|Professor Cyril Enwonwu||Microbial Pathogenesis|
Malnutrition (including obesity) is a key global factor impacting various parameters of human health as well as host resistance to infections. Obesity is a major risk factor for insulin resistance. A malnourished host is immunocompromised and has increased risks of infections and chronic diseases. The close link between nutrition, infection, immunity and modulation of inflammation, is now well established. In recent years, the link has been extended to include the role of specific essential nutrients in phenotypic expression of genotype, cytokine biology, acquired immune function, and virulence of infectious agents.
Underprivileged countries and communities are affected disproportionately by severe oral diseases, particularly periodontitis, necrotizing ulcerative gingivitis, and oro-facial gangrene (noma/cancrum oris) (1, 2). Earlier studies in the same population groups had shown that malnourished children suffered more severe periodontal diseases than could be attributed solely to poor oral hygiene/accumulation of dental plaque (3). We have in the last decade focused our attention on the nutritional , biochemical, immunological and microbiological aspects of noma (4-6), as well as the living conditions of children at risk for the disease (7). Since the malnourished children with noma are usually victims of recent episodes of endemic systemic infections such as measles, malaria and tuberculosis among others, we have also evaluated the relevant metabolic and immunologic parameters in their village counterparts with these infections, but without noma (8-12). We are presently working on the hypothesis that the relatively small subset of malnourished children whose gingival lesions evolve into noma, are victims of intra-uterine growth retardation (IUGR) resulting from maternal malnutrition and infection during pregnancy (13). Noma is reported in Native American children with severe combined immune deficiency (SCID), an observation suggestive of dysfunction in the immune system, including the interleukin-7 signaling system. Defects in several parameters of Cell Mediated Immunity are linked to prenatal and early postnatal hostile events such as undernutrition and infections (13). The immune system like others, bears the long-term scars of adverse prenatal events? Is noma in malnourished children “programmed” in prenatal life? This is a question we need to answer since it has serious widespread public health ramifications in resource-poor countries worldwide.
1. Enwonwu, C.O. 1972. Epidemiological and biochemical studies of necrotizing ulcerative gingivitis and noma (cancrum oris) in Nigerian children. Arch Oral Biol 17:1357-71.
2. Enwonwu, C.O. 1995. Noma: a neglected scourge of children in sub-Saharan Africa. Bulletin World Health Org 73:541-45.
3. Enwonwu, C.O. and Edozien, J.C. 1970. Epidemiology of periodontal disease in Western Nigeria in relation to socio-economic status. Arch Oral Biol 15:1231-44.
4. Contreras, A., Falkler, W.A., Enwonwu, C.O., et al. 1997. Human Herpesviridae in Acute Necrotizing Ulcerative Gingivitis in children in Nigeria. Oral Microbiol Immunol 12:259-65.
5. Falkler, W.A., Enwonwu, C.O., Idigbe, E.O. 1999. Isolation of Fusobacterium necrophorum from Noma (Cancrum oris). Amer J Trop Med Hyg 60:150-6.
6. Enwonwu, C.O., Falkler, W.A., Idigbe, E.O., et al. 1999. Pathogenesis of orofacial gangrene (noma); Confounding interactions of malnutrition and infection. Amer J Trop Med Hyg 60:223-32.
7. Idigbe, E.O., Enwonwu, C.O., and Falkler, W.A. 1999. Living conditions of children at risk for noma. Oral Diseases 5:156-62.
8. Enwonwu, C.O., Phillips, R.S., Ferrell, C.D. 2005. Temporal relationship between the occurrence of fresh noma and the timing of linear growth retardation in Nigerian children. Tropical Medicine and International Health 10:65-73.
9. Phillips, R.S., Enwonwu, C.O., Falkler Jr, W.A. 2005. Pro-versus anti-inflammatory citokine profile in African children with acute oro-facial necrosis (cancrum oris, noma). European Cytokine Network 16:169-176.
10. Enwonwu, C.O., Phillips, R.S., Savage, K.O. 2005. Inflammatory cytokine profile and circulating cortisol level in malnourished children with necrotizing ulcerative gingivitis. European Cytokine Network 16:240-8.
11. Enwonwu, C.O. 2006. Noma: The Ulcer of Extreme Poverty. The New England Journal of Medicine 354:221-224.
12. Enwonwu, C.O., Falkler Jr, W.A., Phillips, R.S. 2006. Noma (cancrum oris): Seminar. The Lancet 368:147-156.
13. Enwonwu, C.O. 2007. Ruminations on causation of noma. Stomatologie 104:43-48.