Genotyping of Trichophyton tonsurans isolate from a Japanese boy reveals infection in the USA.

摘要

Trichophyton tonsurans has been epidemic in Japan since 2000, and is mainly transmitted and spread by combative sports, such as wrestling, judo and sumo, via extensive physical contact in international and domestic games. A large-scale survey among wrestlers using a questionnaire and cultures from hairbrush samples revealed the prevalence of T. tonsurans among wrestlers in Japan. In the 1990s, a survey of tinea capitis in London found a significant rise in the incidence of T. tonsurans infection among schoolchildren, and was suggested to be contagious among schoolmates and family members. Recently, nonwrestling cases have also been sporadically found in Japanese children who had no history of participating in wrestling or similar sports, or any direct contact with such sportspeople. In order to prevent the next outbreak of T. tonsurans via a nonwrestlling infection route as occurred in the UK, it is crucial to clarify the epidemiology in such cases. Although analysis of the interstrain species-specific genetic variation of the mycosis is valuable to confirm the species for molecular diagnosis, characterization of the intrastrain subspecies polymorphism is useful to identify the strains for molecular epidemiology. There are various subtypes of T. tonsurans; however, isolates of T. tonsurans in epidemic waves in Japanese wrestlers showed two molecular subtypes. We applied this molecular method to a nonwrestling case.