No decrease in annual risk of tuberculosis infection in endemic area in Cape Town, South Africa

Trop Med Int Health. 2009 Feb;14(2):136-42. doi: 10.1111/j.1365-3156.2008.02213.x.


Objective: To estimate the change in annual risk of tuberculosis infection (ARTI) in two neighbouring urban communities of Cape Town, South Africa with an HIV prevalence of approximately 2%, and to compare ARTI with notification rates and treatment outcomes in the tuberculosis (TB) programme.

Methods: In 1998-1999 and 2005, tuberculin skin test surveys were conducted to measure the prevalence of Mycobacterium tuberculosis infection and to calculate the ARTI. All 6 to 9-year-old children from all primary schools were included in the survey. Notification rates and treatment outcomes were obtained from the TB register.

Results: A total of 2067 children participated in the survey from 1998 to 1999 and a total of 1954 in 2005. Based on a tuberculin skin test cut-off point of 10 mm, the ARTI was 3.7% (3.4-4.0%) in the 1998-1999 survey and 4.1% (3.8-4.5%) in 2005. The notification rate for pulmonary TB increased significantly from 646 per 100 000 in 1998 to 784 per 100,000 in 2002. In Ravensmead, there was no significant change in ARTI [first survey: 3.5% (3.1-3.9%), second survey: 3.2% (2.9-3.6%)], but in Uitsig the ARTI increased significantly from 4.1% (3.6-4.6%) to 5.8% (5.2-6.5%). The difference in ARTI between the two areas was associated with differences in reported case rates and the proportion of previously treated cases.

Conclusion: Tuberculosis transmission remains very high in these two communities and control measures to date have failed. Additional measures to control TB are needed.

MeSH terms

  • BCG Vaccine / immunology
  • Child
  • Disease Notification / statistics & numerical data
  • Endemic Diseases
  • Female
  • HIV Infections / epidemiology*
  • Humans
  • Male
  • Prevalence
  • Risk Factors
  • South Africa / epidemiology
  • Tuberculin Test
  • Tuberculosis / epidemiology*
  • Tuberculosis / prevention & control
  • Tuberculosis / transmission


  • BCG Vaccine