Which virus is the most common cause of viral conjunctivitis?

• A. Enterovirus
• B. Herpes simplex virus
• C. Varicella-zoster virus
• D. Adenovirus

Answer: (D)

Adenovirus is the most common cause of viral conjunctivitis, reflecting its high transmissibility and ability to infect the conjunctiva across many serotypes. Infected individuals typically develop eye redness, watery discharge, and a follicular conjunctivitis, often with preauricular lymphadenopathy and sometimes mild upper respiratory symptoms. The condition spreads readily in crowded settings like schools and through contact with contaminated surfaces or swimming pool water, making outbreaks common. While other viruses such as herpes simplex virus and varicella-zoster virus can cause ocular involvement, they are less frequent sources of conjunctivitis and often come with more distinctive findings (for example, keratitis with dendritic ulcers in herpes simplex). Enteroviruses can cause conjunctivitis too, but they are not the leading cause overall. Management is mainly supportive—cool compresses, artificial tears, and good hand hygiene to prevent spread—with no proven antivirals for routine adenoviral conjunctivitis.