TaqMan Virus Survey results

Last year I sent some bees off to the National Bee Unit to take part in their TaqMan Virus Survey. And this morning the results arrived (with an apology for the delay).

Of a total of 458 samples from across the UK, just three colonies in two apiaries showed up positive for the presence of Kashmir Bee Virus (KBV). The affected colonies are near Manchester and Hull. My bees are KBV-free.

According to their summary report (small pdf file), the findings suggest that KBV is not necessarily an exotic bee virus spread through imports or bee migrations. KBV may have been here for some time:

... TaqMan products from the three positive samples were cloned and sequenced, and the results confirmed the amplification of KBV sequence. All three colonies were in normal condition with respect to size for the time of year.

The implications for bee management are that varroa levels should be controlled to prevent viruses that are usually present from becoming a problem:

Many honey bee viruses occur in colonies as unapparent infections, they are present but in general do little harm. However, some associated with uncontrolled varroa infestations can intensify the effects of varroosis by acting as secondary associated pathogens and cause significant damage. Since viruses cannot be controlled directly, it is essential to control varroa effectively and in good time, before mite levels reach economic injury levels.

The KBV finding does not change the approach to varroa control. It is important to treat the vector, and keep mite levels down to below damage thresholds. Further work is planned in 2005 to evaluate and validate the use of TaqMan PCR for specific recognition of bee viruses using different strains of KBV. This will be done through a joint CSL/Rothamsted research project and through the continuing applied experimental programme.