Browsing by Author "Siyambango M"

Now showing 1 - 4 of 4

Derivation of a tuberculosis screening rule for sub-Saharan African prisons.
(2014-Jul) Harris JB; Siyambango M; Levitan EB; Maggard KR; Hatwiinda S; Foster EM; Chamot E; Kaunda K; Chileshe C; Krüüner A; Henostroza G; Reid SE; ^¶Zambia Prisons Service, Ministry of Home Affairs, Lusaka, Zambia.; ^§Department of Health Care Organization and Policy, University of Alabama at Birmingham, Alabama, USA.; *Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; ^‡Department of Epidemiology, Birmingham, Alabama, USA.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
SETTING: Lusaka Central Prison, Zambia. OBJECTIVE: To derive screening rules for tuberculosis (TB) using data collected during a prison-wide TB and human immunodeficiency virus (HIV) screening program. DESIGN: We derived rules with two methodologies: logistic regression and classification and regression trees (C&RT). We evaluated the performance of the derived rules as well as existing World Health Organization (WHO) screening recommendations in our cohort of inmates, as measured by sensitivity, specificity, and positive and negative predictive values. RESULTS: The C&RT-derived rule recommended diagnostic testing of all inmates who were underweight (defined as body mass index [BMI] < 18.5 kg/m(2)] or HIV-infected; the C&RT-derived rule had 60% sensitivity and 71% specificity. The logistic regression-derived rule recommended diagnostic testing of inmates who were underweight, HIV-infected or had chest pain; the logistic regression-derived rule had 74% sensitivity and 57% specificity. Two of the WHO recommendations had sensitivities that were similar to our logistic regression rule but had poorer specificities, resulting in a greater testing burden. CONCLUSION: Low BMI and HIV infection were the most robust predictors of TB in our inmates; chest pain was additionally retained in one model. BMI and HIV should be further evaluated as the basis for TB screening rules for inmates, with modification as needed to improve the performance of the rules.
High prevalence of tuberculosis in newly enrolled HIV patients in Zambia: need for enhanced screening approach.
(2016-Aug) Henostroza G; Harris JB; Chitambi R; Siyambango M; Turnbull ER; Maggard KR; Krüüner A; Kapata N; Reid SE; Tuberculosis Department, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA; Tuberculosis Department, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; National Tuberculosis and Leprosy Control Programme, Ministry of Health of Zambia, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
SETTING: Tuberculosis (TB) remains a leading cause of morbidity and mortality in sub-Saharan Africa. In Zambia, smear microscopy and chest radiography (CXR) are the primary TB diagnostic tools, and most cases are not bacteriologically confirmed. OBJECTIVE: We implemented enhanced screening to determine the TB burden among new human immunodeficiency virus (HIV) clinic enrollees. DESIGN: Consecutive adult HIV clinic enrollees were screened, regardless of symptoms. All underwent microscopy (Ziehl-Neelsen/fluorescence microscopy) on three sputum specimens, physical examination, and digital CXR. Sputum, blood and urine specimens were cultured. Xpert(®) MTB/RIF testing was performed retrospectively. RESULTS: From July 2011 to April 2012, 399 patients were enrolled. The median age was 34.4 years; body mass index was 20.8 kg/m(2), CD4 count was 202 cells/μl and 86% were symptomatic. Culture-confirmed TB was diagnosed in 72/399 (18%) patients; an additional 31/399 (8%) were culture-negative but diagnosed clinically. Symptom screening for any cough, fever, weight loss or night sweats had high sensitivity (95%) but low specificity (14%) for detecting culture-confirmed cases. Among culture-confirmed cases, 35/72 (49%) were missed clinically and detected only by culture. Xpert was 64% sensitive and 98% specific. CONCLUSIONS: High TB prevalence was found in Zambians newly enrolled into HIV care. Screening with sensitive diagnostics should be considered with culture when feasible in this population.
Poor continuity of care for TB diagnosis and treatment in Zambian Prisons: a situation analysis.
(2018-Feb) Hatwiinda S; Topp SM; Siyambango M; Harris JB; Maggard KR; Chileshe C; Kapata N; Reid SE; Henostroza G; University of Alabama at Birmingham, Birmingham, AL, USA.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; Zambia Ministry of Health, National Tuberculosis Program, Lusaka, Zambia.; College of Public Health, Medical & Veterinary Sciences, James Cook University, Townsville, Australia.; Zambia Ministry of Home Affairs, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
OBJECTIVES: Prisons act as infectious disease reservoirs. We aimed to explore the challenges of TB control and continuity of care in prisons in Zambia. METHODS: We evaluated treatment outcomes for a cohort of inmates diagnosed with TB during a TB REACH funded screening programme initiated by the Zambia Prisons Service and the Centre for Infectious Disease Research in Zambia. RESULTS: Between October 2010 and September 2011, 6282 inmates from six prisons were screened for TB, of whom 374 (6.0%) were diagnosed. TB treatment was initiated in 345 of 374 (92%) inmates. Of those, 66% were cured or completed treatment, 5% died and 29% were lost to follow-up. Among those lost to follow-up, 11% were released into the community and 13% were transferred to other prisons. CONCLUSIONS: Weak health systems within the Zambian prison service currently undermines continuity of care, despite intensive TB screening and case-finding interventions. To prevent TB transmission and the development of drug resistance, we need sufficient numbers of competent staff for health care, reliable health information systems including electronic record keeping for prison facilities, and standard operating procedures to guide surveillance, case-finding and timely treatment initiation and completion.
Safety, tolerability, and immunogenicity of an oral inactivated ETEC vaccine (ETVAX®) with dmLT adjuvant in healthy adults and children in Zambia: An age descending randomised, placebo-controlled trial.
(2023-Nov-02) Sukwa N; Mubanga C; Hatyoka LM; Chilyabanyama ON; Chibuye M; Mundia S; Munyinda M; Kamuti E; Siyambango M; Badiozzaman S; Bosomprah S; Carlin N; Kaim J; Sjöstrand B; Simuyandi M; Chilengi R; Svennerholm AM; Enteric Disease and Vaccine Research Unit, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. Electronic address: nsofwa.sukwa@cidrz.org.; Enteric Disease and Vaccine Research Unit, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; Enteric Disease and Vaccine Research Unit, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia; Division of Medical Microbiology, Department of Pathology, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa.; Enteric Disease and Vaccine Research Unit, Centre for Infectious Disease Research in Zambia, Lusaka, Zambia; Department of Biostatistics, School of Public Health, University of Ghana, Accra, Ghana.; Scandinavian Biopharma, Sweden.; Department of Microbiology and Immunology, University of Gothenburg, Sweden.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
BACKGROUND: Enterotoxigenic Escherichia coli (ETEC) is an important cause of moderate to severe diarrhoea in children for which there is no licensed vaccine. We evaluated ETVAX®, an oral, inactivated ETEC vaccine containing four E. coli strains over-expressing the major colonization factors CFA/I, CS3, CS5, and CS6, a toxoid (LCTBA) and double mutant heat-labile enterotoxin (dmLT) adjuvant for safety, tolerability, and immunogenicity. METHODS: A double-blind, placebo-controlled, age-descending, dose-finding trial was undertaken in 40 adults, 60 children aged 10-23 months, and 146 aged 6-9 months. Adults received one full dose of ETVAX® and children received 3 doses of either 1/4 or 1/8 dose. Safety was evaluated as solicited and unsolicited events for 7 days following vaccination. Immunogenicity was assessed by evaluation of plasma IgA antibody responses to CFA/I, CS3, CS5, CS6, and LTB, and IgG responses to LTB. RESULTS: Solicited adverse events were mostly mild or moderate with only 2 severe fever reports which were unrelated to the vaccine. The most common events were abdominal pain in adults (26.7 % in vaccinees vs 20 % in placebos), and fever in children aged 6-9 months (44 % vs 54 %). Dosage, number of vaccinations and decreasing age had no influence on severity or frequency of adverse events. The vaccine induced plasma IgA and IgG responses against LTB in 100 % of the adults and 80-90 % of the children. In the 6-23 months cohort, IgA responses to more than 3 vaccine antigens after 3 doses determined as ≥2-fold rise was significantly higher for 1/4 dose compared to placebo (56.7 % vs 27.2 %, p = 0.01). In the 6-9 months cohort, responses to the 1/4 dose were significantly higher than 1/8 dose after 3 rather than 2 doses. CONCLUSION: ETVAX® was safe, tolerable, and immunogenic in Zambian adults and children. The 1/4 dose induced significantly stronger IgA responses and is recommended for evaluation of protection in children. CLINICAL TRIALS REGISTRATION: The trial is registered with the Pan African Clinical Trials Registry (PACTR Ref. 201905764389804) and a description of this clinical trial is available on: https://pactr.samrc.ac.za/Trial Design.