Ah, the feline respiratory infection — the bane of shelters and immune-compromised cats everywhere. Some of them are highly contagious and can take down a shelter full of cats in no time at all, while some lie dormant and only come out to play in high-stress times. Here’s the 411 on kitty colds.

1. Respiratory infections are caused by viruses

Three viruses are responsible for the vast majority of feline upper respiratory tract infections: feline herpesvirus 1, feline calicivirus, and feline parvovirus. All three infections look similar at first, but there are some subtle differences in the signs and symptoms of each.

2. Feline viral rhinotracheitis: snotting and sneezing

FVR is caused by the feline herpes 1 virus. It is a highly contagious virus that is spread in the droplets of mucus and other fluids expelled by ill cats. Cats with FVR are lethargic and sometimes feverish. They sneeze and cough a lot and sometimes develop secondary infections like pneumonia. Because the nose is plugged and the throat is sore, cats with FVR don’t want to eat or drink, which can result in dehydration and weaken the body’s ability to fight off the virus. Even though cats with FVR can make a full recovery, the herpes virus is a chronic infection and the dormant virus can become active again in times of stress.

3. Feline calicivirus: sore mouth, eye discharge

The calicivirus mostly affects the inside of the mouth, the eyes and the nasal passages. The first symptoms of a calicivirus infection are fever, lethargy and loss of appetite. Later on, cats infected with this virus develop conjunctivitis (discharge from the eyes and swelling of the eyelids), mouth ulcers and sneezing. Calicivirus is transmitted by direct contact with an infected cat or objects such as food dishes used by an infected cat.

4. Feline panleukopenia: vomiting, diarrhea, collapse

Panleukopenia, also known as feline distemper, is caused by a parvovirus related to the one that affects dogs. Panleukopenia is characterized by loss of appetite, vomiting and diarrhea. A blood test would show that the number of white blood cells, which fight disease, is too low. This disease has a very high mortality rate ÔÇô as much as 90% in kittens under six months of age, and close to 50% in older cats.

5. All these diseases are preventable with a vaccine

The FVRCP vaccine (feline viral rhinotracheitis, calicivirus, panleukopenia) is designed to build immunity against these respiratory infections. Any respiratory infection can become fatal if a cat refuses to eat or drink for a long period of time. Even if you don’t vaccinate every year, please at least consider making sure your cat gets her “kitten shots.”

6. The best way to manage respiratory infections is with supportive care

First, try to keep your cat as congestion-free as possible. Use a humidifier or keep your cat in the bathroom with you when you shower. If your cat won’t eat, it’s probably because he can’t smell his food; try serving some super-stinky cat food or warming the food in the microwave to make it smellier (take it out of the metal can first, though). If you can’t get him to eat even with warming his food, give him liquids through an oral syringe or eye dropper. At the shelter where I volunteered, we used to put lysine powder in the cats’ food to help strengthen their immune systems, so you may want to try that, too.

7. Antibiotics won’t do anything for respiratory infections

Antibiotics are designed to kill bacteria, not viruses, so they’re useless against uncomplicated respiratory infections. However, some vets will prescribe antibiotics for a cat with a viral illness if a secondary bacterial infection has set in.

8. Feline respiratory viruses are not contagious to people or dogs

Although we humans have our own herpesviruses, one of which is responsible for our colds, the viruses that cause respiratory infections in cats themselves highly species-specific. Likewise, the parvovirus that causes panleukopenia does not affect dogs.

Is there anything else you wish you knew about feline respiratory viruses? Have you had to care for a cat with a respiratory infection? What worked and what didn’t? Share your thoughts in the comments.

About JaneA Kelley: Punk-rock cat mom, science nerd, animal shelter volunteer and all-around geek with a passion for bad puns, intelligent conversation, and role-play adventure games. She gratefully and gracefully accepts her status as chief cat slave for her family of feline bloggers, who have been writing their award-winning cat advice blog, Paws and Effect, since 2003.