Browsing by Author "Sismanidis, Charalambos"
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- ItemPrevalence of tuberculosis, HIV and respiratory symptoms in two Zambian communities: Implications for tuberculosis control in the era of HIV(Public Library of Science (PLOS), 2009-05) Ayles, Helen; Schaap, Albertus; Nota, Amos; Sismanidis, Charalambos; Tembwe, Ruth; De Haas, Petra; Muyoyeta, Monde; Beyers, Nulda; Godfrey-Faussett, PeterBackground: The Stop TB Partnership target for tuberculosis is to have reduced the prevalence of tuberculosis by 50% comparing 2015 to 1990. This target is challenging as few prevalence surveys have been conducted, especially in high burden tuberculosis and HIV countries. Current tuberculosis control strategies in high HIV prevalent settings are therefore based on limited epidemiological evidence and more evidence is needed from community-based surveys to inform improved policy formulation. Methods and Findings: 8044 adults were sampled from 2 sub-districts (wards) in Lusaka province, Zambia. Questionnaires were used to screen for symptoms, respiratory samples were obtained for culture and oral secretions collected for HIV testing. 79 individuals were found to have Mycobacterium tuberculosis in their sputum, giving an adjusted overall prevalence of tuberculosis of 870/100,000 (95% CI 570-1160/100,000). The adjusted overall prevalence of HIV was 28.61% (95% CI 26.04-31.19). HIV- infection was significantly associated with prevalent tuberculosis (Adj OR 2.3, 95% CI 1.42-3.74) and the population attributable fraction of HIV for prevalent tuberculosis was 36%. Symptoms such as prolonged cough (adj OR 12.72, 95% CI 7.05-22.94) and fever (Adj OR 2.04, 95%CI 1.23-3.39), were associated with prevalent tuberculosis, but 8 (10%) individuals with prevalent tuberculosis denied having any symptoms at all and only 34 (43%) would have been classified as a TB suspect by current guidelines. Conclusions: Undiagnosed tuberculosis is a challenge for tuberculosis control and new approaches are needed if we are to reach international targets. Epidemiological studies can inform screening algorithms for both detection and prevention of active tuberculosis. © 2009 Ayles et al.
- ItemRisk factors associated with positive quantiFERON-TB gold in-tube and tuberculin skin tests results in Zambia and South Africa(Public Library of Science (PLOS), 2011-04) Shanaube, Kwame; Hargreaves, James; Fielding, Katherine; Schaap, Ab; Lawrence, Katherine-Anne; Hensen, Bernadette; Sismanidis, Charalambos; Menezes, Angela; Beyers, Nulda; Ayles, Helen; Godfrey-Faussett, PeterIntroduction: The utility of T-cell based interferon-gamma release assays for the diagnosis of latent tuberculosis infection remains unclear in settings with a high burden of tuberculosis. Objectives: To determine risk factors associated with positive QuantiFERON-TB Gold In-Tube (QFT-GIT) and tuberculin skin test (TST) results and the level of agreement between the tests; to explore the hypotheses that positivity in QFT-GIT is more related to recent infection and less affected by HIV than the TST. Methods: Adult household contacts of tuberculosis patients were invited to participate in a cross-sectional study across 24 communities in Zambia and South Africa. HIV, QFT-GIT and TST tests were done. A questionnaire was used to assess risk factors. Results: A total of 2,220 contacts were seen. 1,803 individuals had interpretable results for both tests, 1,147 (63.6%) were QFT-GIT positive while 725 (40.2%) were TST positive. Agreement between the tests was low (kappa = 0.24). QFT-GIT and TST results were associated with increasing age (adjusted OR [aOR] for each 10 year increase for QFT-GIT 1.15; 95% CI: 1.06-1.25, and for TST aOR: 1.10; 95% CI 1.01-1.20). HIV positivity was less common among those with positive results on QFT-GIT (aOR: 0.51; 95% CI: 0.39-0.67) and TST (aOR: 0.61; 95% CI: 0.46-0.82). Smear positivity of the index case was associated with QFT-GIT (aOR: 1.25; 95% CI: 0.90-1.74) and TST (aOR: 1.39; 95% CI: 0.98-1.98) results. We found little evidence in our data to support our hypotheses. Conclusion: QFT-GIT may not be more sensitive than the TST to detect risk factors associated with tuberculous infection. We found little evidence to support the hypotheses that positivity in QFT-GIT is more related to recent infection and less affected by HIV than the TST. © 2011 Shanaube et al.
- ItemZAMSTAR, The Zambia South Africa TB and HIV Reduction study : design of a 2x2 factorial community randomized trial(BioMed Central, 2008-11) Ayles, Helen M.; Sismanidis, Charalambos; Beyers, Nulda; Hayes, Richard J.; Godfrey-Faussett, PeterBackground: TB and HIV form a deadly synergy in much of the developing world, especially Africa. Interventions to reduce the impact of these diseases at community level are urgently needed. This paper presents the design of a community randomised trial to evaluate the impact of two complex interventions on the prevalence of tuberculosis (TB) in high HIV prevalence settings in Zambia and South Africa. Methods: The interaction between TB and HIV is reviewed and possible interventions that could reduce the prevalence of TB in HIV-endemic populations are discussed. Two of these interventions are described in detail and the design of a 2 × 2 factorial community randomised trial to test these interventions is presented. The limitations and challenges of the design are identified and discussed. Conclusion: There is an urgent need to reduce the prevalence of TB in communities highly affected by HIV. Potential interventions are complex and require innovative trial designs to provide the rigorous evidence needed to inform health policy makers and to ensure that resources are used optimally. Trial Registration Number: ISRCTN36729271