Apidologie 30 (1999) 475-484
DOI: 10.1051/apido:19990602

Virus infections in Nordic honey bee colonies with no, low or severe Varroa jacobsoni infestations

Sanna Nordström^a, Ingemar Fries^a, Aasne Aarhus^b, Henrik Hansen^c and Seppo Korpela<sup>d

a</sup>  Swedish University of Agricultural Sciences, Department of Entomology, P.O. Box 7044, S-750 07 Uppsala, Sweden
^b  Agricultural University of Norway, Department of Animal Science, P.O. Box 5025, N-1432 As, Norway
^c  Danish Institute of Agricultural Sciences, Research Group Entomology, Research Center Flakkebjerg, DK-4200 Slagelse, Denmark
^d  Agricultural Research Center of Finland, Plant Production Research, Plant Protection, SF-31 600 Jokioinen, Finland

Abstract - Honey bee viruses in Apis mellifera colonies were studied at eight Nordic locations with disparate Varroa jacobsoni infestations. Cloudy wing virus (CWV) was the most prevalent infection in all apiaries irrespective of mite infestation. Detection of CWV was not associated with colony collapse in this study. In one apiary where colonies collapsed, deformed wing virus (DWV) was detected. When certain mite mortality levels were reached in this apiary, both live and dead bee samples were always positive for DWV. However, colonies with low values of mite mortality could also be positive for DWV, and this virus could be detected several weeks before colony death in some cases. In the second apiary with collapsing colonies acute paralysis virus (APV) was detected in a live bee sample from one colony, close to the time of colony collapse. The following viruses were detected for the first time in the respective countries, CWV: Denmark, Norway and Sweden; BQCV: Denmark; DWV: Sweden. © Inra/DIB/AGIB/Elsevier, Paris

Key words: Apis mellifera / virus infection / Varroa jacobsoni / colony collapse / deformed wing virus