Pneumonia occurs when there is a severe inflammation in the lungs leading to dysfunction of the entire respiratory system. This inflammation may be due to a bacterial, fungal, viral or parasitic infection, or because the rabbit has inhaled a foreign object into its lung.
Environmental factors, such as smoke or chemicals, an inability to swallow, coma, and dental disease may also lead to pneumonia.
Some common signs seen in all four major types of pneumonia include:
The bacterial form of pneumonia occurs when the responsible organism enters the lower respiratory tract, primarily through inhalation or choking, but an organism can also enter the body through the bloodstream. The body responds severely with bronchitis, swelling, lack of blood supply, tissue death, abscess formation, and even lung collapse. If the animal has a poor immune system, then even bacteria that are normally present in the mouth, throat and lungs can become infectious. Due to all of this, there may be very low levels of oxygen available in the blood.
Fungal infections usually occur when the spores are inhaled, entering the lung (and sometimes the bloodstream). This triggers the rabbit's immune system to send white blood cells to fight the invading organism. These cells are then intercepted and engulfed by the organisms, releasing a chemical (cytokine) which impairs oxygen distribution in the lungs.
Viral infections occur in much the same way, except it is the virus which enters the lung and releases the cytokine. However, viruses also make rabbits more susceptible to bacterial infection; for this reason, bacterial pneumonia can be a related complication of viral pneumonia.
Parisitic pneumonia, on the other hand, occurs when a parasite enters the skin or is inhaled, causing cellular damage in the lungs and depriving the rabbit of oxygen.
The making of a fine mist; usually used to administer certain drugs
The part of the respiratory system that holds the bronchial tree and the lungs
The condition of being drowsy, listless, or weak
A localized infection, usually a lesion filled with pus. Can be large or small in size.