Upper Respiratory Infection in Cats: Symptoms, Treatment and When To See a Vet

By Dr Duncan Houston

A sneezing cat with runny eyes may have a mild infection that settles with supportive care. A congested kitten that stops eating, develops a painful eye or begins struggling to breathe is a very different situation.

Feline upper respiratory infections are common, particularly in kittens, shelters, rescue groups, breeding colonies and multi-cat households. Most are caused by feline herpesvirus or feline calicivirus, but bacteria, fungi, inflammatory disease and physical obstructions can produce similar signs. (ABCD cats and vets)

The real concern is not simply whether your cat is sneezing. It is whether they can breathe comfortably, eat enough, stay hydrated and keep their eyes protected while the underlying problem is identified.

Quick Answer

A feline upper respiratory infection commonly causes sneezing, nasal congestion, eye or nasal discharge, conjunctivitis, fever and reduced appetite. Most uncomplicated cases are viral and improve with nursing care over approximately one to two weeks.

Contact your veterinarian promptly if your cat stops eating, develops eye pain, becomes markedly lethargic or is not clearly improving within seven to ten days. Open-mouth breathing, blue or grey gums, collapse or pronounced breathing effort is an emergency. (Vca)

Feline Upper Respiratory Infections at a Glance

Question	Practical answer
What causes most feline URIs?	Feline herpesvirus and feline calicivirus
Are they contagious?	Yes, usually between cats through secretions, close contact and contaminated objects
Can humans catch them?	FHV and FCV are not considered human infections, although a few less common bacterial agents carry rare zoonotic risk
How long do signs last?	Often 7 to 14 days, although some cases last up to 21 days
Do all cats need antibiotics?	No. Most uncomplicated acute cases are viral
Can vaccinated cats still become infected?	Yes. Vaccination mainly reduces disease severity
When should the cat be examined?	Poor appetite, eye pain, fever, lethargy, worsening discharge, coughing or signs lasting beyond 7 to 10 days
What is an emergency?	Open-mouth breathing, marked respiratory effort, abnormal gum colour, collapse or inability to swallow

These are general decision points. Kittens, brachycephalic cats, immunocompromised cats and cats with concurrent disease can deteriorate much faster than a healthy adult. (Vca)

What Is a Feline Upper Respiratory Infection?

The upper respiratory tract includes the:

• Nasal passages

• Sinuses

• Nasopharynx

• Mouth and throat

• Larynx

• Conjunctiva and closely associated eye tissues

An upper respiratory infection affects one or more of these structures. It is sometimes called cat flu, feline respiratory disease complex or feline infectious upper respiratory tract disease.

The name does not identify one specific organism. Several viruses and bacteria can produce a nearly identical combination of sneezing, discharge and conjunctivitis. More than one pathogen may also be present at the same time. (Cornell Vet College)

Is a Feline URI the Same as Pneumonia?

No.

A URI mainly affects the nose, throat and associated eye tissues. Pneumonia affects the lungs.

Pneumonia becomes more concerning when a cat has:

• Persistent coughing

• Rapid breathing at rest

• Increased abdominal breathing effort

• Fever and marked lethargy

• Reduced oxygen levels

• Blue or grey gums

• Abnormal lung sounds

Coughing is possible with feline respiratory infections, but a persistent cough or respiratory effort deserves investigation for lower-airway disease, pneumonia, asthma, parasites or cardiac disease rather than being dismissed as an ordinary cold. Cornell advises that a resting respiratory rate should generally remain below approximately 35 breaths per minute. (Cornell Vet College)

What Causes Upper Respiratory Infections in Cats?

Feline Herpesvirus Type 1

Feline herpesvirus type 1, or FHV-1, causes feline viral rhinotracheitis.

Typical signs include:

• Sneezing

• Nasal discharge

• Conjunctivitis

• Eye discharge

• Fever

• Reduced appetite

• Corneal inflammation or ulceration

Young kittens can develop severe ocular and respiratory disease. Dendritic corneal ulcers are particularly characteristic of acute feline herpesvirus ocular infection. (ABCD cats and vets)

After the acute infection, almost all affected cats establish lifelong latent infection. The virus remains within nerve tissue and may reactivate during periods of stress, illness, surgery, boarding, moving house or introduction of another animal.

Reactivation may cause recurrent conjunctivitis, keratitis or respiratory signs. Some cats shed virus without showing obvious illness. (ABCD cats and vets)

Feline Calicivirus

Feline calicivirus, or FCV, commonly causes:

• Sneezing

• Nasal discharge

• Conjunctivitis

• Fever

• Painful tongue or mouth ulcers

• Drooling

• Reduced appetite

• Temporary shifting-leg lameness in some cats

Mouth ulcers and oral pain are particularly suggestive of calicivirus, although no single sign can confirm the diagnosis. Kittens may occasionally develop viral pneumonia or secondary bacterial pneumonia. (ABCD cats and vets)

FCV is genetically diverse. A cat may recover from one strain without developing reliable lifelong protection against other strains. Cats can also continue shedding FCV after recovering clinically. (ABCD cats and vets)

Chlamydia felis

Chlamydia felis primarily affects the conjunctiva rather than causing severe nasal disease.

Typical signs include:

• One red, swollen eye initially

• Progression to both eyes

• Watery discharge becoming mucopurulent

• Squinting

• Prominent third eyelids

• Mild sneezing or nasal signs in some cats

It is most common in young cats and dense multi-cat environments. PCR testing of conjunctival swabs is useful when the clinical pattern fits. (ABCD cats and vets)

Mycoplasma Species

Mycoplasma felis may be involved in conjunctivitis and respiratory disease, often alongside viruses or other bacteria.

A positive PCR result does not always prove that Mycoplasma is causing the current illness because organisms may also be detected in clinically normal cats. Results must be interpreted alongside examination findings, sampling site and the cat’s history. (dvm360)

Bordetella bronchiseptica

Bordetella bronchiseptica is most important in shelters, colonies, breeding facilities and other high-density environments.

Disease may range from mild sneezing and discharge to severe lower respiratory infection and pneumonia, particularly in kittens. Infected dogs may also be a potential source of exposure for cats. (ABCD cats and vets)

Other Infectious Causes

Less common infectious causes include:

• Streptococcus zooepidemicus

• Feline influenza viruses

• Cryptococcus

• Aspergillus and other fungi

• Nasal parasites

• Toxoplasma gondii in selected systemic cases

These become more important when disease is severe, chronic, bloody, unusual, geographically relevant or unresponsive to ordinary treatment. (Cornell Vet College)

Current H5N1 Consideration

Highly pathogenic avian influenza A(H5N1) is an important modern differential in cats with severe, rapidly progressive respiratory, hepatic or neurological illness, particularly after exposure to infected birds, raw milk, raw poultry or raw meat pet food.

Affected cats may develop fever, loss of appetite, respiratory distress, ataxia, tremors, seizures or sudden death. Such cases require immediate veterinary and public-health guidance rather than routine URI management. (CDC)

How Do Cats Catch Upper Respiratory Infections?

Transmission commonly occurs through:

• Direct nose-to-nose contact

• Saliva

• Nasal secretions

• Eye discharge

• Sneezed droplets over short distances

• Shared bowls

• Bedding

• Hands and clothing

• Grooming equipment

• Contaminated carriers or surfaces

Crowding, frequent movement between groups and stress increase transmission and the likelihood of clinical disease. (ABCD cats and vets)

How Long Do the Viruses Survive Outside the Cat?

FHV is an enveloped virus and is comparatively susceptible to detergents and many routine disinfectants. Its practical survival depends heavily on temperature, moisture and whether secretions have dried.

FCV is much harder to eliminate. It can remain infectious on dry surfaces for up to approximately one month and is resistant to many ordinary disinfectants. Effective products may contain sodium hypochlorite, potassium peroxymonosulfate or chlorine dioxide, used according to their label instructions. (ABCD cats and vets)

Cleaning must remove mucus, faeces, food and other organic material before the disinfectant is applied. Never mix bleach with ammonia, acids or other cleaning products.

Can People or Dogs Catch a Cat’s URI?

Feline herpesvirus and feline calicivirus are species-associated and are not considered infections of people. (ABCD cats and vets)

The broader respiratory complex is slightly more nuanced:

• Chlamydia felis has rarely been associated with human conjunctivitis.

• Bordetella bronchiseptica is a rare potential zoonosis, mainly concerning immunocompromised people.

• H5N1 is a separate zoonotic concern when exposure history and severe clinical signs fit.

Good hand hygiene is sensible after cleaning discharge, administering eye medication or handling a sick cat. Immunocompromised household members should discuss unusual exposure concerns with their physician. (ABCD cats and vets)

What Are the Signs of a Feline URI?

Nose and Airway Signs

Common signs include:

• Sneezing

• Snuffling

• Nasal congestion

• Clear nasal discharge

• Yellow, green or thick discharge

• Reduced airflow through the nostrils

• Noisy nasal breathing

• Reduced sense of smell

• Hoarse or altered vocalisation

Coloured discharge does not automatically prove bacterial infection. Viral inflammation, mucus and immune cells can also produce yellow or green material. (dvm360)

Eye Signs

Possible eye signs include:

• Watery eyes

• Mucous or purulent discharge

• Red conjunctiva

• Swollen eyelids

• Prominent third eyelids

• Squinting

• Light sensitivity

• Corneal cloudiness

• Corneal ulceration

Squinting or keeping an eye closed usually indicates pain. Herpesvirus can damage the cornea, and delay may allow a superficial ulcer to deepen or become infected. (ABCD cats and vets)

Mouth Signs

Calicivirus may cause:

• Tongue ulcers

• Gum or palate ulcers

• Lip or nasal ulcers

• Drooling

• Pawing at the mouth

• Pain while chewing

• Food refusal

A cat may approach food because they are hungry, then retreat because eating hurts. (ABCD cats and vets)

Whole-Body Signs

More systemic signs include:

• Fever

• Lethargy

• Hiding

• Reduced appetite

• Dehydration

• Weight loss

• Enlarged lymph nodes

• Temporary lameness

• Poor grooming

Kittens can become hypoglycaemic and dehydrated more quickly than adults. A kitten that stops eating or becomes quiet deserves earlier examination. (Vca)

How Long Does a Cat URI Last?

The incubation period is often approximately 2 to 10 days, depending on the organism.

An uncomplicated infection commonly lasts 7 to 14 days, although some cats remain symptomatic for up to 21 days. FHV-associated disease may remain active for approximately 10 to 20 days, while recurrent herpes flares can be shorter or more variable. (Vca)

The International Society for Companion Animal Infectious Diseases classifies signs present for up to 10 days as acute. Signs persisting beyond approximately 10 days, recurring repeatedly or failing to respond as expected justify a broader diagnostic investigation. (PubMed)

How Worried Should You Be?

Lower Risk

Your cat has:

• Occasional sneezing

• Clear nasal or eye discharge

• Normal breathing

• Normal appetite

• Normal activity

• No eye pain

• Signs present for only a few days

What it may mean: An uncomplicated viral infection is possible.

What to do: Isolate the cat from other cats, provide supportive care and monitor appetite, breathing and eye comfort at least twice daily.

Moderate Concern

Your cat has:

• Frequent sneezing

• Increasing congestion

• Coloured discharge

• Mild lethargy

• Reduced but continuing food intake

• Mild conjunctivitis

• Signs lasting longer than five to seven days

What it may mean: More substantial viral disease or secondary bacterial involvement may be developing.

What to do: Arrange a veterinary examination within the next day or two, sooner for a kitten or cat with chronic disease.

High Concern

Your cat has:

• Food refusal

• Marked lethargy

• Fever

• Painful mouth ulcers

• Squinting or a cloudy eye

• Thick discharge blocking the nostrils

• Persistent cough

• Rapid breathing

• Significant dehydration

• Signs worsening over several hours

• Illness lasting more than 7 to 10 days without improvement

What it may mean: Corneal ulceration, pneumonia, bacterial complications, severe calicivirus disease or another diagnosis may be present.

What to do: Seek same-day veterinary care.

Critical

Your cat has:

• Open-mouth breathing

• Pronounced abdominal breathing effort

• Blue, grey or very pale gums

• Collapse

• Inability to swallow

• Severe weakness

• Minimal responsiveness

• Repeated seizures

• Rapid facial or limb swelling with skin ulceration

• Severe neurological abnormalities after raw-animal-product or bird exposure

What it may mean: Severe airway compromise, pneumonia, virulent systemic FCV, H5N1 or another life-threatening illness may be present.

What to do: Attend an emergency veterinary hospital immediately. (Cornell Vet College)

When Is This an Emergency?

Seek immediate veterinary care for:

• Open-mouth breathing

• Laboured or noisy breathing with obvious effort

• A persistent sleeping respiratory rate above approximately 35 to 40 breaths per minute

• Blue, grey or white gums

• Collapse or profound weakness

• Inability to swallow saliva

• Choking or repeated aspiration

• Severe dehydration

• A kitten that becomes weak or stops eating

• A painful, cloudy or visibly damaged eye

• Severe facial or limb swelling

• Jaundice

• Seizures or sudden neurological signs

• Suspected H5N1 exposure

Keep the cat calm and transport them in a secure, well-ventilated carrier. Stress increases oxygen demand, so do not force food, water or oral medication into a cat that is struggling to breathe. (Cornell Vet College)

What Else Can Look Like a Cat URI?

Possible condition	Important clues
Nasopharyngeal polyp	Noisy breathing, gagging, swallowing difficulty, recurrent one-sided ear disease
Nasal foreign body	Sudden violent sneezing, often with one-sided discharge
Dental disease	Facial pain, drooling, bad breath, discharge from one nostril
Chronic inflammatory rhinitis	Persistent congestion and discharge following previous infection
Cryptococcosis	Chronic discharge, facial swelling, non-healing nasal lesions or neurological signs
Nasal tumour	Older cat, one-sided or bloody discharge, facial distortion
Nasopharyngeal stenosis	Persistent obstruction after severe inflammation or trauma
Asthma	Coughing, wheezing and expiratory effort rather than sneezing alone
Pneumonia	Fever, rapid breathing, respiratory effort and marked systemic illness
H5N1 influenza	Severe rapid progression following raw milk, raw meat, bird or dairy-farm exposure
Irritant exposure	Smoke, aerosol cleaners, perfume, dust or chemical fumes

Persistent signs should not be treated indefinitely as “another herpes flare” without reconsidering these alternatives. ISCAID recommends advanced investigation for disease lasting more than 10 days or failing appropriate initial management. (dvm360)

What To Do Right Now

1. Separate the Sick Cat

Place the cat in a quiet room away from other cats.

Provide separate:

• Food and water bowls

• Litter tray

• Bedding

• Toys

• Grooming equipment

Handle healthy cats first and the sick cat last. Wash your hands and change contaminated outer clothing when managing an outbreak. (ABCD cats and vets)

2. Monitor Breathing

Count breaths while the cat is sleeping or completely relaxed.

One rise and fall of the chest equals one breath. Contact your veterinarian urgently if the rate remains above approximately 35 to 40 breaths per minute, or if there is abdominal effort, nostril flaring or open-mouth breathing. (Cornell Vet College)

3. Protect Food Intake

Congested cats often stop eating because they cannot smell food. Calicivirus may also make eating painful.

Offer:

• Warmed canned food

• A strongly aromatic familiar diet

• Soft or blended food when oral ulcers are present

• Several small meals

• Food in a quiet area away from other animals

Do not force-feed a cat that is struggling to breathe, gagging or unable to swallow safely.

An adult cat eating little or nothing for approximately 24 hours needs veterinary advice. Kittens, diabetic cats, obese cats and medically fragile cats should be assessed sooner. (ABCD cats and vets)

4. Maintain Hydration

Offer several water sources and add water to familiar wet food when accepted.

Dehydrated or severely affected cats may need subcutaneous or intravenous fluids. Appetite stimulants do not replace hydration, pain relief or treatment of the underlying problem. (ABCD cats and vets)

5. Clean the Eyes and Nose

Gently soften discharge using:

• Warm water

• Sterile saline

• A clean soft cloth or cotton pad

Use a separate clean pad for each eye.

Do not pull off firmly attached crusts or insert cotton buds into the nostrils.

6. Increase Humidity

A humidified room, a brief period in a steamy bathroom or nebulisation with sterile saline may help loosen nasal secretions.

The cat should remain comfortably away from hot water and steam sources. Stop if humidity increases distress or body temperature. (Today's Veterinary Practice)

7. Check the Eyes Carefully

Arrange prompt examination when the cat:

• Squints

• Keeps one eye closed

• Rubs the eye

• Has a cloudy or blue-looking cornea

• Develops marked swelling

• Has thick ocular discharge

• Appears unable to see normally

Do not apply leftover eye medication. Products containing corticosteroids can worsen infectious corneal ulceration and should not be used until the cornea has been properly examined. (ABCD cats and vets)

8. Avoid Human Cold Medication

Do not give human:

• Decongestants

• Cough medicines

• Painkillers

• Nasal sprays

• Essential oils

• Vapor rubs

• Antibiotics

Many are toxic to cats or may worsen the condition. Use only medications prescribed for that patient.

How Do Veterinarians Diagnose a Cat URI?

Clinical Examination

Many uncomplicated cases are diagnosed from:

• Age

• Vaccination history

• Exposure to other cats

• Pattern of eye and nasal signs

• Presence of oral ulcers

• Temperature

• Hydration

• Breathing pattern

• Lung sounds

The veterinarian should also inspect the corneas, mouth, throat and both ears.

PCR Testing

Respiratory PCR panels may test for:

• FHV-1

• FCV

• Chlamydia felis

• Mycoplasma felis

• Bordetella bronchiseptica

• Other regional respiratory organisms

PCR can be helpful during outbreaks, severe disease or unusual presentations. Interpretation is not always straightforward because healthy carriers may test positive, vaccination can affect some results and a negative result does not reliably exclude every infection. Sampling multiple relevant sites may improve FHV detection. (ABCD cats and vets)

When Is More Investigation Needed?

Further investigation becomes more appropriate when:

• Signs persist beyond approximately 10 days

• Disease repeatedly returns

• Only one nostril is affected

• Discharge contains blood

• Facial swelling develops

• The cat loses weight

• Treatment repeatedly fails

• Coughing or breathing difficulty occurs

• A polyp, fungal infection or tumour is possible

Testing may include:

• Blood and urine tests

• FeLV and FIV testing

• Thoracic radiographs

• Skull or dental imaging

• CT

• Rhinoscopy

• Nasopharyngeal examination

• Biopsy

• Fungal antigen testing

• Airway sampling

Repeatedly changing antibiotics without investigating chronic disease is rarely the correct long-term plan. (dvm360)

How Are Feline Upper Respiratory Infections Treated?

Supportive Care

Supportive treatment remains the foundation for most uncomplicated infections.

It may include:

• Nutrition

• Hydration

• Nasal and ocular hygiene

• Humidification

• Pain relief

• Temperature support

• Stress reduction

• Appetite support

• Treatment of nausea

• Feeding-tube support in severe cases

Most cats with uncomplicated FCV require little specific treatment, but oral pain, dehydration and poor intake can make nursing care crucial. (ABCD cats and vets)

When Are Antibiotics Needed?

Antibiotics do not treat FHV or FCV.

ISCAID recommends an observation period of up to approximately 10 days for cats with uncomplicated acute disease, provided they do not have systemic illness.

Antibiotics become more appropriate when mucopurulent discharge occurs together with:

• Fever

• Lethargy

• Anorexia

• Worsening illness

• Evidence of pneumonia

• Strong suspicion of primary bacterial infection

Doxycycline is commonly selected when Chlamydia, Mycoplasma or Bordetella is suspected. Doxycycline tablets and capsules must be followed by food or liquid because dry administration can cause severe oesophageal injury in cats. (PubMed)

The antibiotic choice, formulation and duration should be determined by the veterinarian. Cefovecin, fluoroquinolones and other broad-spectrum medications should not be used automatically when a narrower first-line option is appropriate.

Famciclovir

Famciclovir is a systemic antiviral used for selected FHV-associated disease, particularly:

• Severe primary herpesvirus disease

• Corneal or ocular involvement

• Recurrent herpes keratitis

• Substantial respiratory and ocular disease in vulnerable kittens

• Some chronic FHV-associated presentations

It does not eliminate latent herpesvirus and is not required for every mild flare. Current ABCD guidance lists famciclovir among preferred systemic treatments for acute FHV ocular disease. (ABCD cats and vets)

Topical Eye Medication

Treatment depends on whether the eye problem involves:

• Viral conjunctivitis

• Bacterial conjunctivitis

• Corneal ulceration

• Keratitis

• Secondary infection

• Chlamydia felis

A veterinarian may prescribe:

• Topical antibiotics

• Lubricants

• Topical antiviral medication

• Systemic famciclovir

• Pain relief

Corneal staining should normally be performed before anti-inflammatory eye medication is considered. (ABCD cats and vets)

Pain Relief

Oral ulcers, corneal ulcers and severe inflammation can be painful.

Appropriate veterinary pain relief may substantially improve:

• Eating

• Hydration

• Rest

• Grooming

• Treatment tolerance

Never give paracetamol, ibuprofen, aspirin or another human painkiller unless a veterinarian has specifically prescribed an appropriate feline protocol.

Polyprenyl Immunostimulant

Polyprenyl immunostimulant is licensed in the United States for reducing the severity of feline rhinotracheitis.

Controlled experimental studies have reported clinical effects, and a 2026 experimental rechallenge study found a lower incidence of ocular disease in treated cats. However, ABCD continues to state that independent field studies are needed before routine recommendation. It should be considered an optional veterinary-directed therapy, not a replacement for nutrition, hydration, eye care or proven antiviral treatment where indicated. (ABCD cats and vets)

Is L-Lysine Recommended?

No.

Multiple studies and a systematic review found no reliable benefit for preventing or treating FHV-1 infection. Current ABCD guidance does not recommend it for preventing viral reactivation or shedding. (PubMed Central (PMC))

Is N-Acetylcysteine Needed?

N-acetylcysteine is not a routine home treatment for every congested cat.

Mucolytic treatment may be considered in selected patients, but oral, nebulised or topical use should be prescribed according to the cat’s respiratory condition and tolerance. Saline nebulisation and gentle nasal hygiene are usually safer first supportive measures.

Is Nasal Flushing Needed?

Nasal flushing under anaesthesia is not routine treatment for an uncomplicated viral URI.

It may be considered in chronic or obstructive disease after evaluating for:

• Foreign material

• Polyps

• Fungal disease

• Nasopharyngeal stenosis

• Tumours

• Severe retained secretions

Flushing without establishing the underlying cause may provide only temporary relief.

When Is Hospitalisation Needed?

Hospital treatment may be recommended when a cat:

• Cannot breathe comfortably

• Is significantly dehydrated

• Has stopped eating

• Cannot swallow safely

• Has severe pneumonia

• Requires oxygen

• Has a deep corneal ulcer

• Is a very young or weak kitten

• Develops severe systemic calicivirus disease

• Has suspected H5N1

• Needs a feeding tube

Treatment may include oxygen, intravenous fluids, nutritional support, antibiotics when indicated, antiviral medication, analgesia and close monitoring.

What Is Virulent Systemic Feline Calicivirus?

Virulent systemic feline calicivirus, or VS-FCV, is a rare severe form of calicivirus disease associated with outbreaks in hospitals, shelters and multi-cat settings.

Possible signs include:

• High fever

• Severe depression

• Facial and limb swelling

• Skin ulcers

• Footpad lesions

• Oral ulceration

• Jaundice

• Bleeding abnormalities

• Multi-organ failure

• High mortality

The older term “haemorrhagic calicivirus” is misleading because haemorrhage is not present in every case. Diagnosis depends on the clinical and outbreak pattern, not a routine positive FCV PCR alone. (ABCD cats and vets)

Is There a Special VS-FCV Vaccine?

Some vaccines contain more than one FCV strain, including strains derived from previous severe outbreaks. This may broaden immune responses against selected viruses.

However, VS-FCV outbreaks are rare, and individual outbreak strains may be genetically distinct. USDA guidance states that the expected cross-protection against different virulent isolates is unknown. No product should be presented as a universal guarantee against every form of virulent systemic FCV. (APHIS)

Routine core vaccination and strong outbreak biosecurity remain more important than selecting a vaccine based solely on a “haemorrhagic calicivirus” marketing claim.

Can a Cat Fully Recover?

Most cats with uncomplicated disease recover well.

Many begin improving within several days, although congestion and discharge can take one to three weeks to settle. Oral ulcers, pneumonia, very young age and concurrent disease can extend recovery. (Vca)

Recovery does not always mean the organism has disappeared:

• FHV generally remains latent for life.

• FCV may continue to be shed for weeks, months or occasionally longer.

• Vaccinated cats may still become infected or carry virus.

• Chronic nasal inflammation may remain after severe kittenhood infection.

The prognosis becomes more guarded with severe pneumonia, inability to eat, corneal perforation, virulent systemic FCV, H5N1 or significant immune compromise.

Can URI Signs Keep Coming Back?

Yes.

Recurrent signs may result from:

• Herpesvirus reactivation

• Persistent FCV shedding

• Chronic inflammatory rhinitis

• Permanent turbinate damage after severe kittenhood disease

• Dental disease

• Nasopharyngeal polyps

• Environmental stress

• Repeated exposure to infected cats

• Another undiagnosed disease

Stress reduction can help reduce herpesvirus-associated recurrence, but repeated discharge should not be blamed automatically on stress without examining the cat. (ABCD cats and vets)

Which Vaccines Help Prevent Feline URI?

Vaccines against:

• Feline herpesvirus

• Feline calicivirus

• Feline panleukopenia virus

are commonly combined in the core FVRCP vaccine. WSAVA classifies FHV, FCV and FPV vaccination as core worldwide. (WSAVA)

Current Kitten Schedule

WSAVA recommends beginning the core series at approximately six to eight weeks of age and repeating it every two to four weeks until at least 16 weeks of age.

In especially high-risk settings, vaccination may continue until 20 weeks. A further dose at approximately 26 weeks, around six months of age, is advised to reduce the susceptibility gap in kittens whose maternal antibodies interfered with earlier doses. (WSAVA)

After this, revaccination frequency depends on:

• Vaccine type

• Product licence

• Indoor or outdoor lifestyle

• Boarding

• Shelter or colony exposure

• Regional guidance

• Individual health

Lower-risk adult cats may receive core vaccination at intervals of three years or longer with appropriate products, while higher-risk cats may need more frequent FHV and FCV revaccination. (WSAVA)

Do Vaccines Prevent Infection?

Not completely.

FHV and FCV vaccines mainly:

• Reduce disease severity

• Reduce complications

• Improve population protection

• Sometimes reduce shedding

They do not reliably prevent infection, latent FHV carriage or all FCV shedding. (ABCD cats and vets)

What About Intranasal Vaccines?

Intranasal FHV and FCV vaccines are available in some countries.

Potential advantages include:

• Rapid onset of local protection

• Utility in selected high-risk environments

• Possible use around predictable boarding exposure

Potential limitations include:

• Temporary sneezing or mild respiratory signs

• Accidental spread of live vaccine material

• Need for a separate effective FPV vaccination component in some protocols

They are not automatically superior for every household cat.

Chlamydia and Bordetella Vaccines

Chlamydia felis and Bordetella vaccines are non-core.

They are considered mainly when:

• A pathogen has been confirmed within a multi-cat environment

• Cats live in large colonies

• Shelter or breeding exposure is substantial

• Repeated outbreaks occur

They are not routinely necessary for every indoor pet cat. (WSAVA)

How Can You Reduce Spread at Home?

Isolate New or Sick Cats

Keep a new cat separate for approximately two to three weeks where practical, particularly if their health and vaccination history are uncertain.

Monitor for:

• Sneezing

• Eye discharge

• Nasal discharge

• Oral ulcers

• Fever

• Poor appetite

ABCD recommends a three-week quarantine when protecting an FCV-free household from a newly introduced cat. (ABCD cats and vets)

Improve Hygiene

Use separate equipment and clean:

• Bowls

• Litter trays

• Carriers

• Bedding

• Hard surfaces

• Grooming equipment

Clean organic material away first, then apply an effective disinfectant for the full labelled contact time.

Reduce Stress and Crowding

Provide:

• Separate food and water stations

• Adequate litter trays

• Hiding places

• Vertical space

• Stable social groups

• Predictable routines

• Good ventilation

Reducing stress does not sterilise the environment, but it may reduce herpesvirus reactivation and improve general resilience. (ABCD cats and vets)

Maintain Vaccination

Vaccinate healthy cats according to their age, previous history and exposure risk.

A cat that has recovered from FHV or FCV should still be vaccinated because natural infection does not guarantee lifelong protection against future disease. (ABCD cats and vets)

Avoid High-Risk Raw Products

Do not feed unpasteurised milk, raw poultry or inadequately controlled raw meat products to cats. These exposures have been linked to severe H5N1 disease and death. (CDC)

Common Mistakes With Feline URIs

Assuming Every Cat Needs Antibiotics

Most acute cases are viral. Antibiotics are justified by the clinical pattern, not simply by sneezing or coloured mucus.

Waiting Too Long When the Cat Stops Eating

Congestion and oral pain can lead to clinically important calorie deprivation. Kittens and obese adult cats are particularly vulnerable.

Using Leftover Eye Medication

The wrong eye product may delay treatment or worsen a corneal ulcer.

Treating Every Recurrence as Herpesvirus

Polyps, fungal disease, dental disease, tumours and chronic inflammatory rhinitis can look similar.

Giving Human Cold Remedies

Decongestants, painkillers and essential oils can be dangerous to cats.

Relying on L-Lysine

Current evidence does not support lysine as an effective FHV treatment or preventive supplement.

Assuming Vaccination Prevents All Infection

Vaccination reduces disease severity but does not create a force field around the cat. Exposure management still matters.

Focusing on the Discharge but Ignoring Breathing

The colour of mucus is less important than whether the cat can move air comfortably and maintain normal oxygenation.

Frequently Asked Questions

Does a sneezing cat always need a vet?

No. A bright adult cat with mild sneezing, clear discharge, normal breathing and a good appetite may be monitored initially.

Arrange an examination if signs worsen, appetite falls, the eyes become painful or the cat is not improving within approximately seven to ten days.

Can a cat URI go away without antibiotics?

Yes. Most uncomplicated feline URIs are viral and resolve through immune response and supportive care. Antibiotics are used when bacterial infection or bacterial complications are clinically important. (Antimicrobial Resistance Learning Site)

Why has my cat stopped eating?

Congestion reduces the sense of smell, while fever, nausea, dehydration and calicivirus mouth ulcers can make eating difficult or painful.

Food refusal is one of the most important reasons to contact your veterinarian.

Can my vaccinated cat still get cat flu?

Yes. FHV and FCV vaccines reduce illness severity but do not reliably prevent infection, carrier states or all viral shedding. (WSAVA)

Can I use steam for my congested cat?

Brief humidification may help loosen secretions when your cat remains calm and breathes comfortably. Keep the cat away from hot water and stop if the heat or confinement causes distress.

Open-mouth breathing requires emergency treatment, not a steam session.

Final Thoughts

Feline upper respiratory infections are common, but “common” does not mean every case should be managed the same way.

The most important points are:

1. Most uncomplicated feline URIs are caused by FHV or FCV.

2. FHV commonly creates lifelong latent infection.

3. FCV may cause painful mouth ulcers and prolonged shedding.

4. Coloured discharge alone does not prove bacterial infection.

5. Most mild acute cases do not require antibiotics.

6. Poor appetite is one of the most clinically important warning signs.

7. Squinting or corneal cloudiness requires prompt eye examination.

8. Persistent coughing or rapid breathing may indicate lower respiratory disease.

9. Open-mouth breathing is an emergency.

10. Signs lasting longer than approximately 10 days deserve broader investigation.

11. Famciclovir can help selected FHV cases but is not required for every sneeze.

12. L-lysine is not supported as an effective herpesvirus treatment.

13. Polyprenyl immunostimulant has limited evidence and is not a replacement for established care.

14. Vaccination reduces disease severity but does not prevent every infection.

15. VS-FCV is rare, severe and not covered universally by one special vaccine strain.

16. Modern severe respiratory or neurological cases require consideration of H5N1 exposure.

17. Nutrition, hydration, eye protection and breathing comfort determine urgency more than the colour of the discharge.

The mistake that causes the greatest harm is assuming that every congested cat simply needs time or another course of antibiotics.

A bright cat who continues eating may be safely monitored. A cat who cannot breathe, cannot eat or cannot open a painful eye needs hands-on treatment.

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ASK A VET™ can help you organise photographs, breathing-rate records, appetite changes, vaccination history and the timeline of your cat’s signs while you arrange direct care with your veterinary team. A cat with open-mouth breathing, severe respiratory effort, collapse, abnormal gum colour or inability to eat or swallow still requires immediate hands-on emergency treatment.