Adenovirus
Adenovirus is a non-enveloped, double-stranded DNA virus that commonly causes respiratory infections, conjunctivitis, and gastroenteritis. Outbreaks classically occur in crowded settings such as military barracks and swimming pools.
Adenovirus is a non-enveloped, double-stranded DNA virus with an icosahedral capsid. Dozens of serotypes infect humans, and because the virus lacks an envelope it is hardy in the environment — resistant to drying and many disinfectants — which helps it spread through respiratory droplets, fecal-oral transmission, and contaminated surfaces and water.
Clinically, adenovirus produces a characteristic cluster of syndromes. It is a frequent cause of upper respiratory infections, pharyngitis, and pneumonia, and is classically associated with outbreaks among military recruits living in close quarters. In the eye it causes conjunctivitis ("pink eye"), including pharyngoconjunctival fever linked to swimming pools. Certain serotypes cause gastroenteritis in young children, and adenovirus is also a recognized cause of hemorrhagic cystitis and, less commonly, myocarditis. Most infections are self-limited in healthy hosts, but immunocompromised patients can develop severe disseminated disease.
Beyond causing illness, adenovirus matters in modern medicine as a workhorse viral vector: engineered, replication-deficient adenoviruses deliver genetic material in gene therapy and several vaccines. A live, non-attenuated oral vaccine against specific serotypes is used in U.S. military populations.
For exam purposes, USMLE Step 1 tests adenovirus in virology — remember the naked double-stranded DNA structure and the classic associations: military recruit pneumonia, pool-related conjunctivitis, pediatric gastroenteritis, hemorrhagic cystitis, and myocarditis. The CCMA exam covers adenovirus among the common acute respiratory infections a medical assistant will encounter.
Key takeaways
- Adenovirus is a naked (non-enveloped) double-stranded DNA virus, making it environmentally hardy.
- Classic presentations include respiratory infections and pneumonia in military recruits, conjunctivitis, pediatric gastroenteritis, and hemorrhagic cystitis.
- It spreads by respiratory droplets, fecal-oral routes, and contaminated water or surfaces.
- Engineered adenoviruses serve as vectors for gene therapy and vaccines.
- USMLE Step 1 emphasizes its structure and classic clinical associations; the CCMA covers it among common respiratory diseases.