168 Lymphology 43 (2010) 168-177 PODOCONIOSIS, NON-FILARIAL ELEPHANTIASIS, AND LYMPHOLOGY G. Davey Brighton & Sussex Medical School, University of Sussex, Falmer, Brighton, United Kingdom ABSTRACT HISTORY Several recent reviews of podoconiosis From the time of the Roman Empire, already exist in journals and on public access travelers recorded anecdotes about people websites. After briefly covering the historical with progressive swelling of the feet. A more and epidemiological background, this detailed reference to ‘swollen legs’ appears in narrative review will therefore attempt the Tibetan translations of a fourth century explicitly to link podoconiosis with revelation originally recorded in Sanskrit as lymphology, examining gaps in what is known the second book of rGyud-bzhi (the ‘four of pathogenesis and identifying the areas of tantras’). However, it was not until c.905 research in which input from lymphologists is that the Persian physician Rhazes first most required. Finally, prevention and distinguished elephantiasis ‘of the Greeks’ treatment will be described and the need for (lepromatous leprosy) from that ‘of the operational research to optimize community- Arabs’ (most probably non-filarial based interventions outlined. elephantiasis) (1). In the 1770s, the adventurer James Bruce Keywords: podoconiosis, elephantiasis, gave a graphic description of the elephan- lymphedema, soil tiasis he saw in Gondar, northern Ethiopia: “The chief seat of this disease is from the Podoconiosis is a type of lower limb bending of the knee downwards to the ankle; tropical elephantiasis distinct from lymphatic the leg is swelled to a great degree, becoming filariasis (LF). It is a geographically localized one size from bottom to top, and gathered disease, clinically distinguished from LF into circular wrinkles.... from between these through being an ascending and usually circular divisions a great quantity of lymph bilateral lymphedema. It is highly prevalent constantly oozes. It should seem that the in focal areas, hence its alternative title, black colour of the skin, the thickness of the endemic non-filarial elephantiasis. Podoconi- leg, its shapeless form and the rough osis (endemic non- filarial elephantiasis) has tubercules or excrescences, very like those been recognized as a specific disease entity seen upon the elephant, gave the name to for over one thousand years and is this disease...” widespread in tropical Africa, Central Bruce obtained permission from the America and north India, yet it remains a emperor, Ras Mikhail, to treat a sufferer, neglected and under-researched condition using a range of regimes and medications, (Fig. 1). but beyond assuaging the patient’s thirst with Permission granted for single print for individual use. Reproduction not permitted without permission of Journal LYMPHOLOGY. 169 Fig. 1. Advanced, asymmetrical podoconiosis in a female patient from northern Ethiopia. a constant supply of whey, no treatment among Guatemalan patients with elephan- (including hemlock, mercury and tar-water) tiasis, Robles inferred that the disease (which appeared effective (2). he called ‘pseudo-lepra’) was associated with Through the eighteenth and nineteenth walking barefoot (1). He described the centuries, the pathogenesis of elephantiasis ecological niche and the disease process in was gradually elucidated through Hendy’s detail, noting the lifelong nature of the study of the lymphatic system in affected disease, but his enquiry was not continued in people. Wucherer (in Brazil), Lewis (in South America. India), Manson and Bancroft all recognized Progress in recognizing the international the role of filarial parasites in elephantiasis, distribution of non-filarial elephantiasis came and for a time it was concluded that all as Cohen suggested the use of the term elephantiasis was filarial. Towards the end of ‘idiopathic lymphedema’ in place of the local the nineteenth century, the discrepancy terms ‘verrucosis lymphatica’ in Kenya and between distribution of elephantiasis and ‘mossy foot’ in Ethiopia (3). The location of distribution of filaria in North Africa, central the next set of investigations into non-filarial America and Europe prompted revision of elephantiasis was western Ethiopia, where this theory. Central to current research has in the 1960s, Oomen described a type of been the identification of podoconiosis as a elephantiasis caused neither by onchocerciasis type of elephantiasis distinct from filarial nor filariasis (4). He noted that most cases disease. This distinction was first clearly were found between 1000m and 2000m, made in 1938, when on the basis of repeated but was unable to fully resolve questions negative tests for bacteria and microfilaria about etiology. Permission granted for single print for individual use. Reproduction not permitted without permission of Journal LYMPHOLOGY. 170 Fig. 2. Global distribution of podoconiosis. (Adapted from WHO website) Price extended Oomen’s epidemiological Central American highlands in Mexico and studies (5,6), and described the etiology (7), Guatemala south to Ecuador and Brazil in pathology (8,9), and natural history (10) of South America (19,20). Further east, on the non-filarial elephantiasis in Ethiopia, north coast of South America in Suriname establishing the term podoconiosis (from the and French Guiana, the distinction between Greek for foot: podos, and dust: konos) (11), filarial and non-filarial elephantiasis has not which has gained widespread acceptance. been confirmed. Although filarial elephantiasis predominates in India, podoconiosis has been EPIDEMIOLOGY reported from north-west India, Sri Lanka and Indonesia (Fig. 2). Geographical Distribution Price holds that podoconiosis was previously common in North Africa (Algeria, Podoconiosis is found in highland areas Tunisia, Morocco and the Canary Islands) of tropical Africa, Central America and and Europe (France, Ireland and Scotland) north-west India. Areas of high prevalence but is no longer found in these areas since have been documented in Uganda (12), use of footwear has become standard (19). Tanzania (13), Kenya (14), Rwanda, Burundi, Sudan and Ethiopia (15), and in Equatorial Prevalence Guinea (16), Cameroon (17), the islands of Bioko, Sao Tome & Principe (18) and the Prevalence estimates have been made in Cape Verde islands. Ethiopia and, recently, in Cameroon. Early The condition has been reported in the estimations of prevalence using counts of Permission granted for single print for individual use. Reproduction not permitted without permission of Journal LYMPHOLOGY. 171 attendees at fifty-six markets ranged from goldmine workers, and weavers who sit at a 0.42 to 3.73% (4), and further investigation ground level loom. in Wollamo zone, southern Ethiopia demon- strated prevalence of 5.38% across five Geology and Climate markets. In the village of Ocholo, located at 2000m altitude in the mountains west of An association between podoconiosis and Lake Abaya, southern Ethiopia, elephantiasis exposure to the local soil was suspected by was present in 5.1% of long-term residents Robles in Guatemala at the end of the (21), while in two resettlement schemes in nineteenth century. However, it was not until Ilubabor, western Ethiopia, 9.1% of long-term Price superimposed maps of disease residents were affected, and 5.2% of people occurrence onto geological surveys that resettled some 7-8 years previously (22). More persuasive evidence of a link with red clays recent population-based surveys in northwest derived from volcanic activity was provided (23), southern (24) and western Ethiopia (15,25). The climatic factors necessary for (personal communication), and northwestern producing irritant clays appear to be high Cameroon (17), have documented prevalence altitude (between 1000 and 2500m above sea of 6%, 5.4%, 2.8% and 8.1%, respectively. level) and seasonal rainfall (over 1000mm annually). These conditions contribute to the Age, Gender and Occupation steady disintegration of volcanic ash and the reconstitution of the mineral components into Early reports based on clinic attendees silicate clays. Comparison of soil from an cannot be relied upon to derive an accurate endemic area with that from outside the area sex ratio. Price found a male: female ratio of revealed high levels of beryllium and zirco- 1:1.4 in market studies, which he attributed nium (both known to induce granulomata) to greater use of footwear by men (7). Genene (26), but the role of these elements is not Mengistu documented a male: female ratio of yet established. 1:4.2 in a survey in Ocholo, but many men of Although the earlier literature on working age were absent from the community podoconiosis suggested quartz to be a causal at the time (21). By contrast, Kloos noted agent, it is possible that kaolinite/smectite or higher prevalence among men in three of four smectite clay particles are etiologically resettlement communities in Keffa Region involved. Military surgeons in the United (22). In a single village in Pawe, Hailu Birrie States of America first recognized the found a male: female ratio of 1:1.4 among biologically active properties of sterile soil in sufferers (23). The most recent community- the 1970s. Early research identified clay based study recorded a gender ratio among particles (<2µm diameter) as more powerful podoconiosis sufferers (1:0.98) that was not than sand (2µm<x<20µm) or silt (20µm significantly different from the zonal gender <x<2mm) in potentiating the effect of infec- ratio (1:1.02) (24). tion