It has been only a bit over 5 years since the presence of Nosema ceranae in Apis mellifera colonies has been widely known. 

> At the annual meeting of Society for Invertebrate Pathology in Anchorage, Alaska, 2005 it was reported that N. ceranae had been found in natural infections in A. mellifera in Taiwan (Huang et al., 2005). The apiary where the infection was detected had harboured both A. mellifera and A. cerana. Thus, it was apparent that N. ceranae could cross the host species barrier, although no data on bee pathological repercussions due to N. ceranae in Apis mellifera were mentioned by the authors. 
> 
> Almost at the same time and following progressively increased incidences of problems with nosema disease in Spain, the laboratory of Centro Apícola Regional, involved in diagnosis of honey bee diseases, confirmed for the first time in Europe N. ceranae in field samples of European honey bees.  
> 
> Many species of microsporidia cannot be distinguished using light microscopy and only with difficulty using electron microscopy. When the ultrastructure of spores is examined, differences between the two species are obvious. The polar filament of N. ceranae is consistently shorter with 20–23 coils  compared with N. apis, where the number of filament coils always is larger and spores often contain around 26–32 coils. Sequencing of the 16S SSU rRNA gene of microsporidian isolates clearly distinguishes the two parasite species.

Natural infections of Nosema ceranae in European honey bees
I Fries, et al. Journal of Apicultural Research 45(3): 230–233 (2006)

> Numerous methods have been developed for the diagnosis of microsporidia in hosts, including immunofluorescent staining, electron microscopy, and antigenic or biochemical analysis. Molecular techniques, particularly those involving the PCR and based on the amplification of ribosomal RNA (rRNA) gene fragments, seem to be superior because of their high specificity and sensitivity as well as their ability to detect all microsporidian developmental stages.

Specific and sensitive detection of Nosema bombi (Microsporidia: Nosematidae) in bumble bees (Bombus spp.; Hymenoptera: Apidae) by PCR of partial rRNA gene sequences
Julia Klee, et al. Journal of Invertebrate Pathology 91 (2006) 98–104

* * *

As an aside, German studies did not support the link between Nosema and colony collapse at all.

> In Germany, beekeepers experienced dramatic overwintering losses in the winter of 2002 to 2003, and they have reported an increase in overwintering mortality since then. To evaluate whether or not N. ceranae can be correlated with these losses, we conducted a cohort study over 5 years involving 220 colonies in the northeastern part of Germany, and we determined colony mortality and the incidences and prevalences of the two Nosema species.


> The results of our study also failed to reveal a relation between N. ceranae infection of colonies and colony mortality, even in seasons with unusually high colony loss rates. Likewise, monitoring of the fate of individual N. ceranae-infected colonies over several years did not show a mandatory link between this infection and failure of the colony. Instead, infestation by Varroa destructor and infection with deformed wing virus (DWV) and acute bee paralysis virus (ABPV) could be identified as pathogenic processes related with high significance to increased colony mortality in Germany.

Five-Year Cohort Study of Nosema spp. in Germany: Does Climate Shape Virulence and Assertiveness of Nosema ceranae?

Elke Genersch, et al. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, May 2010, p. 3032–3038 Vol. 76, No. 9


PS. I have an article on Nosema coming out soon in the American Bee Journal, watch for it!

- - - - - - - - - - - - -
Peter Loring Borst
128 Lieb Road
Spencer, NY  14883
peterloringborst.com
607 280 4253

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html

Guidelines for posting to BEE-L can be found at:
http://honeybeeworld.com/bee-l/guidelines.htm