Do Cats with Upper Respiratory Infections Need Antibiotics?


I recently came across the following question in the Catster Answers forum:

I have seven cats, all up to date on shots. One cat began sneezing a week ago, then he seemed to get better, but now he has leaky eyes and is a little congested. He has continued to have a healthy appetite and is playful.

Last night one of my other cats began sneezing, and she is very congested, but she is also still eating and being playful. I have been crushing up lysine for them and putting it in their food and I am going to buy a dehumidifier. I went through giving all seven of them antibiotics before, when they had URIs. My question is, Do I need to get an antibiotic from the vet or will they will be fine with lysine, baby saline nose drops, and a dehumidifier? I really don’t want to go through the antibiotic course again.

Upper respiratory infections (URIs) are common in cats, and they can a serious nuisance for owners and pets in multicat households.

Although they are called respiratory infections, URIs most frequently affect the eyes. The most common symptoms are squinting and watering of one or both eyes. Other common symptoms of URIs include sneezing, coughing, sinus congestion, and nasal discharge.

There are dozens of known and probably dozens more yet-to-be-discovered pathogens that cause URIs. The most common is the feline rhinotracheitis virus, also known as the feline herpes virus. It is related to the human cold sore virus (and also to the other human herpesvirus, but the variety that affects cats is not spread sexually).

Feline rhinotracheitis is not contagious to humans, but is extremely contagious among cats and can spread rapidly through households with multiple cats. Exposed cats are infected for life, and some suffer intermittent symptoms.

L-lysine is a naturally occurring dietary product (an amino acid) that inhibits the virus and is commonly recommended, but it is not a panacea. People generally must suffer through their cold sores for about a week; so, too, must cats with herpesvirus suffer their URIs.

Other common culprits in URIs are Chlamydia bacteria (which, despite the name, also are not STDs) and calicivirus. As I mentioned above, there are dozens — or perhaps hundreds — of less common and less infamous viruses and bacteria.

Many URIs are viral in nature, so antibiotics have no effect on them. Most of the bacterial URIs are self-limiting (which means they’ll get better on their own with time, so antibiotics aren’t really necessary). I therefore do not generally recommend oral antibiotics for URIs as long as the symptoms are mild. Antibiotics can cause side effects such as vomiting and diarrhea, and inappropriate or excessive antibiotic use has been linked to development of resistant bacteria that pose health risks to cats, dogs, and people.

For cats that are behaving and eating normally, the benefits of antibiotics are not likely to outweigh the risks. However, if any cat’s condition deteriorates (or if eye or nasal discharge becomes yellow or green, which often signals a bacterial infection), then antibiotics will be appropriate for that specific cat. I definitely do not recommend administering antibiotics to cats that aren’t sick.

The person who asked the question should be prepared for the possibility that URIs may slowly progress through the house. The situation is likely to be frustrating, but it is not likely to be fatal for any cats involved. Antibiotics are not likely to help with the situation.

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