Vertical transmission of honey bee viruses in a Belgian queen breeding program

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

Comprehensive bee pathogen screening in Belgium reveals Crithidia mellificae as a new contributory factor to winter mortality

Since the last decade, unusually high honey bee colony losses have been reported mainly in North-America and Europe. Here, we report on a comprehensive bee pathogen screening in Belgium covering 363 bee colonies that were screened for 18 known disease-causing pathogens and correlate their incidence in summer with subsequent winter mortality. Our analyses demonstrate that, in addition to Varroa destructor, the presence of the trypanosomatid parasite Crithidia mellificae and the microsporidian parasite Nosema ceranae in summer are also predictive markers of winter mortality, with a negative synergy being observed between the two in terms of their effects on colony mortality. Furthermore, we document the first occurrence of a parasitizing phorid fly in Europe, identify a new fourth strain of Lake Sinai Virus (LSV), and confirm the presence of other little reported pathogens such as Apicystis bombi, Aphid Lethal Paralysis Virus (ALPV), Spiroplasma apis, Spiroplasma melliferum and Varroa destructor Macula-like Virus (VdMLV). Finally, we provide evidence that ALPV and VdMLV replicate in honey bees and show that viruses of the LSV complex and Black Queen Cell Virus tend to non-randomly co-occur together. We also noticed a significant correlation between the number of pathogen species and colony losses. Overall, our results contribute significantly to our understanding of honey bee diseases and the likely causes of their current decline in Europe

Bee pathogens found in Bombus atratus from Colombia : a case study

Bombus atratus bumblebees from Colombia that were caught in the wild and from breeding programs were screened for a broad set of bee pathogens. We discovered for the first time Lake Sinai Virus and confirmed the infection by other common viruses. The prevalence of Apicystis bombi, Crithidia bombi and Nosema ceranae was remarkably high. According to other studies the former two could have been co-introduced in South America with exotic bumble bees as Bombus terrestris or Bombus ruderatus. Given the fact that none of these species occur in Colombia, our data puts a new light on the spread of these pathogens over the South American continent

Holistic screening of collapsing honey bee colonies in Spain: a case study

Background: Here we present a holistic screening of collapsing colonies from three professional apiaries in Spain. Colonies with typical honey bee depopulation symptoms were selected for multiple possible factors to reveal the causes of collapse. Results: Omnipresent were Nosema ceranae and Lake Sinai Virus. Moderate prevalences were found for Black Queen Cell Virus and trypanosomatids, whereas Deformed Wing Virus, Aphid Lethal Paralysis Virus strain Brookings and neogregarines were rarely detected. Other viruses, Nosema apis, Acarapis woodi and Varroa destructor were not detected. Palinologic study of pollen demonstrated that all colonies were foraging on wild vegetation. Consequently, the pesticide residue analysis was negative for neonicotinoids. The genetic analysis of trypanosomatids GAPDH gene, showed that there is a large genetic distance between Crithidia mellificae ATCC30254, an authenticated cell strain since 1974, and the rest of the presumed C. mellificae sequences obtained in our study or published. This means that the latter group corresponds to a highly differentiated taxon that should be renamed accordingly. Conclusion: The results of this study demonstrate that the drivers of colony collapse may differ between geographic regions with different environmental conditions, or with different beekeeping and agricultural practices. The role of other pathogens in colony collapse has to bee studied in future, especially trypanosomatids and neogregarines. Beside their pathological effect on honey bees, classification and taxonomy of these protozoan parasites should also be clarified

Pesticides for apicultural and/or agricultural application found in Belgian honey bee wax combs

In a Belgian pilot study honey bee wax combs from ten hives were analyzed on the presence of almost 300 organochlorine and organophosphorous compounds by LC-MS/MS and GC-MS/MS. Traces of 18 pesticides were found and not a single sample was free of residues. The number of residues found per sample ranged from 3 to 13, and the pesticides found could be categorized as (1) pesticides for solely apicultural (veterinary) application, (2) pesticides for solely agricultural (crop protection) application, (3) pesticides for mixed agricultural and apicultural (veterinary) application. The frequencies and quantities of some environmental pollutants bear us high concerns. Most alarming was the detection of lindane (gamma-HCH) and dichlorodiphenyltrichloroethane (including its breakdown product dichlorodiphenyldichloroethylene), two insecticides that are banned in Europe. The present comprehensive residue analysis, however, also reveals residues of pesticides never found in beeswax before, i.e. DEET, propargite and bromophos

Pesticides for Apicultural and/or Agricultural Application Found in Belgian Honey Bee Wax Combs

Abstract In a Belgian pilot study honey bee wax combs from ten hives were analyzed on the presence of almost 300 organochlorine and organophosphorous compounds by LC-MS/MS and GC-MS/MS. Traces of 18 pesticides were found and not a single sample was free of residues. The number of residues found per sample ranged from 3 to 13, and the pesticides found could be categorized as (1) pesticides for solely apicultural (veterinary) application, (2) pesticides for solely agricultural (crop protection) application, (3) pesticides for mixed agricultural and apicultural (veterinary) application. The frequencies and quantities of some environmental pollutants bear us high concerns. Most alarming was the detection of lindane (gamma-HCH) and dichlorodiphenyltrichloroethane (including its breakdown product dichlorodiphenyldichloroethylene), two insecticides that are banned in Europe. The present comprehensive residue analysis, however, also reveals residues of pesticides never found in beeswax before, i.e. DEET, propargite and bromophos

Vertical transmission of honey bee viruses in a Belgian queen breeding program

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.status: publishe