Do Indoor Kitties Catch the Cat Flu? The Surprising Answer


Cat flu is a common upper respiratory illness in cats caused by viral or bacterial infections. It’s not actually related to human influenza viruses, despite the name. Cat flu affects a cat’s upper airways and sinuses, causing symptoms like sneezing, congestion, eye discharge, reduced appetite, lethargy, and fever (Cats Protection).

Though cat flu itself is not usually fatal, secondary infections caused by the weakened immune system can become serious. Proper care and treatment are important to help afflicted cats recover fully. Cat flu is very contagious between cats, so prevention measures are necessary, especially for multicat households and shelters.


The feline herpesvirus and calicivirus that cause cat flu spread through direct contact between cats, especially through nasal and eye discharge as well as saliva. The viruses can be transmitted through activities like grooming, sneezing, or sharing food bowls and toys. The viruses are extremely contagious and can survive in the environment for several weeks or months. This makes transmission easy in multi-cat households or shelters.

Indoor cats are still at risk of contracting cat flu if they come into contact with objects or people that carry the virus from infected outdoor cats. Viruses can be brought inside on clothing, footwear, or other objects. New cats entering the household should be quarantined and monitored for symptoms. Vaccination helps reduce transmission risks but may not completely prevent infection.

According to the Blue Cross, “It can easily be spread by contact with infected feed bowls or toys, or on people’s clothing after touching an infected cat. Carriers of cat flu can continue shedding the virus, so it can be spread to other cats even if they do not currently have symptoms.”


The most common symptoms of cat flu include sneezing, runny nose and eyes, fever, lethargy, loss of appetite, and ulcers in the mouth. Cats may have discharge coming from their nose and eyes that can be clear, yellow, or greenish in color [1]. They often develop a raspy purr and may cough or gag. In severe cases, cat flu can also cause pneumonia and damage to the cornea [2]. Kittens and cats with weakened immune systems tend to develop more severe symptoms than healthy adult cats.


Cat flu is typically diagnosed by a veterinarian through a physical examination and review of symptoms. The vet will look for common signs of upper respiratory infection like discharge from the eyes and nose, ulcers in the mouth, coughing, and fever. They may also feel for enlarged lymph nodes which can indicate infection.

To confirm cat flu and identify the specific virus involved, the vet may take samples with nasal and throat swabs or brush the back of the throat. These samples can be tested for feline herpesvirus, calicivirus, Chlamydophila, and Bordetella. Cultures may also be taken to look for bacterial infections that can occur alongside cat flu viruses (Blue Cross).

Blood work may also be done to assess the overall health of the cat and look for complications. X-rays of the chest might be taken if pneumonia is suspected. Diagnostic imaging allows the vet to examine the throat, nasal passages, and lungs for signs of infection.


There is no specific treatment that kills the viruses that cause cat flu. However, vets may prescribe antibiotics like doxycycline or amoxicillin to treat secondary bacterial infections that can occur with cat flu (Source). Antibiotics can help resolve symptoms more quickly by fighting the bacterial infection, but they do not kill the underlying viral infection.

Vets may also prescribe anti-inflammatory medications like meloxicam to help reduce fever, upper respiratory congestion, and make cats feel more comfortable while recovering (Source). These medications can provide symptomatic relief but do not cure the viral infection.

Supportive care is an important part of treatment as well. This includes ensuring cats stay hydrated by encouraging eating and drinking. Using humidifiers and clearing nasal passages can also help sick cats breathe and recover more comfortably.


There are several effective ways to prevent cats from getting the cat flu, especially for indoor cats that have limited exposure to other cats. The most important prevention method is vaccination. While the vaccine does not provide 100% protection against the flu, it can reduce the severity of symptoms if a cat does get infected. Kittens should receive their first vaccination between 8-12 weeks old, with a booster 3-4 weeks later, according to the American Association of Feline Practitioners (AAFP) [1]. After the initial kitten shots, cats require annual vaccination boosters. Indoor cats that have limited exposure to other cats may only need boosters every three years according to their veterinarian.

In addition to vaccination, limiting exposure to infected cats and maintaining good hygiene can help prevent transmission. Indoor cats should avoid contact with outdoor cats or cats from multi-cat households. Litter boxes and food bowls should be cleaned daily and thoroughly disinfected weekly. Any new cats introduced to a household should be quarantined for two weeks and screened by a vet for upper respiratory infections before interacting with other household cats. With proper prevention methods, indoor cat owners can significantly reduce their cat’s risk of developing cat flu.


The prognosis for cats with cat flu is generally good, especially with prompt treatment. According to the Blue Cross, most cats will make a full recovery within 2-4 weeks if the illness is caught and treated early. However, the recovery time can be longer, around 4-6 weeks, for more severe cases. The mortality rate is low, around 2-5%, as cited by Purina and Trudell Animal Health. Young kittens, senior cats, or immunocompromised cats are at higher risk for complications and mortality. With supportive care from a veterinarian, most cats will recover fully from cat flu. However, it is important to isolate the sick cat, provide good nutrition, and monitor for secondary infections during recovery. Even after apparent recovery, some cats may experience lingering symptoms such as nasal discharge or eye inflammation. But with continued care and prevention methods, long-term effects can be minimized.


Cat flu can sometimes lead to serious complications if left untreated. The most common complications are secondary infections and pneumonia (source).

Secondary bacterial infections are common with cat flu, especially in the eyes, mouth, throat, and upper respiratory tract. These are often caused by bacteria like Staphylococcus, Streptococcus, and Bordetella bronchiseptica. Secondary infections can lead to more severe symptoms and illness.

Another potential complication is pneumonia, which is an infection of the lungs. Cat flu can spread to the lungs, causing pneumonia. Pneumonia can be life-threatening if not treated promptly with antibiotics and supportive care. Signs of pneumonia include labored breathing, wheezing, and breathing with an open mouth. Pneumonia requires urgent veterinary treatment.

To prevent complications from cat flu, it’s critical to get prompt veterinary care and follow treatment instructions closely. Medications like antivirals and antibiotics, along with supportive care, can help treat the infection and prevent lasting damage or pneumonia (source).

At-Risk Cats

Certain cats are at higher risk of developing severe symptoms or complications from cat flu. These include:

Kittens – Kittens under 12 weeks old have an underdeveloped immune system, making them more susceptible to cat flu. The infection can be especially dangerous in very young kittens, sometimes leading to pneumonia.

Shelter cats – The close quarters in animal shelters allow cat flu to spread rapidly between cats. New arrivals are often not vaccinated yet, and the stress of the shelter environment can weaken cats’ immune response.

Multi-cat households – Homes with several cats are prime locations for cat flu outbreaks. The virus passes easily between cats in frequent close contact. Getting all household cats vaccinated is critical.

Vaccination is crucial for protecting at-risk cats against cat flu. Shelters should quarantine and vaccinate new intakes before integrating them into the general population. Responsible breeders vaccinate kittens starting at 6-8 weeks old. Multi-cat homes should keep all cats up to date on vaccines.


While indoor cats are at lower risk for infectious diseases like cat flu compared to outdoor cats, they can still contract the virus. Cat flu is a highly contagious upper respiratory infection caused primarily by two viruses, feline herpesvirus and feline calicivirus. The main symptoms include sneezing, nasal discharge, fever, lethargy, loss of appetite, and eye inflammation. Most cases are mild, but severe infections can lead to pneumonia and even death in rare cases. Treatment focuses on supportive care and antiviral medication. The best way to prevent cat flu is through vaccination, keeping cats away from infected animals, reducing stress, and maintaining a clean environment. Though disturbing, cat flu rarely has long-term consequences when properly managed by a veterinarian. Being aware of the signs and getting prompt treatment is key to ensuring a good outcome. With proper care, most cats fully recover within 2-4 weeks.

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