The importance of recent infection with Mycobacterium tuberculosis in an area with high HIV prevalence: a long‐term molecular epidemiological study in northern Malawi

Glynn, J. R., Crampin, A. C. , Yates, M. D., Traore, H., Mwaungulu, F. D., Ngwira, B. M., Ndlovu, R., Drobniewski, F. and Fine, P. E.M. (2005) The importance of recent infection with Mycobacterium tuberculosis in an area with high HIV prevalence: a long‐term molecular epidemiological study in northern Malawi. Journal of Infectious Diseases, 192(3), pp. 480-487. (doi: 10.1086/431517) (PMID:15995962)

Abstract

Background: The proportion of cases of tuberculosis due to recent infection can be estimated in long-term population-based studies using molecular techniques. Here, we present what is, to our knowledge, the first such study in an area with high human immunodeficiency virus (HIV) prevalence. Methods: All patients with tuberculosis in Karonga District, Malawi, were interviewed. Isolates were genotyped using restriction-fragment–length polymorphism (RFLP) patterns. Strains were considered to be “clustered” if at least 1 other patient had an isolate with an identical pattern. Results: RFLP results were available from 83% of culture-positive patients from late 1995 to early 2003. When strains with <5 bands were excluded, 72% (682/948) were clustered. Maximum clustering was reached using a 4-year window, with an estimated two-thirds of cases due to recent transmission. The proportion clustered decreased with age and varied by area of residence. In older adults, clustering was less common in men and more common in patients who were HIV positive (adjusted odds ratio, 5.1 [95% confidence interval, 2.1–12.6]). Conclusions: The proportion clustered found in the present study was among the highest in the world, suggesting high rates of recent transmission. The association with HIV infection in older adults may suggest that HIV has a greater impact on disease caused by recent transmission than on that caused by reactivation.

• Item Type: Articles
• Additional Information: Financial support: Until 1996, the Karonga Prevention Study was funded primarily by LEPRA (The British Leprosy Relief Association) and ILEP (The International Federation of Anti-Leprosy Organizations), with contributions from the World Health Organisation/United Nations Development Programme/World Bank Special Programme for Research and Training in Tropical Diseases. Since 1996, the Wellcome Trust has been the principal funder. J.R.G. was supported in part by the UK Department for International Development and is now funded by the UK Department of Health (Public Health Career Scientist award).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Crampin, Professor Mia
• Authors: Glynn, J. R., Crampin, A. C., Yates, M. D., Traore, H., Mwaungulu, F. D., Ngwira, B. M., Ndlovu, R., Drobniewski, F., and Fine, P. E.M.
• College/School: College of Medical Veterinary and Life Sciences > School of Health & Wellbeing > Public Health
• Journal Name: Journal of Infectious Diseases
• Publisher: Oxford University Press
• ISSN: 0022-1899
• ISSN (Online): 1537-6613
• Published Online: 23 June 2005