It turns out that in some areas of the world, leeches are still used for certain medical purposes. This image is from Russia, for example.
Tony, where on earth do you find these? They're great!
A lot of them come from the Yahoo! News area where there are picture galleries from the AP and Reuters. Some of them come from weblogs that I follow. A few I've had for quite a while, just having kept them because they were interesting or funny. And eventually I'll post a few of my own shots, 3-4 of which fit pretty well into the whole scheme of "IotD".