Adenovirus

Human adenoviruses (HAdVs) are non-enveloped, double-stranded DNA viruses in the family Adenoviridae.  Seven species (A–G) and more than 60 genotypes cause human infection. In the United States, from 2017 through 2023, six HAdV types (1-4, 7, and 14) caused 88% of cases. 

Illness tends to occur sporadically and without demonstrated seasonality. Outbreaks of HAdV occur in congregate settings such as dormitories, health care settings, and among military personnel. Adenoviruses are relatively resistant to chemical and physical agents and can exist for a long time outside the body.

Adenoviruses most commonly cause respiratory illness. The symptoms can range from the common cold to pneumonia, croup, and bronchitis. Depending on the type, adenoviruses can cause other illnesses such as gastroenteritis, conjunctivitis, cystitis, and less commonly, neurological disease.

Infants and people with weakened immune systems are at high risk for severe complications of adenovirus infection. Some people infected with adenoviruses can have ongoing infections in their tonsils, adenoids, and intestines that do not cause symptoms. They can shed the virus for months or years. Even if a person test positive for adenovirus, it does not necessarily mean that it is causing the current illness. A person can shed the virus for months or years and not have symptoms.

In late 2021, cases of pediatric hepatitis reported in the United Kingdom and the United States. As of October 5, 2022, there have been 368 cases and 13 deaths in 42 states in the US. Six percent of patients have required liver transplantation. The most likely etiology appears to be coinfection with adenovirus type 41 (HAdV-41) and adenovirus associated virus (AAV2). 

There is no specific therapy for adenoviruses. However, cidofovir has been used to treat severe adenovirus infections in people with immunocompromised systems. Serious adenovirus infections can only be managed by treating symptoms and complications of the infection. 

To prevent nosocomial outbreaks of adenovirus infections, health care providers should strictly follow infection control practices, including contact and droplet precautions. 

Adenovirus infections can be identified using antigen detection, polymerase chain reaction assay, virus isolation, and serology. Specimens for PCR include respiratory specimens, cerebrospinal fluid, ocular swabs and stool or rectal swabs. Adenovirus typing is usually done by hemagglutination-inhibition and/or neutralization with type-specific antisera or by molecular methods.

References

Lion T. Adenovirus infections in immunocompetent and immunocompromised patients. Clin Microbiol Rev 2014;27:441–62.

Abdirizak F, Winn AK, Parikh R, et al. Surveillance of Human Adenovirus Types and the Impact of the COVID-19 Pandemic on Reporting — United States, 2017–2023. MMWR Morb Mortal Wkly Rep 2024;73:1136–1141. 

Lynch JP 3rd, Kajon AE. Adenovirus: epidemiology, global spread of novel types, and approach to treatment. Semin Respir Crit Care Med 2021;42:800–21.