BACKGROUND: Tuberculosis (TB) remains a leading cause of mortality and morbidity in South Africa. While adult TB results from both recent and past infection, childhood TB results from recent infection and reflects ongoing transmission despite current TB control strategies. SETTING: A South African community with high rates of TB and HIV disease. OUTCOMES: A Geographic Information System was used to spatially and temporally define the relationships between TB exposure, infection and disease in children < 15 years of age with exposure to adult HIV-positive and HIV-negative TB disease on residential plots between 1997 and 2007. RESULTS: During the study period the annual adult TB notification rate increased from 629 to 2 106/100 000 and the rate in children aged < 15 years ranged between 664/100 000 and 1 044/100 000. The mean number of exposures to adult TB for TB-uninfected children, latently TB-infected children and TB cases were 5.1%, 5.4% and 33% per annum and the mean number of adult smear-positive cases per exposed child was 1.0, 1.6 and 1.9, respectively. Acquisition of TB infection was not associated with HIV status of the adult TB case to which the child was exposed, and 36% of child TB cases were diagnosed before the temporally closest adult case on their plot. CONCLUSIONS: Childhood infection and disease were quantitatively linked to infectious adult TB prevalence in an immediate social network. Childhood infection should be monitored in high-burden settings as a marker of ongoing TB transmission. Improved knowledge of township childhood and adult social networks could also facilitate targeted active case finding, which may provide an adjunct to currently failing TB control strategies.
BACKGROUND:Tuberculosis (TB) remains a leading cause of mortality and morbidity in South Africa. While adult TB results from both recent and past infection, childhood TB results from recent infection and reflects ongoing transmission despite current TB control strategies. SETTING: A South African community with high rates of TB and HIV disease. OUTCOMES: A Geographic Information System was used to spatially and temporally define the relationships between TB exposure, infection and disease in children < 15 years of age with exposure to adult HIV-positive and HIV-negative TB disease on residential plots between 1997 and 2007. RESULTS: During the study period the annual adult TB notification rate increased from 629 to 2 106/100 000 and the rate in children aged < 15 years ranged between 664/100 000 and 1 044/100 000. The mean number of exposures to adult TB for TB-uninfected children, latently TB-infected children and TB cases were 5.1%, 5.4% and 33% per annum and the mean number of adult smear-positive cases per exposed child was 1.0, 1.6 and 1.9, respectively. Acquisition of TB infection was not associated with HIV status of the adult TB case to which the child was exposed, and 36% of child TB cases were diagnosed before the temporally closest adult case on their plot. CONCLUSIONS: Childhood infection and disease were quantitatively linked to infectious adult TB prevalence in an immediate social network. Childhood infection should be monitored in high-burden settings as a marker of ongoing TB transmission. Improved knowledge of township childhood and adult social networks could also facilitate targeted active case finding, which may provide an adjunct to currently failing TB control strategies.
Authors: Robin Wood; Keren Middelkoop; Landon Myer; Alison D Grant; Andrew Whitelaw; Stephen D Lawn; Gilla Kaplan; Robin Huebner; James McIntyre; Linda-Gail Bekker Journal: Am J Respir Crit Care Med Date: 2006-09-14 Impact factor: 21.405
Authors: P A Selwyn; D Hartel; V A Lewis; E E Schoenbaum; S H Vermund; R S Klein; A T Walker; G H Friedland Journal: N Engl J Med Date: 1989-03-02 Impact factor: 91.245
Authors: Simon P Johnstone-Robertson; Daniella Mark; Carl Morrow; Keren Middelkoop; Melika Chiswell; Lisa D H Aquino; Linda-Gail Bekker; Robin Wood Journal: Am J Epidemiol Date: 2011-11-09 Impact factor: 4.897
Authors: Robin Wood; Simon Johnstone-Robertson; Pieter Uys; John Hargrove; Keren Middelkoop; Stephen D Lawn; Linda-Gail Bekker Journal: Clin Infect Dis Date: 2010-08-15 Impact factor: 9.079
Authors: Robin Wood; Stephen D Lawn; Judy Caldwell; Richard Kaplan; Keren Middelkoop; Linda-Gail Bekker Journal: PLoS One Date: 2011-10-10 Impact factor: 3.240
Authors: Robin Wood; Kimberly Racow; Linda-Gail Bekker; Carl Morrow; Keren Middelkoop; Daniella Mark; Stephen D Lawn Journal: PLoS One Date: 2012-06-29 Impact factor: 3.240