A young man with cough and hoarseness; a small DNA virus with affinity for stratified squamous epithelium; which respiratory structure is most likely affected?

• A. Laryngeal vestibule
• B. Paranasal sinuses
• C. True vocal cords
• D. Tracheal bifurcation

Answer: (C)

The lining of a respiratory structure determines which viruses readily infect it. A small DNA virus that has affinity for stratified squamous epithelium will favor tissues lined by that type of epithelium. The true vocal cords are the part of the larynx covered by stratified squamous epithelium to withstand the friction of speaking. Inflammation here would best explain hoarseness and cough, because disruption of the vocal cords' movement directly affects phonation. Other listed structures—the paranasal sinuses and tracheal bifurcation—are lined by respiratory epithelium (pseudostratified ciliated columnar), and the laryngeal vestibule is also lined similarly, making them less typical targets for a squamous-tropic virus.