Human Adenovirus 8 is a species D adenovirus within the genus *Mastadenovirus*. This non‑enveloped virus with a linear double‑stranded DNA genome is a leading cause of epidemic keratoconjunctivitis, a highly contagious infection of the eye.
Structure and Infection Cycle
Adenovirus 8 virions possess an icosahedral capsid composed of hexon and penton proteins with long fiber projections that bind to ocular epithelial receptors, including sialic acid–containing glycans. Following receptor‑mediated endocytosis, the capsid disassembles and delivers the viral genome to the nucleus. Early gene products alter host cell processes and promote viral DNA replication using a virus‑encoded DNA polymerase; late gene products form structural proteins that assemble into new virions. The virus primarily targets conjunctival and corneal epithelium, and cell lysis releases progeny virions into the tear film.
Clinical Features and Public Health Importance
Type 8 adenoviruses are notorious for causing epidemic keratoconjunctivitis (EKC), characterized by acute onset of conjunctival hyperemia, tearing, photophobia, and pain. A preauricular lymphadenopathy is common. Corneal involvement leads to punctate epithelial keratopathy followed by subepithelial infiltrates that can persist for months, resulting in blurred vision and glare. EKC outbreaks have been linked to contaminated ophthalmic instruments, eye drops, or swimming pools, and the virus is resistant to many common disinfectants. Transmission occurs via direct contact, fomites and contaminated medical equipment. Diagnosis is based on clinical signs and PCR confirmation; treatment is supportive, with topical corticosteroids used in severe keratitis to reduce inflammation. Strict hygiene and instrument sterilization are essential to prevent outbreaks. Human adenovirus 8 emphasizes the ocular tropism of certain adenoviruses and the need for infection control in healthcare and community settings to prevent transmission and protect vision. Related Terms: epidemic keratoconjunctivitis, human adenovirus 37, conjunctivitis, corneal infiltrates, species D adenovirus