Sure, its only in Britain at the moment, but so was Mad Cow until recently. Nature.com is reporting that a specific strain of liver disease in cows actually obscures tests for bovine TB:
The liver fluke Fasciola hepatica was already known to affect the standard skin test for bTB, but it was unclear whether the fluke stopped the disease developing or merely hid the symptoms. A study published today in Nature Communications suggests that the latter is more likely, and that the effect is significant. It estimates that around a third of bTB cases in England and Wales are undiagnosed because the test is less sensitive in cattle infected with the fluke1.
The report goes on to say that the US, Canada and Australia have “eradicated” the liver fluke that is obscuring the test results. But you know how that goes.
