August 19 - Leishmania tropica

"Baghdad Boil"..."Jericho buttons"..."Oriental sore" - these are the common names for a rather nasty infection called cutaneous leishmaniasis by one of several species of Leishmania, including Leishmania tropica. These parasites are single-celled eukaryotes called kinetoplasts, related to trypanosomes such as Tryanosoma brucei and Trypanosoma evansi. L. tropica and its kin are vectored by sandflies and are transmitted when these insects take bloodmeals from humans and other mammals. These nasty little buggers are not afraid of the vertebrate immune system, either - oh no - they go right for the macrophages themselves and invade these cells. The infection causes really disgusting sores on the skin that will not heal and which can become sites for secondary infections. Treating these parasites is itself a very risky venture, as the most commonly used drugs are those containing antimony, which is a heavy metal; new drugs are being developed, however. If you've got a strong stomach, do an image search for "cutaneous leishmaniasis"...but don't say I didn't warn you.