In the absence of mites the virus is thought to persist in the bee populations as a covert infection, transmitted orally between adults (nurse bees) since the virus can be detected in hypopharyngeal secretions (royal jelly) and broodfood and also vertically through the queen's ovaries and through drone sperm. The virus may replicate in the mite but this is not certain.
When there are no mites, it is assumed that the virus remains dormant within bee populations, spread among adults (nurse bees) via oral transmission, as the virus can be detected in saliva (royal jelly), food for young, and also through the queen's reproductive organs and drone sperm. The virus may multiply inside ticks but this has not been proven.