Decline in overall, smear-negative and HIV-positive TB incidence while smear-positive incidence stays stable in Guinea-Bissau 2004-2011

Abstract

Objective: To calculate Tuberculosis (TB) incidence rates in Guinea-Bissau over an 8-year period.

Methods: Since 2003, a surveillance system has registered all TB cases in six suburban districts of Bissau. In this population-based prospective follow-up study, 1205 cases of pulmonary TB were identified between January 2004 and December 2011. Incidence rates were calculated using census data from the Bandim Health and Demographic Surveillance System (HDSS).

Results: The overall incidence of pulmonary TB was 279 per 100,000 person-years of observation; the male incidence being 385, and the female 191. TB incidence rates increased significantly with age in both sexes, regardless of smear or HIV status. Despite a peak with unknown cause of 352 per 100,000 in 2007, the overall incidence of pulmonary TB declined over the period. The incidence of HIV infected TB cases declined significantly from 108 to 39 per 100,000, while the incidence of smear-positive TB cases remained stable; the overall figure was 188 per 100,000.

Conclusions: Overall incidence of pulmonary TB in Guinea-Bissau has declined from 2004 to 2011. The decline was also seen in the subgroups of smear-negative and HIV-positive TB cases, probably due to antiretroviral treatment. Smear-positive TB incidence remains stable over the period.

Keywords: Africa South of the Sahara; Afrique subsaharienne; Guinea-Bissau; Guinée-Bissau; HIV; Incidencia; Tuberculosis; VIH; crachat; esputo; incidence; sputum; tuberculose; tuberculosis; África al Sur del Sahara.