The scientists inadvertently found tobacco ringspot virus (TRSV) during routine screening of bees.
“The results of our study provide the first evidence that honeybees exposed to virus-contaminated pollen can also be infected and that the infection becomes widespread in their bodies,” said lead author Ji Lian Li, at the Chinese Academy of Agricultural Science in Beijing.
He added that the honeybees can also spread TRSV as they move from flower to flower and between plants.
TRSV is particularly dangerous since it produces a flood of mutations that infect in different ways.
Bee colonies found with high levels of various viral strains were less successful in surviving harsh months last winter than those with lower levels of infections.
One-third of U.S. honeybee colonies died off during the winter of 2012-13, a 42 percent increase in fatalities from the previous winter.
TRSV infections could be at least one factor behind colony collapse disorder, which has stumped scientists for years.