Adenovirus

Adenoviruses are a group of viruses that cause respiratory, gastrointestinal, and genitourinary infections.

There are about 60 serotypes of the virus, divided into 7 subgroups, from A to G.

Common respiratory infections caused by adenoviruses include a sore throat, the common cold and pneumonia, whereas diarrhea is the most common gastrointestinal ailment.

Adenoviruses can also cause cystitis, which is the inflammation of the bladder, as well as eye conditions like conjunctivitis.

Adenoviruses are double-stranded linear DNA viruses surrounded by an icosahedral capsid, which is a spherical protein shell made up of 20 equilateral triangular faces.

And they’re “naked” because the capsid isn’t covered by a lipid membrane.

Their capsid is unique among viruses because it has fiber-like projections from each of the 12 vertices of the shell.

Adenovirus is primarily transmitted by respiratory droplets when someone coughs or sneezes and by the fecal-oral route.

In other words, you catch it by ingesting the stool or vomit particles of someone who is sick. Yuck.

This can happen if infected stool ends up in the water supply or on agricultural fields, if flies land on it, and transfers stool particles to other places, or by touching contaminated surfaces.

You can summarize it as the four Fs: fluids, fields, flies, and fingers. As a result, adenovirus can end up in food and drinking water.

Two less common modes of transmission are from mother to newborn via the cervical fluid in the birth canal, and following an organ transplant from a donor who has an adenovirus infection.

After entering the body, the virus heads for epithelial cells, like those that make up the respiratory, GI, or urinary mucosa, where it uses its fiber projections to bind to the coxsackie-adenovirus receptor on cell membranes. This allows it to get inside the cells.

Once inside, adenovirus has multiple cytopathic, or cell-damaging, effects, like blocking synthesis of cellular DNA and the production of proteins.

This results in cell death by lysis, or the breakdown of the cell membrane, which elicits an inflammatory response from the host.