A New Disease Causing Fatigue?

Some chronic fatigue might be caused by human herpesvirus

(RxWiki News) HHV-6 is the common name for two viruses which nearly every human has had by their second birthday. Some people are born with a strain of HHV-6 virus that is inherited from a parent. This inherited HHV might offer a clue to chronic fatigue symptoms.

A new study found that chronic fatigue is more common in people who have an inherited strain of HHV-6.

Inherited HHV-6 makes patients more prone to other HHV infections. The combination of HHV infections may lead to chronic fatigue symptoms

This study also found that these patients might be helped with antiviral therapy. 

"See your doctor if you are continually fatigued."

Shara Pantry, MD, from the University of South Florida's Morsani College of Medicine, and colleagues conducted this study to look at the relationship between human Herpesvirus-6 (HHV-6) and chronic fatigue.

HHV-6 is a name for two similar viruses infecting almost all humans by two years of age.

While most people become infected with HHV-6 early in life, 0.8 percent of the general population inherit HHV-6 genetically from a parent. Some people who are born with HHV-6 have no symptoms. Others have neurological symptoms, including chronic fatigue.

The researchers took blood samples from 337 patients with chronic fatigue syndrome to learn how common HHV-6 was in patients with chronic fatigue.

The samples showed that inherited HHV-6 was twice as common in patients with chronic fatigue than in the general population. The cause for most cases of chronic fatigue is unknown, however.

The researchers said that the cause of chronic fatigue for a small portion of patients might be inherited HHV-6. Inherited HHV-6 might cause patients to catch other HHV infections, making them prone to chronic fatigue syndrome. 

In the second part of the study, the researchers treated four people diagnosed with both inherited HHV-6 and chronic fatigue. These four patients received antiviral therapy — either valganciclovir (brand names Valcyte, Valixa, Darilin, Rovalcyte, Patheon, Syntex, Cymeval and Valcyt) or foscarnet (brand name Foscavir).

Foscarnet is a phosphonic acid derivative antiviral medication used to treat herpes viruses. It costs approximately $240 for a month's supply.

Valganciclovir is an antiviral medication prescribed for cytomegalovirus infections. It can cost from $700 to over $1,900 a month.

The researchers collected blood samples from the participants before and during treatment to see if the antiviral treatment worked.

The researchers found that both treatments in the study worked to relieve symptoms when used long-term in a small number of patients. After six weeks of valganciclovir and foscarnet, the HHV-6 disappeared from the blood samples. Short-term treatments of valganciclovir, however, did not reduce the HHV-6 level.

This study also showed that all four patients with inherited HHV-6 were infected with a second form of HHV-6.

"The good news reported in our study is that antiviral drugs improved the severe neurological symptoms, including chronic pain and long-term fatigue, suffered by a certain group of patients with chronic fatigue syndrome,” Maria Medveczky, MD, one of the study's authors, told the University of South Florida's Health Communications team.

“An estimated 15,000 to 20,000 patients with this chronic fatigue syndrome-like disease in the United States alone may ultimately benefit from the application of this research including antiviral drug therapy,” said Dr. Medveczsky.

This study was very small and non-randomized. Additional research is needed on the use of antivirals for chronic fatigue that is caused by HHV-6. The Centers for Disease Control and Prevention (CDC) notes that the cause of chronic fatigue syndrome is unknown.

This study was published online July 25 in the Journal of Medical Virology.

The researchers received funding from the HHV-6 Foundation and the National Institutes of Health (NIH). The authors reported no conflicts of interest.

Review Date: 
July 29, 2013