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BACKGROUND: Whole-genome sequencing (WGS)-based prediction of drug resistance in Mycobacterium tuberculosis has the potential to guide clinical decisions in the design of optimal treatment regimens. METHODS: We utilized WGS to investigate drug resistance mutations in a 32-year-old Tanzanian male admitted to Kibong'oto Infectious Diseases Hospital with a history of interrupted multidrug-resistant tuberculosis treatment for more than three years. Before admission, he received various all-oral bedaquiline-based multidrug-resistant tuberculosis treatment regimens with unfavourable outcomes. RESULTS: Drug susceptibility testing of serial M. tuberculosis isolates using Mycobacterium Growth Incubator Tubes culture and WGS revealed resistance to first-line anti-TB drugs, bedaquiline, and fluoroquinolones but susceptibility to linezolid, clofazimine, and delamanid. WGS of serial cultured isolates revealed that the Beijing (Lineage 2.2.2) strain was resistant to bedaquiline, with mutations in the mmpR5 gene (Rv0678. This study also revealed the emergence of two distinct subpopulations of bedaquiline-resistant tuberculosis strains with Asp47f and Glu49fs frameshift mutations in the mmpR5 gene, which might be the underlying cause of prolonged resistance. An individualized regimen comprising bedaquiline, delamanid, pyrazinamide, ethionamide, and para-aminosalicylic acid was designed. The patient was discharged home at month 8 and is currently in the ninth month of treatment. He reported no cough, chest pain, fever, or chest tightness but still experienced numbness in his lower limbs. CONCLUSION: We propose the incorporation of WGS in the diagnostic framework for the optimal management of patients with drug-resistant and extensively drug-resistant tuberculosis.
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Antituberculosos , Tuberculose Extensivamente Resistente a Medicamentos , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis , Sequenciamento Completo do Genoma , Humanos , Masculino , Adulto , Tuberculose Extensivamente Resistente a Medicamentos/tratamento farmacológico , Tuberculose Extensivamente Resistente a Medicamentos/microbiologia , Antituberculosos/uso terapêutico , Antituberculosos/farmacologia , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/isolamento & purificação , Farmacorresistência Bacteriana Múltipla/genética , Tanzânia , Mutação , Diarilquinolinas/uso terapêutico , Diarilquinolinas/farmacologia , Genoma Bacteriano , Linezolida/uso terapêutico , Linezolida/farmacologiaRESUMO
BACKGROUND: The Latent Autoimmune Diabetes in Adults (LADA) is a slowly progressive Type 1 diabetes subgroup with onset during middle age. Studies report that about 10% of adults initially diagnosed with clinical Type 2 diabetes (T2D) have LADA. Inappropriate diagnosis and mismanagement of the LADA can increase the risk of diabetic complications, which affect the quality of life and is the cause of increased mortality. In low-income countries setting, data regarding the magnitude of LADA is limited. We carried out this study to estimate the burden of misdiagnosed LADA among T2D patients in selected health facilities in Dar es Salaam and to bring awareness to the use of Glutamic Acid Decarboxylase (GAD) autoantibody in screening for LADA. METHODOLOGY: We enrolled 186 phenotypically T2D patients in this cross-sectional study, through a standardized data collection tool we obtained participants' demographic and clinical information. For testing GAD levels, we used a double-antibody Enzyme-Linked Immunosorbent Assay (ELISA). The Fisher's Exact and student t-tests were used to test the significance of the statistical associations of the glycaemic control and diabetes complications between T2D and LADA. RESULTS: Out of 186 patients, 156 gave conclusive GAD Ab ELISA reading with LADA accounting for 5.1% (95% CI: 2.5 - 10.0). The mean age of subjects was 54.3 years (Range: 33-85 years). The parameters such as mean age, family history of diabetes mellitus status, Fasting Blood Glucose, clinical characteristics, and complications did not show significant statistical differences between patients with LADA and Type 2 diabetes. However, all LADA- Human Immunodeficiency Virus (HIV) comorbid patients had retinopathy, which was statistically insignificant in 20 (87%) T2D-HIV comorbid patients (p = 0.669). Neither neuropathy, nephropathy, nor Diabetic Mellitus (D.M.) foot syndrome was observed among LADA-HIV comorbid patients. Nevertheless, 22 (95.7%), 3 (13%), and 2 (8.7%) of T2D-HIV comorbidity had neuropathy, nephropathy, or D.M. foot syndrome, respectively. CONCLUSIONS: The study established a LADA prevalence of 5.1% among T2D patients and has shown the role of GAD autoantibody in the screening for LADA. The study calls for a well- designed larger longitudinal study to generate strong evidence on the association of risk factors and complications associated with the LADA. This will develop robust evidence on the association of risk factors and complications associated with the LADA and T2D.
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Diabetes Mellitus Tipo 2 , Diabetes Autoimune Latente em Adultos , Adulto , Idoso , Idoso de 80 Anos ou mais , Autoanticorpos , Estudos Transversais , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/epidemiologia , Glutamato Descarboxilase , Humanos , Diabetes Autoimune Latente em Adultos/complicações , Diabetes Autoimune Latente em Adultos/diagnóstico , Diabetes Autoimune Latente em Adultos/epidemiologia , Estudos Longitudinais , Pessoa de Meia-Idade , Prevalência , Qualidade de Vida , TanzâniaRESUMO
BACKGROUND: Tuberculosis (TB), particularly multi- and or extensive drug resistant TB, is still a global medical emergency. Whole genome sequencing (WGS) is a current alternative to the WHO-approved probe-based methods for TB diagnosis and detection of drug resistance, genetic diversity and transmission dynamics of Mycobacterium tuberculosis complex (MTBC). This study compared WGS and clinical data in participants with TB. RESULTS: This cohort study performed WGS on 87 from MTBC DNA isolates, 57 (66%) and 30 (34%) patients with drug resistant and susceptible TB, respectively. Drug resistance was determined by Xpert® MTB/RIF assay and phenotypic culture-based drug-susceptibility-testing (DST). WGS and bioinformatics data that predict phenotypic resistance to anti-TB drugs were compared with participant's clinical outcomes. They were 47 female participants (54%) and the median age was 35 years (IQR): 29-44). Twenty (23%) and 26 (30%) of participants had TB/HIV co-infection BMI < 18 kg/m2 respectively. MDR-TB participants had MTBC with multiple mutant genes, compared to those with mono or polyresistant TB, and the majority belonged to lineage 3 Central Asian Strain (CAS). Also, MDR-TB was associated with delayed culture-conversion (median: IQR (83: 60-180 vs. 51:30-66) days). WGS had high concordance with both culture-based DST and Xpert® MTB/RIF assay in detecting drug resistance (kappa = 1.00). CONCLUSION: This study offers comparison of mutations detected by Xpert and WGS with phenotypic DST of M. tuberculosis isolates in Tanzania. The high concordance between the different methods and further insights provided by WGS such as PZA-DST, which is not routinely performed in most resource-limited-settings, provides an avenue for inclusion of WGS into diagnostic matrix of TB including drug-resistant TB.
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Antituberculosos/uso terapêutico , Farmacorresistência Bacteriana Múltipla/genética , Mutação , Mycobacterium tuberculosis/genética , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Adulto , Estudos de Coortes , Feminino , Humanos , Masculino , Mycobacterium tuberculosis/fisiologia , Tanzânia , Resultado do Tratamento , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Sequenciamento Completo do GenomaRESUMO
BACKGROUND: Non-tuberculous mycobacteria (NTM), which are ubiquitous micro-organisms occurring in humans, animals and the environment, sometimes receive public health and veterinary attention as opportunistic disease-causing agents. In Tanzania, there is limited information regarding the diversity of NTM species, particularly at the human-livestock-wildlife interface such as the Serengeti ecosystem, where potential for cross species infection or transmission may exist. METHODS: Mycobacterial DNA was extracted from cultured isolates obtained from sputum samples of 472 suspect TB patients and 606 tissues from wildlife species and indigenous cattle. Multiplex PCR was used to differentiate NTM from Mycobacterium tuberculosis complex (MTBC) members. NTM were further identified to species level by nucleotide sequencing of the 16S rRNA gene. RESULTS: A total of fifty five (55) NTM isolates representing 16 mycobacterial species and 5 isolates belonging to the MTBC were detected. Overall, Mycobacterium intracellulare which was isolated from human, cattle and wildlife, was the most frequently isolated species (20 isolates, 36.4%) followed by M. lentiflavum (11 isolates, 20%), M. fortuitum (4 isolates, 7.3%) and M. chelonae-abscessus group (3 isolates, 5.5%). In terms of hosts, 36 isolates were from cattle and 12 from humans, the balance being found in various wildlife species. CONCLUSION: This study reveals a diversity of NTM species in the Serengeti ecosystem, some of which have potential for causing disease in animals and humans. The isolation of NTM from tuberculosis-like lesions in the absence of MTBC calls for further research to elucidate their actual role in causing disease. We are also suggesting a one health approach in identifying risk factors for and possible transmission mechanisms of the NTM in the agro-pastoral communities in the Serengeti ecosystem.
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Infecções por Mycobacterium não Tuberculosas/epidemiologia , Micobactérias não Tuberculosas/isolamento & purificação , Adulto , Animais , Animais Selvagens/microbiologia , Bovinos/microbiologia , DNA Bacteriano/análise , Ecossistema , Feminino , Humanos , Gado/microbiologia , Masculino , Infecções por Mycobacterium não Tuberculosas/microbiologia , Infecções por Mycobacterium não Tuberculosas/transmissão , Micobactérias não Tuberculosas/genética , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/análise , Tanzânia/epidemiologia , ZoonosesRESUMO
BACKGROUND: Bovine tuberculosis (bTB) is a chronic debilitating disease and is a cause of morbidity and mortality in livestock, wildlife and humans. This study estimated the prevalence and risk factors associated with bovine tuberculosis transmission in indigenous cattle at the human-animal interface in the Serengeti ecosystem of Tanzania. RESULTS: A total of 1,103 indigenous cattle from 32 herds were investigated for the presence of bTB using the Single Intradermal Comparative Tuberculin Test. Epidemiological data on herd structure, management and grazing system were also collected.The apparent individual animal prevalence of tuberculin reactors was 2.4% (95% confidence interval (CI), 1.7 - 3.5%), whereas the true prevalence was 0.6% CI, 0.6 - 0.7% as indicated by a reaction to avian tuberculin purified protein derivatives (PPD) which is more than 4 mm greater than the reaction to avian tuberculin PPD. The results showed that 10.6% (117/1,103) showed non-specific reactions (atypical mycobacterium). The herd prevalence of 50% (16/32) was found. Tuberculin skin test results were found to be significantly associated with age, location, size of the household and animal tested. Of 108 respondents, 70 (64.8%) individuals had not heard about bovine tuberculosis at all. Thirty five percent (38/108) of respondents at least were aware of bTB. About 60% (23/38) of respondents who were aware of bTB had some knowledge on how bTB is spread. Eighty one percent (87/108) of respondents were not aware of the presence of bTB in wildlife. There is regular contact between cattle and wild animals due to sharing of grazing land and water sources, with 99% (107/108) of households grazing cattle in communal pastures. CONCLUSION: The study has demonstrated a high reported interaction of livestock with wildlife and poor knowledge of most cattle owners concerning bTB and its transmission pathways among people, livestock and wildlife. Although the overall proportion of animals with bTB is relatively low, herd prevalence is 50% and prevalence within herds varied considerably. Thus there is a possibility of cross transmission of bTB at wildlife-livestock interface areas that necessitates use of genetic strain typing methods to characterize them accurately.
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Tuberculose Bovina/epidemiologia , Animais , Animais Selvagens/microbiologia , Bovinos , Ecossistema , Feminino , Masculino , Prevalência , Fatores de Risco , Inquéritos e Questionários , Tanzânia/epidemiologia , Teste Tuberculínico/veterinária , Tuberculose Bovina/etiologiaRESUMO
Background: Chronic kidney diseases (CKD), Type 2 Diabetes Mellitus (T2DM) and cardiovascular diseases (CVDs) are the recent worldwide late age chronic conditions that could be a consequence of renal glycosuria during childhood. This study aimed at determining the extent of glycosuria in secondary school students to obtain information that could be predictive of the situation in late age life of Tanzanians living in Mkuranga District. Methodology: This was school-based cross-sectional study that was conducted in assenting and consenting 800 students from July to October 2019 in Mkuranga district, Pwani-Tanzania. Socio-demographic information was collected using well-structured questionnaires while weight and height were measured using beam balance and tape measure, respectively. Dipstick strip was used to determine urine glucose on clean catch mid-stream urine collected specimens. Results: From a total of 800 enrolled students, 0.6% (5/800) had glycosuria from whom 80% were males and 20% (1/5) were females (p = 0.37). The proportion of glycosuric males was 4 folds higher than that found in females. While height, body mass index (BMI) and waist-hip circumference ratio were associated with renal glycosuria (p < 0.05), other factors showed no association (p > 0.05). Conclusion: Despite the low proportion (0.6%) of glycosuria in this study, the contribution of young age renal glycosuria to old age CKD, T2DM and CVDs cannot be ruled out with males being more prone than females. Thus, it signals for consideration of regular screening for glycosuria in the school health programmes as an intervention strategy to prevent potential late age chronic disease complications.
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Advancing biomedical research in low and middle income countries (LMICs) to expand the capacity for LMICs to integrate biomedical research into their health care systems and education has been the focus of many programs in global health over the past two decades. Central to the success of these programs is effective research mentoring, characterized by academic, career and psychosocial support through culturally appropriate practices. Research mentoring is a learned skill, developed through training, mutual discussions, practice and feedback. The majority of extant training programs are designed and delivered by US partners, so the next stage in building capacity is to train facilitators within the LMIC partner institutions to contextualize and advance mentoring specifically within their cultural and institutional norms by co-developing, delivering and evaluating semi-annual research mentoring training. To this end, we describe the development, delivery and outcome evaluation of a 5-week course in the art and skill of facilitation. Care was taken to explicitly distinguish between concepts of "teaching" and "facilitation," since "teaching" is closely connected to a transmission or banking model of education, which is characterized by "top-down," hierarchical relationship. The course discussed power and positionality, themes that resonate with partners in Nigeria and Tanzania. These themes provided unique entry into deeper conversations core to advancing mentoring practice away from the traditional dyadic power structure that remains from colonization. Evaluation findings indicate significant advances in awareness of differences between teaching and facilitating, increased confidence in facilitation skills, especially in the area of structured planning and organization, as well as improved communication and interpersonal skills. All respondents felt that students in Nigeria and Tanzania would respond well to the facilitation approach conveyed during the course and they found value in participating in the course as a cohort.
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While viral load (VL) testing is critical to effective treatment of human immunodeficiency virus (HIV), little is known about patients' experiences with, and barriers to VL-testing in the context of HIV infection. We assessed patient reported experience measures (PREMs) on VL-testing in public HIV clinics in Tanzania. In a cross-sectional convergent mixed method study, we collected information on VL test related PREMs, clinical and sociodemographic factors. PREMs were measured using a 5-point Likert scale. Focus Group Discussions (FGDs) explored on experience, access, and barriers to VL-testing. Descriptive statistics summarized patients' factors and PREMs. Logistic regression was used to explore association of patient factors, PREMs and satisfaction with VL-testing services. Thematic analysis was used for qualitative data. A total of 439 (96.48%) respondents completed the survey, 331 (75.40%) were female, median (IQR) age was 41(34, 49) years. A total of 253(57.63%) had a VL test at least once in the past 12 months, of whom 242(96.0%) had VL<1000 copies/ml. Investigating barriers to VL-testing, most participants (>92.0%) reported good or very good health services responsiveness (HSR). A scale of very good was chosen by the majority for being treated with respect 174(39.6%), listened to 173(39.4%), following advice 109(24.8%), being involved in decisions 101(23.0%), and for communication 102(23.3%). Satisfaction on VL-testing services was significantly associated with respondents following care providers' advice, (aOR) = 2.07 [95%CI 1.13-3.78], involvement in decisions aOR = 4.16 [95%CI 2.26-7.66], and communication aOR = 2.27 [95%CI 1.25-4.14]. FGDs findings converged with the survey data, with identified barriers to VL test including lack of autonomy in decision making, little awareness on the benefits of the test, long waiting time, stigma, competing priorities for those with comorbidities and transport costs. Satisfaction on VL-testing was largely a result of involvement in decision making, following care provider's advice and good communication; entities needing universal improvement across the country.
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INTRODUCTION: People who use drugs (PWUD) experience stigma from multiple sources due to their drug use. HIV seroprevalence for PWUD in Tanzania is estimated to range from 18 to 25%. So, many PWUD will also experience HIV stigma. Both HIV and drug use stigma have negative health and social outcomes, it is therefore important to measure their magnitude and impact. However, no contextually and linguistically adapted measures are available to assess either HIV or drug use stigma among PWUD in Tanzania. In response, we translated and culturally adapted HIV and drug use stigma measures among Tanzanian PWUD and described that process in this study. METHODS: This was a cross-sectional study. We translated and adapted existing validated stigma measures by following a modified version of Wild's ten steps for translation and adaptation. We also added new items on stigmatizing actions that were not included in the original measures. Following translation and back translation, we conducted 40 cognitive debriefs among 19 PWUD living with and 21 PWUD not living with HIV in Dar es Salaam to assess comprehension of the original and new items. For challenging items, we made adaptations and repeated cognitive debriefs among ten new PWUD participants where half of them were living with HIV. RESULTS: Most of the original items (42/54, 78%), response options and all items with new 12 stigmatizing actions were understood by participants. Challenges included response options for a few items; translation to Swahili; and differences in participants' interpretation of Swahili words. We made changes to these items and the final versions were understood by PWUD participants. CONCLUSION: Drug use and HIV stigma measures can successfully be translated and culturally adapted among Tanzanian PWUD living with and without HIV. We are currently conducting research to determine the stigma measures' psychometric properties and we will report the results separately.
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Infecções por HIV , Transtornos Relacionados ao Uso de Substâncias , Humanos , Tanzânia/epidemiologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Infecções por HIV/psicologia , Estudos Transversais , Estudos Soroepidemiológicos , Estigma Social , Transtornos Relacionados ao Uso de Substâncias/epidemiologiaRESUMO
The COVID-19 pandemic caused significant disruption to medical education globally. Fogarty International Center (FIC) training programs, designed to strengthen research capacity in low- and middle-income countries (LMICs), through partnerships between United States and LMIC institutions were particularly vulnerable to COVID-19 disruptions. We adapted short-term training for our FIC HIV Patient-Centered Outcomes Research program in Tanzania to the virtual environment using synchronous, asynchronous, and blended approaches and a variety of teaching pedagogies. We evaluated the acceptability and effectiveness of the new trainings among trainees and facilitators using a mixed-methods approach. Ninety percent of trainees and Muhimbili University of Health and Allied Sciences (MUHAS) facilitators agreed that the virtual training methods used were effective. Trainees reported high levels of satisfaction with the technology, group work, and relevance to their research. More than 50% of trainees and MUHAS facilitators agreed that learning in the virtual environment was as effective as, or more effective than, traditional in-person learning. However, they desired more interaction, opportunities to ask U.S. facilitators questions, and choices about topics for online versus in-person trainings. Two-thirds of U.S. facilitators agreed that the virtual delivery method was an effective way for participants to learn the material, although they also rated interaction less favorably. Virtual training incorporating pedagogical best practices of blended learning and traditional teaching online was a feasible, acceptable, and effective way of conducting research training to junior scientists during COVID-19. Virtual learning could become an integral part of post-pandemic training with some adaptation to improve interactions.
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COVID-19 , Educação Médica , Humanos , Aprendizagem , Pandemias , Tanzânia , Estados UnidosRESUMO
Immunoglobulin G (IgG) subclasses have been suggested to confer naturally acquired immunity to Plasmodium falciparum malaria. Cytophilic IgG1 and IgG3 with their potential for opsonization, phagocytosis, and antibody-dependent cellular inhibition in association with monocytes have been suggested to have a critical role in malaria. The potential for production of antibodies is influenced by micronutrient status. This study aimed at exploring the effect of micronutrients, particularly zinc status, on the profiles of IgG subclasses in 304 Tanzanian children aged ≤ 5 years. An enzyme-linked immunosorbent assay was performed using whole asexual blood stage malaria antigens to determine plasma malaria-specific antibody titers. This baseline cross-sectional study was done from 2005 - 2010 prior to the larger randomized control trial of the Micronutrient and Child Health (MACH) Study. Plasma concentrations of zinc and magnesium were measured by inductively coupled plasma atomic emission spectrometry and results correlated with plasma IgG subclass levels. The findings reveal zinc deficiency to possibly influence the production of IgM, total IgG, and several IgG subclasses in a malaria status-dependent manner. Among IgG subclasses, IgG3 and partly IgG2 displayed a remarkable association with zinc deficiency, particularly IgG3 which was predominant in children with malaria. Nevertheless, zinc, magnesium, and malaria status did not influence the association between IgG3 and IgG4. The study leads to the conclusion that, under conditions of micronutrient deficiency and malaria status, an imbalance in IgG subclass production may occur leading to predominantly higher levels of IgG3 and IgG2 that may not confer sufficient protection from infection. The profile of both cytophilic and non-cytophilic IgG subclasses has been shown to be variably influenced by zinc status; the effects vary with age at least in under-fives. These results provide insight for inclusion of micronutrients, particularly precise amounts of zinc, in future malaria interventional programs in endemic areas.
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BACKGROUND: It is uncertain to what extent oral supplementation with zinc can reduce episodes of malaria in endemic areas. Protection may depend on other nutrients. We measured the effect of supplementation with zinc and other nutrients on malaria rates. METHODS AND FINDINGS: In a 2×2 factorial trial, 612 rural Tanzanian children aged 6-60 months in an area with intense malaria transmission and with height-for-age z-score≤-1.5 SD were randomized to receive daily oral supplementation with either zinc alone (10 mg), multi-nutrients without zinc, multi-nutrients with zinc, or placebo. Intervention group was indicated by colour code, but neither participants, researchers, nor field staff knew who received what intervention. Those with Plasmodium infection at baseline were treated with artemether-lumefantrine. The primary outcome, an episode of malaria, was assessed among children reported sick at a primary care clinic, and pre-defined as current Plasmodium infection with an inflammatory response, shown by axillary temperature ≥37.5°C or whole blood C-reactive protein concentration ≥ 8 mg/L. Nutritional indicators were assessed at baseline and at 251 days (median; 95% reference range: 191-296 days). In the primary intention-to-treat analysis, we adjusted for pre-specified baseline factors, using Cox regression models that accounted for multiple episodes per child. 592 children completed the study. The primary analysis included 1,572 malaria episodes during 526 child-years of observation (median follow-up: 331 days). Malaria incidence in groups receiving zinc, multi-nutrients without zinc, multi-nutrients with zinc and placebo was 2.89/child-year, 2.95/child-year, 3.26/child-year, and 2.87/child-year, respectively. There was no evidence that multi-nutrients influenced the effect of zinc (or vice versa). Neither zinc nor multi-nutrients influenced malaria rates (marginal analysis; adjusted HR, 95% CI: 1.04, 0.93-1.18 and 1.10, 0.97-1.24 respectively). The prevalence of zinc deficiency (plasma zinc concentration <9.9 µmol/L) was high at baseline (67% overall; 60% in those without inflammation) and strongly reduced by zinc supplementation. CONCLUSIONS: We found no evidence from this trial that zinc supplementation protected against malaria. TRIAL REGISTRATION: ClinicalTrials.gov NCT00623857
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Suplementos Nutricionais/efeitos adversos , Ferro/efeitos adversos , Malária Falciparum/tratamento farmacológico , Micronutrientes/uso terapêutico , Zinco/uso terapêutico , Antimaláricos/administração & dosagem , Combinação Arteméter e Lumefantrina , Artemisininas/administração & dosagem , Pré-Escolar , Suplementos Nutricionais/análise , Combinação de Medicamentos , Etanolaminas , Feminino , Fluorenos/administração & dosagem , Seguimentos , Humanos , Incidência , Lactente , Ferro/administração & dosagem , Ferro/uso terapêutico , Deficiências de Ferro , Malária/classificação , Malária/tratamento farmacológico , Malária/epidemiologia , Malária/prevenção & controle , Malária Falciparum/classificação , Malária Falciparum/epidemiologia , Malária Falciparum/prevenção & controle , Masculino , Desnutrição/sangue , Desnutrição/epidemiologia , Micronutrientes/administração & dosagem , Micronutrientes/deficiência , Prevalência , Análise de Regressão , Tanzânia/epidemiologia , Zinco/administração & dosagem , Zinco/deficiênciaRESUMO
BACKGROUND: It is controversial to what degree α(+)-thalassaemia protects against episodes of uncomplicated malaria and febrile disease due to infections other than Plasmodium. METHODS: In Tanzania, in children aged 6-60 months and height-for-age z-score < -1.5 SD (n = 612), rates of fevers due to malaria and other causes were compared between those with heterozygous or homozygotes α(+)-thalassaemia and those with a normal genotype, using Cox regression models that accounted for multiple events per child. RESULTS: The overall incidence of malaria was 3.0/child-year (1, 572/526 child-years); no differences were found in malaria rates between genotypes (hazard ratios, 95% CI: 0.93, 0.82-1.06 and 0.91, 0.73-1.14 for heterozygotes and homozygotes respectively, adjusted for baseline factors that were predictive for outcome). However, this association strongly depended on age: among children aged 6-17 months, those with α(+)-thalassaemia experienced episodes more frequently than those with a normal genotype (1.30, 1.02-1.65 and 1.15, 0.80-1.65 for heterozygotes and homozygotes respectively), whereas among their peers aged 18-60 months, α(+)-thalassaemia protected against malaria (0.80, 0.68-0.95 and 0.78, 0.60-1.03; p-value for interaction 0.001 and 0.10 for hetero- and homozygotes respectively). No effect was observed on non-malarial febrile episodes. CONCLUSIONS: In this population, the association between α(+)-thalassaemia and malaria depends on age. Our data suggest that protection by α(+)-thalassaemia is conferred by more efficient acquisition of malaria-specific immunity.
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Febre de Causa Desconhecida/epidemiologia , Malária/epidemiologia , Malária/patologia , Talassemia alfa/complicações , Fatores Etários , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Incidência , Lactente , Masculino , Modelos Estatísticos , Estudos Prospectivos , Tanzânia/epidemiologiaRESUMO
BACKGROUND: An appropriate balance between pro-inflammatory and anti-inflammatory cytokines that mediate innate and adaptive immune responses is required for effective protection against human malaria and to avoid immunopathology. In malaria endemic countries, this immunological balance may be influenced by micronutrient deficiencies. METHODS: Peripheral blood mononuclear cells from Tanzanian preschool children were stimulated in vitro with Plasmodium falciparum-parasitized red blood cells to determine T-cell responses to malaria under different conditions of nutrient deficiencies and malaria status. RESULTS: The data obtained indicate that zinc deficiency is associated with an increase in TNF response by 37%; 95% CI: 14% to 118% and IFN-gamma response by 74%; 95% CI: 24% to 297%. Magnesium deficiency, on the other hand, was associated with an increase in production of IL-13 by 80%; 95% CI: 31% to 371% and a reduction in IFN-gamma production. These results reflect a shift in cytokine profile to a more type I cytokine profile and cell-cell mediated responses in zinc deficiency and a type II response in magnesium deficiency. The data also reveal a non-specific decrease in cytokine production in children due to iron deficiency anaemia that is largely associated with malaria infection status. CONCLUSIONS: The pathological sequels of malaria potentially depend more on the balance between type I and type II cytokine responses than on absolute suppression of these cytokines and this balance may be influenced by a combination of micronutrient deficiencies and malaria status.
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Citocinas/biossíntese , Deficiência de Magnésio/imunologia , Malária Falciparum/imunologia , Plasmodium falciparum/imunologia , Células Th1/imunologia , Células Th2/imunologia , Zinco/imunologia , Anemia Ferropriva/sangue , Criança , Pré-Escolar , Citocinas/sangue , Eritrócitos/imunologia , Eritrócitos/parasitologia , Feminino , Citometria de Fluxo , Humanos , Lactente , Deficiência de Magnésio/sangue , Malária Falciparum/epidemiologia , Masculino , Tanzânia/epidemiologia , Células Th1/parasitologia , Células Th2/parasitologia , Zinco/sangue , Zinco/deficiênciaRESUMO
BACKGROUND: Deficiencies in vitamins and mineral elements are important causes of morbidity in developing countries, possibly because they lead to defective immune responses to infection. The aim of the study was to assess the effects of mineral element deficiencies on early innate cytokine responses to Plasmodium falciparum malaria. METHODS: Peripheral blood mononuclear cells from 304 Tanzanian children aged 6-72 months were stimulated with P. falciparum-parasitized erythrocytes obtained from in vitro cultures. RESULTS: The results showed a significant increase by 74% in geometric mean of TNF production in malaria-infected individuals with zinc deficiency (11% to 240%; 95% CI). Iron deficiency anaemia was associated with increased TNF production in infected individuals and overall with increased IL-10 production, while magnesium deficiency induced increased production of IL-10 by 46% (13% to 144%) in uninfected donors. All donors showed a response towards IL-1beta production, drawing special attention for its possible protective role in early innate immune responses to malaria. CONCLUSIONS: In view of these results, the findings show plasticity in cytokine profiles of mononuclear cells reacting to malaria infection under conditions of different micronutrient deficiencies. These findings lay the foundations for future inclusion of a combination of precisely selected set of micronutrients rather than single nutrients as part of malaria vaccine intervention programmes in endemic countries.
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Anemia Ferropriva/sangue , Citocinas/biossíntese , Deficiência de Magnésio/sangue , Malária Falciparum/imunologia , Plasmodium falciparum/imunologia , Zinco/deficiência , Anemia Ferropriva/complicações , Anemia Ferropriva/imunologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Estudos Transversais , Citocinas/sangue , Feminino , Humanos , Lactente , Interleucina-10/biossíntese , Interleucina-10/sangue , Deficiência de Magnésio/complicações , Deficiência de Magnésio/imunologia , Malária Falciparum/complicações , Malária Falciparum/parasitologia , Masculino , Tanzânia , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/sangue , Zinco/sangue , Zinco/imunologiaRESUMO
BACKGROUND: One Health (OH) is an integrated approach, formed inclusive of using multiple disciplines to attain optimal health for humans, animals, and the environment. The increasing proximity between humans, livestock, and wildlife, and its role in the transmission dynamics of mycobacterial infections, necessitates an OH approach in the surveillance of zoonotic diseases. The challenge remains as humans, livestock, and wildlife share resources and interact at various interfaces. Therefore, this review explores the potential of the OH approach to understand the impact of mycobacterial infections in Tanzania in terms of lessons learnt and future perspectives. MATERIALS AND METHODS: Available literature on OH and mycobacterial infections in Tanzania was searched in PubMed, Google Scholar, and Web of Science. Articles on mycobacterial infections in Tanzania, published between 1997 to 2017, were retrieved to explore the information on OH and mycobacterial infections. MAIN BODY: The studies conducted in Tanzania had have reported a wide diversity of mycobacterial species in humans and animals, which necessitates an OH approach in surveillance of diseases for better control of infectious agents and to safeguard the health of humans and animals. The close proximity between humans and animals increases the chances of inter-specific transmission of infectious pathogens, including drug-resistant mycobacteria. In an era where HIV co-infection is also the case, opportunistic infection by environmental non-tuberculous mycobacteria (NTM), commonly known as mycobacteria other than tuberculosis (MOTT) may further exacerbate the impact of drug resistance. NTM from various sources have greatest potential for diverse strains among which are resistant strains due to continued evolutional changes. CONCLUSION: A collaborative interdisciplinary approach among professionals could help in solving the threats posed by mycobacterial infections to public health, particularly by the spread of drug-resistant strains.
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BACKGROUND: DNA analysis has potential for screening for and diagnosing a variety of conditions as well as the characterization of various pathogens for many purposes including to identify genetic disorders and mutations, study genetic diversity, and establish evolutional trends. METHODS: Our study compared the performance of 2 DNA extraction kits: Qiagen and prepITâ¢MAX. The study tested 160 formalin-fixed paraffin-embedded (FFPE) human tissue samples that had been collected at Muhimbili National Hospital (MNH) between 2010 and 2016. For each sample, DNA extraction was performed using both the Qiagen and prepITâ¢MAX kits followed by polymerase chain reaction (PCR) tests to target the RNA polymerase gene and gel electrophoresis. RESULTS: The findings showed that the Qiagen was 3 times superior to the prepITâ¢MAX kit in successfully extracting mycobacterial DNA from presumptive tuberculosis (TB) FFPE tissues. Of the 160 previously Ziehl-Neelsen stain-negative Mycobacterium tuberculosis suspicious tissue samples, 12 (7.5%) tested positive with the PCR. Of the 12 PCR-detected positive samples, 8 (66.7%) yielded positive results with the Qiagen kit only and 4 (33.3%) yielded positive results with both Qiagen and prepITâ¢MAX kits. Additionally, 10 (83.3%) came from well-formed granuloma, 1 (8%) from caseous necrosis, and 1 (8.3%) Langhans-type giant cells endorsing their potential for housing infection such as TB adenitis. CONCLUSIONS: A combination of molecular techniques, microscopy, and pathological features increases detection of M. tuberculosis from FFPE tissues. Both the Qiagen and the prepITâ¢MAX DNA extraction kits have shown a remarkable capability for extracting DNA from M. tuberculosis, although examination of FFPE tissues is not an intended use for the prepIT MAX, according to the manufacturer. In resource-limited countries, however, these kits may complement each other. We recommend further studies for validation and optimization, which includes the cost effectiveness of prepITâ¢MAX extraction kit to advocate for its use in extraction of mycobacterial DNA from FFPE tissues.
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BACKGROUND: Cross-species tuberculosis (TB) transmission between humans and animals has been reported for quite a long time in sub-Saharan Africa. Because humans and animals coexist in the same ecosystem, exploring their potential for cross-species transmission and the impact the disease may have on the health of humans, animals, and their products is critical. OBJECTIVES: This study aimed to identify risk factors for transmission of TB (Mycobacterium tuberculosis) and to assess the potential for zoonotic TB (Mycobacterium bovis) transmission in the Serengeti ecosystem where humans and animals are in intense contact. Our aim is to create a base for future implementation of appropriate control strategies to limit infection in both humans and animals. METHODOLOGY: We administered a semi-structured questionnaire to 421 self-reporting patients to gather information on risk factors and TB occurrence. In a parallel study, researchers screened sputum smears using Ziehl-Neelsen staining and confirmed by mycobacterial culture. We then performed descriptive statistics (Pearson's chi-square test) and logistic regression analysis to establish frequencies, association, and quantification of the risk factors associated with TB cases. RESULTS: Our findings showed 44% (95% confidence interval [CI], 0.40-0.49) of the results were positive from sputum samples collected over a 1-year duration in areas with a high TB burden, particularly the Bunda district, followed by the Serengeti and Ngorongoro districts. Of the culture-positive patients who also had infections other than TB (43/187 patients), 21 (49%) were HIV positive. Contact with livestock products (odds ratio [OR] 6.0; 95% CI, 1.81-19.9), infrequent milk consumption (OR 2.5; 95% CI, 1.42-4.23), cigarette smoking (OR 2.9; 95% CI, 1.19-7.1.2), and alcohol consumption (OR 2.3; 95% CI, 1.22-4.23) were associated with a higher likelihood of TB infection. CONCLUSION: There was no evidence of direct cross-species transmission of either M tuberculosis or M bovis between humans and animals using the study methods. The absence of cross-species TB transmission could be due to limited chances of contact rather than an inability of cross-species disease transmission. In addition, not all people with presumptive TB are infected with TB, and therefore control strategies should emphasise confirming TB status before administering anti-TB drugs.
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In the Ngorongoro Conservation Area (NCA), Tanzania, where wildlife and livestock interaction is intense, greater potential for intra- and interspecies disease transmission is expected. We assessed the prevalence of bovine tuberculosis in African buffalo (Syncerus caffer) residing on the valley floor of the crater in the NCA. Apparently healthy animals were randomly selected from herds in nine sites of the Ngorongoro Crater. Syncerus caffer buffalo herds were located using very high-frequency radio-aided rangers positioned in various observation points around the crater in the NCA. A total of 102 African buffalo from 16 herds were immobilized from the ground using a cocktail of 4-10 mg etorphine hydrochloride (M99) and 60-150 mg azaperone tartrate. The M99 was reversed using 10-25 mg diprenorphine hydrochloride depending on age of animals. An interferon gamma assay was performed on harvested plasma samples using sandwich enzyme linked immunosorbent assay. Of the 102 animals sampled, two (2%) African buffalo tested positive for bovine tuberculosis. These results corroborate those of the skin test done recently in cattle in the NCA. The presence of bovine tuberculosis in livestock and wildlife suggested the possibility of cross-species transmission of the disease, indicating the need for appropriate intervention measures.
Assuntos
Búfalos , Tuberculose Bovina/epidemiologia , Determinação da Idade pelos Dentes/veterinária , Distribuição por Idade , Animais , Animais Selvagens , Bovinos , Feminino , Imobilização/veterinária , Interferon gama/sangue , Testes Intradérmicos/veterinária , Gado , Masculino , Programas de Rastreamento/veterinária , Prevalência , Rádio , Distribuição por Sexo , Tanzânia/epidemiologia , Tuberculose Bovina/diagnóstico , Tuberculose Bovina/transmissãoRESUMO
BACKGROUND: Sulphadoxine-pyrimethamine (SP) has been and is currently used for treatment of uncomplicated Plasmodium falciparum malaria in many African countries. Nevertheless, the response of parasites to SP treatment has shown significant variation between individuals. METHODS: The genes for dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) were used as markers, to investigate parasite resistance to SP in 141 children aged less than 5 years. Parasite DNA was extracted by Chelex method from blood samples collected and preserved on filter papers. Subsequently, polymerase chain reaction (PCR) and restriction fragment length polymorphism (PCR-RFLP) were applied to detect the SP resistance-associated point mutations on dhfr and dhps. Commonly reported point mutations at codons 51, 59, 108 and 164 in the dhfr and codons 437, 540 and 581 in the dhps domains were examined. RESULTS: Children infected with parasites harbouring a range of single to quintuple dhfr/dhps mutations were erratically cured with SP. However, the quintuple dhfr/dhps mutant genotypes were mostly associated with treatment failures. High proportion of SP resistance-associated point mutations was detected in this study but the adequate clinical response (89.4%) observed clinically at day 14 of follow up reflects the role of semi-immunity protection and parasite clearance in the population. CONCLUSION: In monitoring drug resistance to SP, concurrent studies on possible confounding factors pertaining to development of resistance in falciparum malaria should be considered. The SP resistance potential detected in this study, cautions on its useful therapeutic life as an interim first-line drug against malaria in Tanzania and other malaria-endemic countries.