[1] In 1996, Lipa and Triggiani transferred it to the new genus Apicystis on the basis of morphology and life cycle.
[2] Further finds were made in Italy over the next few years with the level of infection in Bombus species being considered low and that in A. mellifera sporadic.
With specimens being found in Canada, France, Italy, Finland and Switzerland, it is likely that the parasite is cosmopolitan in distribution and will be identified in other countries.
[3] However extensive sampling in the Pampas, the most productive honey-producing region of Argentina, failed to detect it there.
[6][7] The introduction of B.terrestris into certain regions of Patagonia and southern South America (starting around the 1980s) have led to the rapid decline of Bombus dahlbomii populations in the area.
They migrate through the wall of the gut before taking up residence in the fat body cells, where they develop and multiply.
[14] There is also some evidence that Deformed wing virus may reduce some of the negative effects of Apicystis bombi.