adenoviruses

Adenoviruses are non-enveloped, icosahedral dsDNA viruses in the genus Mastadenovirus, family Adenoviridae. They infect humans and a wide range of animals and comprise more than 50 serotypes, which are associated with diverse clinical syndromes. The name derives from their initial isolation from adenoids, and these viruses are a common cause of infections worldwide, particularly in children.

Structure and genome: Adenoviruses have a non-enveloped, icosahedral capsid with fiber proteins projecting from the penton bases. They carry linear double-stranded DNA genomes of roughly 26 to 45 kilobases. The genome includes early regulatory genes (such as E1A and E1B) and late structural genes, with replication occurring in the host cell nucleus.

Clinical features and latency: In humans, adenoviruses can cause acute respiratory infections, conjunctivitis, pharyngitis, gastroenteritis, and, in immunocompromised individuals, severe disseminated disease. In otherwise healthy people, infections are typically self-limited but can be more severe in young children or those with weakened immune systems. Adenoviruses can establish latency in lymphoid tissue, with intermittent reactivation and shedding in some cases.

Transmission, diagnosis, and prevention: Transmission occurs via respiratory droplets, fecal-oral routes, and contact with contaminated surfaces. Diagnosis is usually by PCR from appropriate specimens, supported by antigen detection or viral culture. There is no widely used targeted antiviral treatment; cidofovir may be employed in severe cases among immunocompromised patients. A live, oral vaccine against serotypes Ad4 and Ad7 is used in some military settings, but routine vaccination for the general population is not available. Preventive measures include good hygiene and outbreak control to limit spread.