Noma (also known as necrotizing ulcerative stomatitis, gangrenous stomatitis, or cancrum oris) is a rapidly progressive and often fatal infection of the mouth and face. This disease predominantly affects children between the ages of two and six years old in the least developed countries around the world. Signs and symptoms
The mucous membranes of the mouth develop ulcers, followed by rapid, painful tissue degeneration and necrosis of the tissues of the bones in the face. Causes
The underlying causes for this disease are primarily poor sanitation and malnutrition. Although the causative organisms are common in many environments, this disease nearly exclusively affects extremely impoverished and malnourished children in tropical regions.Noma is often reported as a sequela to acute necrotizing ulcerative gingivitis. Fusobacterium necrophorum and Prevotella intermedia are important bacterial pathogens in this disease process, interacting with one or more other bacterial organisms (such as Treponema denticola, Treponema vincentii, Porphyromonas gingivalis, Tannerella forsythia, Staphylococcus aureus, and certain species of nonhemolytic Streptococcus). Treatment of these organisms can help arrest the infection, but does not restore already-missing or disfigured tissue.Predisposing factors include:
malnutrition
vitamin deficiency (particularly deficiencies of Vitamin A and Vitamin B)
contaminated drinking water
immunodeficiency
poor hygiene, particularly oral
recent illness (especially acute necrotizing ulcerative gingivitis, measles, malaria, and severe diarrhea)
living in proximity to livestock

Treatment
The progression of the disease can be halted with the use of antibiotics and improved nutrition; however, its physical effects are permanent and may require oral and maxillofacial surgery or reconstructive plastic surgery to repair.
Moxidectin
Moxidectin was approved for onchocerciasis in 2018 for people over the age of 11 in the United States. The safety of multiple doses is unclear. Epidemiology
About 21 million people were infected with this parasite in 2017; about 1.2 million of those had vision loss. As of 2017, about 99% of onchocerciasis cases occurred in Africa. Onchocerciasis is currently relatively common in 31 African countries, Yemen, and isolated regions of South America. Over 85 million people live in endemic areas, and half of these reside in Nigeria. Another 120 million people are at risk for contracting the disease. Due to the vectors breeding habitat, the disease is more severe along the major rivers in the northern and central areas of the continent, and severity declines in villages farther from rivers. Onchocerciasis was eliminated in the northern focus in Chiapas, Mexico, and the focus in Oaxaca, Mexico, where Onchocerca volvulus existed, was determined, after several years of treatment with ivermectin, as free of the transmission of the parasite.According to a 2002 WHO report, onchocerciasis has not caused a single death, but its global burden is 987,000 disability adjusted life years (DALYs). The severe pruritus alone accounts for 60% of the DALYs. Infection reduces the hosts immunity and resistance to other diseases, which results in an estimated reduction in life expectancy of 13 years. History
Onchocerca originated in Africa and was exported to the Americas by the slave trade, as part of the Columbian exchange that introduced other old world diseases such as yellow fever into the New World.