Breathing Problems in Pet Rats

Respiratory problems are very common in rats

Pet white rat
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Veterinarians see pet rats most frequently for two main reasons. The first one is for tumors (usually mammary), and the second one is breathing problems. Both can be quite serious, but breathing issues are usually more acute and require a quick approach to treatment.

Rats' respiratory systems are delicate and easily irritated, so keeping a clean enclosure is especially important. This may seem contrary to the image most people have of rats in the wild, but for domesticated rats, cleanliness is critical.

Why Do Pet Rats Have Breathing Problems?

Several factors can contribute to breathing problems in rats. The type and condition of its bedding, an unclean environment and diseases can all cause respiratory distress in your pet rat.

Mycoplasmosis and Other Bacteria

Mycoplasma is a bacteria that almost all pet rats normally have. When a pet rat's immune system is weakened, either due to stress or from another disease, these bacteria cause an upper respiratory disease called mycoplasmosis in rats that when left untreated may morph into pneumonia.

Streptococcus, Bordetella (the same bacteria that give your dog a cough), Pasteurella, and other types of bacteria can also play a role in the severity of disease, but Mycoplasma is typically the primary reason for illness.

There is no cure for mycoplasmosis at this time; treating the symptoms of the disease is all you can do to keep your rat comfortable and slow the progression of the disease. Antibiotics and other medications will be prescribed by your vet based on the severity of the disease.

It is also important to note that Mycoplasmosis is very contagious. It can be passed to other pet rats very easily. So if you have other rats in your household, quarantine your infected rat from the others and thoroughly wash your hands after handling it.

New treatment techniques are slowly surfacing so your vet may choose to try something new with your permission, or perhaps one day a vaccine or cure will be found. Until then, rats can still live for several months after being diagnosed with Mycoplasmosis and maintain a decent quality of life while on chronic medications.


While these bacteria appear in rats with Mycoplasmosis and pneumonia, Streptococcus more often afflicts young rats. Under the microscope, it appears as gram-positive diplococci (two tiny purple circles) and is treated with antibiotics.

Treatment should be started immediately since the infection can quickly progress into pneumonia. Rats often die from Streptococcus infections, but you have a chance to save your rat if you start antibiotics before your pet rat contracts pneumonia.

If your rat seems lethargic, has excessive porphyrin tearing (from stress), isn't eating as much, or has any discharge from its nose, it should be brought to the vet as soon as possible. The animal will not just get better on its own and waiting to see if it does usually make things worse and harder to treat.

Bedding Issues

Bedding that's dusty, dirty, or consists of cedar shavings is the main culprit for respiratory disease when cage substrate is to blame. Don't use cedar shavings as substrate, and make sure the bedding stays clean and free of dust.

As with humans, too much dust in a rat's environment can cause respiratory problems, as will dirty bedding where mold might start to grow. Cedar bedding has long been known to irritate the respiratory tract and even cause liver damage. Instead, try shredded newspaper, which is economical and can be removed and replaced easily.

Colds and Pneumonia

Rats can also get colds from being too close to an air conditioning vent, window, or door. This can cause breathing problems and even turn into pneumonia if left untreated.

Upper respiratory tract infections often turn into lower respiratory tract infections and should be taken very seriously. These types of breathing problems may not be due to bacteria like Streptococcus or Mycoplasma but they should still be addressed as soon as possible.

Other causes for respiratory infections besides bacteria include airborne bacteria, or, a mother rat passing on an infection to its pups. A rat that mates with an infected rat also may contract a respiratory infection.


Rats often get tumors, especially along their mammary chains, which are roughly the rodent equivalent of mammary glands. Both male and female rats are susceptible to breast tumors and these tumors can spread throughout the body, including the lungs, causing breathing problems. A radiograph (x-ray) or CT scan are the best ways to tell if your rat has tumors in its lungs.

Treatment and Prevention

If your rat is having problems breathing, whether or not there is nasal or ocular discharge, seek help from your exotics vet and start treatment as soon as possible. The best way to prevent most respiratory problems in rats is to keep their enclosures clean. And don't allow your pet rat to be around other rats if you're not sure what diseases they may carry. Rats transmit disease to each other easily.

Even if your rat is diagnosed with an incurable disease like Mycoplasmosis, with timely treatment, it can still live a better life than if it's not treated.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.