A Centre of Excellence for Biomedical Research and Training In Africa

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A Cluster randomized trial of two intensified TB case finding strategies in an urban community severely affected by HIV.

Project Principal Investigator : DR ELIZABETH CORBETT


Tuberculosis control has markedly deteriorated in Southern Africa because of the HIV epidemic. Case-notification rates in Zimbabwe have increased ten-fold during the last two decades, with urban sites having the highest rates.

Although there is increasing consensus that novel approaches are needed, the ideal strategy for controlling TB in countries severely affected by HIV has not been established. Intensified case finding is one possible approach that has a high potential impact, but little potential for doing harm.

In response to this, DETECTB, a research study is conducting a 4.5 year study (March 2005 to 2009) cluster randomized trial of two intensified TB case-finding strategies in a high density community severely affected by HIV with the aim of comparing the cumulative yield and residual burden of the two methods and to investigate HIV specific point prevalence and incidence of active TB disease in the community before and after the Intervention period.

The study is being conducted in the western part of Harare with the aim of: Providing an extra services to pick up infectious TB more quickly, aiming to reduce the spread of infection (“enhanced TB case-finding”). Improving control

of TB in the selected neighbourhood and if successful, reduce the risk of becoming infected with TB Models of TB infection and disease in high HIV prevalence communities will be developed. The aim will be to allow fuller interpretation of study data and also to explore the likely impact and limitations of intensified case finding and other potential TB control strategies, and the impact of HIV on key aspects of TB epidemiology likely to affect the relative efficacy of different control strategies.

The results may lead to better control of TB in the future, especially in cities where HIV is common The study is funded by Wellcome Trust, UK, and is being conducted in collaboration with: Biomedical Research and Training Institute (BRTI) Harare City Health London School of Hygiene and Tropical Medicine, UK In consultation with the Ministry of Health and Child Welfare World Health Organization International Union Against TB and Lung Disease What the DETECTB study is doing Study Sites Census data was used to subdivide ten neighbourhoods in the study area into forty-six clusters with approximately 2,000 adults per cluster, each of which was surrounded by a buffer zone of approximately 500metres to minimise contamination.

The clusters are in Harare High Density Western Suburbs namely, Rugare, Kambuzuma, Warren Park, Mufakose, Kuwadzana Highfield, GlenNorah, GlenView, Budiriro and Dzivarasekwa. Each of the households in the clusters was chosen for a 4-stage study.

STAGE 1 – HOUSEHOLD SURVEY: 2005 Door to door household visits were made to explain about the study and to find out the number of people in the study areas. Baseline demographic and social data was also collected for each of the households.

STAGE 2 – PREVALENCE SURVEY: 2005-2006 One in ten households that expressed willingness to participate, or were not sure, or were not seen in Stage 1 were offered a thorough check-up for TB and confidential HIV test for

all adults (16 years and above) in the family in a mobile clinic. Participants diagnosed with active TB disease were referred for treatment. Participants taking TB treatment at the time of survey were considered to have active TB

disease only if still culture-positive at the time of their inclusion in the prevalence screen.

STAGE 3 – INTERVENTION SURVEY: 2006-2009 Screening interviews are being conducted to detect individuals with symptoms suggestive of TB (cough for 3 weeks or greater, unintentional weight loss, drenching night sweats), and to collect sputum specimens for smear microscopy from symptomatic individuals identified through 6-monthly door-to-door interviews, or mobile TB clinic visits to each cluster. In each case community sensitisation is being carried out before and during each 6-monthly intervention using posters, leafleting, and meetings with community representatives and community-based organizations involved in HIV and TB care and control. The aim will be to deliver the respective intervention 6 times during a three-year period Identified symptomatic individuals will have

two sputum specimens collected for microscopy and culture. Individuals found to be smear positive or smear negative but persistently symptomatic will be referred to the project clinic for follow-up and further management.

HIV PREVALENCE IN TB PATIENTS SURVEY: 2006 Confidential HIV Screening and interviews are being conducted to determine HIV prevalence among TB Patients registering at Beatrice Infectious Disease Hospital (BRIDH) and Wilkins Hospital for the first time.

STAGE 4 – PREVALENCE SURVEY: 2009 A repeat of STAGE 2 will be conducted. This will provide an estimate of the residual burden of infectious disease left by each strategy, as well as determining whether point prevalence has been reduced in the whole study area during the intervention period.