Clinical implication of novel drug resistance-conferring mutations in resistant tuberculosis.

Evolving novel and/or unfamiliar mutations are revolutionizing the pathways of antibiotic resistance of clinical tuberculosis. The accumulation and interaction of these poorly characterized mutations augment the complexity of resistant pathogenic strains and raise public health concerns. This article reviews our current understanding of the genetic changes that characterize drug resistance in tuberculosis and highlights the imperative for further investigations focusing on the effects of an individual mutation and interacting mutations with detailed strain epidemiology, particularly as these pertain to technology-limited countries with high tuberculosis incidence rates. Concomitantly, there is a need for the development, testing, and uptake of new tools for studying the effects of these mutations in drug resistance and fitness cost of the pathogen. Such genetic data are critical for effective localized and global tuberculosis control interventions and for accurate epidemiological predictions.

'One Health´ approach to end zoonotic TB.

Mycobacterium bovis has a wide host range causing TB in animals, both in wildlife and cattle (bovine TB bTB), and in humans (zoonotic TB zTB). The real burden of bovine and zoonotic TB (b/zTB) remains unknown due to diagnostic challenges. Although progress has been made to reduce the burden of TB, b/zTB has been neglected in low- and middle-income countries (LMICs) with little improvement in prevention, diagnosis or treatment. Using Tanzania as a case study, because of its high TB burden, large wildlife diversity and wide reliance on livestock, we developed an approach to comprehensively estimate the burden and implement multidisciplinary actions against b/zTB. We performed a review of the literature on b/zTB, but there is a lack of available data on the b/zTB burden in Tanzania and, notably, on epidemiological indicators other than incidence. We propose a five-action programme to address b/zTB in Tanzania, and we believe our proposed approach could benefit other LMICs as it operates by implementing and strengthening surveillance and health delivery. The resulting knowledge and system organisation could further prevent and mitigate the effects of such conditions on human and animal health, livestock production, population livelihood and the economy.

IPT coverage and determinants of care coverage in Tanzania.

BACKGROUND: TB is a major cause of mortality worldwide, with the highest risk in people living with HIV/AIDS (PLWHA). Isoniazid preventive therapy (IPT), in combination with antiretroviral therapy (ART), reduces the overall incidence and mortality from TB by up to 90% among PLWHA. Tanzania has limited published data on IPT coverage among PLWHA. OBJECTIVE: To investigate coverage and determinants of IPT among PLWHA receiving care in selected care and treatment clinics in Dar es Salaam, Tanzania. METHODS: An analytical cross-sectional design to study 31,480 HIV-positive adults. Proportions and comparisons were obtained using χ2 tests, while determinants for IPT were assessed using adjusted multivariable analysis. RESULTS: The IPT coverage among eligible PLWHA was generally low (28.9%), with increased coverage over time. The determinants for IPT coverage included age >36 years, having WHO Clinical Stages 1 and 2 compared to 3 and 4, and having normal weight, or being overweight and obesity compared to underweight. CONCLUSION: IPT coverage in Dar es Salaam is very low; individuals with minor HIV disease severity were more likely to initiate IPT. This shows a possible gap in the prescribing practices among healthcare providers. More efforts to ensure IPT coverage implementation in Dar es Salaam are required.

CONTEXTE: La TB est une cause majeure de mortalité dans le monde, le risque étant le plus élevé chez les personnes vivant avec le VIH/SIDA (PLWHA). Le traitement préventif à l'isoniazide (TPI), associé au traitement antirétroviral (ART), réduit l'incidence globale et la mortalité de la TB jusqu'à 90% chez les PLWHA. La Tanzanie dispose de peu de données publiées sur la couverture du TPI chez les PLWHA. OBJECTIF: Étudier la couverture et les déterminants du TPI chez les PLWHA recevant des soins dans des cliniques de soins et de traitement sélectionnées à Dar es Salaam, en Tanzanie. MÉTHODES: Une conception analytique transversale pour étudier 31 480 adultes séropositifs. Les proportions et les comparaisons ont été obtenues à l'aide de tests χ2, tandis que les déterminants du TPI ont été évalués à l'aide d'une analyse multivariable ajustée. RÉSULTATS: La couverture du TPI parmi les PLWHA admissibles était généralement faible (28,9%), avec une augmentation de la couverture au fil du temps. Les déterminants de la couverture du TPI comprenaient l'âge >36 ans, les stades cliniques 1 et 2 de l'OMS par rapport aux stades 3 et 4, et un poids normal ou un surpoids et une obésité par rapport à un poids insuffisant. CONCLUSION: La couverture du TPI à Dar es Salaam est très faible ; les personnes dont la gravité de la maladie VIH était mineure étaient plus susceptibles d'initier un TPI. Cela montre une possible lacune dans les pratiques de prescription parmi les prestataires de soins de santé. Des efforts supplémentaires sont nécessaires pour assurer la mise en œuvre de la couverture TPI à Dar es Salaam.

Does distance to healthcare facility affect care-seeking for TB-related symptoms in Tanzania?

BACKGROUND: In high TB burden countries, delayed diagnosis remains a big challenge in TB control. The objective of this study is to assess the role of distance between residence and healthcare facility (HCF) on care-seeking among individuals with symptoms associated with pulmonary TB in Tanzania.METHODS: In this cross-sectional study, using data from a national TB survey, coordinates of 300 (residential) sites within 62 clusters were obtained through Google searches and average distances to HCF were calculated per cluster. Univariable and multivariable logistic regression analyses were conducted, with care-seeking behaviour being the primary outcome variable.RESULTS: Distance from residence to HCF had no effect on care-seeking behaviour of individuals with TB-related symptoms in this study (OR 1.00, 95% CI 1.00-1.00). Over 85% of HCFs where care has been sought lack TB diagnostic capacity, mostly comprising dispensaries with staff less educated in TB-related symptoms.CONCLUSION: Care-seeking behaviour among individuals with TB-related symptoms in Tanzania was not found to be associated with distance to HCF. First-line diagnostics should be improved 1) by equipping local dispensaries with basic TB diagnostic capacity, and 2) by educating staff of local dispensaries more thoroughly about basic TB symptoms and the importance of swift referrals.

Knowledge, awareness and use of HIV services among the youth from nomadic and agricultural communities in Tanzania.

BACKGROUND: Nomadic life not only prevents the community from accessing and utilising HIV services but also deters them from obtaining reliable information on HIV. METHODS: We conducted a cross-sectional study of youth aged 10-24 years from the Kilindi and Ngorongoro Districts in Tanzania to assess knowledge, accessibility and utilisation of HIV/AIDS services among nomadic and agricultural youths. RESULTS: Of 518 youths interviewed, 279 (53.9%) were males, and 276 (53.3%) were from agricultural communities. A significant proportion of youths from agricultural communities had correct knowledge of AIDS (n = 126, 45.8%; P = 0.002), HIV transmission (n = 273, 98.9%; P = 0.001) and comprehensive knowledge of HIV/AIDS (n = 78, 28.5%; P = 0.009) compared to nomads. Youths from agricultural communities were two times (OR 1.8, 95% CI 1.2-2.6) more likely to be aware of the availability of formal HIV services. Awareness of the availability of HIV services was higher among married individuals than in unmarried ones (OR 3.8, 95% CI 2.0-7.4), and significantly higher among youths with secondary/college education than in those who did not have formal education (OR 5.3, 95% CI 2.3-12.4). The uptake of HIV services was lower among nomadic youths. CONCLUSION: Knowledge, awareness and utilisation of HIV/AIDS transmission services were low in general, and even lower among nomadic youths, calling for more targeted interventions.

CONTEXTE: La vie nomade n'entrave pas seulement l'accès et l'utilisation des services VIH par une communauté mais empêche également l'accès à une information VIH fiable. MÉTHODES: Nous avons réalisé une étude transversale auprès de jeunes de 10­24 ans des districts de Kilindi et de Ngorongoro en Tanzanie pour évaluer les connaissances, l'accessibilité et l'utilisation des services VIH/SIDA parmi les jeunes nomades et agriculteurs. RÉSULTATS: Sur 518 jeunes, 279 (53,9%) étaient des garçons, 276 (53,3%) venaient de communautés agricoles. Une proportion significative des jeunes de communautés agricoles avaient des connaissances correctes en matière de SIDA (n = 126 ; 45,8% ; P = 0,002), de transmission du VIH (n = 273 ; 98,9% ; P = 0,001) de connaissances complètes du VIH/SIDA (n = 78 ; 28,5% ; P = 0,009) comparées à celles des nomades. Les jeunes des communautés agricoles étaient deux fois plus au courant (OR 1,8 ; IC 95% 1,2­2,6) de la disponibilité de services VIH formels. La connaissance de la disponibilité de services VIH était plus élevée chez les jeunes mariés (OR 3,8 ; IC 95% 2,0­7,4) comparés aux célibataires, et significativement plus élevée parmi les jeunes ayant eu une instruction secondaire/supérieure comparés à ceux qui n'avaient eu aucune éducation formelle (OR 5,3 ; IC 95% 2,3­12,4). L'utilisation des services VIH était plus faible parmi les nomades. CONCLUSION: Les connaissances, la sensibilisation et l'utilisation des services de transmission du VIH/SIDA étaient bas et encore plus bas chez les jeunes nomades, appelant des interventions plus ciblées.

Xpert® MTB/RIF assay testing on stool for the diagnosis of paediatric pulmonary TB in Tanzania.

SETTING: Six health facilities in Dar es Salaam, Tanzania. OBJECTIVE: To evaluate the use of stool specimens in the diagnostic workup of paediatric TB using the Xpert® MTB/RIF assay. DESIGN: Between December 2018 and May 2019, we performed a cross-sectional diagnostic study of children aged between 1 month and 14 years with presumptive TB. A single stool specimen was tested using Xpert. The result was compared with the reference microbiological standard for respiratory or gastric specimens tested using Xpert and/or solid culture. The sensitivity, specificity and predictive values of stool Xpert assay were assessed. RESULTS: A total of 225 children with a median age of 2.17 years (IQR 1.16-5.19) were enrolled; 165/225 (73.3%) were aged <5 years. Of 225 children, 8 (3.6%) were diagnosed with TB as they were culture- or Xpert-positive on sputum/gastric aspirate. The stool Xpert assay showed a sensitivity of 62.5% (95% CI 25-92) and specificity of 100% (95% CI 98-100) against the reference standard. CONCLUSION: Use of the Xpert assay on stool specimens had a moderate sensitivity and high specificity in the diagnosis of pulmonary TB in children. Our data adds to the body of evidence for the use of Xpert assay on stool as a non-respiratory specimen to complement conventional methods used to diagnose the disease.

CONTEXTE: Six structures de santé à Dar es Salaam, Tanzanie. OBJECTIF: Evaluer l'utilisation d'échantillons de selles dans le bilan diagnostique de la TB pédiatrique en utilisant le test Xpert® MTB/RIF. SCHÉMA: Entre décembre 2018 et mai 2019, nous avons réalisé une étude transversale de bilans d'enfants âgés d'un mois à 14 ans avec la TB présumée. Un échantillon unique de selles a été testé par l'Xpert. Le résultat a été comparé avec comme référence le standard microbiologique d'échantillons respiratoires ou gastriques testés par test Xpert et/ou culture solide. La sensibilité, la spécificité et les valeurs prédictives de l'Xpert sur les selles ont été évaluées. RÉSULTATS: Ont été enrôlés 225 enfants d'âge médiane 2,17 ans (IQR 1,16­5,19) dont 165 (73,3%) avaient moins de cinq ans. Huit (3,6%) enfants ont eu un diagnostic de TB par culture ou test Xpert positif sur aspiration de crachats/gastrique. Le test Xpert sur les selles a montré une sensibilité de 62,5% (IQR 25­92) et une spécificité de 100% (IQR 98­100) vis-à-vis du standard de référence. CONCLUSION: Le recours au test Xpert sur des échantillons de selles a montré une sensibilité modérée et une spécificité élevée dans le diagnostic de la TB pulmonaire des enfants. Nous données confirment l'intérêt de l'utilisation du test Xpert sur les selles comme échantillon non respiratoire pour compléter les méthodes conventionnelles de diagnostic de la maladie.

Patient's dissatisfaction with the public and private laboratory services in conducting HIV related testing in Tanzania.

BACKGROUND: Patient's satisfaction with both private and public laboratory services is important for the improvement of the health care delivery in any country. METHODS: A cross-sectional survey was conducted in 24 randomly selected health facilities with laboratories that are conducting HIV related testing, in Mainland Tanzania. The study assessed patient's satisfaction with the laboratory services where by a total of 295 patients were interviewed. RESULTS: Of data analyzed for a varying totals from 224 to 294 patients, the percentage of dissatisfaction with both public and private laboratory services, ranged from 4.3% to 34.8%, with most of variables being more than 15%. Patients who sought private laboratory services were less dissatisfied with the cleanness (3/72, 4.2%) and the privacy (10/72, 13.9%) than those sought public laboratory service for the same services of cleanness (41/222, 18.5%) and privacy (61/222, 27.5%), and proportional differences were statistically significant (X2 = 8.7, p = 0.003 and X2 = 5.5, p = 0.01, respectively). Patients with higher education were more likely to be dissatisfied with privacy (OR = 1.8, 95% CI: 1.1-3.1) and waiting time (OR = 2.5, 95% CI: 1.5 - 4.2) in both private and public facilities. Patients with secondary education were more likely to be dissatisfied with the waiting time (OR = 5.2; 95%CI: 2.2-12.2) and result notification (OR = 5.1 95%CI (2.2-12.2) than those with lower education. CONCLUSION: About 15.0% to 34.8% of patients were not satisfied with waiting time, privacy, results notification cleanness and timely instructions. Patients visited private facilities were less dissatisfied with cleanness and privacy of laboratory services than those visited public facilities. Patients with higher education were more likely to be dissatisfied with privacy and waiting time in both private and public facilities.

Dissatisfaction with the laboratory services in conducting HIV related testing among public and private medical personnel in Tanzania.

BACKGROUND: A comprehensive care and treatment program requires a well functioning laboratory services. We assessed satisfaction of medical personnel to the laboratory services to guide process of quality improvement of the services. METHODOLOGY: A cross-sectional survey in 24 randomly selected health facilities in Mainland Tanzania was conducted to assess the satisfaction of the medical personnel with the laboratory services. RESULTS: Of 235 medical personnel interviewed, 196 were valid for analysis and about one quarter were dissatisfied with the laboratory services. Personnel dissatisfied with the services were 38.3% in timely test result, 24.5% in correct and accurate results and 22.4% in clear complete results. The personnel in public laboratories were more dissatisfied with timely test results (OR = 3.6, 95% CI 1.8, 7.3), correct results (OR = 4.1, 95% CI 1.6, 10.8) and clear complete results (OR = 5.0 95% CI 1.6, 15.2). Personnel dissatisfied with the services in 15 laboratories sending specimens to referral laboratories, varied from 13% in availability of equipment to 57% in timely results feedback from the referral laboratories. Personnel dissatisfied with the services in 14 referral laboratories, varied from 28.6% in properly identified specimen to 42.9% in clear, accurate test request and communication. CONCLUSION: About one quarter of medical personnel in sending or receiving laboratories were dissatisfied with the services. Comparing the personnel in public and private, the personnel in public laboratories were 4 times more dissatisfied with the timely test and correct results; and 5 times more dissatisfied with clear and complete test results.

'It makes the patient's spirit weaker': tuberculosis stigma and gender interaction in Dar es Salaam, Tanzania.

SETTING: Dar es Salaam, Tanzania. OBJECTIVES: To describe tuberculosis (TB) related stigma and to understand how it interacts with gender to affect access to care. DESIGN: Eight focus group discussions were held among 48 TB patients and their household members, and a thematic content analysis was carried out. RESULTS: The main components of stigma were fear, self-isolation, ostracization, loss of status in the community, and discrimination by providers. Participants described the cultural context in which stigma operated as characterized by a general lack of health knowledge, cultural beliefs about TB, and engendered beliefs about disease in general. Both genders described some similar effects of stigma, including relationship difficulties and specifically challenges forming new relationships, but many effects of stigma were distinct by gender: women described challenges including assumptions about promiscuity and infidelity, as well as rejection by partners, while men described survival challenges. Stigma acted as a barrier to care through a cyclical pattern of stigma and fear, leading to health-seeking delays, with resulting continued transmission and poor health outcomes that further reinforced stigma. CONCLUSION: TB-related stigma is prevalent in this setting and operates differently for men and women. Interventions designed to increase case detection must address stigma and its interaction with gender.

Prevalence of pulmonary tuberculosis in adult population of Tanzania: a national survey, 2012.

SETTING: Tanzania is classified as one of the 22 high tuberculosis (TB) burden countries; however, the true burden of TB disease in the country remains unknown. OBJECTIVE: To assess the prevalence of bacteriologically confirmed pulmonary TB (PTB) in the adult population. DESIGN: This was a community-based cluster randomised survey with proportional-to-population-size selection of primary sampling units (districts). Participants were screened for TB using a symptom questionnaire and chest X-ray (CXR). Those with abnormal CXR and/or at least one symptom suggestive of TB were classified as individuals with presumptive TB, and asked to submit three sputum specimens for smear microscopy and culture. RESULTS: The weighted prevalence for sputum smear-positive TB cases was 249 per 100 000 adult population (95%CI 192-305) and that for bacteriologically confirmed TB cases was 293/100 000 (95%CI 228-358). Individuals aged ⩾45 years comprised 55% (71/129) of the identified smear-positive cases, but just 28% (6793/24 648) of the notified TB cases. CXR screening identified more TB cases than symptom screening. When weighted for human immunodeficiency virus prevalence among notified new smear-positive cases, the overall case detection of incident TB cases in 2012 was between 37% and 48%. CONCLUSIONS: The prevalence of sputum smear-positive PTB and bacteriologically confirmed PTB in the adult population was higher than previous World Health Organization estimates. There is a potential underestimation of the number of bacteriologically confirmed PTB cases in the adult population. The age distribution of prevalent cases suggests an epidemiological shift towards the older generations, which has been a sign of successful TB control activities in the past. However, the survey shows that many infectious TB cases are currently missed by the National Tuberculosis Programme.

Population impact of factors associated with prevalent pulmonary tuberculosis in Tanzania.

SETTING: Tanzania has an estimated tuberculosis (TB) prevalence of 295 per 100 000 adult population. There is currently no nationally representative information on factors associated with TB in Tanzania. OBJECTIVE: To determine the demographic and clinical factors associated with bacteriologically confirmed TB in the adult general population of Tanzania. DESIGN: A case-control study nested in a nationally representative TB prevalence survey. All patients with bacteriologically confirmed pulmonary TB (PTB) constituted cases and a representative sample of people without bacteriologically confirmed PTB constituted controls. We calculated adjusted odds ratios (aORs) to identify factors associated with TB. RESULTS: Age groups 25-34 years (aOR 3.7, 95%CI 1.5-8.8) and 55-64 years (aOR 2.5, 95%CI 1.1-5.5), male sex (aOR 1.6, 95%CI 1.1-2.3) and low body mass index (BMI) (aOR 1.7, 95%CI 1.1-2.8) were significantly associated with TB. Association with human immunodeficiency virus (HIV) and diabetes mellitus (DM) was not statistically significant. The population attributable fraction (PAF) was 2% (95%CI -2 to 5) for DM and 3% (95%CI -2 to 8) for HIV. CONCLUSION: Being in an older age group, being male and having a low BMI were associated with bacteriologically confirmed PTB. On the population level, classic risk factors for TB have no major effect on prevalent TB from which future transmission may occur.

Patient knowledge, practices and challenges to health care system in early diagnosis of mycobacterial adenitis.

OBJECTIVE: To assess diagnostic delay, knowledge and practices related to tuberculosis among patients with mycobacterial adenitis. DESIGN: A cross sectional study involving comparison analysis of high-risk groups. SETTING: Seven hospitals in rural and semi-rural districts of Arusha. SUBJECTS: Four hundred and twenty six clinically diagnosed adenitis patients. INTERVENTIONS: Biopsy specimens were processed for culture, histology, and sera for HIV testing. A questionnaire was used to assess knowledge, practice, and diagnostic time. MAIN OUTCOME MEASURES: Tribal comparisons were made using proportions and means. RESULTS: About 90% (387/423) of patients first visited medical facilities within a mean time of 10.1(SD, 15.7) weeks after becoming aware of their illness, and a diagnosis was made at a mean of 27 (SD, 25) weeks. Non-Iraqw patients, especially the Datoga, practised drinking raw milk (35.2% 43/122), eating raw animal products (18.8% 24/128) and living in houses with poor ventilation (33.6% 44/131), more than Iraqw patients. Of the investigations done, 14.5% (60/415) were culture positive, 11.3% (16/142) were HIV positive, and 73.6% (128/174) had histological features consistent with tuberculosis. The knowledge of TB spread by air droplets was poorer in Iraqw (74.1%, 203/274) than in non-lraqw (61.1%, 77/126) patients. About 35.0% (45/129) of non-lraqw and 27.3% (79/289) of Iraqw patients were not aware that TB could be transmitted from animals to humans. CONCLUSIONS: The health system diagnostic delay is about twice the patient delay. The knowledge and practices related to both human and bovine TB transmission were poor in all patients, especially in the patients from nomadic tribes.

Health care-seeking behaviour among people with cough in Tanzania: findings from a tuberculosis prevalence survey.

SETTING: The study was conducted within a nation-wide population-based tuberculosis (TB) prevalence survey in the adult population in Tanzania. OBJECTIVE: To assess the health care-seeking behaviour of coughers presumed to have TB. DESIGN: A survey in which participants were screened for TB using a symptom questionnaire and chest X-ray (CXR). Those with cough of ⩾ 2 weeks and/or who were coughing blood were interviewed about their health care-seeking behaviour and socio-demographic and clinical factors. RESULTS: Of 3388 people with presumptive TB, 31.0% (1051/3388) had sought treatment for their symptoms. Of these, about 42% (445/1051) sought care at sites with TB diagnostic capacity, where sputum examination was performed in 37.1% (165/445) and CXR in 28.1% (125/445). In sites with limited TB diagnostic capacity, fewer than 1% were referred for sputum examination or CXR. Individuals with additional symptoms were more likely to seek treatment. Knowledge about TB was significantly associated with care seeking at sites with TB diagnostic capacity. CONCLUSIONS: A third of the persons with cough symptoms consistent with TB had sought health care. About 42% sought care in sites with TB diagnostic capacity, but most did not undergo TB diagnostic procedures, precluding a timely diagnosis.

Screening for pulmonary tuberculosis in a Tanzanian prison and computer-aided interpretation of chest X-rays.

SETTING: Tanzania is a high-burden country for tuberculosis (TB), and prisoners are a high-risk group that should be screened actively, as recommended by the World Health Organization. Screening algorithms, starting with chest X-rays (CXRs), can detect asymptomatic cases, but depend on experienced readers, who are scarce in the penitentiary setting. Recent studies with patients seeking health care for TB-related symptoms showed good diagnostic performance of the computer software CAD4TB. OBJECTIVE: To assess the potential of computer-assisted screening using CAD4TB in a predominantly asymptomatic prison population. DESIGN: Cross-sectional study. RESULTS: CAD4TB and seven health care professionals reading CXRs in local tuberculosis wards evaluated a set of 511 CXRs from the Ukonga prison in Dar es Salaam. Performance was compared using a radiological reference. Two readers performed significantly better than CAD4TB, three were comparable, and two performed significantly worse (area under the curve 0.75 in receiver operating characteristics analysis). On a superset of 1321 CXRs, CAD4TB successfully interpreted >99%, with a predictably short time to detection, while 160 (12.2%) reports were delayed by over 24 h with conventional CXR reading. CONCLUSION: CAD4TB reliably evaluates CXRs from a mostly asymptomatic prison population, with a diagnostic performance inferior to that of expert readers but comparable to local readers.

Contexte : La Tanzanie est lourdement frappée par la tuberculose (TB) et les prisonniers sont un groupe à haut risque qui devrait bénéficier d'un dépistage actif, comme le recommande l'Organisation Mondiale de la Santé. Les algorithmes de dépistage qui débutent par une radiographie pulmonaire peuvent détecter des cas asymptomatiques, mais ils requièrent des lecteurs de radiographies expérimentés, qui sont rares dans le contexte pénitentiaire. Des études récentes sur des patients sollicitant des soins pour des symptômes liés à la TB ont mis en évidence une bonne performance diagnostique du logiciel CAD4TB.Objectif : Evaluer le potentiel d'un dépistage assisté par ordinateur en utilisant CAD4TB au sein d'une population carcérale en majorité asymptomatique.Schéma : Étude transversale.Résultats : CAD4TB et sept professionnels de santé lisant des radiographies dans des services de TB locaux ont évalué un ensemble de 511 radiographies pulmonaires provenant de la prison d'Ukonga à Dar es Salaam et les performances ont été comparées grâce à une radiographie de référence. Deux lecteurs ont été significativement plus performants que CAD4TB, trois ont été comparables et deux ont été significativement moins bons (zone sous la courbe de 0,75 dans l'analyse ROC ­fonction d'efficacité du receveur). Sur un ensemble de 1321 radiographies pulmonaires, CAD4TB en a interprété avec succès plus de 99% avec un délai de détection prévisible court, tandis que 160 (12,2%) réponses ont été retardées de plus de 24 h avec la méthode de lecture conventionnelle.Conclusion : CAD4TB évalue de manière fiable les radiographies pulmonaires dans une population en majorité asymptomatique de détenus, avec une performance diagnostique inférieure à celle de lecteurs experts mais comparable à celle des lecteurs locaux.

Marco de referencia: Tanzania es un país con una alta tasa de morbilidad por tuberculosis (TB) y las personas en los establecimientos penitenciarios constituyen un grupo de alto riesgo de contraer la enfermedad; en esta población se debe practicar la detección sistemática activa como lo recomienda la Organización Mundial de la Salud. Los algoritmos de detección cuya etapa inicial es la radiografía de tórax pueden detectar los casos asintomáticos, pero su eficacia depende de la experiencia del profesional que interpreta las imágenes y esta competencia es escasa en los entornos penitenciarios. Algunos estudios recientes de pacientes que buscan atención sanitaria por síntomas asociados con la TB han revelado un buen rendimiento diagnóstico con la utilización del programa informático CAD4TB. Objetivo: Evaluar la utilidad de la detección sistemática de la TB asistida por el programa CAD4TB, en una población penitenciaria en su mayoría asintomática.Método: Fue este un estudio de tipo transversal.Resultados: Siete profesionales de atención sanitaria de los servicios locales de TB analizaron 511 radiografías de tórax provenientes de la prisión de Ukonga, en Dar es-Salam, con la ayuda del programa CAD4TB; se preparó un conjunto de referencia radiográfica de lectura con el fin de evaluar el rendimiento diagnóstico. El desempeño de dos de los lectores fue significativamente superior al resultado del programa CAD4TB, tres lectores obtuvieron una puntuación comparable al programa y en dos lectores se observó un rendimiento significativamente inferior (área bajo la curva: 0,75 en el análisis de eficacia diagnóstica). En un conjunto especial de 1321 radiografías de tórax el programa CAD4TB interpretó eficazmente más del 99%, con un corto lapso previsible hasta la detección, en contraste con la lectura clásica de las radiografías que dio lugar a un retraso superior a 24 horas en 160 informes (12,2%).Conclusión: El programa CAD4TB realizó una evaluación fiable de las radiografías provenientes de una población penitenciaria en su mayor parte asintomática. El rendimiento diagnóstico del programa fue inferior al rendimiento de los lectores expertos, pero comparable con el rendimiento de los lectores locales.

Impact of human immunodeficiency virus infection on the outcome of treatment and survival of tuberculosis patients in Mwanza, Tanzania.

SETTING: Little is known about the outcome of tuberculosis (TB) treatment and subsequent survival of human immunodeficiency virus (HIV) infected patients treated under routine programme conditions in a developing country. We followed a cohort of HIV-positive and HIV-negative tuberculosis patients during therapy and assessed their vital and tuberculosis status 3 years after completion of treatment in Mwanza, Tanzania. METHODS: Newly diagnosed and relapse tuberculosis cases consecutively registered over a 6-month period were enrolled into an epidemiological study of TB/HIV. Treatment outcome was based on information in tuberculosis treatment registers. Patients surviving treatment were assessed 3 years later by personal interview. Cause of death was determined by verbal autopsy. RESULTS: Of 561 patients enrolled into the study, 505 patients alive at completion of treatment were eligible for assessment at 3 years. Except for mortality, HIV infection was not statistically associated with differing treatment outcomes. At time of follow-up, the overall mortality was 19% and was associated with HIV infection (hazard ratio [hr] 3.7, 95% confidence interval [CI] 2.6-5.2) and age 35 years and over (hr 1.5, 95% CI 1.02-2.1), but not with type of tuberculosis, gender, or initial drug resistance. By life table analysis, probability of survival at 4 years was 35% for HIV-positive patients compared to 90% for HIV-negative patients. Although no relapse cases were diagnosed, verbal autopsy suggested equivalent low rates of relapse in both groups. CONCLUSION: These results demonstrate the effectiveness of the current approach to the treatment of tuberculosis patients regardless of HIV status. However, HIV-related mortality remains high both during and following completion of treatment, and further studies are needed to determine if this mortality might be reduced by simple interventions which are feasible in developing countries.

Tribal differences in perception of tuberculosis: a possible role in tuberculosis control in Arusha, Tanzania.

SETTING: Arusha, Tanzania. OBJECTIVE: To determine tribal differences in knowledge and practices that might influence tuberculosis control. METHOD: Twenty-seven villages were selected randomly out of 242 villages in four districts. In each village, a general and a livestock keeping group were selected at random. The households were home-visited and 426 family members were interviewed. RESULTS: On average, 40% of respondents practised habits that might expose them to both bovine and human tuberculosis. The Barabaig tribe had a significantly higher number of respondents (50%, chi2(2) = 5.1, P = 0.024) who did not boil milk. Eating uncooked meat or meat products was practised by 17.9% of all respondents. The habit was practised more by Iraqw (21.1%, chi2(2) = 6.9, P = 0.008) and Barabaig (31.6%, chi2(2) = 5.6, P = 0.016) than other tribes. About 75% of the respondents had a poor knowledge of tuberculosis. CONCLUSION: All tribes had habits and beliefs that might expose them to both bovine and human tuberculosis. The Iraqw and Barabaig tribes practised such habits more than other tribes. Knowledge of tuberculosis was limited in all tribes.

The role of livestock keeping in tuberculosis trends in Arusha, Tanzania.

SETTING: Arusha, Tanzania. OBJECTIVE: To assess risk factors that might influence TB control in the general population and in livestock-keepers. METHODS: Of 242 villages in four districts, 27 were selected randomly. In each village, a general and a livestock-keeping group were selected at random. The households were home-visited and 426 family members were interviewed. RESULTS: On average, three-quarters of households practised at least one risk activity for transmission of zoonotic tuberculosis, and respondents had poor knowledge about tuberculosis. In the livestock-keeping group, the risks of having a tuberculosis patient in the family were determined by poor ventilation (OR 2.6, 95% CI 1.1-6.5), confining livestock indoors with people (OR 2.3, 95%CI 1.1-5.0) and multiple determinants including poor ventilation (OR 13.5, 95% CI 2.5-71.7). Risk activities and the risks of having a tuberculosis patient in a family were significantly higher in the livestock-keeping group. CONCLUSIONS: The respondents had limited knowledge about tuberculosis, and the households had practices that posed potential risks for both human and bovine tuberculosis infection. Poor ventilation and confining livestock indoors were associated with tuberculosis spread in the households. These risks were observed more in the livestock-keeping group than in the general population group.

Trend in HIV prevalence among tuberculosis patients in Tanzania, 1991-1998.

OBJECTIVE: To determine the trend in human immunodeficiency virus (HIV) prevalence among tuberculosis patients in Tanzania and estimate what proportion of the increase in notification rates between the surveys was directly attributable to HIV infection. METHODS: Consecutive tuberculosis patients were enrolled over 6-month periods in most regions. Demographic and clinical data were collected on standard forms and a single HIV ELISA test performed. Trends in tuberculosis incidence were estimated from regional notification data. RESULTS: Of 10612 eligible tuberculosis patients, 44% had HIV infection, compared with 32% in the previous survey. The largest increase was observed in the youngest birth cohorts, suggesting active HIV transmission. Approximately 60% of the increase in notification rates of smear-positive tuberculosis between surveys was directly attributable to HIV infection. CONCLUSION: The HIV epidemic has had a strong influence on tuberculosis incidence. However, since 1995, tuberculosis notification data have increased less steeply, AIDS notifications have gone down, and HIV prevalence in blood donors has not increased a great deal. Another survey among tuberculosis patients in 5 years' time may show whether the HIV epidemic in Tanzania has reached a maximum or steady state.