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Questions and Answers
What is one of the primary classifications of leishmaniasis that affects visceral tissues?
What is one of the primary classifications of leishmaniasis that affects visceral tissues?
What symptom was notably observed in the case scenario of the 20-year-old Indian male?
What symptom was notably observed in the case scenario of the 20-year-old Indian male?
Which haematological finding was presented in the case scenario that indicates a problem with blood components?
Which haematological finding was presented in the case scenario that indicates a problem with blood components?
What is the geographical distribution characteristic of Old World visceral leishmaniasis?
What is the geographical distribution characteristic of Old World visceral leishmaniasis?
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Which of the following is least likely to be a characteristic of Leishmania spp. causing visceral leishmaniasis?
Which of the following is least likely to be a characteristic of Leishmania spp. causing visceral leishmaniasis?
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Which organism is primarily responsible for causing visceral leishmaniasis in the New World?
Which organism is primarily responsible for causing visceral leishmaniasis in the New World?
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What is the most significant pathological examination finding in the patient's bone marrow?
What is the most significant pathological examination finding in the patient's bone marrow?
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Which of the following is not a typical manifestation of visceral leishmaniasis?
Which of the following is not a typical manifestation of visceral leishmaniasis?
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How do amastigotes transform into promastigotes in sand flies?
How do amastigotes transform into promastigotes in sand flies?
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Which condition increases the risk of severe visceral leishmaniasis?
Which condition increases the risk of severe visceral leishmaniasis?
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What effect do amastigotes have on fixed macrophages?
What effect do amastigotes have on fixed macrophages?
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What condition is characterized by the infiltration of the bone marrow with parasitized macrophages?
What condition is characterized by the infiltration of the bone marrow with parasitized macrophages?
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What leads to ulceration in the intestinal mucosa during leishmaniasis?
What leads to ulceration in the intestinal mucosa during leishmaniasis?
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What type of anemia occurs due to a lack of iron absorption in kala-azar?
What type of anemia occurs due to a lack of iron absorption in kala-azar?
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What is a notable symptom of visceral leishmaniasis during its clinical presentation?
What is a notable symptom of visceral leishmaniasis during its clinical presentation?
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In which organ system do amastigotes lead to significant symptoms such as hepatosplenomegaly?
In which organ system do amastigotes lead to significant symptoms such as hepatosplenomegaly?
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What is the purpose of the Leishmanin skin test (Montenegro test)?
What is the purpose of the Leishmanin skin test (Montenegro test)?
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Which method is NOT used for the indirect immunological diagnosis of Leishmania?
Which method is NOT used for the indirect immunological diagnosis of Leishmania?
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What is a characteristic finding in smears from positive cases following animal inoculation?
What is a characteristic finding in smears from positive cases following animal inoculation?
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What condition is indicated by hypergammaglobulinemia and low albumin levels in the blood picture for Leishmania?
What condition is indicated by hypergammaglobulinemia and low albumin levels in the blood picture for Leishmania?
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After how long is the Leishmanin skin test considered positive after an individual has been cured from Leishmania?
After how long is the Leishmanin skin test considered positive after an individual has been cured from Leishmania?
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Which stain is NOT typically used for smears of body fluids in Leishmania diagnosis?
Which stain is NOT typically used for smears of body fluids in Leishmania diagnosis?
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What is a key feature seen in promastigotes when cultured on Novy-MacNeal-Nicolle (NNN) medium?
What is a key feature seen in promastigotes when cultured on Novy-MacNeal-Nicolle (NNN) medium?
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What is the primary treatment of choice for systemic therapy of Leishmania infection?
What is the primary treatment of choice for systemic therapy of Leishmania infection?
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What is the preferred habitat for Leishmania species in the human body?
What is the preferred habitat for Leishmania species in the human body?
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Which of the following accurately describes the Promastigote form of Leishmania?
Which of the following accurately describes the Promastigote form of Leishmania?
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What mechanism allows Leishmania to infect the human body?
What mechanism allows Leishmania to infect the human body?
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Which of the following is NOT a reservoir host for Leishmania?
Which of the following is NOT a reservoir host for Leishmania?
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What happens after Promastigotes are inoculated into the skin during a sand fly's blood meal?
What happens after Promastigotes are inoculated into the skin during a sand fly's blood meal?
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Which life cycle stage is responsible for the transmission of Leishmania from the insect vector to the human host?
Which life cycle stage is responsible for the transmission of Leishmania from the insect vector to the human host?
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What type of infection mode can occur through nasal secretions during epidemics?
What type of infection mode can occur through nasal secretions during epidemics?
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Which of the following is a common feature of the life cycle of Leishmania in sand fly insects?
Which of the following is a common feature of the life cycle of Leishmania in sand fly insects?
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What is the most fatal complication associated with visceral leishmaniasis (VL)?
What is the most fatal complication associated with visceral leishmaniasis (VL)?
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What type of lesions are characteristic of Post-Kala Azar Dermal Leishmaniasis (PKDL)?
What type of lesions are characteristic of Post-Kala Azar Dermal Leishmaniasis (PKDL)?
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What is the main clinical feature to suspect kala azar in endemic areas?
What is the main clinical feature to suspect kala azar in endemic areas?
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In Para-Kala Azar Dermal Leishmaniasis (Para-KDL), which symptoms are typically present?
In Para-Kala Azar Dermal Leishmaniasis (Para-KDL), which symptoms are typically present?
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Which lab method is used to directly detect amastigotes in suspected visceral leishmaniasis cases?
Which lab method is used to directly detect amastigotes in suspected visceral leishmaniasis cases?
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Which of the following symptoms is NOT typically associated with visceral leishmaniasis?
Which of the following symptoms is NOT typically associated with visceral leishmaniasis?
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How long after treatment can Post-Kala Azar Dermal Leishmaniasis (PKDL) occur?
How long after treatment can Post-Kala Azar Dermal Leishmaniasis (PKDL) occur?
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What causes fever in visceral leishmaniasis patients?
What causes fever in visceral leishmaniasis patients?
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Study Notes
Visceral Leishmaniasis
- Visceral leishmaniasis (VL), also known as kala azar or black fever, is a deadly parasitic disease caused by Leishmania donovani complex.
- The parasite is transmitted through the bite of infected female sandflies.
- Leishmania is an insect-transmitted protozoa that infects the blood and tissues of humans and reservoir hosts.
- VL is the second most deadliest parasitic disease following malaria.
- There are three principle species of Leishmania:
- **L. donovani **, responsible for Old World VL, found in India, Pakistan, Indonesia, Thailand, Ethiopia, East and Central Africa, Mediterranean areas, the Middle East and China.
- **L. infantum **, also responsible for Old World VL, found in Mediterranean areas, the Middle East and China
- **L. chagasi **, responsible for New World VL, found in Central and South America.
Morphology
- Leishmania exists in two forms:
- Amastigote: The round, non-motile form, found inside macrophages.
- Promastigote: The elongated, motile form, found inside the sandfly vector and in culture.
Life cycle
-
Human and Reservoir hosts:
- The parasite enters the body through a sandfly bite.
- The promastigotes transform into amastigotes within macrophages.
- Amastigotes multiply by binary fission, causing destruction of the host's cells.
- Parasitized macrophages travel throughout the body leading to generalized infection.
-
Sandfly Insect:
- Amastigotes are ingested by the sandfly during a blood meal.
- Amastigotes transform into promastigotes inside the insect's gut.
- Promastigotes multiply by binary fission.
- Promastigotes migrate to the sandfly's mouth ready to be transmitted.
Pathogenicity
- VL is an opportunistic infection, where the risk of severe disease is heightened in patients who are immunocompromised, have a low protein diet, and have deficiencies in iron, vitamin A, and zinc.
- Amastigotes multiply within macrophages, leading to enlargement and destruction of these cells.
- Infected macrophages spread to various organs, including the liver, spleen, and lymph nodes, leading to hepato-splenomegaly and lymphadenopathy.
- The bone marrow is heavily infiltrated with parasitized macrophages, resulting in pancytopenia (decreased red blood cells, white blood cells, and platelets).
Clinical Picture
- Incubation Period: 2-6 months.
- Fever is a common symptom, often remittent.
- Hepatosplenomegaly is a hallmark of the disease.
- Other symptoms include: fatigue, weight loss, anemia, emaciation, lymphadenopathy, diarrhea, dysentery, and epistaxis (nosebleeds).
Complications
- Disseminated Intravascular Coagulation (DIC) is the most fatal complication.
- Thrombocytopenia can lead to spontaneous bleeding from the nose and mouth.
- Pancytopenia occurs due to the suppressive effects of the infection on bone marrow, splenic sequestration, and hemolysis.
- Lymphoid macrophages are heavily infiltrated with parasites, leading to ulceration of the intestinal mucosa and the presence of Leishman-Donovan bodies in feces.
- The urinary tract can be infiltrated with parasitized macrophages, leading to mucosal breakdown and the presence of Leishman-Donovan bodies in urine.
Post-Kala Azar Dermal Leishmaniasis (PKDL)
- A chronic, progressive, granulomatous, non-ulcerating, hypopigmented nodular cutaneous lesion that can develop 6 months to 5 years after treatment for kala-azar.
- Characterized by persistent skin papules, especially on the face, resembling lepromatous leprosy or disseminated cutaneous leishmaniasis.
Para-Kala Azar Dermal Leishmaniasis (Para-KDL)
- A condition where PKDL occurs while a patient is still undergoing treatment for VL.
- Characterized by fever, splenomegaly, hepatomegaly, lymphadenopathy, and poor nutritional status.
- Occurs mainly in East Africa and South Asia.
Diagnosis
- A) Clinical:*
- Suspect VL in individuals residing in endemic areas with persistent, irregular, or remittent fever.
- Other clinical features include hepatosplenomegaly, anemia, leucopenia, and emaciation.
- B) Laboratory:*
- I. Direct:*
- Microscopy: Detect amastigotes in smears from peripheral blood, bone marrow, spleen, liver, lymph nodes, nasalopharyngeal secretions, stool, urine, or PKDL lesions.
- Culture: Grow Leishmania promastigotes on Novy-MacNeal Nicolle (NNN) medium.
- Animal inoculation: Inoculate hamsters intraperitoneally and observe for amastigotes in smears from lesions or organs.
- II. Indirect:*
- Immunological diagnosis:
- Serological Tests: Detect antibodies against Leishmania antigens using IFA, IHA, ELISA, CFT, DAT, and Rapid Immunochromatographic Dipstick (ICT).
- Leishmanin Skin Test (Montenegro Test): A delayed hypersensitivity skin test that detects exposure to Leishmania.
- Molecular diagnosis: Assists in species identification.
- Blood picture: Complete blood count may show anemia, leucopenia, and thrombocytopenia (Pancytopenia or Aplastic anemia).
Treatment
- Supportive Treatment: Nutritional support with vitamins and iron, antibiotic therapy, and blood transfusions.
-
Specific Treatment:
-
Systemic Therapy (parenteral, IV):
- Pentavalent Antimony Compounds: Pentostam (Sodium stibogluconate).
- Amphotericin B.
- Interferon gamma + Pentostam (in case of relapse).
-
Systemic Therapy (parenteral, IV):
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Description
This quiz covers the essential aspects of visceral leishmaniasis (VL), including its causative agents and transmission. Learn about the different species of Leishmania and their geographical distribution. Test your knowledge on this serious parasitic disease known as kala azar.
