Figure 2. Stages of the natural history of HHV-6 infection: I. Primary infection occurs in infants, may result in exanthem subitum (rash on the child's chest), and spreads to organs. Question marks denote sites where HHV-6 spread is likely but not proven. II. In healthy infants and adults, HHV-6 is present in a latent or persistent form in lymph nodes and is produced asymptomatically in salivary glands and shed in saliva, the most probable route of transmission. III. HHV-6 infection/reactivation occurs in persons undergoing therapeutic immunosuppression after organ transplant or in AIDS patients.