Researchers have identified a previously unknown species of bacteria in patients with noma, a deadly and disfiguring childhood disease, in what they describe as an 'astonishing' discovery that could lead to better prevention, detection, and treatment.
What is Noma?
Noma, which is fatal in 90% of cases without treatment, begins as a sore on the gums and rapidly destroys the tissues of the mouth and face. It primarily affects young, poor, and malnourished children, earning it the grim nickname 'the face of poverty'. Survivors are left with lifelong scarring and disfigurement. Data on noma is patchy, but experts estimate tens of thousands of cases occur each year, mostly in the Sahel region of Africa, though it also appears elsewhere. While broad-spectrum antibiotics can successfully treat noma, indicating a bacterial cause, the precise underlying pathogen has remained unknown.
The Study
Led by the Liverpool School of Tropical Medicine, the study analyzed the bacterial community in the mouths of 19 children with noma in Nigeria. Using modern genetic analysis, the team found a disturbed microbial community with lower levels of healthy bacteria and elevated levels of other strains. Deeper analysis revealed a previously undescribed species of Treponema bacteria, tentatively named Treponema A, in most noma patient samples. When PhD student Angus O'Ferrall presented the findings, senior author Prof Adam Roberts said he was 'astonished'. Reanalysis of older samples from other noma patients also showed the presence of Treponema A.
Causality and Next Steps
Roberts stressed that causality is not yet established: 'We don't know if it can colonise a noma wound because of the architecture and the environment, or if it causes the noma wound.' The team is now conducting a larger study with more patients and healthy individuals across multiple countries to answer this question. Once noma progresses to its necrotising stage, patients face either swift antibiotic treatment, which often leads to recovery but with massive disfigurement and lifelong stigma, or death. 'We want to stop it reaching that point,' Roberts said.
Future Implications
Roberts hopes that a test for children with gingivitis that detects Treponema A could prevent these outcomes. 'At the moment, the only thing that we have is a clinical diagnosis based on symptoms. That can be a foul smell or holes in the skin and the tissues. But if we know that Treponema A is always or 99% associated with the development of noma at the gingivitis stage, then we could detect and treat prophylactically with antibiotics to stop it progressing.' Current broad-spectrum antibiotic treatment risks increasing antimicrobial resistance, but a targeted treatment against a specific bacteria could reduce that threat. Additionally, the drop in healthy bacteria in noma patients suggests a potential preventive intervention with probiotics, Roberts added.
Expert Reactions
The study, published in Plos Neglected Tropical Diseases, involved researchers from the University of Liverpool, Médecins Sans Frontières, and the Noma children's hospital in Sokoto, Nigeria. Dr Michael Head, senior research fellow in global health at the University of Southampton, called the findings a useful first step to understanding a 'currently mysterious condition'. He noted that a different version of Treponema causes syphilis, which can also cause mouth wounds and ulcers. Prof Philippe Guérin, director of the Infectious Diseases Data Observatory at the University of Oxford, agreed the study is 'a valuable starting point' that should stimulate greater interest from researchers and funders.
