Human adenovirus 8 is a non‑enveloped double‑stranded DNA virus and a member of species D. Its virion measures about 70–90 nm, with a sturdy icosahedral capsid and a linear genome associated with core proteins. This type is a major cause of epidemic keratoconjunctivitis, a severe and highly contagious ocular infection.
Biology and pathogenesis
More than 100 human adenovirus types exist. HAdV‑8 belongs to species D and has a tropism for conjunctival and corneal epithelium. Infection is usually acquired through contact with contaminated ophthalmic instruments, eye drops or swimming pools. After attaching to epithelial cells, the virus enters the nucleus and replicates, producing progeny virions that lyse the host cell. Adenoviruses can persist in lymphoid tissue, but ocular disease is generally associated with acute infection. The host immune response involves neutralising antibodies and cytotoxic T cells.
Clinical features and notable facts
HAdV‑8 is best known for causing epidemic keratoconjunctivitis. Patients develop conjunctival hyperaemia, tearing, photophobia and foreign‑body sensation. Corneal involvement leads to subepithelial infiltrates that can persist for weeks, causing blurred vision. Outbreaks occur in ophthalmology clinics and swimming facilities, and the virus can survive on surfaces for prolonged periods. Other adenovirus types associated with keratoconjunctivitis include 19, 37, 53 and 54. Unlike respiratory types 3, 4, 7 or enteric types 40/41, type 8 rarely causes systemic illness. There is no specific antiviral therapy for adenoviral keratoconjunctivitis; management focuses on supportive care and infection control measures. Strict hand hygiene and disinfection of instruments are essential to prevent outbreaks. Natural infection confers type‑specific immunity but does not protect against other ocular adenovirus types. Related Terms: Human Adenovirus 19, Human Adenovirus 37, Keratoconjunctivitis, Eye infection