ABSTRACT
The rest are RNA viruses and most have particles 30 nm in diameter, thus resembling many of the viruses familiar to animal and plant pathologists. These small isometric viruses of bees, however, are a very heterogeneous group with characteristics that differentiate them from other morphologically similar virus particles. Knowledge of honey bee viruses has now greatly increased and a further 19 have been identified, including some serologically related strains. Several of the viruses, however, are closely associated with and augment the pathogenicity of one or more of these parasites, and a few depend on the relationship for their infectivity. Similar associations may perhaps be anticipated between the viruses and parasites of other insect species. Until about the middle of the century only one virus disease of honey bees, sacbrood of larvae, had been recognized. The filamentous virus of honey bees has been detected in Apis mellifera from almost every continent.
