Shmi and Leia have Chronic Respiratory Disease (CRD)

Hello again, readers,

This will be a fairly lengthy post discussing both Leia's and Shmi recent diagnosis of CRD - Chronic Respiratory Disease.
We've been on this journey, with the help of our phenomenal vet, Sarah Bruce, and the input of some exotic specialists, to try and best manage their clinical symptoms of CRD. We had to be realistic, pratical, and patient, throughout all of this in order to get the outcome we desired for both rats.

First, we will discuss Shmi and her medical history for CRD. Then, we will discuss Leia and her medical history for CRD. Finally, we will close this post with some additional information about CRD including; diagnostic tests, additional treatment (that we haven't tried), prophylaxes. We will add on some useful links for additional information and sources we've used.

Please note; we are not veterinarians, nor do we wish to be thought of as such. Although we will be discussing medical treatments (in very simple terms, may we add), we still recommend seeking professional medical advice from a qualified veterinarian if your pet is ill.


Shmi has always had a particularly sensitive respiration system. For example, if you wore powerful perfumes/body sprays, Shmi would begin to sneeze and crackle - it didn't take much to set her off. 
One evening, when Shmi was sleeping, we could hear very shallow and almost raspy breathing. This became a recurring theme and seemed to get worse, and more frequent, with age. We went through a process at home of swaping and revamping our home care; we swapped to a much more dust-free bedding (finacard), and we even bought an air-purifier, digital thermometer (to monitor temperature and humidity), air coolers, heaters etc. Their environment was already cleaned everyday, they had adequate nutrition, fresh/clean water, kept within safe temperatures (17°- 24°C), they weren't in an over-crowded environment - it was clear her noisy breathing was more than allergies or sensitivities. When all of preventative home healthcare had been fulfilled, and Shmi was still struggling, we decided to take her back to the vet for some real hands on medicinal treatment. 

Shmi - attempts to alleviate clinical symptoms:

It took a really long time before we had to accept that Shmi had CRD. Before we got the official diagnosis, we had to rule out other possibilities first.
When the vet had a listen to Shmi's chest, it sounded as though her lungs were heavily inflamed. Shmi was introduced to a cortiscosteroid injection - Dexafort/Dexamethasone - in the hopes it would resolve the problem.
After a few doses, the problem just continued to return as soon as the steroids wore off. Our vet wasn't happy about the idea of Shmi being on potent steroids for the remainder of her life, especially when she was fairly young at the time. So, our vet took it upon themselves to converse with the exotic specialists to see what would be the best approach for her - we reassured them that we would do whatever it takes to help Shmi. It was at this point we became certain that this would've been some form of chronic illness. We were later told Shmi had CRD.

Clinical signs of respiratory disease are often non-specific and can include:

  • Weight loss - reduced appetite or anorexia 
  • Poor coat condition
  • Excessive porphyrin
  • Sneezing
  • Dyspnoea (if dyspnoeic, oxygen therapy should be started immediately)
  • Laboured Breathing
  • Secondary head tilt
  • Wheezing/Clicking/Rattling respiratory noise (can be audible without auscultation)
The exotic specialists recommended we try either: nebulised normal Saline (not to be confused with Normosol-R), F10, or possibly even Ronaxan/Doxycycline suspension, if Shmi was a particularly severe case. In Shmi's case, both her upper and lower airways are affected by the disease. 
The reason why nebulisation therapy is often very effective is because the process of nebulisation turns the medication into a form of breathable mist which is then inhaled straight to the lungs (particularly the lower airways) - it's a more direct approach than other forms of therapy. 

We had initially hoped that Shmi could get away with some intense therapy and then have a period of short term relief without much, if any, forms of medical treatment. After a few weeks, it became apparent that Shmi wasn't going to get that, whatever combination of drugs we used, she was going to need them daily. We had to be realistic, therapy can be unrewarding and we can only manage the clinical symptoms - not cure. We also had to expect that Shmi could respond to a drug initially, and then relapse.

In Shmi's case, the pathogen (bacterium, virus, or other microorganism that can cause disease) responsible is mycoplasma: a bacterium lacking a cell wall. 
Mycoplasma pulmonis is a species carried by nearly all pet rats and a common cause for chronic persistent respiratory disease. 
Management of the disease usually includes a combination of various medications. We've gradually worked our way through the treatments. We've tried many forms, and combinations, of medications. We will list them all in clearly labeled sections:

First off, we use the following equipment for Shmi's nebulisation therapy:
  • Omron Nebuliser
  • 'Chamber'
  • Towel (limits mist escaping from around the hole which the mouth-piece is inserted into)
  • Duct tape (holds everything in place)

Nebulised Normal Saline (0.9% Sodium Chloride):

Normal Saline is an isotonic crystalloid solution. Saline works to help loosen thick phlegm from the lungs.
We found that the Saline works wonders for Nova who suffers with allergies - something we've written a previous post about. However, for Shmi, it didn't provide much relief at all. 

Nebulised F10 Antiseptic Solution (ready to use):

F10 is very popular because it is a multi-purpose effective preparation against a wide range of bacteria, fungi, viruses and spores. 
Initially, we were blown away by the results of the F10 solution. Shmi had a good few weeks of strong results. Unfortunately, the results started to fade as time went on - as we've mentioned, that's totally normal for CRD. 

Nebulised Bio-Solvan and Normal Saline (0.9% Sodium Chloride):

As we've already mentioned, Normal Saline is an isotonic crystalloid solution. Bio-Solvan has an active ingredient: Bromhexine. Bromhexine is often used for conditions which involves a lot of mucus and works by essentially thinning the mucus. It belongs for a group of medications called mucolytics. 
We used a scoop from a sache of Bio-Solvan mixed with normal Saline so it could be administered to Shmi via nebulisation therapy. This is one of the combinations we found most beneficial to Shmi, and her benefits did last a fair amount of time. Although, the benefits did seem to fade over time.

Corvental and Nebulised F10 Antiseptic Solution (ready to use):

F10 works well due to it's antibacterial properties, it is also likely to have some anti-inflammatory property as well. Corvental is a bronchodilator which has an active ingredient: Theophylline. Ph. Eur. Largely speaking, it works by relaxing the muscles within the lungs and widening the airway, making it easier to breathe.  

Nebulised Enrofloxacin, Doxycycline, Corvental, F10 Antiseptic Solution (ready to use) and oral Meloxicam:

Shmi developed a concerning symptom - sneezing blood. Sneezing blood is often a very clear indication for infection. To treat a bacterial infection, antibiotics are often used. The most common combination of antibiotics used to treat respiratory infections is Enrofloxacin (also known as Baytril) and Doxycycline (Ronaxan). Meloxicam (commonly known a Metacam) is a non-steroidal anti-inflammatory. Unless pneumonia is present, it generally isn't advised to use steroidals - it can make the situation worse. non-steroidals are commonly written as: NSAIDS. As their name indicates, they help reduce inflammation.
In this case, it is recommended to use these antibiotics over a longer course of at least 2 weeks.

Given that the Corvental and F10 still helped Shmi a great deal, we decided not to change them about. However, we did change the frequency/length of therapy from once daily for 30 minutes, to twice daily for 45 minutes.


Leia has suffered with a multitude of illnesses throughout her life. She has been known to have, UTI's (urinary-tract infections), URI's (upper-respiratory infections), and also had an open Pyometra (infection of the uterus). She also suffers with mammary tumours, abscesses, and osteoarthiritis and/or sciatica type pain - likely unrelated.
Needless to say, she's been through the wars. When Leia started to show signs of CRD, we were surprised, but not gobsmacked.

In Leia's case, her upper-respiratory tract seems to be the most affected by the disease. Her symptoms do slightly differ to Shmi's, Leia's breathing audibly sounds more like a wheeze or blow, rather than a rasp or rattle - unlike Shmi. 

Despite trying multiple medications during nebulisation therapy, Leia doesn't get any benefit from nebulisation - if anything, it makes her worse. There is probably a combination of factors which make as to why it makes her symptoms worse; Stress being one of them, and also because nebulisation mainly targets the lower airways - as we've already mentioned, the disease mainly affects Leia's upper-airways.
All hope is not lost, nebulisation is only one of many forms of management for CRD.
We will list the medications, and combinations that Leia has used:

Oral Canine Meloxicam and Corvental:

Meloxicam is mainly known as 'Metacam' (Metacam is just the brand name). It is a form of non-steroidals anti-inflammatorys, known as NSAIDS. Meloxicam is commonly used as a form of pain relief, but can be used as a management for CRD to reduce any inflammation.
As we also mentioned in Shmi's section, Corvental contains Theophylline. Ph. Eur. and is a bronchodilator. Bronchodilators work by relaxing the muscles in the lungs and widens the air ways, making it easier to breathe.
Leia didn't show any improvement for CRD from these medications alone.

Prednisolone, Corvental, Doxycycline, and Enrofloxacin:

Prednisolone is an oral steroidal and is used to treat inflammatory conditions. Our vet opted for an oral steroidal as you can taper the dose throughout treatment, unlike with an injectable steroid such as corticosteroids.
As mentioned above, Covental is a bronchodiolator which relaxed muscles in the lungs and widens the airway.
Doxycycline is an antibiotic. Antibiotics (also called antibacterials) if a form of antimicrobial drug. They're used for both treatment and prevention of bacterial infections. Doxycycline is commonly used to treat respiratory infections. We used doxycycline under the brand name: Ronaxan.
We added the Enrofloxacin at a later date to use in combination with the Doxycycline.  Enrofloxacin is more commonly known as Baytril. Baytril is notorious for having a form of resistance since it has been known for having a 'prescribing cascade'. None the less, it is still a known, and recommended, form of management for CRD - particularly with mild infections with pathogenic mycoplasma. It is recommended to have an extended course of 10-30 days for antimicrobials to provide any improvements. You can nebulise the medications, but as we've already mentioned, the stress from the therapy does not suit Leia, so we try to avoid this wherever possible. 
Leia had a medication change due to the Prednisoloine not being suitable for a separate illness.

Canine Meloxicam, Corvental, Doxycyline, and Enrofloxacin:

We swapped back to the non-steroidal, Meloxicam, as it provides more of a pain-relief effect, as well as an anti-inflammatory effect, where as Prednisolone mainly provides an anti-inflammatory effect. We needed a pain-relief due to Leia having arthiritis and/or sciatica type pain. 
We kept the Corvental, and both antibiotics, as they provided Leia with a great deal of relief when used together.
This is Leia's current medication for CRD management.

Additonal information:

As we mentioned at the start of the post, it took us a fair amount of time to confidently acknowledge that both does had CRD. It is particularly tricky to manage, as there is so many aspects and things to consider.

The first place to start, is with a firm diagnosis. After all, once you know what you're dealing with, then you'll know how to fix it - or in this case, manage it.

Common diagnostic methods for respiratory disease in rodents vary, but include:
  • Deep nasal swap
  • Conjunctival scraping (If conjunctivitis is present)
  • Tracheal lavage (if pneumonia is the concern)
  • Radiography/CT Scan of thorax and skull
  • Culture and sensitivity test
  • Serologic tests
  • Gross pathology
Depending on the diagnosis, will depend on the form of treatment. There are countless treatments available to manage CRD. We've tried multiple forms of medications, but some we've not tried include:
  • Humidified oxygen therapy for severe dyspnoeic animals
  • Additional heat (21-24 C) take care not to overheat
  • Nebulisation mucokinetics for 30-45 mins, 2-3 times daily
  • Systemic antimicrobial therapy 
  • Private eating time and soft moist food to be conisdered with severe dypnoea and if the animal appears in discomfort
  • Corticosteroids at anti-inflammatory dosage 
  • Euthanasia may be indicated in severe non-responsive cases on a welfare ground.

  • Antimicrobials to treat respiratory infections include:
  1. Chloramphenicol
  2. Trimethoprim/sukphamethoxazole
  3. Tylosin
  4. Oxytetracycline

It is just as important, in fact, it is essential to fulfill all prophylaxys in order to best manage CRD:

Ventilation and cage cleanliness with regards to the build up of ammonia. Animals should be housed in a wire enclosure with an absorbent dust-free bedding. As rats are both intelligent and inquisitive animals, nest materials, toys, and other accessories to play with should always be provided within their cage environment. 
Ensure the cage is out of direct sunlight, and keep the temperature within the recommended range of 17° - 24° C with humidity of 45-55%.
Provide clean and fresh water daily and feed rats on a balanced and fresh food diet. 
Finally rats are social animals and are recommended to be kept in groups, but avoid overcrowding. Do not house with different species.
Does and Bucks cages

The following links have some great information which we've sourced bits from throughout this post:
We also recommend reading the following paper:
  1. Common Respiratory Diseases of Rodents by Elisabetta Mancinelli, DVM, MRCVS, CERTZOOMED, ECZM Resident in mall companian exotic mammal medicine and surgery - Great Western Exotic Vets -
We would also like to thank our vet, Sarah Bruce, for always being willing to answer our questions, and happily informs us on the subject.
You can keep up with Leia and Shmi on our Instagram.