I have no idea how virus is transmitted in adeniums. I assume by the same ways as virus is transmitted in orchids which are my favorites.
In orchids, transmission depends upon what type of virus it is.
Transmission can be spread directly by touch. You touch a plant with virus in your collection and then you touch other plants without sterilizing your fingers.
Virus has also been known to be transmitted by splashing tiny water droplets.
Virus can by spread by failure to sterilize garden tools. Pruners, clippers and scissors are the most common tools used.
Years ago one could spread tobacco mosaic virus as a cigarette smoker. The virus could be on a smokers fingers and if they come to my greenhouse and touch my orchid flowers, just like people tend to do, they leave the virus behind.
One small consolation is a big drop in the numbers of smokers.
One prevalent theory in orchids pertains to Cattleyas. Some plants and their descendants have had virus in them for 70-80 years. It doesn't really manifest itself right away. It might take a year or two before it can been seen by us. By then, without knowing, you could spread it everywhere!!!
Viruses are not really curable so for me personally, I assume that it is always present. It does not bother me.
