Adenoviruses (from Latin adenos meaning ‘gland’) are icosahedral (about 90 nm in diam.), nonenveloped, double-stranded DNA viruses with a wide host range (mammals, birds, reptiles, amphibians, and fish). Characteristic antennae-like fibers protrude from the virion surface give them the appearance of miniature satellites. Virus replication occurs inside the nucleus of infected cells. As a group, they are insensitive to lipid solvents indicating the absence of essential lipids in them. Human adenovirus (HAdV)type 5, for example, is used as a representative of medium-sized, non-enveloped viruses in testing microbicidal chemicals.
HAdV are versatile pathogens capable of causing acute respiratory diseases (pneumonia), conjunctivitis (pinkeye), gastroenteritis (e.g., types 40 and 41) and even cancers (oncogenic) in newborn animals. Many HAdV infections are subclinical, with the virus persisting in the host for months. They may spread via indoor air, water, hands and fomites. Enteric HAdV have recently been incriminated in the etiology of acute hepatitis in young children (https://emergency.cdc.gov/han/2022/pdf/CDC_HAN_462.pdf).
Currently, the 110 types and genotypes of HAdVs known are classified into seven species (A-G). Among those, species B, C, and E can infect the upper or lower respiratory tracts, species B and D conjunctivae and species F and G the gastrointestinal tract. Species A–F circulate globally and can cause limited outbreaks of infection.
HAdV outbreaks usually occur in closed populations (e.g., hospitals, long-term care facilities, and military installations). HAdV infections are mostly diagnosed in children younger than 4 years old. The most susceptible populations to HAdVs are young children and immunosuppressed adults, which manifest more severe infections. HAdV outbreaks might also occur in healthy populations, but most such infections are self-limited, and that is why, they are often undetected by public health surveillance. Nevertheless, severe pneumonia due to HAdVs can occasionally occur and be fatal in immunocompetent patients.
In addition to their disease-causing potential, HAdVs are valuable tools in molecular biology and biochemistry. They are also useful vectors for gene therapy and vaccination while providing insights into virus-host interactions.
Pinkeye is a common childhood infection often caused by HAdV types 3, 4a, and 7. Currently, no specific treatment is available against HAdVs. Vaccination in the form of oral tablets against HAdV types 4 and 7 (cause of severe respiratory infections) is available only for U.S. military personnel (CDC’s adenovirus website).
CREM Co Labs has several types of human HAdVs available along with the test protocols to work with them to assess the virucidal activities of environmental surface disinfectants and hand hygiene agents.
Reference:
1) CDC HEALTH ADVISORY: Recommendations for Adenovirus Testing and Reporting of Children with Acute Hepatitis of Unknown Etiology, Distributed via the CDC Health Alert Network, April 21, 2022, 11:00 AM ET, CDCHAN-00462
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