Problems with Pack Rats Sometimes called pack rats due to their habit of lining nests with various objects, woodrats are found throughout the United States. About the size of Norway rats, pack rats have large eyes, protruding ears, and furry tails. Their nests are made up of different materials and may grow over time to more than four feet across. Woodrats can easily infest homes, vehicles, and other structures to build their nests. Once inside, residents can be exposed to a variety of illnesses. Diseases Carried by Pack Rats Pack rat diseases are similar to those carried by other rodents. One of the more serious is plague. Caused by bacteria, plague spreads through direct contact with an infected pack rat or the bite of fleas carried by the pest. Exposure to pack rat urine or feces can lead to other ailments such as leptospirosis, which can cause kidney damage, meningitis, and liver failure. Effective Control and Removal Exposure to pack rat diseases typically occurs when the pests get inside homes or buildings. Once an infestation starts, complete removal and future prevention can be tricky without the help of trained professionals like those at Critter Control.