Mycobacterium tuberculosis Transmission among Elderly Persons, Yamagata Prefecture, Japan, 2009–2015

Junji Seto, Takayuki Wada, Yu Suzuki, Tatsuya Ikeda, Katsumi Mizuta, Taro Yamamoto, Tadayuki Ahiko
2017 Emerging Infectious Diseases  
In many countries with low to moderate tuberculosis (TB) incidence, cases have shifted to elderly persons. It is unclear, however, whether these cases are associated with recent Mycobacterium tuberculosis transmission or represent reactivation of past disease. During 2009-2015, we performed a population-based TB investigation in Yamagata Prefecture, Japan, using in-depth contact tracing and 24-loci variablenumber tandem-repeat typing optimized for Beijing family M. tuberculosis strains. We
more » ... zed 494 strains, of which 387 (78.3%) were derived from elderly patients. Recent transmission with an epidemiologic link was confirmed in 22 clusters (70 cases). In 17 (77.3%) clusters, the source patient was elderly; 11 (64.7%) of the 17 clusters occurred in a hospital or nursing home. In this setting, the increase in TB cases was associated with M. tuberculosis transmissions from elderly persons. Prevention of transmission in places where elderly persons gather will be an effective strategy for decreasing TB incidence among predominantly elderly populations. Mycobacterium tuberculosis Transmission among Elderly Persons, Yamagata Prefecture, Japan
doi:10.3201/eid2303.161571 pmid:28221133 pmcid:PMC5382749 fatcat:z3r3dven4vb2ffx5dhp5vewlkq