Transmission:

https://pedclerk.bsd.uchicago.edu/page/human-herpes-virus-6-and-roseola

Roseola is caused by at least two viruses, herpes virus type 6 and possibly herpes virus type 7. These two diseases have just recently been discovered, so the full range of these diseases are unknown. Roseola is transmitted person to person brought respiratory fluids or saliva of an infected individual. It typically starts as a 3-5 day fever, which breaks abruptly, followed by a rash.