Wild-Type Human Adenovirus (Serotype 24)

Wild-type human adenovirus serotype 24 (HAdV-24) is a nonenveloped, double-stranded DNA virus belonging to the Adenoviridae family. The virus is primarily transmitted through direct contact with infected individuals, respiratory droplets, or contaminated surfaces (fomites). Fecal-oral transmission is also common, especially in crowded or unsanitary environments, as the virus can persist in the gastrointestinal tract. HAdV-24 is known to cause a range of clinical manifestations, including acute respiratory tract infection, conjunctivitis, and gastroenteritis, depending on the host''s immune status and age. Immunocompromised individuals are at increased risk for severe disseminated disease. The virus enters host cells by binding to specific receptors (such as the coxsackievirus receptor or CD46) and undergoing endocytosis. Subsequent viral replication leads to cell lysis and local inflammation, resulting in tissue damage and clinical symptoms.

HAdV-24 has a capsid structure characteristic of adenoviruses, which is approximately 90 nanometers in diameter. The capsid is composed of 252 capsomeres, including 240 hexons and 12 apical pentons. These capsomeres anchor the fiber protein, which is essential for host cell attachment. The fiber protein determines serotype specificity and tropism. Within the capsid, the viral genome consists of a linear double-stranded DNA molecule (approximately 36 kb) encoding early (E1-E4), intermediate, and late (L1-L5) genes. These genes regulate viral replication, immune evasion, and structural protein synthesis. The genome also contains inverted terminal repeats (ITRs), which are essential for DNA replication and packaging.