Risks with Quarantining Mice and Rats in the same airspace

A friend of mine is going on a 10 hour drive to get some rats from another breeder, and asked me to come along. I was thinking I could see if any of the mice breeders out that way wanted to meet up while I was in that area. Then I thought about the QT risks. Is there a risk with transporting mice and rats in the same car (from different breeders). I know a lot of the diseases and stuff are species specific, but Ive never researched it as I am mouse-only.

Sendai is a nasty virus that can infect both rats and mice: http://www.rmca.org/Articles/dosanddonts.htm

And of course Mycoplasma pulmonis: http://ratguide.com/health/bacteria/mycoplasma_mycoplasmosis.php

Also, most parasites (external and internal) are shared between mice and rats. That means fleas, mites, lice, and worms of all kinds (some of which have airborne eggs). So, yes, mice and rats transmit disease between the two readily.

That said, picking up rats and mice from different breeders is no more risky than picking up just mice from the same number of breeders. The risk comes from the number of breeders involved, and also the quality of the husbandry at each of those breeders. If you're picking up from a mass-production-style feeder breeder, there's a bigger chance of infection/infestation than if you're picking up from even two or three small-scale high-quality breeders. If your breeders go to shows or gatherings, that increases your risk as well, because their mice/rats have been exposed in that way. I just mean to say that the fact that they're rats, rather than mice, does not increase the risk significantly.