The Importance of Recent Infection with Mycobacterium tuberculosis in an Area with High HIV Prevalence: A Long-Term Molecular Epidemiological Study in Northern Malawi

BackgroundThe 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 MethodsAll 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 ResultsRFLP results were available from 83% of culture-positive patients from late 1995 to early 2003. When strains with