI was associated with an incremental cost-effectiveness ratio of $2581 per year of life gained, and when viral load was available, the ratio was $6519 per year of life gained. Strategies with triple-nucleoside reverse transcriptase inhibitor regimens in initial therapy were dominated. Results were sensitive to the price of 2bPIs. CONCLUSIONS:About 1 in 4 individuals who start highly active antiretroviral therapy in sub-Saharan Africa will fail currently recommended regimens. At current prices, adding a regimen with a 2bPI is cost effective for South Africa and other middle-income countries by WHO standards.
Project description:BackgroundCryptococcal meningitis (CM) is the most common form of meningitis in Africa. World Health Organization guidelines recommend 14-d amphotericin-based induction therapy; however, this is impractical for many resource-limited settings due to cost and intensive monitoring needs. A cost-effectiveness analysis was performed to guide stakeholders with respect to optimal CM treatment within resource limitations.Methods and findingsWe conducted a decision analysis to estimate the incremental cost-effectiveness ratio (ICER) of six CM induction regimens: fluconazole (800-1,200 mg/d) monotherapy, fluconazole + flucytosine (5FC), short-course amphotericin (7-d) + fluconazole, 14-d of amphotericin alone, amphotericin + fluconazole, and amphotericin + 5FC. We computed actual 2012 healthcare costs in Uganda for medications, supplies, and personnel, and average laboratory costs for three African countries. A systematic review of cryptococcal treatment trials in resource-limited areas summarized 10-wk survival outcomes. We modeled one-year survival based on South African, Ugandan, and Thai CM outcome data, and survival beyond one-year on Ugandan and Thai data. Quality-adjusted life years (QALYs) were determined and used to calculate the cost-effectiveness ratio and ICER. The cost of hospital care ranged from $154 for fluconazole monotherapy to $467 for 14 d of amphotericin + 5FC. Based on 18 studies investigating outcomes for HIV-infected individuals with CM in resource-limited settings, the estimated mean one-year survival was lowest for fluconazole monotherapy, at 40%. The cost-effectiveness ratio ranged from $20 to $44 per QALY. Overall, amphotericin-based regimens had higher costs but better survival. Short-course amphotericin (1 mg/kg/d for 7 d) with fluconazole (1,200 mg/d for14 d) had the best one-year survival (66%) and the most favorable cost-effectiveness ratio, at $20.24/QALY, with an ICER of $15.11 per additional QALY over fluconazole monotherapy. The main limitation of this study is the pooled nature of a systematic review, with a paucity of outcome data with direct comparisons between regimens.ConclusionsShort-course (7-d) amphotericin induction therapy coupled with high-dose (1,200 mg/d) fluconazole is "very cost effective" per World Health Organization criteria and may be a worthy investment for policy-makers seeking cost-effective clinical outcomes. More head-to-head clinical trials are needed on treatments for this neglected tropical disease. Please see later in the article for the Editors' Summary.
Project description:Despite increasing availability of anti-retroviral therapy, invasive cryptococcal disease continues to be a leading cause of death among HIV-infected individuals in resource-limited settings. Screening asymptomatic HIV-infected individuals with advanced immunosuppression for serum cryptococcal antigen clearly identifies a population at high risk of cryptococcal meningitis and death. However, screening with serum cryptococcal antigen alone identifies a heterogeneous clinical population, many of whom have mild clinical symptoms, sub-clinical meningeal infection, or fungemia. Currently, there is wide variation in practice and little evidence to guide the use of anti-fungal and anti-retroviral treatment for asymptomatic cryptococcal antigenemia (ACA). Furthermore, implementing a targeted screening and treatment intervention for ACA presents numerous operational challenges for already overburdened health care systems in resource-limited settings. While such an intervention shows promise, there are critical gaps in our understanding of ACA and its implications in the outpatient setting and an urgent need for additional research in this area.
Project description:BackgroundAlthough laparoscopic surgery has made remarkable progress and become the standard approach for various surgical procedures worldwide over the past 30 years, its establishment in low-resource settings, particularly in public hospitals, has been challenging. The lack of equipment and trained expertise has hindered its widespread adoption in these settings. Cholecystectomy is one of the most commonly performed procedures using laparoscopy world wide AIM: The aim of the study is to determine whether laparoscopic cholecystectomy is feasible in a resource challenged setting METHODS: The research focused on individuals who underwent laparoscopic or open cholecystectomies at Yekatit 12 Hospital in Addis Ababa, Ethiopia, over a one-year period. Comprehensive data collection was conducted prospectively, encompassing both intraoperative and postoperative parameters. Follow-up was carried out via phone calls. The surgical procedures employed innovative techniques, including the reuse of sterilized single-use equipment and the utilization of local resources. The evaluation involved a comparison of demographic information, intraoperative details (such as critical view determination and operative duration), and postoperative complications, including assessments of pain and wound infections RESULTS: From August 2021 to September 2022, 119 patients were assessed. Among these patients, 65 (54.6%) underwent open cholecystectomies, while the remaining 54 (45.4%) underwent laparoscopic cholecystectomies. The average duration of the laparoscopic cholecystectomies was 90.7 min, which is 17.7 min behind the open. Patients in the laparoscopy group had significantly shorter hospital stays than the open group, and 94% were discharged by post operative day 2. The conversion rate from laparoscopic to open surgery was determined to be 3.3% CONCLUSION: To sum up, the safe execution of laparoscopic cholecystectomies is feasible in public hospitals and settings with limited resources, given adequate training and resource distribution. The study findings showcased superior outcomes, including reduced hospitalization duration and fewer complications, while maintaining comparable levels of operative duration and patient satisfaction in both groups.
Project description:ImportanceEndoscopes are paramount to the practice of otolaryngology. To provide physicians in low-middle-income countries with adequate tools to treat otolaryngologic problems, it is necessary to create a low-cost sustainable option.ObjectiveTo describe the design and usability of an open-source, low-cost flexible laryngoscope that addresses the lack of affordable and accessible methods for otolaryngologic visualization in resource-limited settings.Design, setting, and participantsThis quality improvement study used a mixed-methods approach, including a technical description of device design as well as quantitative and qualitative survey evaluation of device usability. Engineering involved device design, sourcing or manufacturing individual components, fabricating a prototype, and iterative testing. Key assumptions and needs for the device were identified in collaboration with otolaryngologists in Zimbabwe, and designed and simulated by biomedical engineers in a US university laboratory. Board-certified otolaryngologists at a single US university hospital trialed a completed prototype on simulated airways between May 2023 and June 2023.Main outcomes and measuresTechnical details on the design of the device are provided. Otolaryngologist gave feedback on device characteristics, maneuverability, and visualization using the System Usability Scale, a customized Likert-scale questionnaire (5-point scale), and semistructured interviews.ResultsA functional prototype meeting requirements was completed consisting of a distal-chip camera, spring bending tip, handle housing the control mechanism and electronics, and flexible polyether block amide-coated silicone sheath housing the camera and control wires; an external monitor provided real-time visualization and ability to store data. A total of 14 otolaryngologists participated in the device review. The mean (SD) System Usability Scale score was 88.93 (10.08), suggesting excellent usability. The device was rated highly for ease of set up, physical attributes, image quality, and functionality.Conclusions and relevanceThis quality improvement study described the design of a novel open-source low-cost flexible laryngoscope that external review with otolaryngologists suggests was usable and feasible in various resource-limited environments. Future work is needed to translate the model into a clinical setting.
Project description:: The choice between "best-known" standards of care (SOC) or "best available" standards as the control arm in a clinical trial is a fundamental dilemma in clinical research in resource-limited settings (RLS). When the health system is delivering less than an optimal level of care, using highest standard of care in a clinical trial may produce results that cannot be implemented or sustained locally. On the other hand, using interventions that are more feasible in the local setting may involve suboptimal care, and clinical outcomes may be affected. The need for improved standards in health systems in RLS, and the difficulty in securing them, has led many researchers advocate for policy changes at the national or international level to improve clinical care more systemically. SOC decisions in a clinical trial affect the level of benefit provided to study participants and the policy implications of the trial findings. SOC choices should provide high-quality care to help advance the health care system in host countries participating in the trial, but balancing the scientific and ethical objectives of SOC choices is difficult, and there is no single formula for selecting the appropriate SOC. Despite the challenges, well-designed and conducted clinical trials can and should make significant contributions to health systems in RLS.
Project description:BackgroundMycetoma is a chronic mutilating disease of the skin and the underlying tissues caused by fungi or bacteria. Although recently included in the list of neglected tropical diseases by the World Health Organization, strategic control and preventive measures are yet to be outlined. Thus, it continues to pose huge public health threat in many tropical and sub-tropical countries. If not detected and managed early, it results into gruesome deformity of the limbs. Its low report and lack of familiarity may predispose patients to misdiagnosis and delayed treatment initiation. More so in situation where diagnostic tools are limited or unavailable, little or no option is left but to clinically diagnose these patients. Therefore, an overview of clinical course of mycetoma, a suggested diagnostic algorithm and proposed use of materials that cover the exposed susceptible parts of the body during labour may assist in the prevention and improvement of its management. Furthermore, early reporting which should be encouraged through formal and informal education and sensitization is strongly suggested.Main textAn overview of the clinical presentation of mycetoma in the early and late phases, clues to distinguish eumycetoma from actinomycetoma in the field and the laboratory, differential diagnosis and a suggested diagnostic algorithm that may be useful in making diagnosis amidst the differential diagnosis of mycetoma is given. Additionally, a proposed preventive measures which may be helpful in the community is also provided. Since treatment is currently based on expert opinion, we encourage active research to establish treatment guideline for it.ConclusionSince delay in visiting health facility results into gruesome complication, early presentation, recognition and initiation of appropriate choice of regimen is helpful in reducing complications. The clinical overview of mycetoma and the suggested algorithm may enhance suspicion and possibly increase recognition of mycetoma in the community and further guide in differentiation of eumycetoma from actinomycetoma. There is an urgent need for research funding for mycetoma, a disease plagued by severe physical disabilities and social stigma leading to isolation.
Project description:ObjectivesThe light-emitting diode (LED) fluorescence microscopy has made acid-fast bacilli (AFB) detection faster and efficient although its optimal performance in resource-limited settings is still being studied. We assessed the optimal performances of light and fluorescence microscopy in routine conditions of a resource-limited setting and evaluated the digestion time for sputum samples for maximum yield of positive cultures.DesignCross-sectional study.SettingFacility-based involving samples of routine patients receiving tuberculosis treatment and care from the main tuberculosis case referral centre in northern Nigeria.ParticipantsThe study included 450 sputum samples from 150 new patients with clinical diagnosis of pulmonary tuberculosis.MethodsThe 450 samples were pooled into 150 specimens, examined independently with mercury vapour lamp (FM), LED CysCope (CY) and Primo Star iLED (PiLED) fluorescence microscopies, and with the Ziehl-Neelsen (ZN) microscopy to assess the performance of each technique compared with liquid culture. The cultured specimens were decontaminated with BD Mycoprep (4% NaOH-1% NLAC and 2.9% sodium citrate) for 10, 15 and 20 min before incubation in Mycobacterium growth incubator tube (MGIT) system and growth examined for acid-fast bacilli (AFB).ResultsOf the 150 specimens examined by direct microscopy: 44 (29%), 60 (40%), 49 (33%) and 64 (43%) were AFB positive by ZN, FM, CY and iLED microscopy, respectively. Digestion of sputum samples for 10, 15 and 20 min yielded mycobacterial growth in 72 (48%), 81 (54%) and 68 (45%) of the digested samples, respectively, after incubation in the MGIT system.ConclusionsIn routine laboratory conditions of a resource-limited setting, our study has demonstrated the superiority of fluorescence microscopy over the conventional ZN technique. Digestion of sputum samples for 15 min yielded more positive cultures.