Feline Common Cold: A Clinical Guide for Veterinarians
A sneezing cat with nasal discharge and fever may seem routine, but are you confident you know what's behind the symptoms?
Cats can develop upper respiratory infections that resemble human colds in outward signs. The symptoms include sneezing, nasal discharge, watery eyes, and mild fever. However, the feline common cold is a bit different from a human cold.
What is Feline Common Cold?
A cat cold is a highly contagious infection of the upper respiratory tract. In veterinary medicine, these conditions are referred to as feline upper respiratory infections or rhinitis and may progress to pneumonia in severe cases.
Feline upper respiratory infections (URIs) are one of the common cat diseases, ranging from mild signs to life-threatening disease.
What Causes Feline Common Cold?
Feline upper respiratory disease complex can be caused by a variety of pathogens, including viruses and bacteria. Feline URIs are most often viral in origin, accounting for roughly 80–90% of cases, while bacteria contribute to around 10%. Clinical findings suggest that feline calicivirus (FCV) is more commonly associated with oral lesions, whereas feline herpesvirus (FHV-1) is more frequently linked with sneezing and upper respiratory signs.
An important clinical consideration with FHV-1 is its ability to establish lifelong latency in the trigeminal ganglia. Reactivation can occur during periods of physiological or environmental stress, such as boarding, transport, surgical procedures, concurrent illness, or corticosteroid administration. Stress-related reactivation is one of the most common reasons for recurrent upper respiratory signs in previously recovered cats, and recognizing these triggers is essential for managing chronic or relapsing cases.
Viral Agents
Feline Calicivirus (FCV):
Feline calicivirus (FCV) is a single-stranded RNA, non-enveloped virus with marked antigenic diversity within a single serotype. Infected cats may continue to shed the virus for long periods, sometimes for life.
Feline Herpesvirus type 1 (FHV-1):
Feline herpesvirus type 1 (FHV-1) is a double-stranded DNA virus found worldwide and is not considered zoonotic. It is a major viral cause of feline viral rhinotracheitis (FVR).
Bacterial Agents
Bordetella bronchiseptica:
Bordetella bronchiseptica is a gram-negative bacterium that affects the respiratory tract in cats and may be associated with sneezing, nasal discharge, conjunctivitis, and other upper respiratory signs, particularly in densely housed or shelter environments.
Chlamydia felis:
Chlamydia felis is an obligate intracellular bacterium that survives only within host cells. Infection often begins with unilateral ocular signs but may progress to bilateral ocular involvement over time.
Mycoplasma felis:
Mycoplasma felis is a small, pleomorphic, cell-wall-deficient bacterium associated with feline upper respiratory tract infections and conjunctival disease.
What are the Symptoms of Common Cold in Cats?
Cat cold symptoms usually appear after an incubation period of 2 to 6 days. The symptoms include:
- Sneezing
- Coughing
- Nasal discharge or congestion
- Fever
- Watery eyes
- Oral ulcers with increased salivation
- Corneal ulcers
- Lethargy
In mild cases, symptoms often begin to improve within 5 to 10 days. More severe infections may take several weeks to resolve, with some signs lasting up to six weeks. Fortunately, most cats recover well with supportive care, and the overall outlook is generally favorable since the illness is often self-limiting.
Moreover, a secondary bacterial infection may cause thick yellow or green discharge from the eyes or nose. As cat nasal congestion worsens, the cat's sense of smell and taste can be reduced, often leading to a decreased appetite or reluctance to eat.
In more serious cases, the infection can progress to pneumonia. Cats with pneumonia may develop a cough, labored breathing, or respiratory distress, and some may need hospitalization for supportive treatment. Oral ulcers caused by FCV may overlap with signs seen in periodontal disease in cats, so careful differentiation is important during clinical examination.
Cats with underlying immunosuppressive conditions, particularly feline immunodeficiency virus (FIV) or feline leukemia virus (FeLV), may experience more severe or prolonged clinical signs. In these patients, upper respiratory infections are more likely to become chronic, respond poorly to standard supportive care, or progress to secondary complications. Retroviral status should be considered as part of the clinical workup, especially in cats with recurrent or non-resolving respiratory disease.
Timeline of a Cat Cold
Incubation Period
After a cat is exposed to a respiratory virus, there is usually a short incubation period before symptoms develop. For feline viral rhinotracheitis (FVR) and feline calicivirus (FCV), signs of illness typically appear within 2 to 6 days. In cases caused by Chlamydia felis, the incubation period is generally longer, ranging from 5 to 10 days.
Symptoms Begin and Peak
The first signs of a respiratory infection in cats are usually sneezing, watery eyes, and nasal discharge. These symptoms often develop quickly and may become more noticeable during the first one to two days.
Recovery Phase
Most cats begin showing clinical improvement within 7 to 10 days with appropriate rest and supportive care. Some mild symptoms, especially in cats with herpesvirus, may linger a little longer.
How is Feline Common Cold Transmitted from One Cat to Another?
Feline common cold can be transmitted from one infected cat to another through direct contact. This occurs when an infected cat sneezes or coughs, releasing saliva and nasal fluids that carry the virus.
Transmission may also occur indirectly, such as via sharing food and water bowls, toys, bedding, and other items that have come into contact with an infected cat's respiratory secretions.
In some situations, transmission may occur during aggressive interactions such as fights.
Cats that live indoors on their own have a lower risk of exposure than outdoor cats or those in homes with multiple cats. Still, germs can occasionally be brought indoors on shoes, clothing, or hands after contact with infected environments.
That is why veterinarians should gather a detailed history from the owner and carry out a full examination to guide further evaluation and management.
If any respiratory signs appear, extra attention to hygiene and separation from other cats can help limit spread.
In clinical and shelter settings, environmental decontamination plays a key role in reducing transmission. Feline calicivirus is notably persistent on surfaces, remaining viable for up to 28 days in certain conditions. Effective disinfection protocols include the use of dilute sodium hypochlorite (bleach at 1:32 dilution), potassium peroxymonosulfate, or accelerated hydrogen peroxide-based products, with a minimum contact time of 10 minutes on cleaned surfaces. Feline herpesvirus, being an enveloped virus, is more susceptible to routine disinfectants. All food bowls, bedding, litter trays, and shared equipment should be disinfected between uses, particularly in multi-cat or high-turnover environments.
How to Diagnose a Feline Cold?
Typical signs that are seen in upper respiratory disease, such as sneezing, conjunctivitis, nasal discharge, watery eyes, salivation, and oral ulcers, support a presumptive diagnosis. Breathing difficulty and pneumonia help veterinarians diagnose severe cases of feline upper respiratory disease.
Feline herpesvirus most often affects the eyes and nasal passages, while feline calicivirus is more commonly linked with mouth ulcers and sometimes lower respiratory involvement. Chlamydia felis tends to show up as a long-lasting, mild conjunctivitis. When more than one agent is involved, the signs can overlap and become harder to separate clinically.
To get a clearer picture, cytology from Giemsa-stained conjunctival scrapings can help detect organisms like chlamydiae and mycoplasmas. Identification of the causative agent provides confirmation of feline URIs.
Samples are usually taken from the eyes, nose, or throat area. In feline herpesvirus cases, shedding may be intermittent, so results may not always correlate with the cat's current condition.
PCR testing from eye, nasal, or throat swabs can help pinpoint the cause, especially in cats with repeated or more severe signs.
How To Treat A Cat With A Cold?
Treatment of the feline common cold is mainly supportive, with attention to comfort and hydration while the infection progresses.
In cases where secondary bacterial infection is suspected, the use of broad-spectrum antimicrobials may be effective. Available options may include amoxicillin clavulanate, cephalosporins, trimethoprim sulfa, fluoroquinolones, tetracyclines, and chloramphenicol. Tetracyclines and fluoroquinolones tend to be more active against Chlamydia felis and Mycoplasma felis.
Nasal and ocular discharge should be gently cleaned to maintain patient comfort. Nebulization or saline drops can loosen thick secretions and make breathing easier. Selected topical agents may reduce nasal discharge in some cases.
If feline herpesvirus leads to corneal ulcers, topical antiviral eye medications such as idoxuridine, trifluridine, or vidarabine may be used at regular intervals.
L-lysine supplementation has been used in some cases with the goal of reducing viral replication; however, current evidence does not consistently support its efficacy, and some studies suggest it may not provide a clinical benefit. Its use remains a topic of ongoing discussion in veterinary literature.
Cats with breathing difficulty may need oxygen support. Fluids can help address dehydration, and some cats may require assisted feeding through syringe feeding or feeding tubes if appetite is poor.
When to Consider Hospitalization
Hospitalization should be considered when clinical signs indicate the disease has progressed beyond what can be managed on an outpatient basis. Key indicators include dehydration estimated at greater than 5%, persistent anorexia lasting more than 72 hours, significant respiratory distress or cyanosis, high or unresponsive fever, and radiographic evidence of pneumonia. Young kittens, geriatric cats, and those with concurrent FIV or FeLV infection carry a higher risk of rapid deterioration and may benefit from earlier intervention, including intravenous fluid therapy, oxygen supplementation, and nutritional support via nasoesophageal or esophagostomy tubes.
Vaccination to Prevent Feline Common Cold
Core vaccination against feline herpesvirus and calicivirus is recommended for all cats. Kittens are typically vaccinated starting at around 6 to 9 weeks of age, with boosters given every 3 to 4 weeks until at least 12 weeks of age. Adult cats then receive booster doses every 1 to 3 years depending on risk and vaccine type.
Some cats may show mild sneezing for a few days after intranasal vaccination. In cases where stress-related anxiety is a concern during vaccination visits, veterinarians may consider premedication strategies such as gabapentin to improve patient compliance and reduce physiological stress that could trigger FHV-1 reactivation in carrier cats.
In higher-risk environments such as shelters or catteries, vaccines that also include protection against Chlamydia felis may be used.
Frequently Asked Questions (FAQs)
Can cats transmit colds to humans?
Feline upper respiratory infections are caused by species-specific pathogens such as FHV-1 and FCV, which are not considered zoonotic. These viruses do not infect humans. However, Bordetella bronchiseptica has been reported in rare cases involving immunocompromised individuals, so standard hygiene practices are still advisable.
How long is a cat contagious with an upper respiratory infection?
An actively infected cat can shed viral particles throughout the symptomatic period, which typically lasts 7 to 10 days. Cats infected with FCV may continue shedding the virus for weeks to months after clinical recovery, and some become lifelong carriers. FHV-1-infected cats can also shed intermittently during periods of stress-induced reactivation.
When should a cat with a cold be seen by a veterinarian?
A veterinary evaluation is recommended if symptoms persist beyond 5 to 7 days without improvement, if the cat stops eating for more than 48 to 72 hours, if there is thick green or yellow nasal discharge suggesting secondary bacterial infection, or if there are any signs of respiratory distress such as open-mouth breathing or labored respiration.
Conclusion
Feline upper respiratory infections are frequently encountered in veterinary practice, often driven by viral agents with secondary bacterial involvement in some cases. While symptoms can vary in intensity, many cats respond well to supportive care, with recovery occurring over days to weeks in most situations.
Early recognition of clinical signs, combined with appropriate diagnostic steps and targeted therapy when needed, helps guide case management. Attention to hydration, nutrition, and ocular and nasal comfort, along with antiviral or antimicrobial use in selected cases, supports a smoother recovery period.
Preventive strategies play a strong role in reducing disease spread, with routine vaccination, good hygiene practices, and reduced exposure in multi-cat environments contributing to lower transmission risk. Overall, prognosis is generally favorable in uncomplicated cases when timely care and preventive measures are applied.
