Scientists say they may have solved a centuries-old whodunit: Why did Europe experience outbreaks of bubonic plague over hundreds of years, starting with the Black Death of 1347 to 1353?

Maybe you can blame gerbils in Asia.

The disease is caused by a bacterium that lives in rodents. The general thought had been that once the germ arrived from Asia to kick off the Black Death, it settled into European rodents and periodically jumped to humans until it disappeared in the early 1800s.

But now, scientific sleuths are suggesting that the true source of those periodic outbreaks was Asia. Maritime trade may have inadvertently imported the disease repeatedly from its ultimate reservoir, great gerbils and other small mammals in Asia, they suggest.

"I don't think there was any sustainable reservoir in Europe," Nils Stenseth of the University of Oslo said Tuesday in an email.