Life cycle Leishmania spp. Flashcards
What is the classification of Leishmania spp.?
Intracellular protozoa in the category flagellates
How is leishmania spp transmitted?
Blood meal of a sandfly on a human host
What are the life cycle steps of leishmania spp. in the human host?
- Infected sandfly bites the host takes a bloodmeal and injects promastigote stage into the skin. This is the infective stage of Leishmania
- Promastigotes which are flagellated are phagocytized by macrophages or other types of mononuclear phagocytic cells. A phagocyte is an immune cell that specializes in ingulfing and destroying foreign particles. A phagolysosome is a cytoplasmic structure inside the phagocytes that possesses several degradative properties such as a low pH.
- Promastigotes can not survive in the harsh environment of the lysosomes so they differentiate into amastigotes form. This is the tissue stage and are non-flagellated. Promastigotes and amastigotes differ in cell membrane. The amastigotes cell membrane allows it to survive the harsh environment of the phagolysosomes.
- Amastigotes multiply by asexual replication in cells of various tissues and infect other cells
What are the lifecycle steps of Leishmania spp. in the sandfly?
- When a sandfly takes another blood meal it ingests macrophages infected with amastigotes.
- Through the ingested macrophages the sandfly has ingested a parasitized cell
- Amastigotes transform into promastigote stages in the gut of the sandfly.
- These cells will develop and divide further in the gut and migrate to the proboscis of the sandfly
- The life cycle starts all over again
What type of life cycle does Leismania spp. have?
Indirect life cycle
What is the definitive and or intermediate host of leismania spp?
Both Human and Sandfly are intermediate hosts
Can Leismania spp. survive without the host?
It’s an obligated parasite so it’s unable to survive without the host
What are reservoirs of Leishmania spp?
Humans. Or small rodents, dogs, gerbils. Can become chronic parasite that helps the parasite survive within them.
What causes Leismania infection to have symptoms and what is the incubation time?
The parasite resides in macrophages or mononuclear phagocytic cells. Amastigotes can multiply here and rapture the cell or infect other macrophages. This causes immunodeficiency and can cause to death.
Incubation time is between 2 weeks to 6 months or even years
What types of clinical outcomes are caused by leismania?
Cutaneous leishmaniasis in the skin
Visceral leishmaniasis in the organs
Muccosal leishmaniasis in the mucous membranes
What are the symptoms of visceral leismaniasis?
fever, weight loss and enlarged spleen and liver. Some patients have swollen glands and certain blood tests are abnormal
95% mortality rate
Which species of Leismania cause cutaneous leishmaniasis?
L. Major
L. Tropica
Which species of Leismania cause visceral leishmaniasis?
L. Infantum
L. Donovani
What species of Leismania causes mucosal leishmaniasis?
L. Braziliensis
L. aethiopica
Where is visceral leishmaniasis mostly found?
India Bangladesh Nepal Sudan Brazil
