No abstract

Microsporidiosis (nosema disease) of the European honeybee (Apis mellifera L.) is present in bee colonies worldwide. Until recently, Nosema apis had been regarded as the causative agent of the disease, which may have many negative effects on the colony and cause heavy economic losses in apicultures. Another microsporidium species, Nosema ceranae, was reported to infest the Asian honeybee (Apis ceranae), but both honeybee species are susceptible to both microsporidia. In the European honeybee N. ceranae was first detected in Spain in the year 2006. As it is difficult to distinguish N. ceranae and N. apis morphologically, a rapid and accurate assay has been developed to differentiate N. apis and N. ceranae based on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the partial large subunit ribosomal RNA. The assay was tested on 38 Nosema-infested bee samples, which were collected from geographically distant Hungarian bee colonies representing all regions of the country. Only one sample contained N. apis, and in the other 37 samples N. ceranae was detected, which indicates the dominance of N. ceranae in Hungarian apiaries. This is the first report on the presence of N. ceranae in Hungary.

1Phylogenetic analysis of 22 Black queen cell virus (BQCV) genotypes collected from 2 honeybee colonies in Poland, Austria and Hungary was performed on a partial helicase 3 enzyme coding region (ORF1) and on a partial structural polypeptide coding region (ORF2). 4While the phylogeny based on the ORF2 region showed -with the exception of one strain 5 from Poland -clustering of the genotypes corresponding to their geographic origin, the 6 ORF1-based tree exhibited a completely different distribution of the Polish strains: three of 7 them clustered within a branch clearly separated from all other central European BQCVs, 8 while four other Polish strains remained well within the central European BQCV genotypes. 9In order to investigate this discrepancy in more detail, the nearly complete genome sequences 10 of the 3 differing Polish strains were determined, together with one Hungarian sample. The 11 sequences were aligned to each other and to the reference strain from South-Africa. 12Comparison of the different genome regions revealed that the 5'-UTR and the intergenic 13 regions of the BQCV genome are highly conserved with longer homologous sections. ORF1 14 (non-structural protein coding region) was found more variable compared to ORF2 (structural 15 protein coding region). The 5'-proximal third of ORF1 was particularly variable and contained 16 several deletions / insertions. The sudden changes in the similarity levels of BQCV strains in 17 different genomic regions are indicative of preceding recombination events.