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Noma (cancrum oris): A scoping literature review of a neglected disease (1843 to 2021)
Noma (cancrum oris) is an ancient but neglected and poorly understood preventable disease, afflicting the most disenfranchised populations in the world. It is a devastating and often fatal condition that requires urgent and intensive clinical and surgical care, often difficult to access as most cases of noma occur in resource-limited settings. We conducted a scoping review of the literature published on noma to understand the size and scope of available research on the disease and identify research gaps that need to be addressed to evolve our understanding of how to address this disease.
We searched 11 databases and collected primary peer reviewed articles on noma in all languages, the final search was conducted on 24th August 2021. The oldest manuscript identified was from 28th March 1843 and the most recently published manuscript was from 3rd June 2021. Search terms included cancrum oris and noma. Data was extracted using a standardised data extraction tool and key areas of interest were identified. The Preferred Reporting Items for Systemic review and Meta-Analyses requirements were followed.
The review included 147 articles, the majority of the studies (n = 94, 64%) were case reports. Most manuscripts (n = 81, 55%) were published in the 2000s, 49 (33%) were from the 1900s and 17 (12%) from the 1800s. The main areas of interest identified were the history and epidemiology of the disease, noma's clinical progression and aetiology, treatment regimens, mortality rates and the risk factors for the development of noma.
Noma has been reported in the literature for hundreds of years; however important gaps in our understanding of the disease remain. Future research should focus on determining the burden and distribution of disease; the true mortality rate, pathogenic cause(s) and the factors that influence prognosis and outcomes after treatment.
Journal Article
Estimated incidence and clinical presentation of Noma in Northern Nigeria (1999–2024)
Noma (Cancrum Oris), a recent addition to the WHO list of neglected tropical diseases, is a severe, rapidly progressing necrotizing disease of the oral cavity and facial complex with a case fatality rate of 90% if untreated. Active disease is common among children between two and six years in Sub-Saharan Africa while noma sequelae may be seen in individuals at any age. Though most cases have been reported in northern Nigeria, little research is available on the incidence of noma and its clinical presentation in this region using comprehensive data. Therefore, this study aims to estimate 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 Children’s Hospital, Sokoto, 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 87.8 cases per 100,000, with Sokoto state having the highest incidence of 691.4 cases per 100,000, while Adamawa state had the lowest incidence of 11.2 cases per 100,000. The annual average and median incidence of noma across all years was 3.4 and 1.6 cases per 100,000 (range: 0.2-16.6 cases per 100,000), although between 2020 and 2024, the annual average and median incidence estimates were 12.0 and 12.6 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.
Journal Article
Knowledge, attitudes and practices of healthcare workers towards noma in Zambezia, Mozambique
Noma is a neglected tropical disease primarily affecting children living in poverty. Despite being preventable and treatable with readily accessible medicines, an estimated 90% of patients die due to lack of access to prompt and appropriate care.
Primary, secondary and quaternary health facilities were visited on a convenience-sampling basis in Zambezia Province, central Mozambique. Health professionals were invited to participate on a quota-sampling basis, and were administered a questionnaire including open and close-ended questions assessing their oral health practices, theoretical knowledge on noma and attitudes towards receiving a noma training. A total of 41 health professionals from 23 different health facilities participated in the study. Of these, 59% were aware of noma, and 26.8% reported having personally attended to an acute noma patient. However, their knowledge of noma's clinical characteristics and management was poor, especially in its early stages. Only 12% correctly diagnosed noma at stage 1, and 5% at stage 2. University-level professionals had a significantly better understanding of the disease than nurses and technicians. All participants were keen on receiving specific noma training.
Noma management competencies in Zambezia are extremely low, particularly among nurses and medical technicians, who serve as the first point of care for noma patients. There is an urgent need to implement comprehensive training programs across all levels of Mozambican healthcare providers, to prevent further avoidable deaths and reduce the severe outcomes associated with delayed treatment.
Journal Article
Performance Analysis of SWIPT-Enabled JT-CoMP-NOMA Networks using Incremental Relaying
This paper examines and analyzes a new design for incremental relaying (IR) with joint transmission of coordinated multipoint non-orthogonal multiple access (JT-CoMP-NOMA) in a network equipped with simultaneous wireless information and power transfer. To analyze the outage characteristics of the incremental relay with the JT-CoMP system, new mathematical formulas are developed to calculate the probability of outages for two users. To validate these formulas, the Monte Carlo approach was also employed. Implementing an incremental relay system within the JT-CoMP network is suggested for a two-user scheme and this IR technique enables the base stations (BSs) to dynamically alternate between a direct non-orthogonal multiple access (NOMA) transmission mode and a cooperative NOMA mode of transmission based on a 1-bit input from the distant user. By analyzing the throughput and outage probability of the suggested system, it has been demonstrated that the optimized structure offers benefits in enhancing both the throughput and outage performance. Adding an IR in the JT-CoMP-NOMA network has been found to decrease the likelihood of system outage and enhance network dependability. It is confirmed that JT-CoMP-NOMA with IR offers a substantial improvement in performance for users located at the cell edge when compared to conventional Cooperative Non-Orthogonal Multiple Access (CCN) and other multiple access schemes.
Journal Article
Defining the noma research agenda
• A 1-day symposium brought together over 100 individuals with lived experience of noma, expertise in neglected tropical diseases, and public health, including researchers, health advocates, and clinicians. The involvement of noma survivors was invaluable and added an important perspective in defining the research agenda. • The most pressing research needs identified were: ○ Clear case definition of noma ○ Early case detection and robust surveillance ○ Psychosocial and economic impact of noma ○ Decision support for diagnosing acute necrotizing gingivitis and associated antibiotic regimen(s) with treatment duration ○ Deeper understanding of risk factors and social determinants ○ Identification of effective information, education, and communication strategies ○ Effectiveness of surgical services ○ Testing decentralized follow-up for patients • An important conclusion was that noma research and control activities must be integrated across sectors and disciplines, such as neglected tropical diseases, oral health, nutrition, and child health programs including immunization.
Journal Article
Improving prevention, recognition and treatment of noma
Global consultations are ongoing in preparation for the launch of World Health Organization’s (WHO) new roadmap for neglected tropical diseases. These consultations will set out the strategic direction for treatment and prevention of these diseases in the coming decade. We therefore argue that it is timely to assess the global progress on noma, a disease endemic to tropical areas and neglected in terms of detection, prevention, treatment, research and policy. Noma is caused by a polymicrobial bacterial infection of the gums, which progresses rapidly to necrotizing gangrene of the face and jaw.1 This disease predominately affects children younger than six years in sub-Saharan Africa and is strongly associated with poor living conditions.2 Available estimates of global incidence and prevalence are several decades old, and are not based on epidemiological surveys. However, in Nigeria, researchers have estimated that in 2010–2018 the national incidence ranged from 4.1 to 17.9 per 100 0000 population.3 Although patients with noma can be cured with antibiotics,1 mortality remains high; nine out of 10 children who contract noma die from the disease.2 Survivors face lifelong stigma and disability, affected by sequelae including salivary incontinence, dysphagia and dysphonia.2 Currently, the recommended treatment for acute noma is empirical; that is, the choice of antibiotics do not account for the drug sensitivities of the causative bacteria, and little is known about the possible presence of multidrug resistance microorganisms.4
Journal Article
A Survey of NOMA for VLC Systems: Research Challenges and Future Trends
Visible light communication (VLC) has become a promising technology for high data rate communications and an attractive complementary to conventional radio frequency (RF) communication. VLC is a secure, energy efficient and cost-effective technology that exploits the existing infrastructure, particularly in indoor environments, for wireless data transmission. Nevertheless, the main limitation of developing high data rate VLC links is the narrow modulation bandwidth of light-emitting diodes (LEDs), which is in the megahertz range. The power domain nonorthogonal multiple access (PD-NOMA) scheme is envisioned to address several challenges in VLC systems. In this paper, we present a detailed overview of PD-NOMA based VLC systems. Moreover, we introduce insights on some PD-NOMA VLC system constraints and challenges such as power allocation, clipping effect, MIMO and security. Finally, we provide open research problems as well as possible directions for future research to pave the way for the implementation of PD-NOMA VLC systems.
Journal Article