Occurrence of acute paralysis virus of the honey bee (Apis mellifera) in a Hungarian apiary infested with the parasitic mite Varroa jacobsoni.

Viruses of the honey bee have been known for a long time; however, recently the attention of scientists and apiculturalists has turned towards the relationship between these viruses and the parasitic mite Varroa jacobsoni. Although clinical symptoms indicated the presence of some of the viruses of bees in Hungary, none have previously been isolated or identified. During July unusual adult bee and brood mortality was observed in some colonies of an apiary in Budapest known to be infested with Varroa jacobsoni. Large amounts of acute paralysis virus (APV) were detected serologically in healthy honey bee pupae killed by the injection of a bacteria-free extract of diseased adult bees. Crystalline arrays of 30 nm particles were seen in ultrathin sections of the tissues of injected pupae and naturally infected adult bees. In spite of the application of acaricide treatments the bee population in several colonies had collapsed by the end of summer and the apiary suffered severe wintering losses.