Introduction
Feline upper respiratory infections (URIs) are very common in cats, especially in crowded living conditions like shelters. According to the Feline Health Foundation, the prevalence of URIs in shelter cats is estimated to be 80-90%. The viruses that cause these infections, such as feline herpesvirus and feline calicivirus, spread easily between cats.1 While many cats can recover from URIs on their own, treatment is often needed to prevent complications. Left untreated, URIs can progress to pneumonia or other secondary infections which have higher mortality rates. That’s why it’s important for cat owners to recognize the signs of URIs early and seek veterinary care when needed.
Causes
The most common causes of upper respiratory infections in cats are viral infections such as herpesvirus and calicivirus. These highly contagious viruses can be transmitted through direct contact with an infected cat or through contaminated objects and surfaces. According to the Cornell Feline Health Center, “80-90% of upper respiratory infections in cats are caused by one or both of these viruses” (https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/respiratory-infections).
Bacterial infections like Chlamydia felis can also lead to upper respiratory infections, though they are less common. Chlamydia spreads through nasal secretions and causes inflammation in the eyes and respiratory tract. Environmental factors like stress, poor ventilation, and exposure to cigarette smoke can weaken a cat’s immune system and make them more susceptible to both viral and bacterial infections (https://www.webmd.com/pets/cats/upper-respiratory-infection-cats).
In many cases, multiple pathogens are involved. The herpesvirus in particular can remain dormant in a cat’s body and become reactivated when the immune system is compromised. This makes recurrent upper respiratory infections common in cats.
Symptoms
The most common symptoms of feline upper respiratory infection (URI) include:
- Sneezing – Cats may have mild to severe sneezing fits.
- Nasal discharge – Thick mucus or pus may drain from the nose. The discharge may be clear, yellow, green, or reddish-brown.
- Eye discharge – URI often causes conjunctivitis, with yellow or greenish eye discharge. The eyes may also water excessively.
- Lethargy – Infected cats tend to be less active and have reduced appetite due to congestion and not feeling well.
- Mouth ulcers – Ulcers may develop on the tongue, palate, lips, or nose.
Severe cases may lead to high fever, pneumonia, dehydration, and significant weight loss. Kittens, senior cats, and cats with weakened immune systems are most at risk for developing complications from URI.
Diagnosis
A veterinarian will diagnose an upper respiratory infection in cats based on a physical exam, medical history, and sometimes laboratory tests. During the physical exam, the vet will check for common symptoms like nasal discharge, conjunctivitis, ulcers in the mouth, fever, and enlarged lymph nodes. They will use an otoscope to look inside the ears for inflammation or discharge. The vet may take samples from the throat and nose to identify the specific pathogen causing the infection through laboratory tests like bacterial culture, PCR testing, or immunofluorescence assay. Identifying the pathogen can help guide treatment decisions. For example, PCR testing can detect feline herpesvirus, calicivirus, Chlamydia, and Mycoplasma – common causes of upper respiratory disease in cats.
Treatment
Treatment for feline upper respiratory infections focuses on addressing the underlying cause and providing supportive care. Antibiotics may be prescribed for secondary bacterial infections that can occur. According to the VCA, “Most cats with an uncomplicated upper respiratory infection can be treated symptomatically at home. Your veterinarian may prescribe an eye medication if your cat has ocular discharge.”
The main categories of treatment include:
- Antibiotics: If a bacterial infection is present, antibiotics may be prescribed. Common antibiotics used include doxycycline, azithromycin, clindamycin, and amoxicillin.
- Antivirals: Antiviral medications are sometimes used for viral infections, especially feline herpesvirus or calicivirus. This may include famciclovir or interferon.
- Supportive care: Providing nutritional support, fluids, keeping nasal passages clear of discharge, and humidified oxygen may help cats recover. Reduce stress and allow rest.
In most cases, upper respiratory infections will resolve within 2-4 weeks with proper care and treatment. However, cats with other medical conditions or resistant infections may require extended treatment. Vets should monitor cases closely for secondary pneumonia, which requires aggressive antibiotic therapy.
Prognosis with Treatment
Most cats recover fully from an upper respiratory infection within 2-4 weeks when provided with proper veterinary treatment. Antibiotics like doxycycline or azithromycin are commonly prescribed to fight the bacterial infection and help reduce symptoms more quickly. Antiviral medications may also be used for viral infections. With medication, symptoms often start improving within 3-5 days.
In most cases, cats make a complete recovery with no long-lasting effects if treatment is started promptly. However, some cats may have lingering nasal congestion or discharge after other symptoms subside. In rare cases, significant damage to the sinuses or lungs can occur and lead to chronic issues. But this is very uncommon when cats receive veterinary care and treatment right away.
According to VCA Animal Hospitals, “Most cats with an uncomplicated upper respiratory infection can be treated symptomatically at home. Your veterinarian may prescribe an eye medication if your cat has ocular discharge or antibiotic drops if there is evidence of secondary bacterial infection.” With supportive care and antibiotics as needed, cats usually bounce back quickly from respiratory infections when addressed in a timely manner.
In summary, with prompt veterinary attention and proper treatment, most cats make a full recovery within 2-4 weeks from upper respiratory infections. However, delays in treatment can lead to more severe illness and potential long-term effects.
Prognosis without Treatment
If left untreated, upper respiratory infections in cats can persist for months or even develop into more serious conditions like pneumonia. According to the Cornell Feline Health Center, “Infections with feline calicivirus and feline herpesvirus can persist for months. Cats can become chronic carriers of these viruses.”
The VCA Animal Hospitals also notes that “Left untreated, 25% of cats with viral upper respiratory infections will develop more serious complications like pneumonia. Other complications include conjunctivitis, keratitis, and corneal sequestration which can lead to blindness.”
Allowing a respiratory infection to go untreated puts cats at risk of chronic illness and other potentially dangerous complications. It’s important to seek veterinary care rather than waiting it out if a cat develops symptoms of an upper respiratory infection.
When to See a Vet
If your cat’s upper respiratory infection symptoms last more than a week without improvement, it’s time to take them to the vet. As stated by Jaax Veterinary Clinic, lethargy that persists beyond the first 2 days of illness is a sign you should contact your veterinarian.
Difficulty breathing is another concerning symptom that warrants a vet visit. Cats with respiratory infections often develop congestion, but labored breathing, wheezing, or open-mouth breathing could indicate a worrisome level of airway obstruction.
Furthermore, if your cat stops eating or becomes very lethargic, it’s important to seek veterinary care. A sick cat who won’t eat can quickly become dehydrated and malnourished. Lethargy also often signals that your cat is feeling too unwell and needs medical intervention to recover.
Prevention
There are several ways cat owners can help prevent upper respiratory infections in their cats:
Vaccines are available for some of the viral causes of URI like feline herpesvirus, calicivirus, and panleukopenia virus. Keeping your cat up to date on these core vaccines can help prevent infection and reduce disease severity if infected. See https://vcahospitals.com/know-your-pet/feline-upper-respiratory-infection
Limiting exposure to infected cats can reduce the risk of contracting URI. This includes adopting healthy cats, keeping cats indoors, and avoiding contact with strays or cats with unknown health status. Cat shows, shelters, and boarding facilities can be high risk environments.
Reducing stress is also important as stress can trigger recurrences in cats with latent viral infections. Providing a calm, stable home environment and minimizing changes helps keep cats’ immune systems strong.
Conclusion
In summary, upper respiratory infections are common in cats and can be caused by viruses, bacteria, or other irritants. While mild cases may clear up on their own, most cats need veterinary care and medication to fully recover from URI and avoid complications or relapses. Antibiotics, anti-inflammatory drugs, and supportive therapies help reduce severity and duration of symptoms. With treatment, the prognosis for recovery is usually good. However, without treatment URIs can become chronic, damage the respiratory tract, or spread infection.
Prevention is key when it comes to feline upper respiratory infections. Keep cats up to date on vaccines, avoid overcrowding, reduce stress, provide good nutrition, and isolate sick cats. Though challenging to control in shelters and multi-cat homes, URI can often be managed with proper care and veterinary treatment. While URI is common in cats, it does not have to decrease quality of life when addressed promptly and appropriately.
