Which of the following is the best discriminating feature between Poliomyelitis (caused by Wild Poliovirus) and Japanese Encephalitis in the context of the Universal Immunisation Programme?

Question

Accepted Answer

B. Poliomyelitis causes flaccid paralysis with lower motor neuron signs, while Japanese Encephalitis causes encephalitis with upper motor neuron signs and altered sensorium. ## Discriminating Features Between Poliomyelitis and Japanese Encephalitis

### Clinical Presentation Differences

**Key Point:** The hallmark clinical feature that distinguishes these two vaccine-preventable diseases is the **pattern and distribution of neurological involvement**.

### Comparative Table

| Feature | Poliomyelitis (Wild Poliovirus) | Japanese Encephalitis |
|---------|--------------------------------|----------------------|
| **Type of Paralysis** | Flaccid (LMN signs) | Spastic (UMN signs) when present |
| **Primary CNS Involvement** | Anterior horn cells (spinal cord) | Brain parenchyma (brainstem, basal ganglia) |
| **Consciousness** | Usually preserved | Altered sensorium, confusion, coma |
| **Fever Pattern** | Biphasic (abortive + paralytic) | Sustained high fever |
| **Asymmetric Paralysis** | Common (one limb or one side) | Rare; more diffuse involvement |
| **Meningeal Signs** | Absent in paralytic form | Present (neck stiffness, photophobia) |
| **CSF Picture** | Lymphocytic pleocytosis | Lymphocytic pleocytosis with higher protein |

### High-Yield Distinction

**Mnemonic: POLIO-LMN vs JE-BRAIN**
- **POLIO**: **L**ower **M**otor **N**euron paralysis (flaccid, asymmetric)
- **JE**: **B**rain inflammation with **R**aised **A**ltered consciousness, **I**ncreased tone, **N**eck stiffness

### Clinical Pearl

In the field, a child presenting with **acute flaccid paralysis (AFP)** with preserved consciousness and no meningeal signs suggests poliomyelitis. Conversely, **fever + altered sensorium + seizures ± paralysis** points to Japanese Encephalitis. This distinction is critical for outbreak investigation and surveillance under the UIP.

### Epidemiological Context

Both are included in India's Universal Immunisation Programme:
- **Poliomyelitis**: IPV (Inactivated Polio Vaccine) — part of routine immunisation since 1995; India declared polio-free in 2014
- **Japanese Encephalitis**: JE vaccine — introduced in endemic states (UP, Bihar, Assam, etc.) and now part of UIP in endemic districts

[cite:Park 26e Ch 5]

Answer

A. Both are viral infections transmitted by respiratory droplets

Answer

C. Japanese Encephalitis is vaccine-preventable while Poliomyelitis is not

Answer

D. Poliomyelitis has a case fatality rate of >50% while Japanese Encephalitis has <10%

Which of the following is the best discriminating feature between Poliomyelitis (caused by Wild Poliovirus) and Japanese Encephalitis in the context of the Universal Immunisation Programme?

Explanation

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