Incidence and Clinical Presentation of Noma in Northern Nigeria (1999-2024)

Noma (Cancrum Oris), the newest neglected tropical disease, is a severe, rapidly progressing necrotizing disease of the oral cavity and facial complex with a case fatality rate of 90% if untreated. It often affects children between two and six years in Sub-Saharan Africa (Noma Belt region), with most cases reported in northern Nigeria. However, little research is available on the incidence of noma and its clinical presentation in this region using comprehensive data. Therefore, this study aims to determine the incidence of noma and its clinical presentation in northern Nigeria among different age groups. We collected retrospective data of 1,383 consecutive patients managed at Noma Childrens Hospital, Nigeria between 1999 and 2024 for incidence estimation and description of the clinical presentation of noma. Incidence calculation was done using the WHO Oral Health Unit strategy designed with the Delphi method. Our results showed that patients were between 8 months and 80 years old with a median age (IQR) of 6 years (3-15). More patients presented with acute noma than arrested noma (67.3% vs 32.7%). The estimated incidence of noma in northern Nigeria during the study period was 114.5 cases per 100,000, with Sokoto state having the highest incidence of 921.9 cases per 100,000, while Adamawa state had the lowest incidence of 6.3 cases per 100,000. The annual average and median incidence of noma across all years was 4.4 and 2.2 cases per 100,000 (range: 0.2-21.3 cases per 100,000), although between 2020 and 2024, the annual average and median incidence estimates were 15.5 and 15.6 cases per 100,000. Also, this study found the incidence of noma cases with gangrene to be higher than cases with oedema or acute necrotizing ulcerative gingivitis. These findings confirm the high incidence and impact of noma in northern Nigeria in the last two and half decades and highlight the need to intensify awareness of risk factors and early signs of noma within communities in the region and to conduct community-based screening to promote the identification and cost-effective treatment of reversible early noma disease. Author SummaryNoma is a severe and deadly gangrenous disease that affects the mouth and other tissues of the face. It is often associated with poverty and is currently prevalent in Sub-Saharan Africa. More cases have been described in northern Nigeria than in any African region. However, the incidence of noma and its clinical presentation in this region is unknown from data available from different states. In this study, we retrospectively collected data from the only dedicated specialist hospital for noma intervention in Nigeria between 1999 and 2024 to calculate noma incidence within this period. Then the incidence of noma was calculated using a method proposed by the World Health Organization (WHO). This study estimates an incidence of 114.5 cases per 100,000 within the study period and an annual average and median incidence of 4.4 and 2.2 cases per 100,000. Of note, the incidence of noma with gangrene (stage 3) was higher than the incidence of oedema (stage 2) or acute necrotizing ulcerative gingivitis (stage 1). These results highlight the importance and impact of noma in northern Nigeria and underscore the need for noma awareness and screening programs for population education and detection of early noma disease which are reversible with cost-effective interventions.