Estimation of the Prevalence of Noma in Ethiopia, 2007–2019: A Retrospective Study

ABSTRACT.

Noma is a rapidly advancing and frequently deadly infection affecting the oral and facial regions. The condition causes severe destruction of the soft and osseous tissues of the face. Noma primarily affects impoverished children with weakened immune systems, yet epidemiological data on the disease are lacking. This cross-sectional study aimed to fill this knowledge gap by estimating the prevalence of noma in Ethiopia. A retrospective review of patients’ medical records was conducted using data from the Facing Africa database, spanning from 2007 to 2019. The prevalence of noma was calculated for the general population and for children under 10 years old at national and regional levels. The estimation process involved analyzing raw data and referring to an expert consultation report organized by the Oral Health Division of the WHO, which used the Delphi method. Based on the analysis of 235 medical records, the study revealed an estimated prevalence of 16 cases per 100,000 population and 0.47 case per 1,000 children under 10 years old nationally, with approximately 1,446 and 1,237 new cases diagnosed annually, respectively. The Gambela region had the highest prevalence of noma, with 276.2 cases per 100,000 population, whereas the Benshangul Gumuz region had the lowest rate at 6.2 cases per 100,000 population. Similarly, the Gambela and Benshangul Gumuz regions exhibited the highest and lowest prevalences per 1,000 children under 10 years old, estimated at 8.12 and 0.18 cases per 1,000, respectively. The findings underscore the public health impact of noma in Ethiopia and the need for effective prevention and treatment strategies.

INTRODUCTION

Noma, a severe oral disease, largely disappeared in developed countries during the twentieth century, with only a few cases observed in concentration camps and more recently in HIV/AIDS patients and patients undergoing intensive immunosuppressive therapy, as well as in Native American children with severe combined immunodeficiency syndrome.¹ However, noma continues to be a growing public health issue that affects economically disadvantaged children in the developing world, particularly in sub-Saharan Africa.² It is estimated that several hundred thousand children under the age of 10 years contract noma globally each year. Although Africa has the highest concentration of cases according to the WHO, instances of noma have also been reported in Asia and Latin America, although reliable quantitative data on prevalence and incidence are lacking.³ The WHO recognized noma as a priority in 1994, prompted by alarming reports from aid agencies operating in Africa.⁴ Despite meeting the criteria to be classified as a neglected tropical disease, noma is not officially recognized as one by the WHO.^2–4 The neglected nature of the disease makes it challenging to assess the extent of the problem and track epidemiological trends.⁵ Although noma’s prevalence does not compare with that of diseases such as malaria or measles, its high mortality rate and the social implications for survivors, who often live in hiding with limited prospects for social integration, highlight the significant impact of the disease.^3–5

Determining the exact prevalence, incidence, and mortality associated with noma poses several challenges.⁶ Before 1992, the WHO did not have standardized noma registration, and less-developed countries did not officially report cases until 1994.⁴ Owing to the high mortality rate of acute noma, many cases go undiagnosed, with only about 10% of patients seeking treatment during the acute stage.⁷ The social stigma surrounding noma leads to affected children missing school, being unable to marry, and being hidden or isolated, further obstructing diagnosis and reporting.⁷ In certain Nigerian village communities, noma is considered a shameful curse, resulting in underreporting of cases.¹ Nomadic populations and those residing in remote areas face difficulties in registering, monitoring, and accessing treatment facilities because of transportation challenges and associated costs.^6–8 In addition, healthcare workers may struggle to accurately diagnose the disease.⁹ These factors make it exceptionally challenging to determine the precise incidence and prevalence of noma, despite its long history alongside humans.¹⁰ In 1998, the WHO estimated the global incidence of noma to be 140,000 cases, with a prevalence of 770,000 survivors experiencing severe complications. However, it remains unclear which stages of noma are included in these estimates.¹¹ The noma belt, spanning from Senegal to Ethiopia and located south of the Sahara, reports the highest concentration of noma cases.^8,12 Isolated cases have also been reported in developed countries,¹³ as well as in Asian and Pacific countries such as Afghanistan, India, and China.^14–16 Available epidemiological data from publications mainly covering the years 1950 to 1970 mention a few isolated cases in industrialized nations, whereas a higher incidence and prevalence have been documented primarily in sub-Saharan African countries.^13,17

Despite the global presence of noma indicated by the WHO map, controversies persist regarding its worldwide incidence and prevalence.^18–21 Similarly, limited data exist on the incidence of noma in Ethiopia, where the disease remains a significant public health concern.²² Understanding the burden of noma is essential for developing effective prevention and treatment strategies.^21–23 Therefore, this study was initiated to estimate the prevalence of noma in Ethiopia by comprehensively reviewing patients’ electronic medical records. By analyzing the available data, the researcher aims to shed light on the epidemiology of noma in the country and provide valuable insights into the magnitude of the disease burden.

MATERIALS AND METHODS

This study aimed to estimate the prevalence of noma in Ethiopia based on data obtained from a retrospective review of electronic patient records and the report of an expert consultation on noma disease organized by the Oral Health Division of the WHO using the Delphi method.²⁴ Overall, the study aimed to estimate the prevalence of noma in the general population and in children under the age of 10 years at the national and regional/urban administrative levels.

Study design.

This study used a retrospective cross-sectional design utilizing patients’ electronic medical records to estimate the prevalence rates of noma in Ethiopia. The study adheres to ethical guidelines and safeguards patient privacy and confidentiality.

Data source and collection.

The study used an electronic database containing medical records from Facing Africa, Ethiopia. Facing Africa was a United Kingdom–based charity organization dedicated to providing complex facial reconstructive surgery to victims of noma and severe facial disfigurement; the organization sponsored two teams of volunteer surgeons from the United Kingdom and Ireland who traveled to Ethiopia twice a year for 2-week surgical missions between 2007 and 2019. The noma cases were treated at several healthcare facilities in Addis Ababa, Ethiopia. These included Yekatit 12 Hospital, where treatment occurred from October 13, 2007 to October 18, 2008; Cure Hospital from October 9, 2009 to October 24, 2009; Myungsung Christian Medical Center, where cases were treated from February 26, 2010 to October 21, 2016; and Hallelujah General Hospital, where treatment took place from May 5, 2017 to October 21, 2018. In addition, treatment of noma cases was given at Nordic Medical Center from May 11, 2018 to October 23, 2019. Accordingly, the database included records spanning between 2007 and 2019, typically several years, encompassing vital clinical and demographic data needed to estimate prevalence rates of noma at national and regional/city administration levels in Ethiopia. Data collection involved extracting relevant information from electronic medical records pertaining to patients diagnosed with noma during the defined study period.

Case identification.

Cases of noma were identified through systematic screening of electronic medical records using standardized search criteria. The search terms included relevant diagnostic codes, clinical descriptions, or keywords associated with noma. The screening process aimed to identify all potential cases for further analysis.

Data extraction.

A structured data extraction form was designed to capture relevant information from the identified noma cases. The extraction form included variables such as patient demographics (age, gender, residence), clinical characteristics (year of diagnosis, clinical presentation, disease stage), and relevant comorbidities or risk factors. The author of this article reviewed the medical records and extracted the required data following a standardized protocol.

Data analysis.

The collected data underwent a comprehensive analysis to provide a reliable estimation of the prevalence of noma in Ethiopia. For the estimation of prevalence, the analysis followed the guidelines outlined in the 1994 consultation report of the WHO Oral Health Unit, utilizing the Delphi method.²⁴ The process of estimating the total prevalence (P) involves two steps. First, the number of surviving cases (S) is determined. This is achieved by determining the percentage (χ) of the total S that corresponds to the number of cases referred to and reaching treatment centers (R). The formula used to calculate S is as follows:

$$S=R\times 100/\chi ;\text{where}\hspace{0.17em}\chi =12.5\text{.}$$

In the second step, the annual P is calculated by considering that the number of surviving cases is a percentage of the total P, based on the case survival rate (y/100). Therefore, the total P can be estimated using the following formula:

$$P=S\times 100/y;\text{where}\hspace{0.17em}y=10\text{.}$$

These calculations were vital for the determination of the P of noma in Ethiopia, providing valuable insights into the magnitude of the disease burden in the country. The prevalence estimates also considered data from the Central Statistical Authority of Ethiopia on children under 10 years, representing 29.1% of the total population.²⁵

RESULTS

This section addresses the findings of the study, focusing on the estimated prevalence in the distinct study groups (general population and children under 10 years of age) and in the multiple regions/city administrations of Ethiopia and at the national level.

Prevalence and regional variations.

The analysis of data from Facing Africa, Ethiopia yielded compelling insights into the incidence of noma in Ethiopia. Nationally, 235 (139 female and 96 male) noma patients aged 5 to 66 years were referred to Facing Africa. Of these, 52.4% (n = 123) had left-sided facial deformities, whereas 45.5% (n = 107) and 2.1% (n = 5) noted right-sided and central facial deformities, respectively. The anatomic landmarks reported in the reviewed medical records had varying degrees of tissue damage, ranging from mild to severe. Affected landmarks included the cheek, upper lip, lower lip, nose, hard palate, maxilla, corner of the mouth, zygomatic bone, infraorbital area, eyes, ear, mandible, and chin. According to the NOITULP (nose, outer cheek , inner cheek skin, trismus, upper lip, lower lip and special problems) grading of facial tissue damage, 40 cases (17%) were found to have mild tissue damage (NOITULP grade 1), affecting 0–25% of the facial area. Grade 2 tissue damage (25–50% of the facial area) was observed in 74 cases (31.5%) of noma. Seventy-six cases (32.3%) suffered grade 3 tissue damage (50–75%). The most severe form of tissue damage (75–100% of the facial area) occurred in 45 cases (19.2%) of noma. Except for six cases in the acute stage, the remaining 229 individuals were in a nonprogressive (arrested) stage of noma. Furthermore, two comorbidities, HIV/AIDS and hepatitis B infection, were reported in six and three cases, respectively, at the time of disease development. Potential risk factors such as malnutrition, living with pets, drinking river water, diarrheal diseases, and measles and malarial infections were reported in 71.9% of cases (n = 169). A previous study by the current author revealed that in 85.4% of noma cases that reported the onset of the condition, the disease occurred during childhood between the ages of 0 and 10 years.²⁶ The prevalence estimation in children ≤ 10 years in this study considered the above assertion. Accordingly, out of 235 noma cases studied, 201 were children 10 years old and under. A further important consideration in estimating the prevalence of noma in children ≤ 10 years was to investigate the proportion of children in the general population.

The estimated prevalence for the general population and children ≤ 10 years was found to be 16 and 0.47 per 100,000 population and per 1,000 children, respectively, at the national level during this period. On average, approximately 1,446 and 1,237 new cases of noma were diagnosed annually in the general population and children ≤ 10 years old levels, respectively, highlighting the ongoing burden of the disease among children 10 years old and younger.

The regional distribution of noma cases exhibited notable variations. The Gambela region had the highest prevalence in the general population and children ≤ 10 years old levels, with 276.2 and 8.12 cases per 100,000 population and per 1,000 children, respectively. In contrast, the Benshangul Gumuz region had the lowest prevalence in the general population and children ≤ 10 years old levels, with 6.2 and 0.18 cases per 100,000 population and per 1,000 children, respectively. These regional prevalence estimations were based on 161 medical files that included patients’ residential or geographic data, whereas the national prevalence estimation was based on information retrieved from all 235 medical records obtained from the Facing Africa database (Table 1).

Table 1.

Estimated prevalence of noma cases by region

Noma epidemiologic data	Regions and city administrations	Number of noma cases	Prevalence in children ≤ 10 years old	Prevalence per 1,000 in children ≤ 10 years old	Prevalence in the general population	Prevalence per 100,000 general population
Regional and city administration levels	Addis Ababa	7	479	0.238	560	12.9
	Afar	No report	NA	NA	NA	NA
	Amhara	43	2,942	0.37	3,440	12.5
	Benshangul Gumuz	1	68	0.18	80	6.2
	Dire Dawa	No report	NA	NA	NA	NA
	Gambela	17	1,163	8.12	1,360	276.2
	Harari	2	137	1.61	160	54.6
	Oromia	51	3,490	0.28	4,080	9.4
	Somali	6	411	0.2	480	6.8
	SNNP	28	1,916	0.28	2,240	9.4
	Tigray	6	411	0.2	480	6.94
	Cases not identified by region	74	NA	NA	NA	NA
National level	Total	235	16,080	0.47	18,800	16

NA = not applicable; SNNP = Southern Nations, Nationalities, and People's Region.

DISCUSSION

The available data suggest an annual incidence of 30,000 to 40,000 noma cases worldwide, with approximately 25,600 cases originating from sub-Saharan Africa.^27–29 Although noma cases have been reported on all continents, the majority are concentrated in sub-Saharan countries such as Nigeria, Niger, Senegal, and Burkina Faso, which have a significant disease burden and high mortality rates in the absence of treatment.^20,30 Noma’s prevalence is particularly pronounced in the noma belt, spanning from Senegal to Ethiopia, south of the Sahara.²⁰

This study aimed to determine the prevalence of noma, a severe facial infection, in Ethiopia. Because Facing Africa, Ethiopia recorded new and old cases of noma, prevalence rather than incidence of the disease was determined. To accomplish this, the author analyzed data from a comprehensive review of medical records from 2007 to 2019 in the Facing Africa, Ethiopia database. The findings revealed that the estimated prevalence of noma was 16 cases per 100,000 population and 0.47 case per 1,000 children aged 10 years or younger on a national scale. Annually, approximately 1,446 new cases of noma were diagnosed among the general population, whereas 1,237 new cases were reported among children in this age group. Regarding regional disparities, the Gambela region had the highest prevalence of noma, with a rate of 276.2 cases per 100,000 population. In contrast, the Benshangul Gumuz region exhibited the lowest prevalence of 6.2 cases per 100,000 population. When noma cases specifically in children aged 10 years or younger are considered, the Gambela region had the highest prevalence at 8.12 cases per 1,000 children, whereas the Benshangul Gumuz region had the lowest rate at 0.18 case per 1,000 children. It is worth noting that no cases of noma were reported in the Afar region and Dire Dawa city administration during the period under study.

The estimated prevalence of 16 cases per 100,000 and 0.47 case per 1,000 children aged 10 years or younger on a national scale suggests that noma is a public health concern in Ethiopia. The estimated prevalence of noma at regional/city administration levels in Ethiopia was also found to be alarming. The estimated prevalence of noma at regional/city administration levels in Ethiopia is generally higher than regional estimates of the condition across various states in Nigeria, where it ranges from 4.1 to 17.9 cases per 100,000 people.³¹ Generally speaking, the estimated prevalence of noma in African countries ranges from one to seven cases per 1,000 population, reaching up to 12 cases per 1,000 population in severely affected communities, which is much higher than the prevalence finding of the current study. Specifically, in countries such as Niger, Nigeria, and Senegal, the estimated prevalence per 1,000 children aged 0 to 6 years is 1.34, 0.80, and 0.7 to 1.2, respectively.²⁰ These reports were found to align well with the findings of this study. The other comparatively close finding to the estimated prevalence rate of 1.61 per 1,000 children aged 10 years or younger in the Harari region of Ethiopia was made by Galli et al.²⁰ According to Galli et al., the average prevalence of noma was estimated to be 1.64 per 100,000 children in noma-endemic sub-Saharan African countries.¹⁴ The regional variations in noma prevalence rates within Ethiopia can be attributed to a range of factors. One possible explanation is the limited accessibility of healthcare facilities in certain regions, leading to underreporting of cases. In addition, poor documentation practices and a lack of reporting from some regions may contribute to the lower incidence observed. Furthermore, there may be a lack of awareness about the disease among both the community and healthcare professionals, which could result in cases going undiagnosed or unreported. Socioeconomic barriers, such as poverty and limited resources, may also play a role in the lower prevalence observed in specific regions.

In summary, the limitations of this study can be attributed to the factors mentioned above, as well as the reliance on analysis of medical records from a single center for the current findings. On the other hand, the annual occurrence of 1,446 new noma cases in Ethiopia is noteworthy, particularly when the global context of noma is considered. Worldwide, an estimated 30,000 to 40,000 new cases of noma are reported each year.¹⁴ Thus, the number of cases identified in Ethiopia represents a significant proportion of the global burden. It is important to highlight that the prevalence in regions and city administrations would likely be higher if all the medical files reviewed had been stratified by region or residential data, as this would have allowed for a more accurate assessment of disease distribution within the country. Similarly, if the analysis had included data from two other noma treatment centers in Ethiopia, namely Yekatit 12 Hospital (with 68 cases) and Project Harar (with 33 cases) as reported by Gebretsadik²⁵ in addition to the cases reported by Facing Africa (with 235 cases), the estimated prevalence would have been even higher. Including these additional cases would provide a more comprehensive picture of the noma burden in Ethiopia.

Although this study was retrospective and did not examine the reasons for regional differences in noma incidence in Ethiopia, the results obtained by analyzing a relatively large data set of 235 medical records provide valuable insights into the impact of the disease in this country. The varying prevalences among different regions underscore the importance of targeted interventions and resource allocation to areas with higher incidence. The absence of reported noma cases in the Afar region and Dire Dawa city administration raises questions about potential underlying factors, such as differences in healthcare access, awareness, or environmental conditions, which warrant further investigation. In general, the variation in regional prevalence and the absence of cases in certain areas underscore the need for tailored interventions and further research to understand the underlying factors. The analysis of noma cases in Ethiopia, considering data from Facing Africa, Ethiopia and other treatment centers, highlights the significant burden of the disease in the country. Thus, the findings of this study contribute to our understanding of noma’s prevalence in Ethiopia, providing valuable information for public health planning and resource allocation to combat this devastating disease.