Leishmania Parasite

Question 1

Life cycle

Answer 1

1. Sandfly takes a blood meal in which it injects the promastigote stage into the skin.
2. Promastigotes are phagocytized by macrophages or other types of mononuclear phagocytic cells.
3. Promastigotes transform into amastigotes.
4. Amastigotes multiply in cells of various tissues and infect other cells.
5. Sandfly take a blood meal in which it ingests macrophages infected with amastigotes.
6. Ingestion of parasitized cell
7. Amastigotes transform into promastigote stage in the gut.
8. Divide in the gut and migrate to proboscis

Question 2

Vectors

Answer 2

Sand flies are the vectors for Leishmania as well as some bacterial (bartonellosis) and viral (sand fly fever) diseases.

Question 3

Control

Answer 3

Vector control is difficult and rely on personal protection by Insecticide
impregnated bednets and repellents

Question 4

Etiological Agents

Answer 4

Cutaneous: L. mexicana complex, L. tropica, L. mjor

Mucocutaneous: L. braziliensis

Question 5

Diagnosis

Answer 5

Diagnosis is based on clinical examination and demonstration of parasites in lymph and bone marrow smears or spleen biopsies.

Serological methods, such as rK39 and DAT are useful in diagnosis

Treatment by Pentostam (Sodium Stibogluconate) and Miltefosine.

Question 6

Signs and Symptoms

Answer 6

Therefore, cell mediated immunity (manifested through certain cytokines) is
the effective immune response that can cure or protect against the
infection. This is called TH1.

Humoral immune response called TH2 (manifested through antibodies) has
little effect on the parasite

Morphologically identical Leishmania parasites result in diverse clinical
manifestations that range from self-healing cutaneious lesions fatal visceral
disease.

Variations in human immune response to different Leishmania species is still
awaiting description

Treatment of visceral leishmaniasis can lead to a dermatosis known as Post-
Kala azar Dermal leishmaniasis

Question 7

Type of parastie

Answer 7

Heteroxenous

Question 8

Cutaneous leishmaniasis

Answer 8

Cutaneous leishmaniasis (CL) is the most common manifestation of the disease and is characterized by benign self-healing lesions that are generally painless and non-pruritic.

Question 9

Mucocutaneous leishmaniasis

Answer 9

mucocutaneous leishmaniasis (MCL). This manifestation is primarily due to members of the L. braziliensis complex. Mucocutaneous disease begins as simple skin lesions that metastasize via the blood stream or lymphatics, particularly to the mucosae of the nose and mouth.