The prevalence of infections with Trichophyton tonsurans in schoolchildren: the CAPITIS study.

BACKGROUND: Although Trichophyton tonsurans has become the leading cause of tinea capitis in the United States, reported infection rates vary widely, and prevalence estimates for the pediatric population at large remain poorly characterized.

METHODS: A prospective, cross-sectional, surveillance study of children attending kindergarten through fifth grade in 44 schools across the bi-state (Kansas/Missouri), Kansas City metropolitan area was conducted. Fungal cultures were collected from all participants, and molecular analyses were used to characterize the patterns of infection within the population.

RESULTS: Of 10,514 children (age: 8.3 +/- 1.9 years) examined for the presence of T tonsurans on their scalps, 6.6% exhibited positive cultures. Infection rates at participating schools ranged from 0% to 19.4%, exceeding 30% at a given grade level in some schools. Black children demonstrated the highest rates of infection (12.9%), with prevalence estimates for the youngest members of this racial group approaching 18%. Infection rates for Hispanic (1.6%) and white (1.1%) children were markedly lower. A single genetic strain of T tonsurans was identified in only 16.6% of classrooms, whereas each child harbored a unique genetic strain in 51.4%.

CONCLUSIONS: We report a large-scale, citywide, surveillance study of T tonsurans infection rates among children in primary school in a metropolitan area. The striking prevalence rates and genetic heterogeneity among the fungal isolates confirm the relatively large degree to which this pathogen has become integrated into metropolitan communities.