Incidence and molecular characterization of viruses found in dying New Zealand honey bee (Apis mellifera) colonies infested with Varroa destructor

The virus status of New Zealand honey bee colonies infested with Varroa destructor was studied from 2001 to 2003. The viruses CBPV, BQCV, SBV, CWV, and KBV were all found during the study, with CWV and KBV the most common, as inferred from serological and protein profile analyses. DWV, SPV and ABPV were not detected in these colonies. CWV was present in the colonies throughout the season, while the appearance of KBV generally coincided with autumn colony collapse when V. destructor populations were large. Inconsistencies between serological analyses and viral capsid protein profiles of the extracts containing CWV and KBV were probably a result of strain differences between the viruses found in New Zealand and those used to generate the diagnostic antisera. The genome of the New Zealand KBV strain was partially sequenced. Phylogenetic and serological analyses showed this strain to be unique and most closely related to Canadian KBV isolates.