Filariasis — MCQs
In a patient presented with a fever and a positive filarial antigen test, what is the next appropriate method of management?
Filariasis is caused due to lymphatic obstruction by which of the following?
Mass Drug Administration is NOT routinely used as the primary strategy for:
Tropical pulmonary eosinophilia is most characteristically seen due to which of the following infections?
Most sensitive test for detecting microfilariae?
Which of the following is not used as treatment for lymphatic filariasis -
Man is the only host for
In which condition is a night blood survey performed?
Which of the following conditions is characterized by the sign of the groove?
A young female presents with a history of fever and a nodular lesion over the shin. Histopathology reveals foamy histiocytes with neutrophilic infiltration. There is no evidence of vasculitis. What is the most probable diagnosis?
Filariasis Indian Medical PG Practice Questions and MCQs
Question 1: In a patient presented with a fever and a positive filarial antigen test, what is the next appropriate method of management?
- A. Bone marrow biopsy
- B. DEC provocation test
- C. Detection of microfilariae in the blood smear (Correct Answer)
- D. Ultrasound of the scrotum
Explanation: ***Detection of microfilariae in the blood smear*** - A positive **filarial antigen test** indicates the presence of adult worms, and the next step is to confirm active infection by identifying **microfilariae**. [1] - **Nocturnal blood samples** are crucial because microfilariae of *Wuchereria bancrofti* and *Brugia malayi* exhibit **nocturnal periodicity**, meaning they are most abundant in peripheral blood between 10 PM and 2 AM. [1] *Bone marrow biopsy* - This procedure is typically used to diagnose **hematological disorders**, such as leukemia or lymphoma, or investigate causes of unexplained fever, but it is not indicated for filariasis. - While filariasis can rarely lead to **eosinophilia**, a bone marrow biopsy is not a diagnostic tool for filarial infection itself. *DEC provocation test* - The **diethylcarbamazine (DEC) provocation test** is used to bring out microfilariae into the peripheral blood during the daytime for species that exhibit nocturnal periodicity. [1] - However, it carries a risk of severe adverse reactions due to rapid killing of microfilariae, especially in cases of heavy infection, and is generally avoided when antigen tests are positive. [1] *Ultrasound of the scrotum* - Scrotal ultrasound can detect the characteristic "filarial dance sign" (motile adult worms) in the **lymphatic vessels of the scrotum and epididymis**, confirming lymphatic filariasis. [2] - While useful for assessing advanced disease manifestations like **hydrocele**, it does not quantify microfilaremia or replace the need for microscopic confirmation of circulating microfilariae to guide treatment.
Question 2: Filariasis is caused due to lymphatic obstruction by which of the following?
- A. V. bancrofti (Correct Answer)
- B. C. sinensis
- C. S. haematobium
- D. P. vivax
Explanation: ***V. bancrofti*** - **Wuchereria bancrofti** is a parasitic nematode that causes **lymphatic filariasis**, leading to lymphatic obstruction. - The adult worms reside in the lymphatic vessels and disrupt normal lymphatic drainage, resulting in chronic **lymphedema** and **elephantiasis**. *P. vivax* - **Plasmodium vivax** is a species of parasite that causes **malaria**, a disease characterized by fever, chills, and anemia. - It primarily infects **red blood cells** and liver cells, and does not cause lymphatic obstruction. *C. sinensis* - **Clonorchis sinensis** is a **liver fluke** that causes **clonorchiasis**, an infection of the biliary ducts. - It leads to inflammation and fibrosis of the bile ducts and is not associated with lymphatic obstruction. *S. haematobium* - **Schistosoma haematobium** is a **blood fluke** that causes **urinary schistosomiasis**. - It infects the **bladder** and urinary tract, leading to hematuria and fibrosis, but does not cause lymphatic obstruction.
Question 3: Mass Drug Administration is NOT routinely used as the primary strategy for:
- A. Vitamin A Deficiency
- B. Scabies (Correct Answer)
- C. Lymphatic Filariasis
- D. Worm infestation
Explanation: ***Scabies*** - While **mass drug administration with oral ivermectin** has shown effectiveness in specific endemic outbreak settings, MDA is generally **not the primary recommended strategy** for routine scabies control in most public health contexts. - Scabies control typically prioritizes **case finding, contact tracing, simultaneous household treatment, and environmental decontamination**—which are more complex to implement than standard MDA programs. - Unlike the other conditions listed, scabies lacks well-established **routine MDA programs** at the scale of national public health initiatives, making it the least suitable option for MDA among these choices. *Vitamin A Deficiency* - **Vitamin A supplementation** through MDA is a **highly effective and widely implemented** WHO-recommended strategy to combat Vitamin A deficiency in at-risk populations, particularly children under 5 years. - Regular mass supplementation helps prevent **xerophthalmia** and reduces morbidity and mortality from infectious diseases. - This is a cornerstone of routine public health programs globally. *Lymphatic Filariasis* - **Lymphatic filariasis** is a classic example where MDA with anti-filarial drugs like **diethylcarbamazine (DEC), albendazole,** or **ivermectin** is the cornerstone strategy for interrupting transmission. - MDA is the **primary WHO-recommended approach** to achieve elimination of lymphatic filariasis, with established national programs in endemic countries. *Worm infestation* - **Mass deworming programs** using drugs like **albendazole** or **mebendazole** represent highly effective and well-established forms of MDA for controlling **soil-transmitted helminth infections**. - These routine programs significantly reduce disease burden in school-aged children, improving nutritional status, growth, and learning outcomes.
Question 4: Tropical pulmonary eosinophilia is most characteristically seen due to which of the following infections?
- A. Roundworm
- B. Trichinella
- C. Ancylostoma
- D. Filaria (Correct Answer)
Explanation: *Filaria* - **Tropical pulmonary eosinophilia (TPE)** is a hypersensitivity reaction to microfilariae from filarial nematodes like *Wuchereria bancrofti* and *Brugia malayi* [1]. - It is characterized by cough, dyspnea, wheezing, and marked **peripheral eosinophilia**, with interstitial infiltrates on chest X-ray [1]. *Roundworm* - **Ascaris lumbricoides** can cause **Loeffler's syndrome**, a transient pulmonary infiltration with eosinophilia during larval migration, but not chronic TPE [2]. - Symptoms are usually less severe and self-limiting compared to TPE [2]. *Trichinella* - **Trichinella spiralis** causes **trichinellosis**, presenting with muscle pain, fever, and periorbital edema, possibly with eosinophilia, but typically does not manifest as TPE. - Pulmonary involvement is rare and not the characteristic feature. *Ancylostoma* - **Hookworm (Ancylostoma duodenale, Necator americanus)** larvae can cause mild pulmonary symptoms and eosinophilia during migration through the lungs [3]. - However, they also do not typically lead to the severe and chronic pulmonary symptoms seen in TPE [3].
Question 5: Most sensitive test for detecting microfilariae?
- A. Membrane filtration technique (Correct Answer)
- B. Diethylcarbamazine (DEC) challenge test
- C. Fluorescence-based immunoassay
- D. Thick blood smear
Explanation: ***Membrane filtration technique*** - The **membrane filtration technique** is considered the most sensitive test for detecting **microfilariae** because it concentrates microfilariae from a larger volume of blood (typically 1 mL or more) onto a filter membrane, increasing detection rates, especially in low-parasite density infections. - This method physically traps the microfilariae, allowing for microscopic examination of the concentrated sample after staining, which enhances visualization. *Diethylcarbamazine (DEC) challenge test* - The **DEC challenge test** uses **diethylcarbamazine** to provoke the release of microfilariae into the peripheral blood, especially in cases of occult filariasis or when microfilaria numbers are low. - While it can be useful in certain diagnostic situations, it is **less sensitive** than membrane filtration for directly detecting circulating microfilariae and carries the risk of inducing severe adverse reactions due to rapid parasite killing. *Fluorescence-based immunoassay* - **Fluorescence-based immunoassays** detect **antigens** or **antibodies** related to filarial infection, providing evidence of exposure or active infection. - While valuable for diagnosis, especially in antibody detection for chronic or occult infections, they do not directly detect live microfilariae and thus are not the most sensitive method for *detecting microfilariae themselves*. *Thick blood smear* - A **thick blood smear** is a common and quick method for detecting microfilariae by examining a drop of blood for their presence. - However, it is **less sensitive** than the membrane filtration technique, particularly in persons with low microfilaremia, as it examines a much smaller volume of blood.
Question 6: Which of the following is not used as treatment for lymphatic filariasis -
- A. DEC
- B. Albendazole
- C. Ivermectin
- D. Praziquantel (Correct Answer)
Explanation: ***Praziquantel*** - **Praziquantel** is primarily an **anthelmintic drug** effective against **schistosomiasis** and **tapeworm infections**. - It does not have a significant role in the treatment of **lymphatic filariasis**. *Ivermectin* - **Ivermectin** is one of the **mainstays** of treatment for **lymphatic filariasis**, particularly in combination therapies. - It works by paralyzing and killing **microfilariae**, reducing their numbers in the bloodstream. *DEC* - **Diethylcarbamazine (DEC)** is a **highly effective antifilarial drug** used to kill both **microfilariae** and **adult worms** in lymphatic filariasis. - It is often used in mass drug administration programs and for individual treatment. *Albendazole* - **Albendazole** is an **anthelmintic drug** often used in combination with **Ivermectin** or **DEC** for the treatment of **lymphatic filariasis**. - It helps to kill **microfilariae** and has some macrofilaricidal effects, reducing the viability of adult worms.
Question 7: Man is the only host for
- A. Onchocerca volvulus
- B. Trichuris trichiura
- C. Wuchereria bancrofti (Correct Answer)
- D. Dracunculus medinensis
Explanation: ***Wuchereria bancrofti*** - This parasite is largely **restricted to humans** as its definitive host, causing **lymphatic filariasis**. - Its life cycle involves transmission via mosquitoes, but it relies solely on humans for the maturation of adult worms and the production of microfilariae. *Onchocerca volvulus* - While humans are the primary definitive hosts for **Onchocerca volvulus**, leading to **onchocerciasis** or **river blindness**, certain **simian primates** have also been found to harbor the parasite, making humans not the *exclusive* host. - The parasite is transmitted by **blackflies**. *Trichuris trichiura* - This parasite, commonly known as the **human whipworm**, primarily infects humans. - However, **other primates** like monkeys and apes can also be infected, thus humans are not the sole host. *Dracunculus medinensis* - While humans are the main and most well-known definitive host for **Dracunculus medinensis** (guinea worm), **dogs** and **other carnivores** have also been identified as hosts. - The infection is acquired by ingesting **copepods** containing larvae in contaminated water.
Question 8: In which condition is a night blood survey performed?
- A. Lymphatic filariasis (Correct Answer)
- B. Typhoid fever
- C. Malaria infection
- D. Visceral leishmaniasis
Explanation: ***Lymphatic filariasis*** - A **night blood survey** is crucial for diagnosing lymphatic filariasis because the microfilariae of species like *Wuchereria bancrofti* and *Brugia malayi* exhibit **nocturnal periodicity**, meaning they are most abundant in peripheral blood between 10 PM and 2 AM. - Collecting blood at night maximizes the chance of detecting these parasites, which are responsible for the disease. *Typhoid fever* - Diagnosis of **typhoid fever** primarily relies on **blood cultures** taken during the febrile phase, or stool/urine cultures later in the disease. - A night blood survey is not relevant for detecting the causative bacterium, *Salmonella Typhi*. *Malaria infection* - While a **blood smear** is essential for diagnosing malaria, the timing of blood collection is less critical than for filariasis, although peak parasite density can vary. - **Malaria parasites** are typically detected in blood samples taken during symptomatic periods, regardless of specific time of day. *Visceral leishmaniasis* - **Visceral leishmaniasis** is diagnosed by detecting parasites in samples from **bone marrow**, spleen, or lymph nodes, or through serological tests for antibodies. - A night blood survey is not used in the diagnosis of *Leishmania donovani* infection.
Question 9: Which of the following conditions is characterized by the sign of the groove?
- A. Lymphogranuloma venereum (Correct Answer)
- B. Granuloma inguinale
- C. Syphilis
- D. Chancroid
Explanation: **Explanation:** **Lymphogranuloma venereum (LGV)** is caused by the **L1, L2, and L3 serovars of *Chlamydia trachomatis***. The "Sign of the Groove" (Greenblatt’s sign) is a pathognomonic clinical finding in the secondary stage of LGV. It occurs when the inguinal and femoral lymph nodes enlarge simultaneously, separated by the rigid **inguinal ligament**. This creates a visible depression or "groove" between the two groups of inflamed lymph nodes. **Analysis of Incorrect Options:** * **B. Granuloma Inguinale (Donovanosis):** Caused by *Klebsiella granulomatis*. It presents with painless, beefy-red, velvety ulcers. It is characterized by "pseudobuboes" (subcutaneous granulation tissue) rather than true lymphadenopathy. * **C. Syphilis:** Primary syphilis presents with a painless, indurated "hard chancre." While it causes bilateral inguinal lymphadenopathy, the nodes are discrete, rubbery, and do not form a groove. * **D. Chancroid:** Caused by *Haemophilus ducreyi*. It presents with painful, soft ulcers and painful inflammatory buboes that are usually unilateral and may suppurate, but they do not form the characteristic groove sign. **High-Yield Clinical Pearls for NEET-PG:** * **Stages of LGV:** Primary (painless papule/ulcer), Secondary (Inguinal syndrome with the Groove sign), and Tertiary (Genito-anorectal syndrome/Elephantiasis). * **Diagnosis:** Frei test (historical), NAAT (current gold standard), and **Donovan bodies** (safety-pin appearance) are seen in Donovanosis, NOT LGV. * **Treatment:** Doxycycline (100 mg BID for 21 days) is the drug of choice for LGV.
Question 10: A young female presents with a history of fever and a nodular lesion over the shin. Histopathology reveals foamy histiocytes with neutrophilic infiltration. There is no evidence of vasculitis. What is the most probable diagnosis?
- A. Sweet's Syndrome
- B. Erythema nodosum (Correct Answer)
- C. Erythema nodosum leprosum
- D. Behcet's syndrome
Explanation: ### Explanation **Correct Answer: B. Erythema nodosum** **Why it is correct:** Erythema nodosum (EN) is the most common form of **septal panniculitis**. Clinically, it presents as tender, erythematous nodules typically located over the **pretibial area (shins)**, often accompanied by fever and malaise. Histopathologically, early lesions show edema and neutrophilic infiltration of the septa. As the lesion evolves, it is characterized by **Miescher’s radial granulomas**—small clusters of spindle-shaped or **foamy histiocytes** surrounding a central cleft. The absence of vasculitis is a hallmark feature that distinguishes EN from other forms of panniculitis. **Why the other options are incorrect:** * **A. Sweet’s Syndrome:** This is a neutrophilic dermatosis characterized by "juicy" erythematous plaques and high fever. Histology shows dense dermal neutrophilic infiltrate with papillary dermal edema, but it is not a primary panniculitis and does not typically present with foamy histiocytes in the septa. * **C. Erythema nodosum leprosum (ENL):** While ENL also presents with tender nodules and fever, it is a Type 2 Lepra reaction. Histologically, it is a **lobular panniculitis** and, crucially, it **must show evidence of vasculitis** (leukocytoclastic vasculitis) and the presence of *M. leprae* (AFB positive). * **D. Behcet’s syndrome:** While it can cause EN-like lesions, the systemic involvement (oral/genital ulcers, uveitis) and the characteristic histopathology (often showing vasculitis) do not fit the isolated description provided. **NEET-PG High-Yield Pearls:** * **Most common cause of EN:** Idiopathic (followed by Streptococcal infections, Sarcoidosis, and TB). * **Histopathology Key:** Septal panniculitis **without** vasculitis = Erythema Nodosum. * **Löfgren Syndrome:** Triad of EN, bilateral hilar lymphadenopathy, and arthritis (highly suggestive of Sarcoidosis). * **Miescher’s Radial Granulomas:** Pathognomonic histological finding for EN.
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