Both of my dogs have started leaking in there sleep. What is this?

Hello there. I have two Pit Terriers who have almost simultaneously started "leaking" as they sleep. I just read a response to a similar issue (http://www.askavetquestion.com/answer_np.php?id=20-dog-leaking-urine-when-sleeping) but my brother is worried that it could be something one dog caught from the other. Is this at all plausible?To expand on his concern, he fears that it's a virus or some sort of infection because a lot of canine disease is transferred through stool and urine.

Are they male or female? Spayed and Neutered? Incontinence, and a UTI are the most common cause of "leakage." They both should see the Vet.