Slow Bee Paralysis Virus (SBPV)
SBPV was discovered in England in 1974. It is in the iflaviridae family of viruses and two strains have been identified. It is spread by the varroa mite.

It infects both honey bees and bumble bees. Infected bees are found to have their front and middle legs paralysed. It takes at least 12 days from exposure to the virus for the symptom to be apparent.

It is transmitted directly to adults and pupae when the mite feeds upon and infects the bee's hemolymph. The virus accumulates mainly in the head, salivary glands, and fatty tissues of the bee; it accumulates to a much lesser degree in the hindlegs, midgut, and rectum. Thus the virus may also be spread through oral transmission between bees.

Good apiary hygeine and integrated pest management are the best tools against SBPV
Condition-dependent virulence of slow bee paralysis virus in Bombus terrestris: are the impacts of honeybee viruses in wild pollinators underestimated?
Scientific Beekeeping