Leishmania is a parasitic protozoan, a single-celled organism of the genus Leishmania that is responsible for the disease leishmaniasis. They are spread by sandflies of the genus Phlebotomus in the Old World, and of the genus Lutzomyia in the New World. At least 93 sandfly species are proven or probable vectors worldwide. Their primary hosts are vertebrates; Leishmania commonly infects hyraxes, canids, rodents, and humans.
African trypanosomiasis is an insect-borne parasitic infection of humans and other animals.
Leishmaniasis is a wide array of clinical manifestations caused by protozoal parasites of the Trypanosomatida genus Leishmania. It is generally spread through the bite of phlebotomine sandflies, Phlebotomus and Lutzomyia, and occurs most frequently in the tropics and sub-tropics of Africa, Asia, the Americas, and southern Europe. The disease can present in three main ways: cutaneous, mucocutaneous, or visceral. The cutaneous form presents with skin ulcers, while the mucocutaneous form presents with ulcers of the skin, mouth, and nose. The visceral form starts with skin ulcers and later presents with fever, low red blood cell count, and enlarged spleen and liver.
Trypanothione is an unusual form of glutathione containing two molecules of glutathione joined by a spermidine (polyamine) linker. It is found in parasitic protozoa such as leishmania and trypanosomes. These protozoal parasites are the cause of leishmaniasis, sleeping sickness and Chagas' disease. Trypanothione was discovered by Alan Fairlamb. Its structure was proven by chemical synthesis. It is present mainly in the Kinetoplastida but can be found in other parasitic protozoa such as Entamoeba histolytica. Since this thiol is absent from humans and is essential for the survival of the parasites, the enzymes that make and use this molecule are targets for the development of new drugs to treat these diseases.
Melarsoprol is an arsenic-containing medication used for the treatment of sleeping sickness. It is specifically used for second-stage disease caused by Trypanosoma brucei rhodesiense when the central nervous system is involved. For Trypanosoma brucei gambiense, eflornithine or fexinidazole is usually preferred. It is effective in about 95% of people. It is given by injection into a vein.
Cutaneous leishmaniasis is the most common form of leishmaniasis affecting humans. It is a skin infection caused by a single-celled parasite that is transmitted by the bite of a phlebotomine sand fly. There are about thirty species of Leishmania that may cause cutaneous leishmaniasis.
Visceral leishmaniasis (VL), also known as kala-azar or "black fever", is the most severe form of leishmaniasis and, without proper diagnosis and treatment, is associated with high fatality. Leishmaniasis is a disease caused by protozoan parasites of the genus Leishmania.
Glutathione reductase (GR) also known as glutathione-disulfide reductase (GSR) is an enzyme that in humans is encoded by the GSR gene. Glutathione reductase catalyzes the reduction of glutathione disulfide (GSSG) to the sulfhydryl form glutathione (GSH), which is a critical molecule in resisting oxidative stress and maintaining the reducing environment of the cell. Glutathione reductase functions as dimeric disulfide oxidoreductase and utilizes an FAD prosthetic group and NADPH to reduce one molar equivalent of GSSG to two molar equivalents of GSH:
Miltefosine, sold under the trade name Impavido among others, is a medication mainly used to treat leishmaniasis and free-living amoeba infections such as Naegleria fowleri and Balamuthia mandrillaris. This includes the three forms of leishmaniasis: cutaneous, visceral and mucosal. It may be used with liposomal amphotericin B or paromomycin. It is taken by mouth.
Leishmania major is a species of parasite found in the genus Leishmania, and is associated with the disease zoonotic cutaneous leishmaniasis. L. major is an intracellular pathogen which infects the macrophages and dendritic cells of the immune system. Though Leishmania species are found on every continent aside from Antarctica, Leishmania major is found only in the Eastern Hemisphere, specifically in Northern Africa, the Middle East, Northwestern China, and Northwestern India.
In enzymology, a trypanothione-disulfide reductase (EC 1.8.1.12) is an enzyme that catalyzes the chemical reaction
In enzymology, a trypanothione synthase (EC 6.3.1.9) is an enzyme that catalyzes the chemical reaction
Canine leishmaniasis (LEESH-ma-NIGH-ah-sis) is a zoonotic disease caused by Leishmania parasites transmitted by the bite of an infected phlebotomine sandfly. There have been no documented cases of leishmaniasis transmission from dogs to humans. Canine leishmaniasis was first identified in Europe in 1903, and in 1940, 40% of all dogs in Rome were determined to be positive for leishmaniasis. Traditionally thought of as a disease only found near the Mediterranean basin, 2008 research claims new findings are evidence that canine leishmaniasis is currently expanding in continental climate areas of northwestern Italy, far from the recognized disease-endemic areas along the Mediterranean coasts. Cases of leishmaniasis began appearing in North America in 2000, and, as of 2008, Leishmania-positive foxhounds have been reported in 22 U.S. states and two Canadian provinces.
Leishmania donovani is a species of intracellular parasites belonging to the genus Leishmania, a group of haemoflagellate kinetoplastids that cause the disease leishmaniasis. It is a human blood parasite responsible for visceral leishmaniasis or kala-azar, the most severe form of leishmaniasis. It infects the mononuclear phagocyte system including spleen, liver and bone marrow. Infection is transmitted by species of sandfly belonging to the genus Phlebotomus in Old World and Lutzomyia in New World. The species complex it represents is prevalent throughout tropical and temperate regions including Africa, China, India, Nepal, southern Europe, Russia and South America. The species complex is responsible for thousands of deaths every year and has spread to 88 countries, with 350 million people at constant risk of infection and 0.5 million new cases in a year.
Leishmania tropica is a flagellate parasite and the cause of anthroponotic cutaneous leishmaniasis in humans. This parasite is restricted to Afro-Eurasia and is a common cause of infection in Afghanistan, Iran, Syria, Yemen, Algeria, Morocco, and northern India.
Leishmania braziliensis is a Leishmania species found in South America. It is associated with leishmaniasis.
Post-kala-azar dermal leishmaniasis (PKDL) is a complication of visceral leishmaniasis (VL); it is characterised by a macular, maculopapular, and nodular rash in a patient who has recovered from VL and who is otherwise well. The rash usually starts around the mouth from where it spreads to other parts of the body depending on severity.
Fexinidazole is a medication used to treat African trypanosomiasis caused by Trypanosoma brucei gambiense. It is effective against both first and second stage disease. Also a potential new treatment for Chagas disease, a neglected tropical disease that affects millions of people worldwide. It is taken by mouth.
A Leishmaniasis vaccine is a vaccine which would prevent leishmaniasis. As of 2017, no vaccine for humans was available. Currently some effective leishmaniasis vaccines for dogs exist.
David Horn FRSE, is a Welcome Trust Senior Investigator, professor of parasite molecular biology, deputy head of the Division of Biological Chemistry and Drug Discovery and deputy director of the Welcome Trust Centre for Anti-Infectives Research in the School of Life Sciences, University of Dundee. His research is focused on antigenic variation, drug action and resistance and the application of genetic screens to African trypanosomes: parasitic protists that cause sleeping sickness or Human African Trypanosomiasis (HAT) and the livestock disease, nagana.
