Undiagnosed tuberculosis in a community with high HIV prevalence: implications for tuberculosis control.
BACKGROUND
Although failure of tuberculosis (TB) control in sub-Saharan Africa is attributed to the HIV epidemic, it is unclear why the directly observed therapy short-course (DOTS) strategy is insufficient in this setting. We conducted a cross-sectional survey of pulmonary TB (PTB) and HIV infection in a community of 13,000 with high HIV prevalence and high TB notification rate and a well-functioning DOTS TB control program.


METHODS
Active case finding for PTB was performed in 762 adults using sputum microscopy and Mycobacterium tuberculosis culture, testing for HIV, and a symptom and risk factor questionnaire. Survey findings were correlated with notification data extracted from the TB treatment register.


RESULTS
Of those surveyed, 174 (23%) tested HIV positive, 11 (7 HIV positive) were receiving TB therapy, 6 (5 HIV positive) had previously undiagnosed smear-positive PTB, and 6 (4 HIV positive) had smear-negative/culture-positive PTB. Symptoms were not a useful screen for PTB. Among HIV-positive and -negative individuals, prevalence of notified smear-positive PTB was 1,563/100,000 and 352/100,000, undiagnosed smear-positive PTB prevalence was 2,837/100,000 and 175/100,000, and case-finding proportions were 37 and 67%, respectively. Estimated duration of infectiousness was similar for HIV-positive and HIV-negative individuals. However, 87% of total person-years of undiagnosed smear-positive TB in the community were among HIV-infected individuals.


CONCLUSIONS
PTB was identified in 9% of HIV-infected individuals, with 5% being previously undiagnosed. Lack of symptoms suggestive of PTB may contribute to low case-finding rates. DOTS strategy based on passive case finding should be supplemented by active case finding targeting HIV-infected individuals.
Wood
Robin
R
The Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine, Health Science Faculty, UCT Observatory, Cape Town 7925, South Africa.
Middelkoop
Keren
K
Myer
Landon
L
Grant
Alison D
AD
Whitelaw
Andrew
A
Lawn
Stephen D
SD
Kaplan
Gilla
G
Huebner
Robin
R
McIntyre
James
J
Bekker
Linda-Gail
LG
D000293:Adolescent; D000328:Adult; D003140:Communicable Disease Control / Q000592:standards*; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control; D005260:Female; D006678:HIV / Q000302:isolation & purification; D015658:HIV Infections / Q000150:complications* / Q000453:epidemiology*; D006801:Humans; D008297:Male; D015995:Prevalence; D013019:South Africa; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000209:etiology / Q000517:prevention & control*