TY - JOUR

T1 - The prevalence of latent Mycobacterium tuberculosis infection based on an interferon-γ release assay

T2 - A cross-sectional survey among urban adults in Mwanza, Tanzania

AU - Jensen, Andreas V.

AU - Jensen, Lotte

AU - Faurholt-Jepsen, Daniel

AU - Aabye, Martine .G.

AU - Praygod, George

AU - Kidola, Jeremiah

AU - Faurholt-Jepsen, Maria

AU - Changalucha, John

AU - Range, Niagosya

AU - Krarup, Henrik

AU - Friis, Henrik

AU - Andersen, Aase B.

N1 - CURIS 2013 NEXS 140

PY - 2013

Y1 - 2013

N2 - Introduction:One third of the world's population is estimated to be latently infected with Mycobacterium tuberculosis (LTBI). Surveys of LTBI are rarely performed in resource poor TB high endemic countries like Tanzania although low-income countries harbor the largest burden of the worlds LTBI. The primary objective was to estimate the prevalence of LTBI in household contacts of pulmonary TB cases and a group of apparently healthy neighborhood controls in an urban setting of such a country. Secondly we assessed potential impact of LTBI on inflammation by quantitating circulating levels of an acute phase reactant: alpha-1-acid glycoprotein (AGP) in neighborhood controls.Methods:The study was nested within the framework of two nutrition studies among TB patients in Mwanza, Tanzania. Household contacts- and neighborhood controls were invited to participate. The study involved a questionnaire, BMI determination and blood samples to measure AGP, HIV testing and a Quantiferon Gold In tube (QFN-IT) test to detect signs of LTBI.Results:245 household contacts and 192 neighborhood controls had available QFN-IT data. Among household contacts, the proportion of QFT-IT positive was 59% compared to 41% in the neighborhood controls (p = 0.001). In a linear regression model adjusted for sex, age, CD4 and HIV, a QFT-IT positive test was associated with a 10% higher level of alpha-1-acid glycoprotein(AGP) (10 1.10, 95% CI 1.01; 1.20, p = 0.03), compared to individuals with a QFT-IT negative test.Conclusion:LTBI is highly prevalent among apparently healthy urban Tanzanians even without known exposure to TB in the household. LTBI was found to be associated with elevated levels of AGP. The implications of this observation merit further studies.

AB - Introduction:One third of the world's population is estimated to be latently infected with Mycobacterium tuberculosis (LTBI). Surveys of LTBI are rarely performed in resource poor TB high endemic countries like Tanzania although low-income countries harbor the largest burden of the worlds LTBI. The primary objective was to estimate the prevalence of LTBI in household contacts of pulmonary TB cases and a group of apparently healthy neighborhood controls in an urban setting of such a country. Secondly we assessed potential impact of LTBI on inflammation by quantitating circulating levels of an acute phase reactant: alpha-1-acid glycoprotein (AGP) in neighborhood controls.Methods:The study was nested within the framework of two nutrition studies among TB patients in Mwanza, Tanzania. Household contacts- and neighborhood controls were invited to participate. The study involved a questionnaire, BMI determination and blood samples to measure AGP, HIV testing and a Quantiferon Gold In tube (QFN-IT) test to detect signs of LTBI.Results:245 household contacts and 192 neighborhood controls had available QFN-IT data. Among household contacts, the proportion of QFT-IT positive was 59% compared to 41% in the neighborhood controls (p = 0.001). In a linear regression model adjusted for sex, age, CD4 and HIV, a QFT-IT positive test was associated with a 10% higher level of alpha-1-acid glycoprotein(AGP) (10 1.10, 95% CI 1.01; 1.20, p = 0.03), compared to individuals with a QFT-IT negative test.Conclusion:LTBI is highly prevalent among apparently healthy urban Tanzanians even without known exposure to TB in the household. LTBI was found to be associated with elevated levels of AGP. The implications of this observation merit further studies.

UR - http://www.scopus.com/inward/record.url?scp=84877939106&partnerID=8YFLogxK

U2 - 10.1371/journal.pone.0064008

DO - 10.1371/journal.pone.0064008

M3 - Journal article

C2 - 23700446

AN - SCOPUS:84877939106

VL - 8

JO - PLoS ONE

JF - PLoS ONE

SN - 1932-6203

IS - 5

M1 - e64008

ER -