There are several baddies that can be gotten from rat droppings.
Hanta virus for one, was a problem on indian reservations in the four corners area a few years ago.
One of the others is a fungal disease called histoplasmosis (probably not spelled that way.) Histo is a real baddie and hard diagnose from what I have seen, however I think they have some new reaction markers for it, the lab mixes the culture with the marker and it lights up in spots or turns a certain color or some other indication that indicates weather the histo is positive,.
Have you tried contacting your local poison control center? May be they can help you or give you some where to go.