Buruli ulcer in Nigeria: results of a pilot case study in three rural districts.

Background: Buruli ulcer (BU), also known as Mycobacterium ulcerans disease, is the third most common mycobacterial disease worldwide. Although BU disease has been diagnosed among Nigerians in neighbouring West African countries, data on the burden of the disease in Nigeria itself are scanty. This study aimed to assess the magnitude and epidemiology of BU in the South South region of Nigeria.

Methods: We conducted a cross-sectional survey in the Ogoja territory (comprising 31 communities). We undertook sensitisation programmes centred on BU in 10 of the communities. Participants were asked to identify community members with long-standing ulcers, who were then invited for evaluation. We also contacted traditional healers to refer their clients who had non-healing ulcers. All suspected cases had a full clinical evaluation and laboratory testing. Confirmed cases were given treatment in a referral hospital in the territory.

Results: We diagnosed 41 clinical BU cases; 36 (87.8 %) of which were confirmed by quantitative polymerase chain reaction (qPCR). These 36 PCR-confirmed cases were diagnosed in a total population of 192,169 inhabitants. Therefore, the estimated crude prevalence of BU was 18.7 per 100,000 population, varying from 6.0 to 41.4 per 100,000 in the districts surveyed. The majority (66.7 %) of the cases were females. About 92 % of the BU lesions were located on the patients' extremities. No differences were observed between the sexes in terms of the location of the lesions. The age of the patients ranged from four to 60 years, with a median age of 17 years. All 35 (100 %) patients who consented to treatment completed chemotherapy as prescribed. Of the treated cases, 29 (82.9 %) needed and received surgery. All cases healed, but 29 (82.9 %) had some limitations in movement. Healing with limitations in movement occurred in 18/19 (94.7 %) and 8/10 (80.0 %) of patients with lesions >15 cm (Category III) and 6-15 cm in diameter (Category II), respectively. The median duration of treatment was 130 (87-164) days for children and 98 (56-134) days for adults (p = 0.15).

Conclusions: In Nigeria, BU is endemic but its severity is underestimated-at least in the study setting. There is a need to identify and map BU endemic regions in Nigeria. A comprehensive BU control programme is also urgently needed.