This virus infects human white blood cells, specifically T lymphocytes. Symptoms of this illness include fever and a distinct type of rash. Most infants are infected with HHV-6 before age two, but many display mild or no symptoms. Some symptoms, such as fever, may be incorrectly attributed to conditions other than roseola. Transmission of this virus is believed to occur as a result of exposure to saliva.
Most primary infections are asymptomatic.
Thereafter, the virus remains dormant in the body. HHV-6 reactivation in adulthood can result in illness. HHV-6 is also known to infect and destroy the cells that produce myelin, the fatty coating that surrounds and protects nerve cells. Additionally, the virus demonstrates the ability to cause disruption of the normal functioning of the human immune system. Primary infection with HHV-6A is believed to occur later in childhood or during adulthood and may occur without symptoms.