Rat Respiratory Health: The Definitive Guide to Sneezing, Infections, and When to Act

Last updated: March 2026 | Read time: 15 min | Sources: 28 veterinary and academic references

Quick summary: Respiratory disease is the most common health problem in pet rats. Nearly every rat carries Mycoplasma pulmonis from birth. It cannot be cured, but it can be managed. This guide covers the biology, the warning signs, how to tell normal sneezing from something serious, what treatment looks like, and how to keep your rats breathing well for as long as possible.

Disclaimer: This guide is for education only. It is not a substitute for professional veterinary diagnosis and treatment. Always consult an exotic-experienced vet for your rats.

In this guide:

• Why almost every rat carries Mycoplasma
• How respiratory disease actually works
• New home sneezes vs respiratory infection: the decision tree
• Symptom progression: mild to emergency
• The "Is my rat sick?" symptom checker
• Environmental triggers: what makes it worse
• What treatment looks like
• Prevention: the things you can actually control
• Living with chronic respiratory disease
• Finding an exotic vet in the UK
• Downloadable: emergency vet card

Why almost every rat carries Mycoplasma

Mycoplasma pulmonis is an atypical bacterium that colonises the respiratory tract of rats. It is considered enzootic in pet populations worldwide, meaning it is permanently established.^1 Transmission happens vertically from mother to offspring at birth, through direct nose-to-nose contact, and via aerosol over short distances.

By the time you bring a rat home from a breeder, rescue, or pet shop, it is almost certainly carrying M. pulmonis. This is not a failure of breeding or husbandry. It is the biological reality of the species.

The critical distinction: carrying Mycoplasma is not the same as having respiratory disease. Many rats coexist with the organism for months or their entire lives without developing clinical symptoms. Problems begin when the balance tips. Stress, poor air quality, a secondary infection, ageing, or a weakened immune system can all trigger the shift from carrier to clinically ill.

This is why prevention is centred on environment and immune support, not on trying to eliminate an organism that cannot be eliminated.

How respiratory disease actually works

The attack on your rat's airways

M. pulmonis lacks a cell wall, which makes it inherently resistant to common antibiotics like penicillin and cephalosporins.^2 Once conditions favour it, the bacterium attaches to the ciliated cells lining the respiratory tract using specialised surface proteins.

Cilia are microscopic, hair-like projections that beat in coordinated waves to move mucus, debris, and pathogens up and out of the lungs. This system is called the mucociliary escalator, and it is the primary physical defence against lung infection.

When M. pulmonis colonises these cells, it releases toxic peroxides that cause direct tissue damage. The resulting inflammation triggers the immune system to flood the area with plasma cells and lymphocytes, leading to Bronchus-Associated Lymphoid Tissue (BALT) hyperplasia, a thickening of the airway walls that progressively narrows the breathing passages.^3

What happens as disease progresses

In advanced cases, the cycle of infection, inflammation, and tissue damage leads to:

• Bronchiectasis: Permanent dilation and scarring of the bronchioles. Irreversible.
• Atelectasis: Collapse of lung lobes due to blockage by purulent exudate (pus and fluid).
• "Cobblestone lung": A macroscopic appearance where the lung surface is covered in raised, pale nodules representing dilated airways and abscesses.^4

This is why early intervention matters. Structural lung damage cannot be undone.

Viral complications: SDAV and Sendai

Respiratory disease in rats is rarely caused by a single agent. Two viruses are particularly dangerous when they coincide with M. pulmonis:

Sialodacryoadenitis Virus (SDAV): A rat-specific coronavirus that targets the salivary and Harderian glands. Symptoms include swollen neck glands ("thick neck") and bulging eyes. SDAV causes temporary but severe damage to the respiratory epithelium, creating an open door for secondary bacterial pneumonia.^5

Sendai Virus (SeV): A highly contagious parainfluenza virus that causes necrotizing bronchiolitis. Self-limiting in 2-3 weeks, but the pulmonary scarring it leaves behind permanently reduces respiratory reserve.^6

Neither virus is common in well-managed pet populations, but both circulate at shows, rescues, and multi-rat households. Quarantine new arrivals for a minimum of three weeks. The NFRS advises even longer for rats from unknown health backgrounds.^7

New home sneezes vs respiratory infection: the decision tree

This is the question every new rat owner types into a search engine at 11pm. Your rats have been home for a day and they are sneezing. Normal? Or the start of something bad?

The 72-hour window

New home sneezes are a mild, temporary reaction to new environmental factors: different dust particles, cleaning products, air fresheners, unfamiliar substrate. They are an adjustment response, not an infection.

A respiratory infection gets worse over time and brings systemic symptoms along with it.

Decision tree: is this new home sneezes or a URI?

Step 1: How long has the rat been in your home?

→ Less than 72 hours:

- Occasional sneezing (a few times per hour) with no other symptoms → Most likely new home sneezes. Go to Step 2.

- Sneezing with discharge, lethargy, porphyrin staining, or laboured breathing → Skip to Step 3. These symptoms are not normal adjustment.

→ More than 72 hours:

- If sneezing is decreasing and no other symptoms → Still likely adjustment, particularly if you recently changed substrate or cleaning products. Continue monitoring.

- If sneezing is the same or increasing → Go to Step 3.

Step 2: Monitor for 72 hours. Check against this list twice daily:

• [ ] Eating and drinking normally?
• [ ] Active and curious during wake hours?
• [ ] No discharge from nose or eyes?
• [ ] No red-brown staining (porphyrin) around eyes or nose?
• [ ] Breathing silent when you hold the rat to your ear?
• [ ] Coat smooth and well-groomed?

All boxes ticked and sneezing reducing → New home sneezes. Continue observing. Reduce environmental irritants: no scented candles, no aerosols, ensure good cage ventilation.

Any box unticked → Go to Step 3.

Step 3: Assess the additional symptoms.

The golden rule: When in doubt, book the vet appointment. A £40 consultation that finds nothing wrong is better than waiting three days while a treatable infection becomes entrenched.

Symptom progression: mild to emergency

Mild (monitor closely)

• Occasional sneezing, not constant
• Slight porphyrin around the eyes (may only be visible on light-coloured rats)
• No change in breathing sounds, appetite, behaviour, or weight
• Rat is grooming normally and engaging with cagemates and environment

What to do: Monitor twice daily. Ensure the cage is clean, substrate is dust-free, and air quality is good. If symptoms persist beyond a week without worsening, a vet check is still worthwhile to establish a baseline.

Moderate (vet appointment needed)

• Sneezing is frequent throughout the day
• Noticeable porphyrin staining around both eyes and nose, not fully groomed away
• Audible congestion: wheezing, soft clicking, or wet-sounding breaths (hold the rat to your ear in a quiet room)
• Slight reduction in activity or appetite
• Coat may look less sleek than usual

What to do: Book a vet appointment. At this stage, the infection may still be confined to the upper respiratory tract. A course of antibiotics now can prevent progression to pneumonia.

Severe (urgent vet visit)

• Laboured breathing visible in the body (sides heaving, hunched posture)
• Pronounced rattling, crackling, or "honking" sounds
• Significant weight loss
• Lethargy: rat moves slowly, does not engage, may sit hunched in one spot
• Coat rough and unkempt
• Obvious porphyrin deposits caked around eyes and nose

What to do: Urgent vet appointment (same day or next day at the latest). The infection has likely moved into the lower respiratory tract. Pneumonia may be developing. Delay at this stage means structural lung damage that cannot be reversed.

Emergency (immediate veterinary care)

• Open-mouth breathing (gasping with mouth visibly open)
• Panicked dashing, or conversely, complete stillness and unresponsiveness
• Cyanosis: blue or pale tint to the ears, feet, gums, or tail tip
• Flank breathing: abdominal muscles visibly pumping to push air in and out
• Collapse

What to do: This is a life-threatening emergency. Contact your vet or an emergency out-of-hours service immediately. If driving to the vet, keep the carrier warm and quiet. Do not attempt to administer medication without veterinary guidance. Your rat may need oxygen therapy and aggressive treatment to survive.

The "Is my rat sick?" symptom checker

Interactive element spec: "Is My Rat Sick?" Symptom Checker

Purpose: Help rat owners assess whether their rat's symptoms need veterinary attention. Not a diagnostic tool. Always ends with a recommendation.

Format: Branching questionnaire, 4-7 questions depending on path, with a clear outcome at each endpoint.

Question flow:

Q1: What is the primary symptom you are concerned about?

• A) Sneezing → Q2
• B) Noisy breathing (wheezing, clicking, rattling) → Q4
• C) Red/brown discharge around eyes or nose → Q3
• D) Head tilt or loss of balance → Outcome: URGENT VET
• E) Open-mouth breathing or gasping → Outcome: EMERGENCY VET NOW
• F) Lethargy or loss of appetite → Q5

Q2: How long has the sneezing been happening?

• A) Less than 72 hours, rat is new to my home → Q6
• B) Less than 72 hours, rat is established → Q3
• C) More than 72 hours and getting worse → Q4
• D) More than 72 hours but staying the same → Q3

Q3: Are there any other symptoms alongside the primary one?

• A) No other symptoms, eating and active normally → Outcome: MONITOR (recheck in 48 hours, book vet if no improvement in 5-7 days)
• B) Slight porphyrin but otherwise normal → Outcome: BOOK VET CHECK (within a few days)
• C) Reduced appetite, less active, or rough coat → Outcome: VET WITHIN 24 HOURS
• D) Laboured breathing, weight loss, or hunched posture → Outcome: URGENT VET

Q4: How would you describe the breathing sounds?

• A) Soft clicking or mild congestion → Outcome: VET WITHIN 48 HOURS
• B) Loud rattling or crackling → Outcome: URGENT VET (same day if possible)
• C) Honking or gasping sounds → Outcome: EMERGENCY VET NOW

Q5: How long has the lethargy/appetite loss lasted?

• A) Less than 24 hours → Q3
• B) 24-48 hours → Outcome: VET WITHIN 24 HOURS
• C) More than 48 hours → Outcome: URGENT VET

Q6: Is the rat otherwise eating, drinking, and active?

• A) Yes, completely normal apart from sneezing → Outcome: LIKELY NEW HOME SNEEZES. Monitor for 72 hours. Remove scented products from the room. Ensure good cage ventilation. Recheck using this tool in 3 days.
• B) Mostly normal but slightly less active → Outcome: MONITOR CLOSELY. Recheck tomorrow. Book vet if any decline.
• C) No, there are other symptoms too → Q3

All outcomes must include:

• Clear recommendation (monitor / book vet / urgent / emergency)
• Timeframe for action
• Link to relevant guide section
• Disclaimer: "This tool helps you assess urgency. It is not a diagnosis. When in doubt, contact your vet."

Avoid

Cigarette smoke, scented candles, air fresheners, and cooking fumes all trigger respiratory flares in susceptible rats. Keep rat rooms free of airborne irritants at all times.

Avoid

Pine and cedar bedding are directly linked to respiratory disease in rats. The aromatic phenols irritate the airways and compromise the immune response. Use paper-based bedding only — this is one of the most impactful changes you can make.

Environmental triggers: what makes it worse

1. Ammonia from urine

The single biggest environmental risk factor. Urine breaks down into ammonia through bacterial action, and ammonia directly damages the respiratory epithelium. Research shows that ammonia concentrations in static (non-ventilated) cages can exceed 20 ppm by day 9-11 of a cleaning cycle.^9 At 20 ppm, cilia stop functioning (ciliostasis), and the mucociliary escalator shuts down.

The fix: Clean the cage every 3-5 days at minimum. Spot-clean daily. Choose substrates that suppress ammonia effectively.

2. Bedding choice

Not all substrates are equal. Research comparing intracage ammonia levels across four bedding types found significant differences in how long each maintained safe conditions.^10

The RVC and PDSA both specifically recommend avoiding dusty materials including sawdust and untreated wood shavings. Particulate matter acts as a mechanical irritant to the airway lining, compounding the ammonia problem.

3. Ventilation

Wire cages allow multi-directional airflow that dilutes ammonia and prevents humidity buildup. Glass tanks and plastic vivaria rely on vertical convection alone, which is insufficient to clear ammonia (a heavy gas that sinks to floor level).^12

Balance ventilation against draughts. Position the cage in a room with decent air movement but away from open windows, fans aimed directly at the cage, and doorways with constant traffic.

4. Temperature and humidity

Avoid placing cages near radiators that cycle on and off, or in rooms with significant temperature swings between day and night.

5. Aerosols and scented products

Rats have extremely sensitive respiratory systems. Avoid using the following in the room where your rats live:

• Aerosol sprays of any kind
• Plug-in air fresheners
• Scented candles
• Incense
• Strong cleaning products (allow the room to fully ventilate after cleaning)
• Cigarette smoke

6. Stress

Immune suppression from chronic stress creates the window that M. pulmonis exploits. Common stressors:

• Overcrowded housing
• Introducing new rats without proper protocols
• Lack of hiding spaces (rats need places where they feel safe)
• Constant noise or bright light
• Social isolation (rats housed alone)

Enrichment, appropriate group sizes, and multiple hides are not luxuries. They are respiratory health measures. See our enrichment ideas guide for practical ways to reduce stress through cage design.

Key Tip

Doxycycline and enrofloxacin are the standard treatment protocol for rat respiratory infections. A vet familiar with small animals will prescribe the correct dose. Never dose by assumption — rat metabolism differs from cats and dogs.

What treatment looks like

Antibiotics

The gold standard combination in UK rat medicine is enrofloxacin (Baytril) and doxycycline, used together.^13 Enrofloxacin is a fluoroquinolone; doxycycline is a tetracycline. They work synergistically to target both Mycoplasma and common secondary bacteria like Pasteurella and Streptococcus.

Azithromycin, a macrolide antibiotic, is used for chronic or treatment-resistant cases. It has a long half-life and achieves high concentrations within lung macrophages, making it effective against deep-seated infections.^14

Treatment courses typically run 2-4 weeks for acute flare-ups. Chronic cases may need 6-8 weeks or longer. Some rats require intermittent courses throughout their lives. Your vet will determine the right medication, dosage, and duration.

Note: We name these medications so you know what to expect at the vet. We do not provide dosages. Dosing depends on your rat's weight, health status, and other medications. Always follow your vet's instructions.

Anti-inflammatory medication

Meloxicam (Metacam) is a non-steroidal anti-inflammatory (NSAID) commonly prescribed alongside antibiotics. It reduces airway inflammation and provides pain relief, helping your rat breathe more comfortably.

In acute crises, short courses of prednisolone (a corticosteroid) can be life-saving by rapidly reducing the inflammatory swelling in the lungs. Long-term steroid use is limited by the risk of immunosuppression.^15

Nebulisation therapy

Nebulisation delivers medication as a fine mist (particles 1-5 microns) directly into the airways. It is well tolerated by most rats and can be performed at home.^16

Sessions run 30-45 minutes, 2-3 times daily during acute flare-ups, reducing to maintenance frequency as symptoms improve. Your vet will prescribe the appropriate solution and schedule.

Supportive care at home

• Keep the cage clean and warm (not hot)
• Offer easy-to-eat, high-value foods to encourage appetite: baby food, mashed banana, soaked pellets, cooked egg
• Ensure fresh water is always accessible
• Elevate sleeping areas above cage floor level where ammonia concentrates
• Reduce stress: minimise handling if the rat is very unwell, keep the environment calm and quiet
• Consider a small room humidifier if indoor air is very dry (below 40% humidity)

Prevention: the things you can actually control

Clean the cage every 3-5 days. Spot-clean daily. The goal is to keep ammonia below 20 ppm at all times.

Choose the right substrate. Paper-based bedding, hemp, or dust-extracted aspen. Never cedar, never pine, never dusty sawdust.

Use a wire cage. Ventilation is not negotiable. Glass tanks trap ammonia. If your cage is in a room with poor airflow, consider a small fan positioned to circulate air near (not directly at) the cage.

Elevate sleeping areas. Ammonia is heavier than air and concentrates at the lowest point of the cage. Rats sleeping in hanging hammocks and elevated hides breathe cleaner air than those on the cage floor. This is a simple change that makes a measurable difference. Our cast stone hides and shelf sets are designed to sit on upper cage levels, keeping your rats above the ammonia line while providing the weight and stability that prevents tipping.

Maintain stable temperature and humidity. 19-23C, 45-55% humidity. Avoid rooms with wild temperature swings.

Remove all aerosols and scented products from the room where rats live.

Feed a balanced, pelleted diet. Vitamin A deficiency from selective feeding directly impairs respiratory defences. Nuggets, not muesli.

Reduce stress through enrichment. Multiple hides, varied enrichment, appropriate group sizes, regular but gentle handling. See our enrichment ideas guide.

Quarantine new arrivals for 3+ weeks. House new rats in a separate room. Wash hands between handling groups. This protects your existing rats from novel strains of Mycoplasma, viruses (especially SDAV and Sendai), and ectoparasites.

Living with chronic respiratory disease

For many rats, respiratory disease becomes a lifelong companion. There will be good periods and bad periods. The goal is management, not cure.

Keep a symptom log. A simple notebook or phone note tracking:

• When sneezing increases or decreases
• When you first hear breathing changes
• What treatment was given and how the rat responded
• Any environmental changes that coincided with a flare-up

This log is invaluable for your vet when planning long-term management. It turns "my rat seems worse" into "sneezing increased on Tuesday after we changed substrate brands, and this is the third flare-up in four months."

Know the flare-up triggers. Over time, you will learn your rats' specific sensitivities. Some rats flare up with weather changes. Others react to specific substrates. Some decline predictably in winter when central heating dries the air. The log helps you identify patterns.

Accept the treatment cycle. Rats with CRD may need 2-5 antibiotic courses over their lifetime. Some need semi-permanent low-dose maintenance treatment. This is normal. Work with your vet to find the long-term plan that gives your rat the best quality of life.

Quality of life is the measure. A rat with chronic respiratory disease who is eating, interacting, playing, and grooming is a rat with a good quality of life. When those things stop, the conversation shifts. Your vet can help you with that conversation when the time comes.

Finding an exotic vet in the UK

How to find a rat-experienced vet:

• "Rat Vet Reviews UK" Facebook group: Community-sourced recommendations with honest reviews
• RCVS Find a Vet (findavet.rcvs.org.uk): Filter by species to find practices that see small mammals
• Royal Veterinary College Exotics Service (London): Specialist referral centre for complex cases
• The Rat Wiki (theratwiki.co.uk): Maintains a UK-wide list of recommended rat-savvy vets

Questions to ask a new practice:

• "How many rats do you see per month?" (more experience = faster, more accurate diagnosis)
• "Do you stock enrofloxacin and doxycycline?" (the standard respiratory treatments)
• "Can you perform surgery on rats if needed?" (tumour removal, abscess drainage)
• "Do you have out-of-hours emergency cover for exotic pets?"

The proposed CMA veterinary reforms include a cap on prescription charges at £16 and mandatory written estimates for treatments over £500. These changes are not yet implemented but signal a direction towards greater pricing transparency.

Register with your chosen vet before you need them urgently. Having an established relationship means faster access when your rat is actually ill.

Downloadable: emergency vet card

Spec for downloadable PDF: Emergency Vet Card

Title: "Rat Emergency Vet Card"

Format: Credit card / wallet sized (85.6mm x 53.98mm), double-sided, printable on thick card stock

Front:

• Header: EMERGENCY RAT VET CARD
• Fields to fill in:

- My vet: ________________

- Phone: ________________

- Out-of-hours emergency: ________________

- Nearest 24hr exotic emergency: ________________

- My rat's name(s): ________________

Back:

• CALL THE VET NOW IF YOU SEE:

- Open-mouth breathing

- Gasping or panicked movement

- Blue/pale ears, feet, or tail

- Complete lethargy or collapse

- Head tilt with circling

- Sudden severe weight loss

• While you wait:

- Keep the carrier warm and quiet

- Do not force food or water

- Note the time symptoms started

- Bring your symptom log if you have one

Footer: ripleysnest.co.uk/blogs/journal/respiratory-health-guide | QR code to this page

Branding: Ripleys Nest logo, teal accent, clean medical-card styling

Sources

Veterinary and Academic

1. Royal Veterinary College. "Respiratory Disease in Rats." Exotics Service Factsheet, December 2022. rvc.ac.uk
2. PMC. "Respiratory Diseases in Rats." Veterinary Clinics: Exotic Animal Practice, 2020. pmc.ncbi.nlm.nih.gov
3. PMC. "Clinical Investigation of Mycoplasma pulmonis in Rats." 2017. pmc.ncbi.nlm.nih.gov
4. Charles River Laboratories. "Mycoplasma pulmonis." criver.com
5. PMC. "SDAV, the Rat Coronavirus." 2021. pmc.ncbi.nlm.nih.gov
6. Rat Guide. "Sendai Virus (SeV)." ratguide.com
7. Rat Guide. "Sialodacryoadenitis (SDA)." ratguide.com
8. BSAVA. "Respiratory Disease." Manual of Rodents and Ferrets. bsavalibrary.com
9. PMC. "Intracage Ammonia Levels on 4 Bedding Substrates." JAALAS, 2014. pmc.ncbi.nlm.nih.gov
10. PMC. "Effects of Intracage Ammonia on Pulmonary Endothelial Integrity." 2018. pmc.ncbi.nlm.nih.gov
11. CABI Digital Library. "A Quick Method to Assess Rodent Cage Ammonia Levels." 2016. cabidigitallibrary.org
12. PMC. "CO2, O2, and NH3 Levels in Disposable IVC." 2022. pmc.ncbi.nlm.nih.gov
13. VetHive. "How to Manage Respiratory Disease in Rats." vethive.com
14. Ask A Vet. "The Vet's Guide to Rat URIs in 2025." askavet.com
15. Vet Times. "Respiratory Diseases in Rodents." vettimes.com

Professional Organisations

1. RSPCA. "Rat Health and Welfare Tips." rspca.org.uk
2. PDSA. "Rats as Pets." pdsa.org.uk
3. National Fancy Rat Society. "Show Regulations." nfrs.org (quarantine and biosecurity protocols)
4. National Fancy Rat Society. "Guidelines for Rat Condition." nfrs.org
5. Blue Cross. "Caring for Your Rat." bluecross.org.uk
6. NC3Rs. "Housing and Husbandry: Rat." nc3rs.org.uk

Community and Specialist Resources

1. Rat Guide. "Mycoplasma / Mycoplasmosis." ratguide.com
2. Isamu Rats. "Respiratory Issues." isamurats.co.uk
3. Rat Fan Club. "Respiratory and Heart Disease in Rats." ratfanclub.org
4. SASH Vets. "Chronic Respiratory Disease in Rats and Mice." PDF
5. Purdue ADDL. "Murine Respiratory Mycoplasmosis." addl.purdue.edu

Further Reading

• The Complete First-Time Rat Owner Guide (Ripleys Nest)
• 30+ Enrichment Ideas for Happier, Healthier Rats (Ripleys Nest)
• Rat Cage Accessories Collection (Ripleys Nest)

Footnotes

^1 M. pulmonis is considered enzootic in the global pet rat population, transmitted vertically from doe to pup at birth. Charles River Laboratories technical reference; Purdue ADDL; RVC factsheet.

^2 M. pulmonis lacks a cell wall, rendering beta-lactam antibiotics (penicillin, amoxicillin, cephalosporins) ineffective. Treatment requires antibiotics with intracellular penetration. PMC 2020; BSAVA Manual.

^3 BALT hyperplasia is the characteristic histopathological finding in chronic murine respiratory mycoplasmosis. PMC 2017; Charles River.

^4 "Cobblestone lung" is a macroscopic finding in advanced MRM, representing multiple coalescing abscesses and dilated airways. Charles River; Purdue ADDL.

^5 SDAV is a Group 2 coronavirus targeting salivary and lacrimal glands. Epithelial damage provides a co-factor for secondary bacterial pneumonia. PMC 2021.

^6 Sendai virus causes necrotizing bronchiolitis; self-limiting in 2-3 weeks but leaves permanent pulmonary scarring. Rat Guide; SASH Vets.

^7 NFRS show regulations mandate minimum 3-week quarantine. For rats from unknown backgrounds, treatment with Ivermectin and broad-spectrum antibiotics is advised during quarantine. NFRS.

^8 Otitis media (middle ear infection) is frequently secondary to descending M. pulmonis infection. Symptoms: head tilt, circling, loss of balance. Requires systemic antibiotics and analgesia. BSAVA; RVC.

^9 Ammonia exceeds 20 ppm by day 9-11 in static cages. At 20 ppm, ciliostasis occurs. PMC 2014; PMC 2018.

^10 Comparative bedding study: corncob maintained safe ammonia levels longest; reclaimed wood pulp performed worst. PMC 2014.

^11 Cedar and pine shavings contain phenolic compounds (plicatic acid, abietic acid) that cause direct respiratory irritation and induce hepatic enzyme changes. RVC; PDSA; multiple veterinary sources.

^12 Glass and plastic enclosures rely on convection alone, insufficient to clear ammonia which is denser than air. Wire cages provide passive ventilation through bar gaps. NC3Rs; PMC 2022.

^13 Enrofloxacin + doxycycline is the established first-line combination in UK rat medicine. Synergistic coverage of Mycoplasma and secondary bacteria. VetHive; Ask A Vet; Vet Times.

^14 Azithromycin achieves high intracellular concentrations in pulmonary macrophages, making it effective against tissue-resident Mycoplasma. Used in refractory cases. Ask A Vet; SASH Vets.

^15 Prednisolone rapidly reduces inflammatory oedema in acute respiratory crises. Long-term use risks immunosuppression, contraindicated in chronic management. Vet Times; BSAVA.

^16 Nebulisation delivers 1-5 micron particles to the terminal airways. Well-tolerated in rats; sessions of 30-45 minutes, 2-3 times daily in acute phases. RVC; Rat Fan Club; SASH Vets.

This guide was written by Ripleys Nest, a small creative workshop in the Cumbria countryside. We keep rats ourselves and make cage accessories designed for rat health and enrichment. This guide is not a substitute for professional veterinary advice. Always consult an exotic-experienced vet for diagnosis and treatment. Last reviewed: March 2026.