Leishmaniasis

Question 1

What is Leishmaniasis?

Answer 1

Leishmaniasis is a vector-borne protozoan disease, also known as leishmaniosis. It is transmitted by the bite of infected female sandflies and is a zoonotic disease, affecting both humans and animals.

Question 2

Which regions of the world are most affected by Leishmaniasis?

Answer 2

It is found in tropical and subtropical regions, notably in Africa, Asia, South America, and the Mediterranean basin.

Question 3

Name the two main genera of sandflies that transmit Leishmaniasis, specifying Old World and New World.

Answer 3

Old World: Phlebotomus spp. New World: Lutzomyia spp.

Question 4

Describe the taxonomic classification of the Leishmania parasite.

Answer 4

Kingdom: Protista; Phylum: Euglenozoa; Class: Kinetoplastea; Order: Trypanosomatida; Genus: Leishmania.

Question 5

List at least four species of Leishmania that cause disease in humans.

Answer 5

Examples include: L. donovani, L. tropica, L. braziliensis, L. mexicana.

Question 6

What are the two morphological forms of Leishmania and where is each found?

Answer 6

1. Promastigote: Found in the sandfly vector; it is flagellated and elongated. 2. Amastigote: Found within macrophages of the vertebrate host; it is non-flagellated and oval.

Question 7

Describe step 1 and 2 of the Leishmania life cycle.

Answer 7

1. An infected female sandfly takes a blood meal and injects promastigotes into the skin. 2. Promastigotes are phagocytosed by macrophages and transform into amastigotes inside the cells.

Question 8

Describe step 3 and 4 of the Leishmania life cycle.

Answer 8

3. Amastigotes multiply by binary fission within the host cells, eventually causing the cell to rupture and release amastigotes to infect new cells. 4. Another sandfly bites the infected host, ingesting amastigotes, which then transform back into promastigotes in the fly’s midgut and migrate to its proboscis.

Question 9

How many countries are considered endemic for Leishmaniasis?

Answer 9

It is endemic in more than 90 countries worldwide.

Question 10

What are the main reservoir hosts for Leishmaniasis?

Answer 10

Dogs, rodents, and humans (for anthroponotic forms, where humans are the primary reservoir).

Question 11

List five risk factors associated with Leishmaniasis infection.

Answer 11

Poverty, malnutrition, deforestation, living in conflict zones, and immunosuppression (e.g., HIV co-infection).

Question 12

What is the average incubation period for Leishmaniasis?

Answer 12

On average, the incubation time is 2 to 3 months.

Question 13

According to a study in Kaduna State, what was the point prevalence of Cutaneous Leishmaniasis among pupils?

Answer 13

The point prevalence was 3.9% among 10,226 pupils, with the highest rate (4.9%) in the 13-15 year-old age group, suggesting the disease is endemic there.

Question 14

What was the reported prevalence of Visceral Leishmaniasis in the Gboko Health Division of Benue State?

Answer 14

The prevalence was 13.5% in females and 12.2% in males.

Question 15

Which age group is at a higher risk for Cutaneous Leishmaniasis and why?

Answer 15

Younger age groups, particularly those aged 13-15 years, are at higher risk, possibly due to increased outdoor activity and exposure to sandfly bites.

Question 16

Name three high-burden countries for Leishmaniasis outside of Nigeria.

Answer 16

Sudan, Ethiopia, Kenya, India, and Brazil are high-burden countries.

Question 17

Which Leishmania species have been reported in northern Nigeria?

Answer 17

L. major and L. donovani have been reported in northern regions of Nigeria.

Question 18

What are the three main clinical forms of Leishmaniasis?

Answer 18

1. Cutaneous Leishmaniasis (CL) 2. Mucocutaneous Leishmaniasis (MCL) 3. Visceral Leishmaniasis (VL)

Question 19

What is the common name for Cutaneous Leishmaniasis and what does it look like?

Answer 19

It is often called an “oriental sore.” It typically presents as a painless skin ulcer with raised edges.

Question 20

Which species commonly cause Cutaneous Leishmaniasis?

Answer 20

L. tropica, L. major, and L. mexicana.

Question 21

What is the key feature of Mucocutaneous Leishmaniasis (MCL)?

Answer 21

It involves the destruction of mucous membranes of the nose, mouth, and throat. It can appear months or years after the initial skin lesion has healed.

Question 22

Which Leishmania species complex causes Mucocutaneous Leishmaniasis?

Answer 22

It is caused by the L. braziliensis complex.

Question 23

What is the common name for Visceral Leishmaniasis?

Answer 23

It is known as “Kala-azar.”

Question 24

What are the primary symptoms of Visceral Leishmaniasis (Kala-azar)?

Answer 24

Prolonged fever, weight loss, hepatosplenomegaly (enlarged liver and spleen), and anemia. It is fatal if left untreated.

Question 25

Which species cause Visceral Leishmaniasis?

Answer 25

L. donovani, L. infantum, and L. chagasi.

Question 26

What is Post-kala-azar dermal leishmaniasis (PKDL)?

Answer 26

A condition that can occur after apparent recovery from Visceral Leishmaniasis, characterized by macular, maculopapular, or nodular rash, often on the face.

Question 27

Name four laboratory methods used to diagnose Leishmaniasis.

Answer 27

1. Microscopy 2. Culture 3. Serology 4. Molecular methods (PCR)

Question 28

What is the primary microscopic finding for diagnosing Leishmaniasis?

Answer 28

Visualization of amastigotes (Leishman-Donovan bodies) in Giemsa-stained smears from spleen, bone marrow, or skin lesions.

Question 29

What culture medium is commonly used to grow promastigotes?

Answer 29

NNN medium (Novy-MacNeal-Nicolle medium).

Question 30

Name three serological tests used for Leishmaniasis diagnosis.

Answer 30

rk39 dipstick test, IFAT (Indirect Fluorescent Antibody Test), and ELISA.

Question 31

What is the first-line treatment for most forms of Leishmaniasis?

Answer 31

Pentavalent antimonials, such as Sodium Stibogluconate.

Question 32

List four alternative drugs used to treat Leishmaniasis.

Answer 32

Amphotericin B, Miltefosine, Paromomycin, and Pentamidine.

Question 33

What are the major challenges in the treatment of Leishmaniasis?

Answer 33

Drug resistance, drug toxicity, and the potential for relapse.

Question 34

Name four key strategies for the prevention and control of Leishmaniasis.

Answer 34

1. Vector control (insecticide spraying, insecticide-treated bed nets) 2. Reservoir control (e.g., dog culling or vaccination) 3. Health education and surveillance 4. Early diagnosis and prompt treatment.

Question 35

Is there a widely available, effective human vaccine for Leishmaniasis?

Answer 35

No, there is no effective human vaccine available yet, though research is ongoing.