Summary Points

• The latent properties of adenovirus make it a threat to immunocompromised hosts
• Immunocompromised persons often experience pneumonia and hepatitis
• Adenovirus infection can cause gastrointestinal disease in AIDS patients
• New and Sexy! Adenovirus infections can cause serious complications, including enterocolitis in pediatric patients

One of the hallmark properties of adenoviruses is their ability to become latent. The benefit of this feature is twofold - an unapparent infection aids the spread of the virus to new hosts and also allow the virus to "reappear" and cause symptoms in an immunocompromised host.

Immunocompromised hosts can experience serious complications as a result of an adenovirus infection; the more commonly observed complications include pneumonia, hepatitis and a gastrointestinal infection.

Because adenoviruses have the ability to invade the host's lungs, it is not surprising that an infection could result in viral pneumonia. While pnemonia can usually be tolerated by the host, it is especially severe in immunocompromised hosts.

Adenovirus can also cause hepatitis in its hosts. Hepatitis is commonly seen in children, especially in those who receive a liver transplant. Hepatitis is commonly caused by serotypes 1, 2, and 5. While it is not clear if the hepatitis patients experience is caused by a primary infection or the reactivation of latent virus, it is especially harmful because some patient must be taken off of immunosuppressive therapy in order to allow their immune system to combat the adenovirus.

Adenovirus infections can also be reactivated in patients whose immune systems are suppressed due to an HIV infection. Studies of AIDS patients have successfully isolated adenoviruses, particularly of subgroup D, in the stools of AIDS patients. This discovery implies that some of the diarrhea that AIDS patients experience may be due to adenovirus infection.

Above: 3D reconstruction of adenovirus particle, courtesy of Knipe and Howley, Adenoviridae: The Viruses and Their Replication, Fundamental Virology, 2001, p. 1056

Below: You can escape adenovirus, the latent nature of the virus allows it to "hide" in your body for extended periods of time, graphic courtesy of www.zaksrealm.net/Screencap_Gallery/ Quest/

New and Sexy!

A case report of two individuals, a 17 year old boy and a 3 year old boy highlighted the severity of adenovirus infection in immunocompromised hosts during bone marrow transplant. The first patient, the 17 year old boy, managed to overcome his adenoviral infection and was relatively stable at the end of the study. The second patient, the 3 year old boy, died of multi-organ failure. While both boys also suffered from graft versus host disease, the combined infection was too overwhelming for the 3 year old child.

The important points in these cases are the following:

• Adenovirus infection can be deadly in an immunocompromised host, with a mortality rate as high as 10% in organ recipients
• Antiviral treatments may aid the outcome of organ recipients

While both boys suffered from adenovirus enterocolitis, the 17 year old boy's body was better able to manage the adenovirus infection. He was given ribavirin as his antiviral treatment and combined with other therapies, had no evidence of recurrent adenovirus enteritis. The younger patient had many underlying health problems, including metachromatic leukodystrophy and graft versus host disease. The infection with adenovirus may not have been causal to his death; it complicated his case and caused additional stress on his immune system.