Feline Upper Respiratory Infections, or URI, is similar to the common cold in people. It can be a frustrating disease for both cats and owners; however, the prognosis is generally good for most cats. Some cats may have chronic symptoms that don’t resolve, but this is a rarer occurrence.

The symptoms seen in cats are like what we would see in a person with a cold. You may notice sneezing, lethargy caused by a fever, discharge from the eyes and/or nose, red and puffy eyes, depression, decreased appetite, sores in the mouth (ulcerations), drooling, eye ulcers, or squinting. For some cats, the symptoms may be very mild, while other cats are very ill from the URI. Healthy cats without symptoms can also be carriers. They are shedding the virus and infecting other cats but not show any signs of illness.

Most feline URIs are caused by highly contagious viruses. The most common virus is a Feline Herpesvirus (FHV-1), but we also see Feline Calicivirus (FCV), Chlamydolphila felis (C. felis), Mycoplasma, and Bordetella bronchiseptica. Cats can also get secondary bacterial infections including Pasteurella, E. coli, Enterobacter, and Staphylococcus species.

• FHV-1: Also called Feline Rhinotracheitis Virus, FHV-1 is common in kittens and in places where there are groups of cats like shelters, multi-cat households, and breeding colonies. Transmission of the virus occurs through direct contact of excretions, like a sneeze or discharge from the eyes or nose, or through contamination in the environment. Once a cat is infected with FHV-1 it will always carry the virus. This is called viral latency, where the virus will often hide in the trigeminal nerve. We can see periodic recurrence of symptoms, especially during times of stress. FHV-1 can also lead to chronic URI symptoms.

• FCV: Like FHV-1, FCV is also common in kittens and places where there are groups of cats. Transmission is through direct contact with an infected cat or environmental contamination. There are many strains of FCV. Besides causing an URI, FCV also can cause oral ulcerations, lameness, and gum disease called stomatitis.

• C. felis: C. felis is a bacterium that can cause URIs in cats, but we often see it affect the eyes and cause conjunctivitis. Transmission is through direct contact with an affected cat.

• Mycoplasma: Mycoplasma is a bacterium that can contribute to URI symptoms in cats and may even cause asthma like symptoms. It rarely causes disease by itself, but can add to clinical signs if another organism is involved in the URI.

• Bordetella bronchiseptica: Bordetella is a bacterium that can cause URI symptoms as well as increased lymph nodes and a cough. Transmission is through direct contact, and can even spread from infected dogs to cats. The bacteria can be shed long after the signs of the URI have resolved.

Often the exact cause of an upper respiratory infection is not identified since the treatment is the same despite what the infectious agent is. We can base our diagnosis on the history and physical examination.

In complex cases, or cases that aren’t responding to treatment we can do a blood test called PCR or a culture to try to identify the causative organism. Testing for URIs is complicated by the fact that normal, healthy cats will also test positive for these organisms; however, a negative result means that organism is not causing any symptoms at that time. We use the results of the test in conjunction with our exam findings and the history to determine the best treatment options.

Prevention of URIs is key. The FVRCP vaccine contains FHV-1 and FCV viruses. Kittens should have a series of FVRCP vaccines starting between 6-8 weeks and given every 3-4 weeks until they are older than 16 weeks of age. Adult cats should receive 2 vaccines 3-4 weeks apart if their vaccine history is unknown or they were never vaccinated before. Cats get a booster 1 year after the initial series then every 3 years. Vaccination can reduce the severity of the symptoms and the length of illness with an URI.

Stress reduction can prevent the outbreak of URIs. Cats can experience stress from many different sources- being indoors, living in a multi-cat household, access to resources is limited, other cats coming into their field of vision outside, change in routine, etc. We can help reduce our cats stress in many ways. The best resource for information on what causes stress in cats and how to help is found here:

https://indoorpet.osu.edu/cats

For cats with symptoms of an URI, symptomatic treatment is often effective. Most infections will resolve in 7-10 days. Some cats may take longer, or become chronically symptomatic. It is important to make sure your cat is eating and staying hydrated while sick.

If the signs are mild, and your cat is eating we often monitor and allow the signs to resolve on their own. For more serious infections, your cat may need medications and even hospitalization to get them through the URI. Antibiotics are only effective if a bacterial or secondary bacterial infection is present as they have no efficacy against viruses. Topical or oral anti-viral medication can be used to help speed up the recovery process. Keeping a humidifier on or allowing your cat to spend time in a steamy bathroom can help keep the nasal passages moist. Saline drops or medicated nose drops can also be used if needed. Keep the eyes and nose clean by wiping the area with warm water a few times a day. Please check with your veterinarian before starting any home treatments.

For cats that have chronic URI symptoms, further work up is needed. URI signs are not specific to the above infections. We will investigate other causes of these signs like dental disease, polyps, fungal infections, masses, etc. It is important to tell your veterinarian if the symptoms are not improving after 14 days

https://icatcare.org/advice/cat-health/cat-flu-%E2%80%93-upper-respiratory-infection

http://www.winnfelinefoundation.org/docs/default-source/cat-health-library-educational-articles/upper-respiratory-infections-in-cats-2016.pdf?sfvrsn=2