Chronic bee paralysis as a serious emerging threat to honey bees

Chronic bee paralysis is a well-defined viral disease of honey bees with a global distribution that until recently caused rare but severe symptomatology including colony loss. Anecdotal evidence indicates a recent increase in virus incidence in several countries, but no mention of concomitant disease. We use government honey bee health inspection records from England and Wales to test whether chronic bee paralysis is an emerging infectious disease and investigate the spatiotemporal patterns of disease. The number of chronic bee paralysis cases increased exponentially between 2007 and 2017, demonstrating chronic bee paralysis as an emergent disease. Disease is highly clustered spatially within most years, suggesting local spread, but not between years, suggesting disease burnt out with periodic reintroduction. Apiary and county level risk factors are confirmed to include scale of beekeeping operation and the history of honey bee imports. Our findings offer epidemiological insight into this damaging emerging disease.


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Giles Budge
Mar 24, 2020 Case data were not collected using software, instead they were downloaded from government SQL database via a licence agreement.
All analyses were performed using R version 3.6.0. Packages are stated in the manuscript text.
Visit data contain personal information and were obtained under a restricted data confidentiality license agreement from the Animal and Plant Health Agency (contact enquiries@apha.gsi.gov.uk). Honey bee import data were obtained under license from the EU TRACES database and are presented in Fig. 5

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We determined the location of chronic bee paralysis using information from an existing government honey bee health inspection regime. We explored metadata from each apiary visit to assign, location, county, beekeeper type (amateur or professional), and import history. We then obtained honey bee import data from the EU Trade Control and Expert System (TRACES) that had been deposited into a government database. In 2017, we requested that NBU inspectors and bee farmers collect adult honey bee samples from apiaries that were either asymptomatic (n=24) or symptomatic (n=25) for chronic bee paralysis virus. Adult bees showing symptoms of paralysis were sampled from symptomatic colonies and healthy returning foragers were sampled from asymptomatic colonies. We compared virus levels in these adult bees.
We did not subsample the data, instead we sampled the entire population of data available.
We did not subsample the data, instead we sampled the entire population of data available.
Chronic bee case data were recorded by the National Bee Unit based at the Animal and Plant Health Agency. Data were gathered on behalf of the Department for Environment Food and Rural Affairs and Welsh government to fulfil honey bee health surveillance programmes. Apiary visit data were recorded by appointed bee inspectors of the National Bee Unit when they visited apiaries and assessed the health of the honey bee colonies therein. Import data were obtained under license through the EU TRACES system. RT qPCR data were gathered by Dr. Nicola Simcock as described in the methods.
Apiary visit data with the appropriate metadata for our study were collected from 2006 through to 2017 with between 4,714 and 8,926 observations per annum. Except for seasonality if inspections, there are no gaps in the visit data and their spatial scale is across England and Wales. Honey bee import data were gathered between 2006 and 2017, with no gaps and honey bee imports were received from 25 countries (as stated in the manuscript).
Some apiary visit data fell outside the land mass of the UK and so was excluded due to location recording errors (40 of 79,873). Similarly, 2% of the honey bee imports could not be assigned spatially and so were also excluded.