|Chen, Yanping - Judy|
|Boncristiani jr, Humberto|
Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/13/2009
Publication Date: 5/27/2009
Citation: Chen, Y., Evans, J.D., Zhou, L., Boncristiani Jr, H.F., Kimura, K., Xiao, T., Litkowski, A.M., Pettis, J.S. 2009. Asymmetrical Coexistence of Nosema ceranae and N. apis in Honey Bees. Journal of Invertebrate Pathology. 101:204-209. Interpretive Summary: Nosema is a small parasite that lives in the digestive tract of honey bees and causes serious damage to adult honey bees and may also be associated with Colony Collapse Disorder (CCD). In order to develop effective preventive and control measures for this parasite, we developed a novel method for simultaneous detection and quantification of Nosema infections in honey bees. This has great practical value, as Nosema causes no obvious disease symptoms even though the disease it causes has significant impact on honey bee health. The strategy reported in the present study should contribute to the better design of appropriate measures for bee populations at risk for Nosema infections. The results have relevance to scientists, regulators, and beekeepers seeking to mitigate recent bee losses.
Technical Abstract: Globalization has provided opportunities for parasites/pathogens to cross geographic boundaries and expand to new hosts. Recent studies showed that Nosema ceranae, originally considered as a microsporidian parasite of Eastern honey bees, Apis ceranae, was the disease agent of Nosemosis in European honey bees, A. mellifera, along with resident species, N. apis. Further studies indicated that N. ceranae is highly pathogenic to its new host and that disease caused by N. ceranae is far more prevalent than that caused by N. apis in European honey bees. In order to gain more insight into the evolutionary history and epidemiology of Nosema parasitism in honey bees, we conducted studies to investigate Nosema infection in its original host, Eastern honey bees, using conventional PCR and duplex real time quantitative PCR methods. Our results showed that host shifting also occurred for N. apis and that N. apis not only attacks European honey bees but also Eastern honey bees. Within co-infected bees, N. ceranae is the more predominant infection of the two Nosema species in Eastern honey bees, as shown by its greater infection rate and higher concentration within bee hosts, compared to N. apis. Phylogenetic analysis based on partial small subunit ribosomal RNA (SSUrRNA) gene sequences of N. apis and N. ceranae revealed that natural selection and adaptive processes in the new host environment appear to be the major forces responsible for genetic variability of both Nosema species and that geographical distance do not appear to have influence on the genetic diversity of Nosema populations.