Q&A with: Dr. Gail Davey on Podoconiosis
Q&A with Dr. Gail Davey
1. What is your title?
I’m a medical epidemiologist based at Addis Ababa University, in the School of Public Health.
The disease
1. What is podo?
Podo (or podoconiosis, from the Greek for 'foot' and 'dust') is a non-infectious type of elephantiasis. It is also called 'Mossy Foot' (because the skin changes look like moss) or 'verrucosis lymphatica'.
2. What causes the disease, and who discovered it?
Ernest Price, a British surgeon, figured out in the 1970s that podo was caused by years of barefoot exposure to red clay soil [2]. We are not certain which particle within this soil causes the problems, but several people think that very tiny grains of silica are responsible.
3. How does podo differ from elephantiasis?
Podo (or to give it its full name, podoconiosis) is one type of elephantiasis.
4. In which countries are there confirmed or suspected cases of podo? Why focus on Ethiopia?
Podo has been confirmed in eight countries in tropical Africa [1], and is thought to occur in several other countries in the tropics, including in Central America and northern India. The focus on Ethiopia has arisen because of the heavy load of podo – one million people (out of a population of around 80 million) are affected.
5. How many people have podo worldwide?
An estimated 4 million people have podo worldwide.
6. Why have so few people heard of podo?
Podo is truly a disease of the voiceless – it only affects people in rural communities who are too poor to afford shoes. It is also neglected because it is a tropical disease that visitors to the tropics will never develop, unlike, for example, malaria.
7. How much exposure to the soil is required to get podo? Are kids more susceptible for any reason?
Several years’ exposure to irritant soil is needed. Shoe wearing habits during childhood may be particularly important, since the skin of the feet is soft at this age.
8. Can people walk with this disease or is it paralyzing?
People can walk in the early stages of podo, but often feel aching discomfort as they walk. In the later stages of disease, it may become impossible to move because of the weight of the swollen leg.
9. Is the disease curable?
If the disease is treated early, the patient can regain a normal foot and leg if she or he follows a careful, lifelong program of foot hygiene and wears socks and shoes throughout waking hours. Patients with advanced disease show great improvements if they follow the same program, but it may be difficult to get back to a normal-looking foot. The aim for these patients is that the disease is controlled such that they can wear normal shoes, earn a living, and be accepted back into their society.
10. How does podo affect an individual socially and personally?
People with podo are often badly treated in many ways. Children and youth with podo get chased out of school, adults are shunned and find it difficult to participate at church or mosque [7].
11. How effective can shoes be in preventing podo?
Because podo has vanished from parts of the world where irritant soil exists and where shoe wearing is the norm, we assume that shoes are highly effective in preventing podo.
The future of podo
12. Where do you see podo in 5, 10, or 20 years?
If everyone living on irritant soil had access to shoes, podoconiosis could be a thing of the past in only 20 years. This sounds simple, but helping communities understand the importance of shoe wearing, and actually delivering shoes to them are huge tasks.
13. What actions would help podo gain more visibility among health organizations?
Awareness of podo must be increased at every level – affected communities, local organizations, national governments, NGOs, and international bodies. Podo needs not just a stronger scientific basis, but engagement across disciplines, from ethics to literature, law, IT and economics.
References
1. Podoconiosis: non-filarial elephantiasis. Price EW. Oxford Medical Publications, 1990.
2. The association of endemic elephantiasis of the lower legs in East Africa with soil derived from volcanic rocks. Price EW. Trans R Soc Trop Med Hyg 1976; 70, 288-295.
3. Community-based care of a neglected tropical disease: The Mossy Foot Treatment and Prevention Association. Davey G, Burridge E. PLoS NTD 2009;3(5):e424.
4. Prevalence of podoconiosis (non-filarial elephantiasis) in Wolaitta, Southern Ethiopia. Destas K, Ashine M, Davey G. Trop Doc 2003;32:217-220.
5. Wanji S, Tendongfor N, Esum M, Che JN, Mand S, Tanga Mbi C et al. Elephantiasis of non-filarial origin (podoconiosis) in the highlands of north-western Cameroon. Annals of Tropical Medicine & Parasitology 2008;102(6):1-12.
6. Podoconiosis: a tropical model of gene-environment interaction? Davey G, GebreHanna E, Adeyemo A, Rotimi C, Newport M, Desta K. Trans Roy Soc Trop Med Hyg 2007;101:91-96.
7. High levels of misconceptions and stigma in a community highly endemic for podoconiosis in southern Ethiopia. Yakob B, Deribe K, Davey G. Trans Roy Soc Trop Med Hyg. 2008;102:439-444.
8. Economic costs of podoconiosis (non-filarial elephantiasis) in Wolaita Zone, Ethiopia. Tekola F, HaileMariam D, Davey G. Trop Med Int Health 2006;11:1136-1144.
9. Neglected Tropical Diseases in Sub-Saharan Africa: Review of their Prevalence, Distribution and Disease Burden. Hotez PJ, Kamath A. PLoS NTD 2009;3(8):e412.
