Bee populations have taken a hard hit, and it appears humans are to blame for the recent decline. Researchers from the Universities of Exeter and California, Berkeley, have discovered that a deadly bee disease that originated in European populations has spread worldwide as the result of importing infected honeybees.

What's worse: bee colonies are suffering from what researchers call a "double blow." The dreaded Deformed Wing Virus paired with Varroa destructor mites, which feed on bee larva, has wiped out millions of honeybees within recent decades.

Now researchers have finally tracked that the vast majority of infected hives can be to one source – Apis mellifera, the European honey bee.

"This is the first study to conclude that Europe is the backbone of the global spread of the bee killing combination of Deformed Wing Virus and Varroa," lead author Dr. Lena Wilfert, of the University of Exeter's Centre for Ecology and Conservation, said in a news release. "This demonstrates that the spread of this combination is largely manmade – if the spread was naturally occurring, we would expect to see transmission between countries that are close to each other, but we found that, for example, the New Zealand virus population originated in Europe."

Bees, and especially queen bees, are frequently traded to improve crop pollination. For their study, researchers analyzed genetic samples collected from honeybees and Varroa mites in 32 locations of 17 countries.

"This significantly strengthens the theory that human transportation of bees is responsible for the spread of this devastating disease. We must now maintain strict limits on the movement of bees, whether they are known to carry Varroa or not," Wilfert added in Exeter's news release. "It's also really important that beekeepers at all levels take steps to control Varroa in their hives, as this viral disease can also affect wild pollinators."

The study was recently published in the journal Science.

Related Articles

Wild Bee Decline Threatens US Agriculture; First National Map of Bee Populations Created In Response

Plastic Pollution Impacts Oyster Reproduction, Researchers Say

For more great nature science stories and general news, please visit our sister site, Headlines and Global News (HNGN).

-Follow Samantha on Twitter @Sam_Ashley13