> fumagillin has been implicated as contributing to the near universal replacement of N. apis by N. ceranae
> If this case is true why In the EU where Fumagillin is not registered or allowed?

I already commented on this. The key word is *implicated*. The actual statement appeared in Rogers and Williams 2008 paper:

> Future studies should also investigate if fumagillin is favoring displacement of N. apis by N. ceranae because it is more effective against the former.

Williams includes the statement in his 2013 thesis. However, he adds to this:

> N. ceranae has a high prevalence in countries that outlaw the use of antibiotics, such as Switzerland, Greece, and Italy (Klee et al., 2007; Charrière and Neumann, 2010). It is therefore unlikely that management with Fumagilin-B® favours one Nosema species over the other; however, experiments are needed to confirm this and other potential management options.

He goes on to present other possible explanations:

> The apparent displacement of N. apis by N. ceranae in many regions of the world as reported by Klee et al. (2007) could be explained by asymmetric competition resulting in greater spore production by N. ceranae that subsequently results in increased parasite horizontal transmission. Genetic and environmental factors (e.g. temperature as discussed previously) experienced under natural conditions likely influence fecundity of both N. apis and N. ceranae. This possibly created opportunities for asymmetric competition, and subsequent spatial and temporal heterogeneous displacement of N. apis.

These are conjectures, of course. And they could be reinforced or dismissed by future discoveries, such as the discovery that N. c. has been in Brazil for many decades. I already stated that I brought the topic up solely as an example of what could happen if antibiotics are misused. They have unwanted side effects, that much is certain. And one clear example of the misuse of antibiotics is feeding them to livestock solely for prophylactic or stimulative purposes, in the absence of a clear cause and effect relationship between 1) the pathogen and the host and 2) the drug and the pathogen. In Williams and Rogers work, considerable doubt is raised. For example:

> I observed that N. ceranae infection significantly reduced honey bee longevity in the laboratory but did not influence overall colony health or strength in the field.

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