Confinement causes dysentery. Nosema apis causes dysentery. Nosema ceranae has almost completely displaced Nosema apis and it does not cause dysentery.
"...and the rest of the Americas, where
the more virulent N. ceranae has possibly displaced N. apis..."
http://www.sciencedirect.com/science/article/pii/S0022201107001735
Freezing will kill Nosema ceranae spores. Freezing will not kill Nosema apis spores.
http://entomology.ucdavis.edu/files/147621.pdf
Fumigillan contributes to Nosema cernanae infection:
http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003185
And by killing the bacteria in their gut that protects them from Nosema, makes them more susceptible:
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033188
There is a good chance you just have simple dysentery. You can get a microscope and find out. There is much information on the internet on how to identify and count Nosema spores. Unfortunately it's not so simple to distinguish Nosema apis from Nosema Ceranae.
"...and the rest of the Americas, where
the more virulent N. ceranae has possibly displaced N. apis..."
http://www.sciencedirect.com/science/article/pii/S0022201107001735
Freezing will kill Nosema ceranae spores. Freezing will not kill Nosema apis spores.
http://entomology.ucdavis.edu/files/147621.pdf
Fumigillan contributes to Nosema cernanae infection:
http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003185
And by killing the bacteria in their gut that protects them from Nosema, makes them more susceptible:
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033188
There is a good chance you just have simple dysentery. You can get a microscope and find out. There is much information on the internet on how to identify and count Nosema spores. Unfortunately it's not so simple to distinguish Nosema apis from Nosema Ceranae.