In situ hybridization assays for localization of the chronic bee paralysis virus in the honey bee (Apis mellifera) brain

Chronic bee paralysis virus (CBPV) is a common single-stranded RNA virus which may cause significant losses in honey bee colonies. As this virus seems to exhibit neurotropism, an in situ hybridization based method was developed to localize the genomic and antigenomic CBPV RNAs in infected honey bee brains. Double-stranded cDNA probes as well as genomic and antigenomic-specific single-stranded cDNA probes were prepared, using the polymerase chain reaction in presence of labelled d-UTP with non-radioactive digoxigenin. Both genomic and antigenomic RNAs were detected the brain of honey bee infected naturally or artificially. Hybridization signals were obtained in some somata and neuropile regions of the brain. In particular, high signals were observed at the level of the mushroom bodies and central complex, regions that are known to be engaged in higher neuronal functions and in the optic and antennal lobes that are sensorial neuropiles. Thus, the presence of virus at these levels may explain the nervous symptoms observed in infected bees. The in situ hybridization procedure proved to be a useful tool to localize specifically CBPV and may be helpful for understanding the observed symptoms. (C) 2008 Elsevier B.V. All rights reserved.