Negri bodies are found in cells infected with?

ESIC Nursing Officer 2016 (shift-1)

Microbiology

Easy

Appeared in: ESIC Nursing Officer 2016 (shift-1)

Explanation

Negri bodies are the specific, pathognomonic finding for rabies virus infection.
These are eosinophilic, round-to-oval inclusion bodies found within the cytoplasm of infected neurons.
They are most commonly located in the pyramidal neurons of the hippocampus and the Purkinje cells of the cerebellum.
Their presence confirms a post-mortem diagnosis of rabies encephalitis.

Option A: Fowl pox virus infection is characterized by Bollinger bodies, which are large, granular, acidophilic cytoplasmic inclusions found in the epithelial cells of birds.
Option B: Vaccinia virus, a member of the poxvirus family, is associated with Guarnieri bodies. These are eosinophilic inclusions found in the cytoplasm of infected cells.
Option D: Arbo virus (arthropod-borne virus) is a very broad category of viruses transmitted by arthropods like mosquitoes and ticks. It includes many different viruses (e.g., Dengue, West Nile, Japanese encephalitis). There is no single, specific inclusion body named 'Negri body' that characterizes all arboviruses.

Visual 1: Micrograph - A high-magnification image of a neuron's cytoplasm clearly showing a distinct, pink-staining (eosinophilic) Negri body. This helps visualize the key diagnostic feature described.
Visual 2: Diagram - A comparative table illustrating different viruses and their corresponding inclusion bodies (e.g., Rabies → Negri body, CMV → Owl's eye, Herpes → Cowdry type A). This serves as a memory aid for differential diagnosis.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Identification of pathognomonic viral inclusion bodies in pathology as background academic context rather than a clinical decision trigger.
For nurses, suspicion of rabies exposure in a patient (e.g., from an animal bite) is a critical medical emergency. It necessitates immediate and meticulous post-exposure prophylaxis (PEP) to prevent the onset of the invariably fatal disease.
The definitive diagnosis of rabies in an animal or human is made post-mortem by identifying Negri bodies in brain tissue, which guides public health responses and contact tracing.
What if? If a patient is bitten by a domestic pet that is fully vaccinated and available for observation, immediate PEP might be deferred while the animal is observed for 10 days. However, if the bite is from a wild or stray animal that cannot be captured, PEP must be initiated immediately.

How to Approach the Question

Identify the core of the question: it asks to link a specific histological finding ('Negri bodies') to its causative virus. This is a factual recall question from pathology/microbiology.
Access your knowledge of classic viral inclusion bodies. The term 'Negri body' should be a strong trigger for a specific disease.
Recall that Negri bodies are the pathognomonic (hallmark) sign of Rabies virus infection.
Evaluate the other options to confirm your choice. Fowl pox virus (Bollinger bodies) and Vaccinia virus (Guarnieri bodies) are associated with different, distinctly named inclusions. 'Arbo virus' is a broad category, making it an unlikely answer for such a specific finding.
Conclude that Rabies virus is the only correct association with Negri bodies.

Concept Tested & Keywords

Concept Tested: Identification of pathognomonic viral inclusion bodies in pathology.
Stem keywords: Negri bodies, infected cells
Lead-in keywords: BEST, MOST RELEVANT CLUE
Negative lead-in flag: false

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