Viral infections since a rat that is infected with the seoul virus can transmit the infection to other rats and people, the center for disease control (cdc) recommends euthanasia of infected rats. bedding issues a clean environment is key to a healthy rat. try using shredded paper in the cage instead of wood shavings. Up to that point the gas exchange of breathing occurs by way of smooth-walled channels and saccules. by day 13 the restructuring of lung parenchyma is complete. respiratory disease is among the most common health issue in rats. learning to recognize your rat’s normal healthy behavior can alert you to early signs of illness. The lower respiratory system is comprised of the trachea, bronchi, and lungs. the lungs of the rat, like in humans, lie on each side of the heart in the chest cavity, but rat lungs differ from humans in the division of lobes. the left lung of the rat contains one lobe while the right contains 4 lobes. in humans the right lung contains three lobes ...