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Assessing the effectiveness of the shook swarm method for controlling European Foul Brood - PH0502

Bees make an essential contribution to agriculture and the environment through pollination: they also produce honey and wax. The honey bee (Apis mellifera) plays a dominant role, being the major managed pollinator available to provide this service. Recent estimates for agricultural/horticultural crops grown commercially in the UK that benefit from bee pollination are in the region of £200m p.a. (Carreck & Williams, 1998: Bee World 79:3 115-123) while the value of honey production UK fluctuates between £10m and £35m p.a. Honey bees also importantly pollinate many wild species of flora. Pest and disease impact at its worst can cause high colony losses. High losses of bees to pest/diseases have occurred in the European Union (EU report, October 2003: Varroa situation in the European Union). There are an estimated 274,000 colonies of honey bees in the UK kept by about 44,000 beekeepers. Some 250,000 colonies are managed by 37,000 beekeepers in England and Wales. Around 300 beekeepers manage bees on a professional basis and are members of the Bee Farmers’ Association; collectively they manage around 40,000 colonies. The remainder are small-scale producers. The National Bee Unit (NBU) at the Central Science Laboratory implements the national bee health programme in England and Wales, underpinned by a programme of research and development to provide up to date technical support to beekeepers. The work includes disease/pest diagnosis, development of contingency plans for emerging threats, import risk analysis, related extension work and consultancy services to both government and industry.

As with other forms of livestock, honeybees are subject to a range of harmful diseases. Some of these affect the adult bees, others affect the immature stages of the bees' development (larvae and pupae) and these are referred to as brood diseases. One of these diseases is the serious and infectious brood disease known as European foul brood caused by the bacterium Melissococcus plutonius. Larvae usually die within 1-2 days before being sealed in their cells, or sometimes shortly afterwards, but always before pupation. The bacteria multiply in the mid-gut of an infected larva, competing with the larva for its food. They remain in the gut and do not invade the larval tissue; larvae that die from disease do so because they have been starved of food. Infected larvae that survive through receiving an abundance of food develop into adult bees. However, when such larvae pupate, they void the contents of their gut into the cell, contaminating as they do so the comb with millions of infective bacteria. Eventually the bacteria infect a high proportion of the brood and the colony will be weakened and ultimately killed. Currently there are several options for the control of EFB employed by CSL bee inspectors. If disease levels are perceived as low, applications of an antibiotic, Oxytetracycline (OTC), are known to assist colony recovery. Alternatively in cases of higher disease levels, the only course of action is to destroy the colony by burning. A third option is a husbandry technique known as the shook swarm.

Shook swarm has been developed as an alternative to the use of antibiotics to achieve improved disease control of EFB. Shook swarm involves transferring all adult bees from an infected hive into a clean hive, thereby removing the infected brood from the colony. Provisional results have shown shook swarm can offer higher levels of success with lower levels of recurrence of infection than OTC application. Shook swarm removes the primary inoculum source from the colony rather than simply suppressing the bacterial to sub-clinical levels. However, insufficient data is available on bacterial incidence to recommend shook swarm as an effective alternative to antibiotics for the treatment of EFB. The aim of this project is to measure the levels the bacterium Melissococcus plutonius, the causative organism of European foul brood disease, within colonies prior to and post the shook swarm treatment. Lightly and heavily infected colonies will be treated by shook swarm and monitored over one year. Sampling pre and post treatment during the active season followed by a further sample in the spring of the following season will track bacterial levels. Direct comparisons will be made with colonies conventionally treated with OTC and with apparently healthy colonies. In addition samples of bees and brood will be taken from apparently healthy colonies in disease free counties of England and Wales to attempt to map geographical incidence of the disease causing organisms and threshold levels of bacteria within colonies that lead to development of clinical signs of disease. All samples of adult bees and brood will be taken from each colony in the trial and levels of bacteria will be determined in the laboratory using quantitative molecular diagnosis.
This project will aim to:

1. Plant Health Division will establish a project steering group to discuss project progress and results. The group will provide guidance to the project team as necessary and appropriate.

2. Select infected apiaries and apparently healthy apiaries over the active beekeeping season for the purposes of the project. These will include lightly and heavily EFB infected colonies across England and Wales, and apparently healthy colonies in disease free areas and apparently healthy colonies in known diseased apiaries/areas.

3. Samples of adult bees, brood (larvae) will be taken from the colonies prior to and post carrying out the appropriate treatment. These will be: a) shook swarm, b) conventional antibiotic treatment with Oxytetracycline (OTC) and c) no treatment in the case of apparently healthy colonies. Sampling intervals will be prior to, just after treatment, at the end of the active beekeeping season, and at the beginning of the following active beekeeping season in Spring 2007.

4. These samples will be analysed for bacterial load at the CSL Molecular technology facility using TaqMan real time PCR technology and the results data added directly to BeeBase on line R&D secure pages. Details of sampling distribution will be mapped onto the NBU GIS and tracking of the project will also be included.

5. Colony condition: i.e. development and status of the colonies in the trial will be monitored and evaluated at monthly intervals post treatment until the beginning of the following active beekeeping season in April/May 2007

6. Disseminate information to stakeholders, beekeepers and inspectors and incorporate findings into extension programmes on managing foul brood disease effectively. Where appropriate scientific publications will also be produced.

Additional objectives proposed for 2007/8:

7. Assessment of whole apiary approach versus the current recommended best practice.

8. Cost benefit analysis of two shook swarm treatments.

9. Investigation of the role of adult bees and secondary bacteria in the epidemiology of EFB.

10. Investigation of the epidemiology of M. plutonius in adult honey bees.
Project Documents
• Final Report : Bee Health Final Project Report for PH0502   (658k)
• ROAME Document : Bee Health ROAME   (203k)
Time-Scale and Cost
From: 2006

To: 2008

Cost: £185,393
Contractor / Funded Organisations
Central Science Laboratory
Bee Diseases              
Bee Health              
Plants and Animals              
Fields of Study
Plant Health