European foulbrood disease: Status of New Zealand’s honey bees

European foulbrood disease caused by the bacterium Melissococcus pluton is notifiable under the New Zealand Biosecurity Act 1993 and the honey bee population is free from the disease. This statement is based on information from the Ministry of Agriculture apiculture surveillance programme.

1. New Zealand Beekeeping Industry

The New Zealand beekeeping industry is composed of 5,306 beekeepers with 24,379 apiaries containing 286,806 hives of bees (as at June 30 1996). A commercial beekeeper is one that has at least 50 hives and this group of 502 beekeepers own 17,513 apiaries containing 260,729 hives.

All beekeepers are required by legislation (Apiaries Act 1969 as saved by Section 182 of the Biosecurity Act 1993 and its amendments) to register all their apiaries and to provide the Ministry of Agriculture with an annual report on their disease status. The Ministry of Agriculture maintains the register which contains detailed information on all beekeepers, including the location of their apiaries, the number of hives in each apiary and the disease status of the bees.

2. Ministry of Agriculture apiculture surveillance programme

2.1 Active surveillance:

The Ministry of Agriculture has 19 trained and experienced apiculture officers who with support from the government animal health laboratories undertake active surveillance for a number of exotic and endemic diseases. Five hundred apiaries in what are considered high risk areas for entry of exotic bee diseases are inspected annually for the presence of European foulbrood disease. Samples from colonies showing suspicious symptoms are sent to an animal health laboratory for smear examination.

A further 500 apiaries producing live bees for export are inspected during the 6 months prior to the export season. Hives exhibiting suspicious symptoms are sampled for laboratory examination.

In the year ending 30 June 1996, 48 samples were taken for testing for European foulbrood disease. Since 1990 there have been four cases were the results of the bacteriological smears have been suspicious and the samples have been referred to a reference microbiologist for further examination and culture. The cultures have all been negative for M. pluton.

In October 1991 a sample of brood taken from a beehive in Nelson produced a suspicious smear result and when referred to a reference laboratory in Camden, Australia was tentatively identified as containing M. pluton. A total of 4,163 hives from 377 apiaries in the surrounding area were inspected and 988 smears were taken from 755 hives. All were negative for M. pluton. Streptococcus faecium was cultured from the sample sent to Camden. It was considered that the clinical signs that initiated the exotic disease response were those associated with halfmoon disorder and that the bacteria seen on the smear were S. faecium which resemble M. pluton.

2.2 Passive Surveillance:

As part of the beekeeping industry funded disease control programme Ministry of Agriculture inspectors annually inspect 990 apiaries for the presences of the endemic disease American foulbrood. During these visits inspectors maintain surveillance for all exotic diseases including European foulbrood. Up to 1000 additional apiaries are inspected by members of the beekeeping industry as part of the same programme.

Further inspections occur as part of the Export Certification audit programme. Beekeepers in New Zealand are required to inspect their own hives at least once during the spring months of each year and furnish a report to Ministry of Agriculture.

There is an active public relation and training programme for beekeepers and the industry is very aware of the importance of reporting any suspicious clinical symptoms.

3. Polymerase chain reaction (PCR) development

Because the culture test for M. pluton is slow and limited in its sensitivity the New Zealand Ministry of Agriculture is developing a PCR for diagnostic screening of samples. This test should be available for routine use in 1998.

Conclusion

The results from the active and passive surveillance programmes provide good evidence that M. pluton is not present in the New Zealand honey bee population.

References

Anon. Suspected European foulbrood investigation. Surveillance 15(5), 7, 1988

Reid GM. Diseases of honey bees in New Zealand. Surveillance 15(5), 15-7, 1988.

Van Eaton C. New developments in the control of honey bee diseases in New Zealand. Surveillance 19(1), 8-9, 1992.

Page last updated: 7 August 2008