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.     

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 magnitude and factors associated with delays in management of smear positive tuberculosis in Dar es Salaam,Tanzania

Objective  

To assess the magnitude and factors responsible for delay in TB management.     

Quality of HIV laboratory testing in Tanzania: a situation analysis

Tanzania is scaling up prevention, treatment, care and support of individuals affected with HIV. There is therefore a need for high quality and reliable HIV infection testing and AIDS staging. The objective of this study was to assess laboratories capacities of services in terms of HIV testing and quality control. A baseline survey was conducted from December 2004 to February 2005 in 12 laboratories which were conveniently selected to represent all the zones of Tanzania. The questionnaires comprised of questions on laboratory particulars, internal and external quality control for HIV testing and quality control of reagents. Source and level of customer satisfaction of HIV test kits supply was established. Of 12 laboratories, nine used rapid tests for screening and two used rapid tests for diagnosis. In the 12 laboratories, four used double ELISA and five used single ELISA and three did not use ELISA. Confirmatory tests observed were Western Blot in three laboratories, DNA PCR in two laboratories, CD4 counting in seven laboratories, and viral load in two laboratories. Although all laboratories conducted quality control (QC) of the HIV kits, only two laboratories had Standard Operating Procedures (SOPs). Internal and external quality control (EQC) was done at varied proportions with the highest frequency of 55.6% (5/9) for internal quality control (IQC) for rapid tests and EQC for ELISA, and the lowest frequency of 14.3% (1/ 7) for IQC for CD4 counting. None of the nine laboratories which conducted QC for reagents used for rapid tests and none of the five which performed IQC and EQC had SOPs. HIV kits were mainly procured by the Medical Store Department and most of laboratories were not satisfied with the delay in procurement procedures. Most of the laboratories used rapid tests only, while some used both rapid tests and ELISA method for HIV testing. In conclusion, the survey revealed inadequacy in Good Laboratory Practice and poor laboratory quality control process for HIV testing reagents, internal and external quality control.     

p24 antigen detection on dried blood spots is a feasible and reliable test for infant HIV infection in rural Tanzania

The difficulty of diagnosing HIV in infants is a major obstacle to early antiretroviral therapy (ART) in resource-limited settings. As serological tests are unreliable during the first 18 months of life, and the cost and complexity of polymerase chain reaction (PCR)-based assays limit their access in resource-limited settings, p24 antigen detection has emerged as an alternative diagnostic tool. In this study, the performance of an ultrasensitive p24 antigen assay on dried blood spots was evaluated under field conditions in rural Tanzania. Specimens were stored and shipped at tropical room temperature, and analysed within six weeks. In total, 27 consecutive children aged <18 months and exposed to vertical HIV transmission were enrolled. Overall sensitivity and specificity was 100% (95% confidence interval [CI], 47.8-100) and 95.5% (95% CI, 77.2-99.9), respectively. Our findings suggest that detection of p24 antigen on dried blood spots can be a reliable and feasible diagnostic tool for infant HIV infection in rural resource-limited settings.     

Knowledge of causes,clinical features and diagnosis of common zoonoses among medical practitioners in Tanzania

Background  

Many factors have been mentioned as contributing to under-diagnosis and under-reporting of zoonotic diseases particularly in the sub-Sahara African region. These include poor disease surveillance coverage, poor diagnostic capacity, the geographical distribution of those most affected and lack of clear strategies to address the plight of zoonotic diseases. The current study investigates the knowledge of medical practitioners of zoonotic diseases as a potential contributing factor to their under-diagnosis and hence under-reporting.     

Mycobacterium bovis in rural Tanzania: risk factors for infection in human and cattle populations

Although bovine tuberculosis is widespread throughout Africa, very little is known about risk factors for Mycobacterium bovis infection in either human or cattle populations. A human case-control study was conducted in northern Tanzania, comparing risk factors and prevalence of cattle interdermal test positives of cases (cervical adenitis cases from which M. bovis was isolated) with age- and sex-matched controls (selected at random from potential hospital attendees within the community). A cattle cross-sectional study was also set-up involving 27 villages selected at random in four districts, with 10,549 cattle and 622 herds tested, and questionnaire surveys conducted in 239 households. M. bovis was confirmed in seven of 65 (10.8%) human cervical adenitis cases, of which only one came from a household owning infected cattle. M. bovis in human patients was associated with families in which a confirmed diagnosis of tuberculosis had previously been made (p<0.001) and with households far (>100m) from neighbours (p=0.003). In cattle, overall prevalence of intradermal test positives was low at 0.9% (0.70-1.06%), but widespread, with 11.8% (8.44-13.17%) herds containing at least one reactor. Prevalence of intradermal test positives increased significantly with cattle age (p<0.001). Herds with the following risk factors had a significantly greater prevalence of intradermal test positives: >50 cattle in the herd (p=0.024); herds housed inside at night (p=0.021) and herds in contact with wildlife (p=0.041). Furthermore, villages that experienced annual flooding had a higher prevalence of infection (p=0.043).     

Barriers to conducting effective obstetric audit in Ifakara: a qualitative assessment in an under‐resourced setting in Tanzania

Objective To explore barriers to and solutions for effective implementation of obstetric audit at Saint Francis Designated District Hospital in Ifakara, Tanzania, where audit results have been disappointing 2 years after its introduction. Methods Qualitative study involving participative observation of audit sessions, followed by 23 in‐depth interviews with health workers and managers. Knowledge and perceptions of audit were assessed and suggestions for improvement of the audit process explored. Results During the observational period, audit sessions were held irregularly and only when the head of department of obstetrics and gynaecology was available. Cases with evident substandard care factors were audited. In‐depth interviews revealed inadequate knowledge of the purpose of audit, despite the fact that participants regarded obstetric audit as a potentially useful tool. Insufficient staff commitment, managerial support and human and material resources were mentioned as reasons for weak involvement of health workers and poor implementation of recommendations resulting from audit. Suggestions for improvement included enhancing feedback to all staff and managers to attend sessions and assist with the effectuation of audit recommendations. Conclusion Obstetric staff in Ifakara see audit as an important tool for quality improvement. They recognise, however, that in their own situation, insufficient staff commitment and poor managerial support are barriers to successful implementation. They suggested training in concept and principles of audit as well as strengthening feedback of audit outcomes, to achieve structural health care improvements through audit.