Abstract
Unfortunately, in the last few years a large-scale colony loss called Colony Collapse Disorder syndrome reduced the overall number of hives in different countries. However, the cause of this is still not clear and for this reason the Department for Environment, Food and Rural affairs (DEFRA) funded this research in order to gain a better knowledge of honey bee virus epidemiology and taxonomy in England and Wales. A National level sampling plan was designed to be statistically representative of the honey bee population present in England and Wales. In order to detect viruses at low prevalence level, a new viral RNA extraction method based on virus precipitation was developed and the viral RNAs obtained were screened for eight honey bee viruses using Real Time rt-PCR. Once information about the prevalence and the distribution of the eight honey bee viruses was obtained, a further characterisation of Deformed wing virus DWV and Black queen cell virus BQCV was performed using classic rt-PCR coupled with Sanger sequencing, and phylogenetic trees were obtained using bioinformatic tools. The viruses, grouped according to their nucleotide similarity, were reported on a geographically referenced map in order to highlight the distribution of the variants found in England and Wales. The results obtained in this thesis have resulted in a better knowledge of the epidemiology and taxonomy of honey bee viruses, determination of the full sequence of Slow paralysis virus SBPV for the first time, and a new virus RNA extraction method that can be exploited in other research fields.