Podoconiosis: non-infectious geochemical elephantiasis

Abstract

This article reviews peer-reviewed publications and book chapters on the history, epidemiology, genetics, ecology, pathogenesis, pathology and management of podoconiosis (endemic non-filarial elephantiasis). Podoconiosis is a non-infectious geochemical elephantiasis caused by exposure of bare feet to irritant alkalic clay soils. It is found in at least 10 countries in tropical Africa, Central America and northwest India, where such soils coexist with high altitude, high seasonal rainfall and low income. Podoconiosis develops in men and women working barefoot on irritant soils, with signs becoming apparent in most patients by the third decade of life. Colloid-sized silicate particles appear to enter through the skin, are taken up into macrophages in the lower limb lymphatics and cause endolymphangitis and obliteration of the lymphatic lumen. Genetic studies provide evidence for high heritability of susceptibility to podoconiosis. The economic burden is significant in affected areas dependent on subsistence farming. Podoconiosis is unique in being an entirely preventable non-communicable disease. Primary prevention entails promoting use of footwear in areas of irritant soil; early stages are reversible given good foot hygiene, but late stages result in considerable economic and social difficulties, and require extended periods of elevation and occasionally nodulectomy.

The Association of Beliefs About Heredity with Preventive and Interpersonal Behaviors in Communities Affected by Podoconiosis in Rural Ethiopia

“…This study was conducted in rural Ethiopian communities affected by podoconiosis, a geochemical (nonfilarial) elephantiasis caused by the absorption of ultrafine silica particles from the soil through the skin of the feet. 26,27 Evidence suggests that heightened susceptibility to soil exposure clusters in families, 28 with estimates of heritability at 63%. 27 The disease is entirely preventable if genetically high-risk individuals consistently protect their feet from exposure to irritant particles by wearing shoes starting at a young age.…”

Environmental and health impact of potentially harmful elements distribution in the Panyam (Sura) volcanic province, Jos Plateau, Central Nigeria

“…Presumably, the endemic non-filarial elephantiasis observed affecting some inhabitants of the volcanic province might have been caused by the exposure of the unprotected feet to Be and Zr, in volcanic soils, known to induce the development of podoconiosis (Frommel et al 1993;Davey et al 2007;Price 1974), (Plate 1).…”

Podoconiosis and Soil-Transmitted Helminths (STHs): Double burden of Neglected Tropical Diseases in Wolaita zone, Rural Southern Ethiopia.

“…Anemia in podoconiosis patients in the absence of STH infection may reflect the chronic inflammatory process thought to be associated with disease progression in podoconiosis patients [4], or may reflect the marginalisation and undernutrition that are consequences of disease for many patients. Hemoglobin levels were lower in podoconiosis patients infected with any STH than patients without parasitic infection, probably reflecting direct blood loss (through ingestion and mechanical damage of the mucosa) and indirect blood loss by affecting the supply of nutrients necessary for erythropoiesis [34,35,36].…”

“…The MFTPA provides treatment to approximately 30,000 podoconiosis patients per year, through a carefully structured system of 15 'outreach clinics'. This infrastructure has been utilized successfully for previous research studies, and the investigators have a long history of research collaboration with the MFTPA [4,6,8,9]. The 'outreach clinics' at which cases were identified are situated between 1300 and 2050 meters above sea level, altitudes at which lymphatic filariasis would be uncommon.…”

“…Podoconiosis is a geochemical (non-filarial) elephantiasis thought to be caused by the absorption of ultrafine mineral particles from the soil through the skin of the feet [4,5]. In Ethiopia, 11 million people are at risk through exposure to irritant soil, and an estimated 500,000 to 1 million people are affected nationwide [6].…”