Leishmania spp.

Question 1

What is the classification of the Leishmania spp. parasite?

Answer 1

obligate intracellular protozoa category flagellates

Question 2

How is Leishmania spp. transmitted

Answer 2

Mainly
- By the infected female phlebotomine sand fly

Other possibilities:

• Contaminated needles
• Blood transfusion
• Congenital transmission

Question 3

Can Leishmania spp. survive outside the host?

Answer 3

No, it is an obligate parasite

Question 4

What is the life cycle of Leishmania spp.?

Answer 4

1. Infected sandfly takes a blood meal and injects promastigote stage into the skin
2. Promastigotes (flagellated) are phagocytized by macrophages/ mononuclear phagocytic cells
3. Promastigotes differentiate into amastigotes (non flagellated)
4. Amastigotes multiply by asexual reproduction in various tissue and infect other cells
5. Sandfly takes a blood meal and ingests macrophages infected with amastigotes
6. Amastigotes transform into promastigote stages in the gut of the sandfly and migrate to the proboscis of the sandfly

Question 5

What type of life cycle has Leishmania spp.

Answer 5

Indirect, it needs two hosts to complete its life cycle (sandfly and mammal). Both these hosts are intermediate as there is only asexual reproduction.

Question 6

What are reservoirs of Leishmania spp. and how does this benefit the parasite?

Answer 6

Humans or small rodents, dogs, gerbils. They can become chronic carriers which enable the parasite to survive within them.

Question 7

What is the incubation time of Leishmania spp.

Answer 7

between 2 weeks to 6 months or even years

Question 8

What is the infective stage of Leishmania spp

Answer 8

the promastigote stage

Question 9

Leishmania spp is intracellular, in which cells does it reside?

Answer 9

macrophages or mononuclear phagocytic cells

Question 10

What are the symptoms of infection

Answer 10

Cutaneous leishmaniasis (skin)

• caused by L. major and L. tropica
• causes skin sores
• develop within a few weeks after bite sandfly

Mucous membranes

• caused by L. braziliensis and L. aethiopica
• sores in the mucous membrane (nose, mouth, or throat)

Visceral Leishmaniasis (systematic Leishmaniasis/ Kala azar)

• caused by L. infantum and L. donovani
• affects several internal organs
• develops within months
• if not treated - fetal

Question 11

Where is Leishmania spp endemic?

Answer 11

Tropics and subtropics
- rain forest in central & south America to deserts in West Asia

Visceral Leishmaniasis is usually found in: India, Bangladesh, Nepal, Sudan, and Brazil

Question 12

Which stage of Leishmania spp. is diagnosed?

Answer 12

Amastigotes

Question 13

How can Leishmania spp. be diagnosed?

Answer 13

Microscopy
- tissue specimens by visualising amastigotes
Serology
- antibody detection
Molecular diagnosis (PCR)
-DNA of the parasite is examined (very sensitive, but complicated and expensive)
rK39 rapid diagnostic test against K39 antign