Bee keeping is global. The honey bee, Apis mellifera is not native to North America. It was intentionally introduced by Europeans who migrated to North America. Ever since, there has been movement of honey bees between Europe and many parts of the globe. Trade has greatly increased in the past quarter century as bee keepers ship bees to share their stock.
The increase in trade has its downsides. The Varroa Mite, is an exotic parasite of honey bees introduced to North America late last century. The spread of Varroa Mite eliminated most feral honey bee colonies and bee keepers in North America were forced to control mites in their bee hives. Global trade is suspected of transporting additional bee parasites and pathogens. Further facilitating the spread, commercial bee keepers transport over half the bee hives in the US to California for almond pollination every year. The close contact allows pathogens to freely pass between hives enhances continental spread.
Australian bee biologist, Robert Owen* writes about these issues. His article is a call for bee keepers to reexamine practices and make modifications that limit the spread of disease and parasites.
*Robert Owen. Role of Human Action in the Spread of Honey Bee Pathogens. Published: 06 April 2017 J Econ Entomol tox075.