I have a pet rat and two ferrets. My rat’s cage is pretty near the ferret cage. We keep her very clean, but I think she has something wrong with her. She has a huge lump on her abdomen. She’s 3 years old, and I lost her sister to a tumor about a year ago so I’m pretty sure this is the same, but at the same time I’m worried she may have some kind of disease that she could pass along to my ferrets. Is that possible?