title: Vertical transmission of honey bee viruses in a Belgian queen breeding program.
abstract: BACKGROUND
  The Member States of European Union are encouraged to improve the general conditions for the production and marketing of apicultural products. In Belgium, programmes on the restocking of honey bee hives have run for many years. Overall, the success ratio of this queen breeding programme has been only around 50%. To tackle this low efficacy, we organized sanitary controls of the breeding queens in 2012 and 2014.
  
  
  RESULTS
  We found a high quantity of viruses, with more than 75% of the egg samples being infected with at least one virus. The most abundant viruses were Deformed Wing Virus and Sacbrood Virus (≥40%), although Lake Sinai Virus and Acute Bee Paralysis Virus were also occasionally detected (between 10-30%). In addition, Aphid Lethal Paralysis Virus strain Brookings, Black Queen Cell Virus, Chronic Bee Paralysis Virus and Varroa destructor Macula-like Virus occurred at very low prevalences (≤5%). Remarkably, we found Apis mellifera carnica bees to be less infected with Deformed Wing Virus than Buckfast bees (p < 0.01), and also found them to have a lower average total number of infecting viruses (p < 0.001). This is a significant finding, given that Deformed Wing Virus has earlier been shown to be a contributory factor to winter mortality and Colony Collapse Disorder. Moreover, negative-strand detection of Sacbrood Virus in eggs was demonstrated for the first time.
  
  
  CONCLUSIONS
  High pathogen loads were observed in this sanitary control program. We documented for the first time vertical transmission of some viruses, as well as significant differences between two honey bee races in being affected by Deformed Wing Virus. Nevertheless, we could not demonstrate a correlation between the presence of viruses and queen breeding efficacies.
authors.affiliation: Laboratory of Molecular Entomology and Bee Pathology, Ghent University, Krijgslaan 281 S2, B-9000, Ghent, Belgium. Jorgen.Ravoet@UGent.be.
authors.forename: Jorgen
authors.initials: J
authors.lastname: Ravoet
authors.affiliation: Laboratory of Molecular Entomology and Bee Pathology, Ghent University, Krijgslaan 281 S2, B-9000, Ghent, Belgium. Lina.DeSmet@UGent.be.
authors.forename: Lina
authors.initials: L
authors.lastname: De Smet
authors.affiliation: Laboratory of Socioecology and Social Evolution, KU Leuven, Naamsestraat 59, B-3000, Leuven, Belgium. Tom.Wenseleers@bio.kuleuven.be.
authors.forename: Tom
authors.initials: T
authors.lastname: Wenseleers
authors.affiliation: Laboratory of Molecular Entomology and Bee Pathology, Ghent University, Krijgslaan 281 S2, B-9000, Ghent, Belgium. Dirk.deGraaf@UGent.be.
authors.forename: Dirk C
authors.initials: DC
authors.lastname: de Graaf
mesh_terms: D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D001516:Bees / Q000821:virology*; D001530:Belgium; D056631:Colony Collapse / Q000517:prevention & control / Q000821:virology; D018445:Infectious Disease Transmission, Vertical / Q000662:veterinary; D007304:Insect Viruses / Q000472:pathogenicity