THE SCOTTISH ENCOUNTER WITH TROPICAL DISEASE
LEISHMANIASIS The leishmaniases are a family of diseases that are prevalent throughout much of the tropics and sub-tropics; some 88 countries harbour the causative Leishmania parasites with 350 million people at risk of this disease. Leishmania are protozoa, closely related to trypanosomes with which they share many features. Diseases caused by these parasites range from a relatively mild skin ailment to a fatal affliction of the visceral organs. 1. Leishmania flagellated forms (green)
A particularly unpleasant type of leishmaniasis is the mucocutaneous type which occurs in parts of Latin America. A well known TV documentary about “The Boy David” tells the story of how Dr Ian Jackson, a Scottish surgeon, reconstructed the face of David Lopez, a young Peruvian boy afflicted by mucocutaneous leishmaniasis. Around 1.5 million people contract cutaneous disease each year and half a million or so get the visceral disease. Over 90% of the world’s cases are in India, Bangladesh, Nepal, Sudan and Brazil.
The disease has also emerged as a considerable problem in southern Europe associated with the HIV/AIDS epidemic. The parasites are transmitted between mammals by blood sucking sandflies, so called because of their sandy colour. Mammals such as rodents and dogs act as reservoirs of the disease. Drugs do exist to treat leishmaniasis. Antimony, in various forms, has been a mainstay of treatment, although recent advances have enabled a number of safer drugs to emerge, including some frequently used to treat fungal diseases.
Photo credits: 1. Gerald Späth and Stephen Beverley (Washington University’ St. Louis, USA), 2, 4, 5 Mosby International from Peters, W. & Pasvol, G. Tropical Medicine and Parasitology 5th Edition, 3. WHO/TDR
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