blue-tongue moves north

A disease that normally only occurs in tropical or subtropical parts of the world made its first appearance in the UK last spring. It could be the first hard evidence that global warming is starting to change disease patterns around the world.

While this story carries an important message about human disease, this time at least, it was an animal disease that has moved. It’s the blue tongue virus, which affects cattle, sheep and goats.

It can be a devastating illness with up to a 70% mortality rate in sheep. The warmer temperatures have allowed blue tongue to gradually spread northwards in recent years, from Africa into southern Europe. That’s because the virus is carried by midges, which have headed north with the warmer weather.

But a shock came two years ago…blue tongue stopped following its well-predicted path and suddenly jumped into much colder northern Europe.

Professor Peter Mertens: An experienced veterinarian in Holland who saw a sick sheep and said: “Hey guys that looks like blue tongue to me, you know, out of the blue” and I imagine most people said “you’re kidding, it’s never been this far north”.

ABC (Australia) Catalyst, 8 May 2008