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

• Published in: Tropical medicine & international health Vol. 14; no. 2; pp. 136 - 142
• Main Authors: Kritzinger, Fiona E, den Boon, Saskia, Verver, Suzanne, Enarson, Donald A, Lombard, Carl J, Borgdorff, Martien W, Gie, Robert P, Beyers, Nulda
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.02.2009; Blackwell Publishing Ltd; Blackwell
• Subjects: Afrique du Sud; annual risk of infection; Bacterial diseases; BCG Vaccine - immunology; Biological and medical sciences; Child; Disease control; Disease Notification - statistics & numerical data; Endemic Diseases; Female; General aspects; Health risk assessment; HIV Infections - epidemiology; Human bacterial diseases; Humans; Infectious diseases; Male; Medical sciences; Mene; Mycobacterium tuberculosis; notification rates; Pero; Prevalence; resultado del tratamiento; riesgo anual de infección; Risk Factors; risque annuel d’infection; résultat du traitement; South Africa; South Africa - epidemiology; Sudáfrica; tasas de notificación; taux de notification; treatment outcome; tuberculin; Tuberculin Test; tuberculina; tuberculine; tuberculose; Tuberculosis; Tuberculosis - epidemiology; Tuberculosis - prevention & control; Tuberculosis - transmission; Tuberculosis and atypical mycobacterial infections; Urban areas; South Africa; Africa; Cape Town South Africa; Norway, Alta; South Africa, Western Cape, Cape Town; annual risk of infection; notification rates; Prognosis; Mycobacterial infection; Tuberculin; treatment outcome; Infection; Treatment; Tuberculosis; Risk factor; Bacteriosis; Tropical medicine; South Africa
• ISSN: 1360-2276; 1365-3156
• DOI: 10.1111/j.1365-3156.2008.02213.x

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