When fatigue stretches beyond the typical exhaustion posed by everyday life, it can be a conundrum for both sufferers and doctors. After a slew of likely contenders such as heart disease, anemia, thyroid disease, depression or a sleep disorder are ruled out, getting to the source of fatigue gets murky.
Among the many next-tier suspects is the Epstein-Barr virus (EBV). EBV belongs to the family of herpes viruses including those that cause cold sores, genital herpes, chickenpox and shingles. Infection with EBV is virtually inescapable; in the US, 95% of all adults will be infected by age 40, and 50% of all children by age 5. Many people don't realize they have been infected because they never feel sick. Once infected however, you harbor the virus for good. There is growing concern about the aftereffects of an EBV infection; a number of chronic diseases, including some types of cancers, have been linked to this infection.
The Epstein-Barr Virus M.O.
Unlike bacteria, which multiply comfortably on their own given the right environment, viruses need to insert themselves into a host's cells in order to persevere. Once a virus has taken a human cell hostage, it continues to conquer cell after cell.
For the most part, a healthy immune system can derail these viral interlopers so they don't do too much damage. The virus is detected, a customized antibody is made and an all out attack is mounted by killer cells. But like other herpes viruses, EBV is quite clever and can evade an all out antibody strike. It can stay in suspended animation for the rest of a person's life. lying dormant for months or years. There are no good treatments, no cures and no vaccines to prevent the spectrum of diseases (testing of a EBV vaccine is currently underway).
The EBV Infection Spectrum
EBV has a particular affinity for the cells that line the mouth and throat. Once the virus inserts itself into to a specialized immune lymphocyte (B cell), it hijacks the DNA to take control of the cell forever. When cells of the mouth and throat naturally slough off, EBV is shed into saliva. Anyone coming in contact with the virus-laden mucous becomes infected.
Children are susceptible as soon as the mother's protective immunity wanes. When very young children are exposed they may experience mild symptoms or none at all. The symptoms are not unique and mimic many run-of-the-mill childhood infections that also cause sore throat, fever and swollen glands.
Infections that occur later can produce a wide range of symptoms if any at all. It may take between 30-50 days for symptoms to appear.