Honeybees are essential pollinators for most of the crops, oil seeds, vegetables and ornamental flowers. In 2000, the value of American crops pollinated by bees was estimated to be $ 14.6 billion. Simultaneous infections of deformed wing virus and acute bee paralysis virus were most frequengly observed in colonies suffering from weakness, depopulation and sudden collapse. Variances were found in the distribution of black queen cell virus and sacbrood bee virus. There was less than a 2% difference in the RNA-dependent RNA polymerase (RdRp) sequences between kakugo virus strains from aggressive workers and those from other worker populations. The distribution of deformed wing virus infection within the honeybee reproductive castes (queens, drones) was investigated by in situ hybridization and immunohistology from paraffin embedded sections. It spread in digestive tract of the bee but also in the whole body, including queen ovaries, queen fat bodies and drone seminal vesicles. It was suggesting that colony disease outbreaks might result from environmental factors that lead to activation of viral replication in bees.