The organism responsible for Filaria?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2019

Applied Microbiology & Infection control

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2019

Explanation

Wuchereria bancrofti is a filarial nematode (roundworm) and is the primary causative agent for lymphatic filariasis.
It is responsible for approximately 90% of cases of lymphatic filariasis worldwide.
The adult worms reside in the lymphatic vessels of humans, where they can live for many years, causing chronic inflammation and obstruction.
The offspring, called microfilariae, circulate in the blood and are ingested by mosquitoes during a blood meal, continuing the life cycle.

Option A: Entamoeba histolytica is a protozoan parasite, not a nematode. It infects the large intestine and causes amoebiasis (amoebic dysentery), which is characterized by abdominal pain and diarrhea.
Option B: The Anopheles mosquito is a vector, not the causative organism. It transmits pathogens but does not cause the disease itself. While it can transmit filariasis, it is more famously known as the vector for malaria.
Option D: Taenia saginata is the beef tapeworm, a type of cestode. It causes taeniasis, an intestinal infection that occurs when a person consumes raw or undercooked beef containing the parasite's larvae.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Causative agent of Filariasis (Lymphatic Filariasis) as background academic context rather than a clinical decision trigger.
Nurses play a crucial role in managing chronic lymphedema caused by filariasis, focusing on hygiene, skin care, and preventing secondary infections to improve the patient's quality of life.
Patient education is a key nursing responsibility, teaching individuals in endemic areas about mosquito bite prevention and the importance of participating in Mass Drug Administration (MDA) programs to interrupt transmission.
What if? If a patient with filarial lymphedema develops red, hot, and painful swelling in the affected limb with a fever, the nurse should suspect secondary bacterial cellulitis (dermatolymphangioadenitis) and prioritize notifying the physician for antibiotic therapy, in addition to continuing supportive limb care.

How to Approach the Question

First, identify the key term in the question: 'Filaria'. This is a specific parasitic disease.
Next, analyze the question's requirement: it asks for the 'organism responsible', meaning the causative pathogen, not the vector that transmits it.
Evaluate each option based on your knowledge of microbiology and parasitology.
Eliminate 'Anopheles mosquito' as it is a known vector, not a causative organism.
Differentiate between the remaining pathogens: 'Entamoeba histolytica' (causes amoebiasis), 'Wuchereria bancrofti' (a filarial worm), and 'Taenia saginata' (a tapeworm).
Select 'Wuchereria bancrofti' as it is the specific nematode that causes the majority of filariasis cases.

Concept Tested & Keywords

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E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart B (pp 202-403 of 604) p. 132-134

E6 Medicine Harrison 22e Part 1 p. 1861-1863