Mycobacterium ulcerans disease (Buruli ulcer) in Gabon: 2005-2011

Abstract

The first cases of Buruli ulcer (BU) in Gabon were described in the 1960s. Between 2005 and 2011, 301 clinically suspected cases of BU were found in all nine provinces of Gabon, and their lesions sampled for microbiological confirmation. Polymerase chain reaction (PCR) found 120 (39.9%) of these lesions positive and 181 (60.1%) negative for Mycobacterium ulcerans. The confirmed cases came mainly from the province of Moyen-Ogooué, particularly from localities along the Ogooué River (n=117; 52.5% of the samples in this province were PCR-positive). The detection rates per 100,000 inhabitants in this province ranged from 94.7 cases in 2005 to 28 in 2007, after an absence of active case-finding in 2006. The final three PCR-positive cases were found in the province of Estuaire. The characteristics of the confirmed BU patients (that is, PCR-positive) were identical to those described in other African countries: most patients were younger than 15 years old, and most lesions were found on both the upper and lower limbs. The group of suspected cases (PCR-negative) differed from the PCR-positive group for patient age (most patients were aged 15 to 49 years), lesion location (more frequently on the lower limbs), and ulceration (more frequent in the suspected cases). Some PCR-negative patients probably had other diseases; this underlines the importance of the differential diagnosis of BU. The cure rate of PCR(-)confirmed cases in our study was 88%; treatment was the antibiotic combination recommended by the World Health Organization (WHO). Our study demonstrates that BU is endemic in Gabon and is a public health problem there. Patients consult late with often extensive lesions. Awareness campaigns should be pursued to ensure earlier treatment of patients. The influence of HIV on BU in Gabon also deserves particular attention.