Lung and Airway Disorders in Rats

PetMD Editorial
By PetMD Editorial
Published: June 19, 2010
Lung and Airway Disorders in Rats

Murine Mycoplasmosis and Other Respiratory Affections in Rats

Respiratory infections are quite common in rats. There are several bacteria and viruses that can lead to disorders of the lungs and airway. Among the lung and airway disorders affecting rats, murine mycoplasmosis, or chronic respiratory disease, is a bacterial infection that has the potential to become a very severe condition, causing both short term and long term respiratory problems. The murine mycoplasmosis infection is also capable of traveling to the genitals and infected these organs as well as those of the respiratory system.


  • Sneezing, sniffling, coughing
  • Difficult breathing
  • Reddish-brown staining around the eyes and nose
  • Rough hair coat
  • Lethargy
  • Weight loss
  • Head tilt due to ear infection
  • Hunching, avoiding contact
  • Genital symptoms may include inflammation or blood in urine (hematuria)
  • Infertility in female rats due to spread of untreated and severe infections from the respiratory tract to the internal organs (i.e., uterus, ovaries)


An unclean housing environment is the primary cause for lung and airway disorders such as murine mycoplasmosis. Many other lung and airway diseases may be transmitted between rats by several routes, depending on the specific organism, including direct contact with infected rats, contaminated feces, or sneezing and/or coughing on one another. Other frequent causes include:

  • Direct contact with airborne bacteria
  • Sexual contact with an infected rat
  • Infected mother (which then passes it along to her offspring during birth)


Lung and airway disorders can be diagnosed by the characteristic respiratory symptoms that are exhibited by the affected rat. The underlying causes can be confirmed mainly by culturing and identifying the bacterial or viral species that is causing the infection.



There is no cure for this condition. However, this is a chronic rather than acute (sudden) condition, so suffering is generally not an issue unless the condition is not addressed and it is allowed to progress over a long period of time. If the condition is treated early, with the appropriate antibiotics, your rat may live happily for another two to three years. Supportive care, along with keeping your rat's environment clean will also be helpful in maintaining its health over a long term.

Living and Management

Keeping your rat's living environment clean, and in particular, reducing ammonia levels (due to urine) in the cage, along with prompt, regular treatment for the infection, are the best ways to fight this disease. Consult your veterinarian about the best supportive care, and what your rat's needs are during the recovery period.


Respiratory infections in rats can be highly contagious to other rats. The bacterial and viral causes for these types of respiratory infections are transmitted through contact with contaminated feces, urine, and bedding material. Properly cleaning your rats cages regularly, removing any feces and urine daily, and changing soiled bedding material routinely are essential. As much as possible, avoid housing rats that are showing signs of respiratory infections with other rats in order to prevent the spread of respiratory infections to the healthy rats.

In keeping with a sanitized environment, be mindful of keeping your hands clean between caring for each rat.


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