Infection with one of the many adenoviruses may be asymptomatic or result in specific syndromes, including mild respiratory infections, keratoconjunctivitis, gastroenteritis, cystitis, or primary pneumonia. Diagnosis is clinical. Treatment is supportive.
Adenoviruses are DNA viruses classified according to 3 major capsid antigens: hexon, penton, and fiber. There are 7 human adenovirus species (A to G) and > 100 genotypes (1). Different genotypes are associated with different clinical manifestations.
Adenoviruses are commonly acquired by contact with respiratory secretions (including those on the fingers of infected people) from an infected person or by contact with a contaminated object (eg, towel, instrument).
This illustration shows the surface structure of the adenovirus with outer protein coat (capsid) primarily made up of hexons (green). The protrusions are penton fibers (purple) and are found at each of the 12 vertices of the capsid. Each fiber is tipped with proteins, which allow the virus to enter its target cell.
Dr_Microbe/stock.adobe.com
Infection is most commonly transmitted via an airborne or waterborne route (eg, acquired while swimming in lakes or in swimming pools without adequate chlorine). In addition, potentially infectious, asymptomatic respiratory or gastrointestinal viral shedding may continue for months, or even years.
Adenoviral genotypes exhibit tissue tropism. Genotypes that are most commonly responsible for specific disease include (2):
Acute respiratory illness: Types 1, 2, 3, 4, 7, 14, and 55
Pharyngoconjunctival fever: Types 3, 4, and 7 (3)
Epidemic keratoconjunctivitis: Types 8, 37, 53, and 54
Gastroenteritis and hepatitis: Types 40 and 41
General references
1. Ukuli QA, Erima B, Mubiru A, et al. Molecular characterisation of human adenoviruses associated with respiratory infections in Uganda. BMC Infect Dis. 2023;23(1):435. Published 2023 Jun 27. doi:10.1186/s12879-023-08403-9
2. Centers for Disease Control and Prevention (CDC). Guidelines for Outbreaks. December 17, 2025. Accessed April 20, 2026.
3. Li J, Lu X, Sun Y, et al. A swimming pool-associated outbreak of pharyngoconjunctival fever caused by human adenovirus type 4 in Beijing, China. Int J Infect Dis. 2018;75:89-91. doi:10.1016/j.ijid.2018.08.009
Symptoms and Signs of Adenovirus Infections
In immunocompetent hosts, most adenovirus infections are asymptomatic. When infections are symptomatic, a broad spectrum of clinical manifestations is possible because most adenoviruses that cause mild disease exhibit affinity for a variety of tissues.
Most symptomatic infections occur in children and cause fever and upper respiratory symptoms, including pharyngitis, otitis media, cough, and exudative tonsillitis with cervical adenopathy that can be difficult to distinguish from group A streptococcal pharyngitis. A distinct syndrome of conjunctivitis, pharyngitis, and fever (pharyngoconjunctival fever) can occur in children with a history of swimming in unchlorinated water.
Epidemic keratoconjunctivitis is sometimes severe and also occurs sporadically. Conjunctivitis is frequently bilateral. Preauricular adenopathy may develop. Chemosis, pain, and punctate corneal lesions that are visible with fluorescein staining may be present. Systemic symptoms and signs are mild or absent. Epidemic keratoconjunctivitis usually resolves within 3 to 4 weeks, but corneal lesions may persist much longer.
Rare adenoviral syndromes in infants include severe bronchiolitis and pneumonia. In populations of young adults living in congregate settings (eg, military personnel), outbreaks of respiratory illness may occur; symptoms include fever and lower respiratory tract symptoms, usually tracheobronchitis but occasionally pneumonia. Case clusters of severe respiratory and other clinical disease caused by adenoviruses have occurred in healthy adults.
In immunocompromised adults, adenoviruses are recognized as causes of severe respiratory and other clinical disease.
Nonrespiratory adenoviral syndromes include hemorrhagic cystitis, diarrhea in infants, hepatitis, and meningoencephalitis.
Diagnosis of Adenovirus Infections
History and physical examination
Serologic tests
For severe disease, polymerase chain reaction (PCR) testing of respiratory secretions and blood
The diagnosis of adenovirus infection is primarily clinical and may be suspected based on characteristic organ system findings along with knowledge of local outbreak patterns.
Laboratory diagnosis of adenovirus infection rarely affects management (1). During the acute illness, the virus can be isolated from respiratory and ocular secretions and frequently from stool and urine. A 4-fold rise in the serum antibody titer can indicate recent adenoviral infection but has little clinical utility.
When patients have severe disease and a diagnosis is needed, PCR testing is the most widely available method for confirmation of infection because it can detect adenovirus DNA in respiratory secretions and blood. It is available as a multiplex panel, and some laboratories offer stand-alone testing. Virus culture and adenovirus genotyping are also available, but they are not commonly used in clinical settings and are more often used for epidemiologic purposes.
Diagnosis reference
1. Centers for Disease Control and Prevention (CDC). Laboratory Testing for Adenovirus December 16, 2025. Accessed April 20, 2026.
Treatment of Adenovirus Infections
Symptomatic treatment
Treatment of adenovirus infection is symptomatic and supportive. No antiviral agents are proven effective, although cidofovir may provide the highest likelihood of antiviral efficacy (1).
Most patients recover fully. Even severe primary adenoviral pneumonia is not fatal except for rare fulminant cases, predominantly in infants, military personnel, and immunocompromised patients.
Treatment reference
1. Florescu DF, Schaenman JM; AST Infectious Diseases Community of Practice. Adenovirus in solid organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice. Clin Transplant. 2019;33(9):e13527. doi:10.1111/ctr.13527
Prevention of Adenovirus Infections
A live vaccine containing adenovirus types 4 and 7 is available for use in military personnel aged 17 through 50 in the United States (1). It is administered orally in an enteric-coated capsule and can prevent most illness caused by these 2 types. It should not be given to patients who are pregnant or breastfeeding. No versions of the vaccine are available for civilian use worldwide.
Adenoviruses are resistant to many common disinfectants; bleach-based products containing 2000 to 5000 ppm chlorine are recommended, as are the United States Environmental Protection Agency (EPA) recommended antimicrobial products effective against norovirus. The United States Centers for Disease Control and Prevention (CDC) provides specific recommendations for disinfecting ophthalmologic equipment to prevent epidemic keratoconjunctivitis.
Prevention reference
1. CDC. Adenovirus Vaccine VIS. January 8, 2020. Accessed April 20, 2026.
Key Points
Adenoviruses can be spread through contact with secretions from an infected person or contact with a contaminated object or can be acquired while swimming in lakes or in swimming pools without adequate chlorine.
Most infections are mild; manifestations (eg, fever, upper and lower respiratory symptoms, pharyngitis, conjunctivitis) vary widely depending on the specific viral subtype.
Severe illness occurs mainly in infants and immunocompromised patients but occasionally occurs in healthy adults.
Treatment is supportive.
An oral live vaccine can reduce incidence of lower respiratory disease but is available only for military personnel.
Drug Information for the Topic
