1. Strep or Sore Throat Slideshow Pictures
2. Take the MRSA Quiz!
3. Infectious Mononucleosis Slideshow Pictures

Medical Author:

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.

View Full Profile

Medical Editor:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

View Full Profile

In this Article

• Leishmaniasis facts
• What is leishmaniasis?
• What are the different types of leishmaniasis?
• What causes leishmaniasis? How is leishmaniasis transmitted?
• What are risk factors for leishmaniasis?
• What are leishmaniasis symptoms and signs?
• How is leishmaniasis diagnosed?
• What is the treatment for leishmaniasis?
• What is the prognosis of leishmaniasis?
• Can leishmaniasis be prevented?
• Where can people get more information about leishmaniasis?
• Leishmaniasis Index

Leishmaniasis is divided into clinical syndromes according to what part of the body is affected most. In visceral leishmaniasis (VL), the parasite affects the organs of the body. Infections from India, Bangladesh, Nepal, Sudan, Ethiopia, and Brazil account for 90% of cases of VL. Cutaneous leishmaniasis (CL) is the most common form of leishmaniasis and, as the name implies, the skin is the predominate site of infection. Over 90% of cases of CL are acquired in Afghanistan, Algeria, Iran, Saudi Arabia, Syria, Brazil, Colombia, Peru, or Bolivia. Less commonly, cases are reported from other countries including southern Europe. Of note, U.S. troops stationed in Iraq and Afghanistan have acquired CL. Very rarely, isolated cases have been reported from border states like Texas. In some people, CL progresses to involve the mucocutaneous membranes, a condition known as mucocutaneous leishmaniasis (ML). Mucocutaneous leishmaniasis occurs only in the New World and is most common in Bolivia, Brazil, and Peru.

Leishmaniasis is caused by protozoal parasites from the Leishmania species. The organisms are microscopic in size. There are about 21 species of Leishmania that affect humans, including the L. donovani complex and the L. Mexicana complex, among others. The life cycle is relatively simple. When the sand fly bites a human, it injects small numbers of parasites which are rapidly taken up by mononuclear blood cells. This stage is called the promastigote stage. Once inside the human mononuclear cells, the parasite enters the amastigote stage and begins to multiply and infect other cells and tissues. Uninfected sand flies acquire the parasite by feeding on infected people or infected animals such as dogs, foxes, or rodents.

Figure 2: Life cycle of Leishmania

Less commonly, parasites may be transmitted by blood transfusion or through drug users sharing contaminated needles. Leishmania may also be transmitted from a pregnant mother to her fetus.