53 Questions
What is the geographical distribution of Old World leishmaniasis?
Africa and Asia
What is the natural reservoir host for Leishmania?
Dogs
What are the two known stages in the life cycle of Leishmania?
Amastigote and Promastigote
How do promastigotes enter the human host?
Through a sandfly bite
Why is the Leishmanin test negative in active cases of kala-azar?
Due to impaired cell-mediated immunity in active kala-azar patients.
How can a diagnosis of PKDL (post-kala-azar dermal leishmaniasis) be established?
Demonstration of amastigote form of L. donovani by a microscope.
Which type of leishmaniasis causes both skin and mucosal ulcers primarily affecting the nose and mouth?
Mucocutaneous leishmaniasis
What is the pathogenesis of New World leishmaniasis caused by L. braziliensis and L. mexicana?
Intracellular replication inside macrophages of the skin and mucous membrane.
What is one recommended method for preventing leishmaniasis?
Using insecticides to kill sandflies.
Why do most vaccine trials for leishmaniasis not provide effective protection?
Because they trigger only a humoral immune response.
What is the main habitat for Leishmania in cutaneous leishmaniasis?
Macrophage cells
Which form of leishmaniasis is known as black fever and is associated with high fatality?
Visceral leishmaniasis
What is a common risk factor for developing Leishmaniasis?
Malnutrition
What leads to the progressive enlargement of organs in visceral leishmaniasis?
Spread of the parasite to reticuloendothelial cells
Which diagnostic method for leishmaniasis involves delayed-type hypersensitivity reaction to intradermal crude Leishmania antigen?
Leishmanin skin test
What causes an open sore at bite sites in cutaneous leishmaniasis?
Intracellular replication in skin cells
Which form of leishmaniasis may resemble leprosy due to widespread skin lesions?
Diffuse cutaneous leishmaniasis
What is the main method of transmission for Old World leishmaniasis?
By the bite of sandflies in the Phlebotomus genus
Which stage of Leishmania is known for its spindle shape with a flagellum?
Promastigote
What distinguishes New World leishmaniasis from Old World leishmaniasis in terms of sandfly genera?
Transmitted by Lutzomyia and Psychodopygus sandflies
Which host is NOT a natural reservoir for Leishmania?
Cats
What is the primary mode of feeding for adult female sandflies?
Feeding on blood, usually at night
How do promastigotes of Leishmania reproduce in the sandfly vector?
Asexually in the alimentary canal
Where do promastigotes reside in the sandfly?
Alimentary canal
What happens to promastigotes when the sandfly bites a reservoir host or an infected person?
They transform into amastigotes in the skin
In which region of the world is New World leishmaniasis mainly found?
The Americas
What is the main habitat for Leishmania in visceral leishmaniasis?
Bone marrow cells
What type of shape does an amastigote of Leishmania usually have?
Spherical or subspherical
What symptom is NOT typically associated with visceral leishmaniasis?
Jaundice
What is the pathogen that causes Leishmaniasis disease?
Protozoa
Which parasite causes cutaneous leishmaniasis resembling leprosy?
Leishmania tropica
What is the primary time frame when adult female sandflies feed?
At night
What leads to the breakdown of the host cell in leishmaniasis?
Pressure from mass multiplication
Which form of leishmaniasis is NOT associated with skin changes?
Visceral leishmaniasis
What is the most common form of Old World leishmaniasis?
Cutaneous leishmaniasis (oriental sore)
What is the diagnosis method that involves a skin scraping with microscopic analysis using Wright or Giemsa stain?
$Parasitological$ diagnosis
What symptom may develop at the site of the bite in cutaneous leishmaniasis?
$Ulcer$
Which form of leishmaniasis is known as black fever?
$Visceral$ leishmaniasis
"Post kala-azar dermal leishmaniasis" (PKDL) manifests as what type of skin lesions?
$Measle-like lesions$
What is NOT a common risk factor for Leishmaniasis?
High altitude
What is one way to diagnose Leishmaniasis involving Serological testing?
Blood count and haemoglobin test
Why does the Leishmanin test show a negative result in active cases of kala-azar?
Impaired cell-mediated immunity
What is the primary cause of damage in New World leishmaniasis - Mucocutaneous leishmaniasis?
Skin and mucosal ulcers
What is the main habitat of Leishmania parasites in cutaneous leishmaniasis?
Inside macrophages of the skin and mucous membrane
Which drug may be used as a treatment for cutaneous leishmaniasis?
Fluconazole
What can cause an open sore at the site of a sandfly bite in leishmaniasis?
Presence of amastigote forms in the skin
In New World leishmaniasis, which part of the body is primarily affected by tissue damage?
Nose and mouth
What type of immunity is crucial for controlling Leishmania parasites in the human body?
Cell-mediated immunity
How can leishmaniasis be partly prevented?
Using insecticide-treated nets
Which diagnostic method is used for visceral leishmaniasis?
Delayed-type hypersensitivity reaction
What is a characteristic feature of PKDL (post-kala-azar dermal leishmaniasis)?
Demonstration of amastigote forms in biopsy material
What is a primary treatment option for visceral leishmaniasis?
Liposomal amphotericin B
What causes reappearing lesions elsewhere after healing in cutaneous leishmaniasis?
Replication and spread of Leishmania parasites
Study Notes
Geographical Distribution and Natural Reservoir
- Old World leishmaniasis is found in the Old World, including Africa, Asia, and Europe
- The natural reservoir host for Leishmania is animals and humans
Life Cycle of Leishmania
- The two known stages in the life cycle of Leishmania are:
- Amastigote stage: occurs within host cells
- Promastigote stage: occurs in the sandfly vector
Transmission and Entry into Human Host
- Promastigotes enter the human host through the bite of an infected sandfly
- Sandflies become infected by feeding on the blood of infected animals or humans
Diagnosis and Testing
- The Leishmanin test is negative in active cases of kala-azar due to immunological tolerance
- Diagnosis of PKDL (post-kala-azar dermal leishmaniasis) can be established through biopsy and histopathology
- The Montenegro skin test is used to diagnose leishmaniasis and involves a delayed-type hypersensitivity reaction to intradermal crude Leishmania antigen
Types of Leishmaniasis
- Cutaneous leishmaniasis causes skin ulcers and is primarily caused by L. major and L. tropica
- Mucocutaneous leishmaniasis causes both skin and mucosal ulcers, primarily affecting the nose and mouth, and is caused by L. braziliensis and L. mexicana
- Visceral leishmaniasis, also known as kala-azar, causes progressive enlargement of organs and is caused by L. donovani
- PKDL (post-kala-azar dermal leishmaniasis) manifests as hypopigmented skin lesions
Prevention and Treatment
- One recommended method for preventing leishmaniasis is using insecticide-treated bed nets
- Most vaccine trials for leishmaniasis do not provide effective protection due to variation in parasite strains and lack of correlates of protection
- Treatment options for leishmaniasis include antimonial compounds, amphotericin B, and miltefosine
Vector and Habitat
- The main habitat for Leishmania in cutaneous leishmaniasis is the skin
- The main habitat for Leishmania in visceral leishmaniasis is the spleen, liver, and bone marrow
- Adult female sandflies are the primary vectors of Leishmania transmission
- Sandflies primarily feed on blood at night
Explore the differences between Old World and New World Leishmaniasis, caused by different species of Leishmania and transmitted by distinct types of sandflies. Learn about the geographical distribution and transmission methods of this parasitic disease.
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