Determinants of cluster size in large, population-based molecular epidemiology study of tuberculosis, northern Malawi.

Tuberculosis patients with identical strains of Mycobacterium tuberculosis are described as clustered. Cluster size may depend on patient or strain characteristics. In a 7-year population-based study of tuberculosis in Karonga District, Malawi, clusters were defined by using IS6110 restriction fragment length polymorphism, excluding patterns with <5 bands.

Mycobacterium tuberculosis Beijing genotype, northern Malawi.

In a 7-year population-based study in Malawi, we showed that Beijing genotype tuberculosis (TB) increased as a proportion of TB cases. All the Beijing genotype strains were fully drug sensitive. Contact histories, TB type, and case-fatality rates were similar for Beijing and non-Beijing genotype TB.

DNA fingerprint changes in tuberculosis: reinfection, evolution, or laboratory error?

Background: DNA fingerprint patterns of Mycobacterium tuberculosis strains vary within individuals and between epidemiologically linked individuals because of pattern evolution, new infections, and laboratory error. We explored the importance of these factors.

Methods: Cultures from individuals in northern Malawi who had been diagnosed with tuberculosis (TB) during 1996-2001 were fingerprinted with restriction fragment-length polymorphism (RFLP).

Trends in tuberculosis and the influence of HIV infection in northern Malawi, 1988-2001.

Objective: To document the changing incidence and patterns of tuberculosis (TB) in rural Africa and the extent to which they are influenced by HIV.

Methods: As part of longstanding epidemiological studies in Karonga District, Malawi, a series of case control studies of TB and HIV were conducted from 1988 onwards. Data from these studies, from a total population survey, and from the Malawi national census have been used to reconstruct the changes in the TB epidemic in the area from 1988 to 2001, examining the role of HIV.