I just had my rat dissection today and my rat had an abnormality in which the smell was even more intense than usual and the kidneys were extremely enlarged. The supervisors all seemed to be talking about it but they didn't tell me anything and got me to just use one of the supervisor's mice. I'm a bit concerned - I know the rats are supposed to be disease-free and all but what if mine wasn't? I don't want to get infected or anything. :S
There are a very, very, very tiny number of diseases that humans share with rats (though wasn't it a mouse dissection? same goes anyway). Furthermore, there are plenty of diseases that can cause those kind of symptoms that have nothing to do with a pathogen.
Although I will make the point, Alon, they don't actually allow us to wear gloves :| Well, we can bring in our own, but the university refuses to supply any for dissections, nor do they warn students before their first dissection.