Leishmaniasis

  • a parasitic disease that causes damage to the skin, internal organs or mucous membranes
  • infects more than 12 million people worldwide 
  • causes 20,000 to 30,000 deaths each year
  • usually characterized by large outbreaks in densely populated cities, transforming the disease from a sporadic to an epidemic threat

Leishmaniasis is caused by more than 20 species of the protozoan Leishmania parasite, and is transmitted by the bites of infected sand flies.1 Worldwide, 310 million people are at risk of infection. The disease affects the poorest populations on the planet, and is associated with malnutrition, poor housing, a lack of resources and a weak immune system. 

There are three main forms of the disease: visceral (often known as kala-azar), cutaneous and muco-contaneous.2 Visceral leishmaniasis (VL) is the most serious form of the disease. It affects internal organs and is fatal if left untreated. Cutaneous leishmaniasis (CL) is the most common form and causes skin sores, leaving life-long scars and serious disability. Least common is mucocutaneous leishmaniasis, which causes partial or total destruction of mucous membranes of the nose, mouth and throat. 

Over the past decades, global spread of the disease has greatly accelerated  due to VL/HIV co-infection. The two diseases are mutually reinforcing: VL accelerates3 the progression to AIDS, while HIV-infected people are particularly vulnerable to VL. Although VL occurs mostly in India, Nepal, Bangladesh, Sudan and Brazil, it is spreading throughout the Mediterranean,4 including Southern European regions. The World Health Organization (WHO) estimates that there are 2 million new cases annually: 1.5 million cases of CL and 500,000 cases of VL.5 

Only a handful of drugs are available to treat this complex disease. The treatment mainstays remain those first introduced in the 1930s6: pentavalent antimony compounds. However, prolonged treatment is required and, particularly in South Asia, resistance has become widespread.7 Newer treatment options, such as lipid formulations of amphotericin B, are expensive and not widely available in most endemic countries. The PDE4NPD consortium therefore aims to find and develop novel drugs to treat leishmaniasis that are safe, effective and affordable.  
 


References and further reading

  1. Centers for Disease Control and Prevention: Leishmaniasis life cycle
  2. World Health Organization; Leishmaniasis fact sheet
  3. Alvar et al.; The Relationship between Leishmaniasis and AIDS: the Second 10 Years; Clin Microbiol Rev. 2008
  4. Dujardin et al.; Spread of Vector-borne Diseases and Neglect of Leishmaniasis, Europe; Emerg Infect Dis. 2008
  5. World Health Organization; Leishmaniasis – Magnitude of the problem
  6. Medscape; Leishmaniasis Treatment & Management; Pharmacotherapy
  7. Croft et al.; Drug Resistance in leishmaniasis; Clin Microbiol Rev. 2006