Environmental mycobacteria in northern Malawi: implications for the epidemiology of tuberculosis and leprosy.

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TitleEnvironmental mycobacteria in northern Malawi: implications for the epidemiology of tuberculosis and leprosy.
Publication TypeJournal Article
AuthorsFine PE, Floyd S, Stanford JL, Nkhosa P, Kasunga A, Chaguluka S, Warndorff DK, Jenkins PA, Yates M, Ponnighaus JM
Abbrev. JournalEpidemiol. Infect.
JournalEpidemiology and infection
Year of Publication2001
Volume126
Issue3
Pagination379-87
Publication Languageeng
KeywordsAdolescent, Adult, Age Distribution, Antigens, Bacterial, Child, Environmental Exposure, Female, Follow-Up Studies, Humans, Incidence, Leprosy, Malawi, Male, Mycobacterium, Population Surveillance, Risk Factors, Rural Health, Sex Distribution, Skin, Soil Microbiology, Surveys and Questionnaires, Tuberculin Test, Tuberculosis, Water Microbiology
Abstract

More than 36000 individuals living in rural Malawi were skin tested with antigens derived from 12 different species of environmental mycobacteria. Most were simultaneously tested with RT23 tuberculin, and all were followed up for both tuberculosis and leprosy incidence. Skin test results indicated widespread sensitivity to the environmental antigens, in particular to Mycobacterium scrofulaceum, M. intracellulare and one strain of M. fortuitum. Individuals with evidence of exposure to 'fast growers' (i.e. with induration to antigens from fast growers which exceeded their sensitivity to tuberculin), but not those exposed to 'slow growers', were at reduced risk of contracting both tuberculosis and leprosy, compared to individuals whose indurations to the environmental antigen were less than that to tuberculin. This evidence for cross protection from natural exposure to certain environmental mycobacteria may explain geographic distributions of mycobacterial disease and has important implications for the mechanisms and measurement of protection by mycobacterial vaccines.

PubMed URL

http://www.ncbi.nlm.nih.gov/pubmed/11467795?dopt=Abstract

DOI10.1017/s0950268801005532
Link to full texthttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC2869706/pdf/11467795.pdf
PubMed Central IDPMC2869706