How natural infection by Nosema ceranae causes honeybee colony collapse, an article by M. P. Higes et al., Bee Pathology laboratory, Centro Apícola Regional, Spain, which was presented at OIE Apimondia Symposium Freiburg 2008, appears in the current issue of Environmental Microbiology, 18 July 2008.
In recent years, honeybees (Apis mellifera) have been strangely disappearing from their hives, and strong colonies have suddenly become weak and died. The precise aetiology underlying the disappearance of the bees remains a mystery. However, during the same period, Nosema ceranae, a microsporidium of the Asian bee Apis cerana, seems to have colonized A. mellifera, and it’s now frequently detected all over the world in both healthy and weak honeybee colonies. For first time, we show that natural N. ceranae infection can cause the sudden collapse of bee colonies, establishing a direct correlation between N. ceranae infection and the death of honeybee colonies under field conditions. Signs of colony weakness were not evident until the queen could no longer replace the loss of the infected bees. The long asymptomatic incubation period can explain the absence of evident symptoms prior to colony collapse. Furthermore, our results demonstrate that healthy colonies near to an infected one can also become infected, and that N. ceranae infection can be controlled with a specific antibiotic, fumagillin. Moreover, the administration of 120 mg of fumagillin has proven to eliminate the infection, but it cannot avoid reinfection after 6 months. We provide Koch’s postulates between N. ceranae infection and a syndrome with a long incubation period involving continuous death of adult bees, non-stop brood rearing by the bees and colony loss in winter or early spring despite the presence of sufficient remaining pollen and honey. PMID: 18647336 [PubMed - as supplied by publisher]
It’s worth repeating that healthy colonies near to an infected one can also become infected. Treatment with fumagillin can control Nosema ceranae, but it can’t prevent the colony from becoming infected again after 6 months. And of special interest, perhaps, for our beekeepers who have experienced unusual over-wintering losses in recent years: “Signs of colony weakness were not evident until the queen could no longer replace the loss of the infected bees.”
When you’ve been into honey bees for a while, don’t all the bee books start to look the same? Well, The Buzz about Bees by Jürgen Tautz, translated into English just this summer by David Sandeman, is a honeybee book with a real difference. 
Eleven teams compete in the 13th series of 