Prevalence and causative fungal species of tinea capitis among schoolchildren in Gabon.

Tinea capitis is endemic among schoolchildren in tropical Africa. The objective was to determine the prevalence of symptomatic tinea capitis in schoolchildren in Gabon. A cross-sectional study was conducted with 454 children aged 4-17 years, attending a rural school and an urban school. The diagnosis of tinea capitis was based on clinically manifest infection, direct microscopic examination using 20% potassium hydroxide (KOH) solution and fungal culture. Based on clinical examination, 105 (23.1%) of 454 children had tinea capitis. Seventy-four (16.3%) children were positive by direct examination (KOH) and/or fungal culture. The prevalence of tinea capitis depended on the school studied and ranged from 20.4% in the urban school with a higher socioeconomic status to 26.3% in the rural school with a lower socioeconomic status. Similarly, the spectrum of causative species varied between the different schools. Taken the schools together, Trichophyton soudanense (29.4%) was the most prominent species, followed by Trichophyton tonsurans (27.9%) and Microsporum audouinii (25.0%). Clinically manifest tinea capitis is endemic among schoolchildren in the Lambaréné region in Gabon. The prevalence of tinea capitis and the causative species depended on the type of school that was investigated.

Diagnosis of common dermatophyte infections by a novel multiplex real-time polymerase chain reaction detection/identification scheme.

BACKGROUND: In the absence of a functional dermatophyte-specific polymerase chain reaction (PCR), current diagnosis of dermatophytoses, which constitute the commonest communicable diseases worldwide, relies on microscopy and culture. This combination of techniques is time-consuming and notoriously low in sensitivity. OBJECTIVES: Recent dermatophyte gene sequence records were used to design a real-time PCR assay for detection and identification of dermatophytes in clinical specimens in less than 24 h. PATIENTS AND METHODS: Two assays based on amplification of ribosomal internal transcribed spacer regions and on the use of probes specific to relevant species and species-complexes were designed, optimised and clinically evaluated. One assay was for detecting the Trichophyton mentagrophytes species complex plus T. tonsurans and T. violaceum. The second assayed for the T. rubrum species complex, Microsporum canis and M. audouinii. RESULTS: The analytical sensitivity of both assays was 0.1 pg DNA per reaction, corresponding to 2.5-3.3 genomes per sample. The protocol was clinically evaluated over 6 months by testing 92 skin, nail and hair specimens from 67 patients with suspected dermatophytosis. Real-time PCR detected and correctly identified the causal agent in specimens from which T. rubrum, T. interdigitale, M. audouinii or T. violaceum grew in culture, and also identified a dermatophyte species in an additional seven specimens that were negative in microscopy and culture. CONCLUSIONS: This highly sensitive assay also proved to have high positive and negative predictive values (95.7% and 100%), facilitating the accurate, rapid diagnosis conducive to targeted rather than empirical therapy for dermatophytoses.