I blogged previously (last 15 December) about some of the studies that are being carried out to try to understand the mechanistic bases for the variety of means by which bee colonies are disappearing (and we have announced a £10M initiative in this area). Some of these causes are likely to differ considerably, since while Colony Collapse Disorder (CCD, mainly in the USA) or Honey Bee Depopulation Syndrome (HBDS, in Europe) is characterised by a disappearance of the bees, other causes of death leave the bees dead in hives in situ. A genomic study in 2007 by Cox-Foster and colleagues suggested that Israeli Acute Paralytic Virus might be a major culprit, though inspection of the data was at least consistent with the view – and maybe more so – that a microsporidian fungus called Nosema ceranae might make more of a contribution to CCD. It was also recognised that there is unlikely to be a unitary cause – “varroa mites, bacteria, viruses, fungi, temperature changes, food shortages, herbicides/pesticides/insecticides and other sources of stress may be well tolerated if the challenges are presented alone, but when they appear together may overwhelm an organism’s defences”, such that the exact combination in any given instance may well vary considerably. There was an excellent programme on “Who killed the honeybee?” on BeeBeeC4 that I thought covered a great many of the issues with estimable scientific accuracy (and that was very scary).

Higes and colleagues (e.g. papers by Higes et al. (2006), by Martín-Hernández et al. (2007), and by Klee et al. (2007) and by Higes et al. (2008)) have championed the view that it is indeed N. ceranae that is of especial significance, and a particularly attractive result was the fact that the infection underlying the CCD caused by N. ceranae could be controlled using the antifungal fumagillin.

In a new paper, Higes and colleagues now report that in a number of professional hives in two regions of Spain that experienced a syndrome akin to CCD, N. ceranae was the only pathogen observed in all cases, that pesticides seemed not to be involved, and that even in these colonies, post-application of fumagillin proved effective in stopping reinfection and permitting survival. Although the numbers of colonies were comparatively small, if this important result holds up it could provide a means of stemming and maybe preventing the damage caused by the fungus. It could also help as a tool in achieving a greater understanding of the detailed mechanisms of infection and dispersal of the organism. All of this will contribute to the Food Security agenda, a topic I discussed on the Today programme recently.

Related posts (based on tags and chronology):