Tuberculosis burden in an urban population: a cross sectional tuberculosis survey from Guinea Bissau
1 Bandim Health Project, INDEPTH Network, Apartado 861, 1004 Bissau Codex, Guinea-Bissau
2 Department of Infectious Diseases, Aarhus University Hospital Skejby, Brendstrupgaardvej, 8200 Aarhus N, Denmark
3 Department of Infectious Diseases 144, Copenhagen University Hospital Hvidovre, Kettegaards Allé 30, 2650 Hvidovre, Denmark
4 Department of Epidemiology, Statens Serum Institut, Artillerivej 5, 2300 Copenhagen S, Denmark
5 Department of Infectious Diseases, Odense University Hospital, Sdr. Boulevard 29, 5000 Odense C, Denmark
6 Infectious Diseases Research Group, Department of Clinical Sciences, SE-205 02 Malmö, Lund University, Sweden
BMC Infectious Diseases 2010, 10:96 doi:10.1186/1471-2334-10-96Published: 16 April 2010
Little 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.
Two 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.
In 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.
In 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.