02481nas a2200541   4500000000100000008004100001260001300042653001500055653001000070653002100080653002400101653001000125653002700135653001100162653002200173653001100195653001400206653001200220653001100232653000900243653001800252653002800270653001700298653001700315653002100332653000900353653002200362653003100384653002000415653001700435653002300452100001200475700001200487700001700499700001300516700001400529700001600543700001800559700001600577700001200593700001900605245011400624856007400738300001100812490000800823520109400831022001401925       2001                            d  c2001 Jun10aAdolescent10aAdult10aAge Distribution10aAntigens, Bacterial10aChild10aEnvironmental Exposure10aFemale10aFollow-Up Studies10aHumans10aIncidence10aleprosy10aMalawi10aMale10aMycobacterium10aPopulation Surveillance10aRisk Factors10aRural Health10aSex Distribution10aSkin10aSoil Microbiology10aSurveys and Questionnaires10aTuberculin Test10aTuberculosis10aWater Microbiology1 aFine PE1 aFloyd S1 aStanford J L1 aNkhosa P1 aKasunga A1 aChaguluka S1 aWarndorff D K1 aJenkins P A1 aYates M1 aPonnighaus J M00aEnvironmental mycobacteria in northern Malawi: implications for the epidemiology of tuberculosis and leprosy.  uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC2869706/pdf/11467795.pdf  a379-870 v1263 a<p>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.</p>  a0950-2688