Citation: Chen, Y., Evans, J.D., Murphy, C.A., Gutell, R., Lee, J., Zuker, M., Gundersen, D.E., Pettis, J.S. 2009. Morphological, molecular, and phylogenetic characterization of Nosema cerana, a microsporidian parasite isolated from the European honey bee, Apis mellifera. Journal of Eukaryotic Microbiology. 56(2):142-147.
Interpretive Summary: Nosema is a serious disease of honey bees. Previously, we showed that Nosema ceranae, a newly recognized cause of this disease, is in fact a long-term and predominant pathogen of honey bees in the U.S. Here we present the first full pathological analysis of this pathogen. The results indicated that Nosema ceranae not only infects the digestive tract of honey bees, but also spreads to multiple tissues in the host. The information from this study can be used by other researchers and apiary inspectors to investigate honey bee colonies for disease infections and to develop effective strategies for disease control.
Technical Abstract: Nosema ceranae, a microsporidian parasite originally described from Apis cerana, has been found to infect Apis melllifera and is highly pathogenic to its new host. In the present study, data on N. ceranae ultrastructure, host tissue tropism, secondary structures of ribosomal RNA, and phylogenetic relationship with other microsporidia species are described. The ultrastructural features indicate that N. ceranae processes all of the characteristics of the genus Nosema. Spores of N. ceranae were measured approximately 4.4 x 2.2 µm on fresh smears. The number of coils of polar filament inside spores was 18 to 21. The infection of N. ceranae was found not only in the primary infection site, the midgut, but also in the tissues of hypopharyngeal glands, salivary glands, malpighian tubules and fat body. The infection rate and parasite dosage in fat body were relatively low compared to other examined tissues. Maximum parsimony analysis of the SSUrRNA showed that N. ceranae appeared to be more closely related to the wasp parasite, N. vespula than to N. apis, a parasite infecting the same host. The complex biological features and virulence of this parasite in the honey bee host invite further research.