Laboratory diagnosis of AFB

Samples suitable for laboratory testing

Getting suspect material tested for AFB spores can be a useful tool in eliminating AFB. Also samples of abnormal brood can be examined in the laboratory for the presence of AFB spores. It is also possible to test samples of bees or honey from beehives for the presence of spores. See more on sample types.

What the tests involve

Two tests are used. The first is a microscopic analysis, and is only used for samples of suspect larvae or pupae. The test involves making a smear on a microscope slide, fixing the smear to the slide using heat and carbol fuchsin stain, and then examining the smear for AFB spores using the oil immersion objective of a microscope. The total magnification required is 1000x.

The second test is a culture test, and involves growing out bacterial cultures of AFB. The test can be used with samples of adult bees, honey, or suspect larvae/pupae, and can be carried out in a home laboratory. A dilution of the sample is prepared, and then heated at 92°C for 20 minutes to kill all competing bacteria, but not the AFB spores. A small amount of the liquid is applied to a Petri dish containing sterile brain heart infusion agar, and then the plate is incubated at 37°C for three days. The plate is then inspected for the presence of AFB bacterial colonies.

Laboratory testing is free of charge

The cost of testing suspected larvae or pupae in New Zealand is currently paid for by the AFB NPMS. If you wish to get a sample tested, contact the Management Agency for instructions and a laboratory submission form.

 

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