Tuberculosis burden in an urban population: a cross sectional tuberculosis survey from Guinea Bissau

BackgroundLittle is known about the prevalence of pulmonary tuberculosis (TB) in low income countries. We conducted a cross sectional survey for pulmonary TB and TB symptoms in Bissau, Guinea-Bissau, in an urban cohort with known HIV prevalence. TB surveillance in the area is routinely based on passive case finding.MethodsTwo cohorts were selected based on a previous HIV survey, but only 52.5% of those enrolled in the adult cohort had participated in the HIV survey. One cohort included all adults living in 384 randomly selected houses; in this cohort 8% (135/1687) were HIV infected. The other included individuals 50 years or older from all other houses in the study area; of these 11% (62/571) were HIV infected. Symptom screening was done through household visits using a standardised questionnaire. TB suspects were investigated with sputum smear microscopy and X-ray.ResultsIn the adult cohort, we found 4 cases among 2989 individuals screened, giving a total TB prevalence of 134/100,000 (95% CI 36-342/100,000). In the >50 years cohort, we found 4 cases among 571 individuals screened, giving a total prevalence of 701/100,000 (191-1784/100.000). Two of the eight detected TB cases were unknown by the TB program. Of the total TB cases five were HIV uninfected while three had unknown HIV status. The prevalence of TB symptoms was 2.1% (63/2989) and 10.3% (59/571) in the two cohorts respectively.ConclusionsIn conclusion we found a moderately high prevalence of pulmonary TB and TB symptoms in the general population, higher among elderly individuals. By active case finding unknown cases were detected. Better awareness of TB and its symptoms needs to be promoted in low income settings.

[1]  C. Dye,et al.  Three-fold reduction in the prevalence of tuberculosis over 25 years in Indonesia. , 2007, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease.

[2]  R. Hayes,et al.  Epidemiology of Tuberculosis in a High HIV Prevalence Population Provided with Enhanced Diagnosis of Symptomatic Disease , 2007, PLoS medicine.

[3]  M. Datta,et al.  Survey for tuberculosis in a tribal population in North Arcot District. , 2001, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease.

[4]  P. Johansson,et al.  Tuberculosis in Bissau: incidence and risk factors in an urban community in sub-Saharan Africa. , 2004, International journal of epidemiology.

[5]  C. Dye,et al.  Global tuberculosis control: surveillance planning financing. WHO report 2003. , 2003 .

[6]  Anthony D. Harries,et al.  TB/HIV : a clinical manual , 2004 .

[7]  D. Sack,et al.  Prevalence of sputum smear-positive tuberculosis in a rural area in Bangladesh , 2006, Epidemiology and Infection.

[8]  B G Williams,et al.  Measuring tuberculosis burden, trends, and the impact of control programmes. , 2008, The Lancet. Infectious diseases.

[9]  H. Whittle,et al.  Mobility and the spread of human immunodeficiency virus into rural areas of West Africa. , 2003, International journal of epidemiology.

[10]  China Tuberculosis Control Collaboration.  The effect of tuberculosis control in China , 2004, The Lancet.

[11]  T. Frieden,et al.  A baseline survey of the prevalence of tuberculosis in a community in south India at the commencement of a DOTS programme. , 2003, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease.

[12]  D E Snider,et al.  Global epidemiology of tuberculosis. Morbidity and mortality of a worldwide epidemic. , 1995, JAMA.

[13]  G. Bjune,et al.  A systematic review of delay in the diagnosis and treatment of tuberculosis , 2008, BMC public health.

[14]  G. Baird.  The Clinical Manual , 1996 .

[15]  A. Rodrigues,et al.  Changes in prevalence and incidence of HIV-1, HIV-2 and dual infections in urban areas of Bissau, Guinea-Bissau: is HIV-2 disappearing? , 2008, AIDS.

[16]  R. Hayes,et al.  Human immunodeficiency virus and the prevalence of undiagnosed tuberculosis in African gold miners. , 2004, American journal of respiratory and critical care medicine.

[17]  N. Kassim,et al.  Determining the burden of tuberculosis in Eritrea: a new approach. , 2007, Bulletin of the World Health Organization.

[18]  M. Borgdorff,et al.  How to measure the prevalence of tuberculosis in a population , 2007, Tropical medicine & international health : TM & IH.

[19]  P. Aaby,et al.  Tuberculosis mortality during a civil war in Guinea-Bissau. , 2001, JAMA.

[20]  Paul Nunn,et al.  Diagnosis of smear-negative pulmonary tuberculosis in people with HIV infection or AIDS in resource-constrained settings: informing urgent policy changes , 2007, The Lancet.

[21]  L. Myer,et al.  Undiagnosed tuberculosis in a community with high HIV prevalence: implications for tuberculosis control. , 2007, American journal of respiratory and critical care medicine.

[22]  B. Lindtjørn,et al.  Prevalence of smear-positive pulmonary tuberculosis in a rural district of Ethiopia. , 2006, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease.

[23]  Christopher Dye,et al.  Evolution of tuberculosis control and prospects for reducing tuberculosis incidence, prevalence, and deaths globally. , 2005, JAMA.

[24]  C. Dye.  Global epidemiology of tuberculosis , 2006, The Lancet.

[25]  Shenglan Tang,et al.  The effect of tuberculosis control in China. Comment , 2004 .

[26]  T. Tupasi,et al.  The 1997 Nationwide Tuberculosis Prevalence Survey in the Philippines. , 1999, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease.