|Description:||This micrograph revealed the presence of a single leptomonad-staged, i.e. promastigote, Leishmania sp. protozoan.|
Leishmaniasis, a vector-borne disease that is transmitted by sand flies, and caused by these obligate intracellular protozoa, is a human leishmanial infections, which can result in 2 main forms, “cutaneous” leishmaniasis and “visceral” leishmaniasis (kala-azar). The forms depend upon the leishmanial species, geographic location, and immune response of the host.
Cutaneous leishmaniasis is characterized by one or more cutaneous lesions on areas where sand flies have fed. Patients manifest one or more sores on their skin. The sores can change in size and appearance over time. They often end up looking somewhat like a volcano, with a raised edge and central crater. A scab covers some sores. The sores can be painless or painful. Some people have swollen glands near the sores (for example, in the armpit if the sores are on the arm or hand).
Persons who have visceral leishmaniasis usually have fever, weight loss, and an enlarged spleen and liver (usually the spleen is bigger than the liver), and some have swollen glands. Certain blood tests are abnormal, e.g., patients usually have low blood counts, including a low red blood cell count (anemia), low white blood cell count, and low platelet count. Some develop post kala-azar dermal leishmaniasis. Visceral leishmaniasis is becoming an important opportunistic infection in areas where it coexists with HIV.