What is the relationship between poliovirus tissue tropism and disease manifestation?

• A. Infection of nasal epithelium causes sneezing
• B. Infection of liver causes jaundice
• C. Infection of motor neurons leads to loss of motor function and muscle control
• D. Infection of kidney causes polyuria

Answer: (C)

Poliovirus has a strong preference for motor neurons in the spinal cord (the anterior horn cells) and in brainstem motor nuclei. This tissue-specific targeting means the disease symptoms arise from the loss of motor neuron function. When these neurons die, the brain cannot effectively send signals to muscles, producing weakness, flaccid paralysis, and loss of reflexes—classic features of paralytic poliomyelitis. Other tissues like the liver, nasal epithelium, or kidney aren’t the primary targets, so symptoms such as jaundice, sneezing, or polyuria are not typical manifestations of poliovirus infection. The virus starts in the gut, can spread through the bloodstream, and CNS involvement explains the paralysis, while many infections remain limited to the gut or are nonparalytic.