Leishmaniasis — MCQs
All of the following helps in the diagnosis of leishmaniasis except:
At what altitude is kala azar unlikely to occur?
A Giemsa stain of a thin peripheral blood smear is prepared. Which of the following cannot be diagnosed?
Insane paresis is associated with -
Match the following drugs in Column A with their contraindications in Column B. | Column A | Column B | | :-- | :-- | | 1. Morphine | 1. QT prolongation | | 2. Amiodarone | 2. Thromboembolism | | 3. Vigabatrin | 3. Pregnancy | | 4. Estrogen preparations | 4. Head injury |
A lady from West Rajasthan presented with an ulcer surrounded by erythema on the right leg. Microscopy of the biopsy from the edge of the ulcer showed organisms with dark staining nuclei and kinetoplast. What is the most likely causative agent? (Refer to the provided image)
Kala azar is transmitted by:
A woman traveling from Bihar to Delhi is suspected to have Kala-azar. Suitable investigation is?
A 24-year-old female presented with an ulcer in the genital area. A giemsa stained cervical smear was prepared. Identify the causative agent: (AIIMS Nov 2015)
The ELISA test for virulence antigen is used to diagnose which type of Escherichia coli?
Leishmaniasis Indian Medical PG Practice Questions and MCQs
Question 1: All of the following helps in the diagnosis of leishmaniasis except:
- A. Immobilisation test (Correct Answer)
- B. Examination of the bone marrow
- C. Blood smear
- D. Aldehyde test
Explanation: ***Immobilisation test*** - The **immobilisation test** is used to detect antibodies that inhibit the motility of organisms like *Trypanosoma cruzi* (Chagas disease), not *Leishmania*. - This test is not relevant for the diagnosis of leishmaniasis, as it targets a different parasitic mobility mechanism. *Examination of the bone marrow* - **Bone marrow aspiration** is a highly sensitive and specific method for diagnosing visceral leishmaniasis because **amastigotes** of *Leishmania* parasites are found intracellularly within macrophages in the bone marrow. - Direct visualization of the parasites in bone marrow smears confirms the diagnosis. *Blood smear* - While generally less sensitive than bone marrow aspiration, a **peripheral blood smear** can occasionally reveal **amastigotes** in circulating monocytes during the acute phase of visceral leishmaniasis. - However, its diagnostic utility is limited as the parasitic load in peripheral blood is often low. *Aldehyde test* - The **formol gel test** (also known as the **aldehyde test** or Napier's aldehyde test) is a non-specific test for **hypergammaglobulinemia**, which is a common finding in long-standing visceral leishmaniasis. - A positive result (gelation of serum after adding formaldehyde) suggests chronic infection but does not specifically confirm leishmaniasis nor differentiate it from other chronic inflammatory conditions.
Question 2: At what altitude is kala azar unlikely to occur?
- A. 400 meters
- B. 500 meters
- C. 600 meters (Correct Answer)
- D. 200 meters
Explanation: ***600 meters*** - Kala-azar, or **visceral leishmaniasis**, is primarily found in **low-lying areas** and is rarely reported at altitudes above 600 meters due to the specific ecological requirements of its **sand fly vector**. - The **Phlebotomus argentipes sand fly**, the main vector in the Indian subcontinent, prefers warm, humid climates and **lower altitudes**. *400 meters* - This altitude is within the **typical endemic range** for kala-azar, especially in regions like the Indian subcontinent. - The environmental conditions at 400 meters are generally conducive for the **survival and breeding** of the sand fly vector. *500 meters* - Similar to 400 meters, 500 meters is still considered within the **favorable altitude range** for kala-azar transmission. - The **sand fly vector** can thrive in the climate often found at this elevation. *200 meters* - This altitude represents a **highly endemic zone** for kala-azar, as it provides optimal conditions for the sand fly vector. - Lower altitudes are typically associated with increased **humidity and warmth**, favoring vector density and parasite transmission.
Question 3: A Giemsa stain of a thin peripheral blood smear is prepared. Which of the following cannot be diagnosed?
- A. Coxiella burnettii (Correct Answer)
- B. Bartonella henselae
- C. Ehrlichia chaffeensis
- D. Toxoplasma gondii
Explanation: ***Coxiella burnettii*** - *Coxiella burnettii* causes **Q fever** and is an **obligate intracellular bacterium** that resides primarily in **tissue macrophages** (lungs, liver, bone marrow), not in circulating blood cells. - It is **not found in peripheral blood smears** because it does not infect circulating leukocytes in significant numbers that would allow microscopic visualization. - Diagnosis requires **serology** (most common), **PCR**, or specialized culture in BSL-3 facilities—direct microscopic visualization in blood smears is not possible. *Bartonella henselae* - Causes **Cat scratch disease** and can invade **red blood cells**, making it potentially visible on Giemsa-stained blood smears, particularly in immunocompromised patients with bacillary angiomatosis or bacteremia. - While difficult and not the primary diagnostic method, it *can* be visualized in peripheral blood, unlike *Coxiella*. *Ehrlichia chaffeensis* - Causes **human monocytotropic ehrlichiosis (HME)** and forms characteristic **morulae** (berry-like clusters) within the cytoplasm of **monocytes**. - These morulae are readily visible on **Giemsa-stained peripheral blood smears** and are a key diagnostic finding, making this condition easily diagnosed by this method. *Toxoplasma gondii* - An **intracellular parasite** whose **tachyzoites** can occasionally be found in **peripheral blood leukocytes** during acute infection, especially in immunocompromised patients. - While rare and not the primary diagnostic method (serology/PCR preferred), tachyzoites *can* be observed in blood smears during active parasitemia.
Question 4: Insane paresis is associated with -
- A. Leishmaniasis
- B. Yellow fever
- C. Syphilis (Correct Answer)
- D. Neisseria meningitidis
Explanation: ***Syphilis*** - **General paresis**, or "insane paresis," is a neuropsychiatric manifestation of **tertiary syphilis**, resulting from chronic meningoencephalitis. - It presents with progressive **dementia**, personality changes, delusions, and neurological deficits. *Leishmaniasis* - This parasitic disease is characterized by various forms including **cutaneous**, **mucocutaneous**, and **visceral leishmaniasis** (kala-azar). - It typically causes skin lesions, mucocutaneous destruction, or systemic symptoms like fever, hepatosplenomegaly, and pancytopenia, but not general paresis. *Yellow fever* - **Yellow fever** is a viral hemorrhagic disease transmitted by mosquitoes, primarily affecting the liver and kidneys. - Symptoms include fever, jaundice, hemorrhage, and shock, but not the neurological degeneration seen in general paresis. *Neisseria meningitidis* - This bacterium causes **meningococcal meningitis** and **meningococcemia**, which are acute and severe infectious diseases. - While it can lead to acute neurological symptoms due to meningitis, it does not cause the chronic, progressive neuropsychiatric syndrome known as general paresis.
Question 5: Match the following drugs in Column A with their contraindications in Column B. | Column A | Column B | | :-- | :-- | | 1. Morphine | 1. QT prolongation | | 2. Amiodarone | 2. Thromboembolism | | 3. Vigabatrin | 3. Pregnancy | | 4. Estrogen preparations | 4. Head injury |
- A. A-1, B-3, C-2, D-4
- B. A-4, B-1, C-3, D-2 (Correct Answer)
- C. A-3, B-2, C-4, D-1
- D. A-2, B-4, C-1, D-3
Explanation: ***A-4, B-1, C-3, D-2*** - **Morphine** is contraindicated in **head injury** as it can increase intracranial pressure and mask neurological symptoms. - **Amiodarone** is contraindicated in patients with **QT prolongation** due to its risk of inducing more severe arrhythmias like Torsades de Pointes. - **Vigabatrin** is contraindicated during **pregnancy** due to its potential for teratogenicity and adverse effects on fetal development. - **Estrogen preparations** are contraindicated in patients with a history of **thromboembolism** due to their increased risk of blood clot formation. *A-1, B-3, C-2, D-4* - This option incorrectly matches **Morphine** with QT prolongation and **Estrogen preparations** with head injury, which are not their primary contraindications. - It also incorrectly links **Vigabatrin** with thromboembolism and **Amiodarone** with pregnancy. *A-3, B-2, C-4, D-1* - This choice incorrectly associates **Morphine** with pregnancy and **Vigabatrin** with head injury, which are not the most critical or direct contraindications. - It also misaligns **Amiodarone** with thromboembolism and **Estrogen preparations** with QT prolongation. *A-2, B-4, C-1, D-3* - This option incorrectly matches **Morphine** with thromboembolism and **Amiodarone** with head injury, which are not their most significant contraindications. - It also incorrectly links **Vigabatrin** with QT prolongation and **Estrogen preparations** with pregnancy.
Question 6: A lady from West Rajasthan presented with an ulcer surrounded by erythema on the right leg. Microscopy of the biopsy from the edge of the ulcer showed organisms with dark staining nuclei and kinetoplast. What is the most likely causative agent? (Refer to the provided image)
- A. Leishmania tropica (Correct Answer)
- B. Babesia microti
- C. Trypanosoma brucei
- D. Histoplasma capsulatum
Explanation: ***Leishmania tropica*** - The presence of an ulcer with surrounding erythema in **West Rajasthan**, along with microscopy showing organisms with a **nucleus and kinetoplast**, is highly characteristic of **cutaneous leishmaniasis** caused by *Leishmania tropica*. - The organisms seen are **amastigotes** within macrophages in skin lesions, which are identified by their distinct **nucleus and kinetoplast** on microscopy. - West Rajasthan is an **endemic area** for cutaneous leishmaniasis. *Babesia microti* - *Babesia microti* causes **babesiosis**, a tick-borne illness affecting red blood cells, leading to **hemolytic anemia** and malaria-like symptoms. - It does not typically cause **skin ulcers** and its characteristic form in smears is a **ring form or tetrad ("Maltese cross")** within red blood cells, not organisms with kinetoplasts in macrophages. *Trypanosoma brucei* - *Trypanosoma brucei* causes **African trypanosomiasis (sleeping sickness)**, presenting with fever, headaches, joint pain, and neurological symptoms, possibly a **chancre** at the inoculation site. - While it has a **kinetoplast**, it exists as a flagellated **trypomastigote** in the blood and CSF, not as an **amastigote** in macrophages within a skin ulcer. - Additionally, this is **geographically incorrect** for West Rajasthan. *Histoplasma capsulatum* - *Histoplasma capsulatum* is a **fungus** that causes **histoplasmosis**, primarily affecting the respiratory system, especially in immunocompromised individuals. - It does **not possess a kinetoplast** and while it can cause disseminated disease with skin lesions, the microscopic appearance would be **yeast forms** within macrophages, not organisms with kinetoplasts.
Question 7: Kala azar is transmitted by:
- A. Tse tse fly
- B. Sandfly (Correct Answer)
- C. Hard tick
- D. Culex mosquito
Explanation: ***Sandfly*** - **Kala azar**, also known as **visceral leishmaniasis**, is a severe parasitic disease caused by **Leishmania donovani**. - This parasite is transmitted to humans through the bite of an infected female **phlebotomine sandfly**. *Tse tse fly* - The **tse tse fly** is the vector for **African trypanosomiasis**, also known as **sleeping sickness**. - It transmits **Trypanosoma brucei**, a different parasitic organism than the one causing kala azar. *Hard tick* - **Hard ticks** are vectors for several diseases, including **Lyme disease** (Borrelia burgdorferi), **Rocky Mountain spotted fever** (Rickettsia rickettsii), and **anaplasmosis**. - They are not associated with the transmission of leishmaniasis. *Culex mosquito* - The **Culex mosquito** is a common vector for diseases such as **West Nile virus**, **Japanese encephalitis**, and **filariasis**. - It does not transmit the **Leishmania parasite** responsible for kala azar.
Question 8: A woman traveling from Bihar to Delhi is suspected to have Kala-azar. Suitable investigation is?
- A. P24 antigen
- B. Rk-39 test (Correct Answer)
- C. Combo RDT
- D. HRP-2 antigen
Explanation: ***Rk-39 test*** - The **Rk-39 test** is a rapid diagnostic test highly sensitive and specific for detecting antibodies against the **kinesin-related protein K39** of *Leishmania donovani*, the causative agent of **Kala-azar (visceral leishmaniasis)**. - It is particularly useful in **endemic regions** like Bihar for quick and accurate diagnosis, especially in patients with suspected Kala-azar presenting with fever, splenomegaly, and pancytopenia. *P24 antigen* - **P24 antigen** testing is primarily used for the diagnosis of **HIV infection**. - It detects the **core protein p24** of the HIV virus, which is not relevant for the diagnosis of Kala-azar. *Combo RDT* - A **Combo RDT** (Rapid Diagnostic Test), without further specification, typically refers to tests for **malaria**, which detect antigens like **HRP-2** and **aldolase**. - While RDTs are used for parasitic diseases, this general term does not specifically refer to a test for **Kala-azar**. *HRP-2 antigen* - **HRP-2 (Histidine-rich protein 2) antigen** is a specific marker for **Plasmodium falciparum**, used in the diagnosis of **malaria**. - It is not associated with the diagnosis of **Kala-azar**, which is caused by *Leishmania donovani*.
Question 9: A 24-year-old female presented with an ulcer in the genital area. A giemsa stained cervical smear was prepared. Identify the causative agent: (AIIMS Nov 2015)
- A. Gardnerella vaginalis
- B. Chlamydia
- C. Calymmatobacterium granulomatosis
- D. Haemophilus ducreyi (Correct Answer)
Explanation: ***Hemophilus ducreyi*** - The image shows numerous small, pleomorphic, gram-negative coccobacilli arranged in **'school of fish'** or parallel chains, characteristic of **_Haemophilus ducreyi_** on a Giemsa-stained smear. - This morphology, especially from a genital ulcer, is highly indicative of **chancroid**, caused by _H. ducreyi_. *Gardnerella vaginalis* - _Gardnerella vaginalis_ is associated with **bacterial vaginosis** and is characterized by the presence of **"clue cells"** (vaginal epithelial cells covered with coccobacilli) on microscopy. - It does not form the "school of fish" arrangement seen in the image, nor does it typically cause ulcerative lesions. *Chlamydia* - **_Chlamydia trachomatis_** causes various infections, including genital ulcers in cases of **lymphogranuloma venereum (LGV)**, but it is an obligate intracellular bacterium. - It would appear as **intracellular inclusions** on a Giemsa stain and would not show extracellular coccobacillary forms arranged in clusters as depicted. *Calymmatobacterium granulomatosis* - Previously known as _Calymmatobacterium granulomatosis_, now designated as **_Klebsiella granulomatis_**, this bacterium causes **granuloma inguinale (donovanosis)**, characterized by large, beefy-red ulcers. - Diagnostic features on Giemsa stain include **Donovan bodies** (intracellular bacilli within macrophages), which are not a prominent feature in the provided image.
Question 10: The ELISA test for virulence antigen is used to diagnose which type of Escherichia coli?
- A. ETEC
- B. EIEC
- C. EPEC (Correct Answer)
- D. EHEC
Explanation: ***EPEC (Enteropathogenic E. coli)*** - The **ELISA test for virulence antigen** is specifically used to detect **Bundle-Forming Pilus (BFP)** and **EAF (E. coli adherence factor) plasmid antigens** in EPEC - EPEC is a major cause of **infantile diarrhea** in developing countries - The virulence antigen detection by ELISA is a **standard diagnostic method** for identifying typical EPEC strains - EPEC demonstrates **localized adherence** pattern on HEp-2 cells and possesses the **LEE (locus of enterocyte effacement) pathogenicity island** *ETEC (Enterotoxigenic E. coli)* - ETEC causes **traveler's diarrhea** by producing **heat-labile (LT)** and **heat-stable (ST) enterotoxins** - Diagnosis involves detecting these **specific toxins or their genes** using PCR or toxin-specific immunoassays - ELISA for virulence antigens is not the primary diagnostic method for ETEC *EIEC (Enteroinvasive E. coli)* - EIEC invades intestinal epithelial cells, causing **dysentery-like illness** similar to *Shigella* - Diagnosis relies on detecting **invasion plasmid antigen H (IpaH)** or demonstrating **invasive properties** in cell culture assays - Serotyping and molecular methods are preferred over ELISA for virulence antigens *EHEC (Enterohemorrhagic E. coli)* - EHEC (particularly **O157:H7**) produces **Shiga toxins (Stx1 and Stx2)** causing hemorrhagic colitis and HUS - Diagnosis focuses on detecting **Shiga toxins** using specific ELISA or **stx genes** by PCR - Sorbitol-MacConkey agar is used for initial screening of O157:H7 strains
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