ABSTRACT
Using population-based data from rural Vietnam, we assessed tuberculosis (TB) transmission within and outside of households. Eighty-three percent of persons with recent household TB were infected by different strains of Mycobacterium tuberculosis than were their household members. This result argues against the effectiveness of active TB case finding among household members.
Subject(s)
Tuberculosis, Pulmonary/epidemiology , Tuberculosis, Pulmonary/transmission , Adult , Aged , Family Characteristics , Female , Genotype , Humans , Male , Middle Aged , Minisatellite Repeats , Mycobacterium tuberculosis/classification , Mycobacterium tuberculosis/genetics , Mycobacterium tuberculosis/isolation & purification , Polymorphism, Restriction Fragment Length , Prospective Studies , Rural Population , Tuberculosis, Pulmonary/microbiology , Vietnam/epidemiologyABSTRACT
Tuberculosis case notification rates (CNRs) for young adults in Vietnam are increasing. To determine whether this finding could reflect emergence of Mycobacterium tuberculosis Beijing genotype, we studied all new sputum smear-positive pulmonary tuberculosis patients registered for treatment in 3 rural districts in Vietnam during 2003-2006. Beijing strain infections were more frequent in younger patients (15-24 years of age, 53%) than in older patients (31%; p<0.001). The increase in CNRs for youngest patients was larger for disease caused by the Beijing genotype than by other genotypes, but the difference was not significant. For patients 15-24 years of age, 85% of fluctuations in CNRs between years was caused by fluctuations in Beijing genotype infections compared with 53% and 23% in the groups 25-64 and >or=65 years of age, respectively (p<0.001). These findings suggest that young adults may be responsible for introducing Beijing strains into rural Vietnam.
