**Question:** All are true about poliovirus, except-

A. Poliovirus is a non-enveloped virus and belongs to the Picornaviridae family.
B. Poliovirus primarily infects neurons and causes flaccid paralysis.
C. Poliovirus is the causative agent of poliomyelitis, a disease affecting the central nervous system.
D. Poliovirus is eliminated from the body by the immune system without any treatment.

**Correct Answer: D. Poliovirus is eliminated from the body by the immune system without any treatment.**

**Core Concept:** Poliovirus is a small, non-enveloped virus belonging to the Picornaviridae family. It primarily infects neurons in the central nervous system (CNS), leading to the inflammation of these neurons and causing paralysis, particularly flaccid paralysis, due to the destruction of motor neurons. Poliomyelitis is the clinical syndrome resulting from the infection with poliovirus, affecting the CNS and leading to the inflammation and destruction of motor neurons.

**Why the Correct Answer is Right:** Poliovirus is not eliminated from the body by the immune system without any treatment. Instead, the virus primarily infects and damages the neurons, leading to the disease poliomyelitis. In severe cases, the disease can cause paralysis and even death.

**Why Each Wrong Option is Incorrect:**

A. Poliovirus is a true statement, as it is a non-enveloped virus belonging to the Picornaviridae family. It infects neurons, leading to paralysis and other clinical manifestations.

B. Although the immune system plays a role in combating the virus, the poliovirus is not eliminated from the body without any treatment. Treatment is essential in severe cases to manage complications and support the patient's condition.

C. Poliomyelitis, caused by poliovirus, is a clinical syndrome resulting from the infection and damage to the motor neurons in the CNS. Poliovirus is not responsible for the elimination of the virus from the body.

**Clinical Pearl:** Poliomyelitis is a severe disease with high morbidity and mortality rates, particularly in cases where the virus spreads to the brainstem, leading to respiratory failure. Early diagnosis and appropriate treatment with antiviral therapy and supportive care are crucial in reducing morbidity and mortality associated with poliomyelitis.