Cats can catch a cold just like people do. The vast majority of these upper respiratory infections are viral in nature, and the primary culprit is the feline herpesvirus. Once exposed to the virus, there is an incubation period of two to five days, after which, cats develop clinical signs. A variety of signs are possible: sneezing is by far the most common and runny eyes, snotty nose, congested breathing, decreased appetite and generalized lethargy are also often present. Feline herpesvirus treatment is largely aimed at managing the symptoms. Adult cats with mild symptoms — a little sneezing, slight watery nasal and ocular discharge, no lethargy or decreased appetite — may not require any specific treatment other than close monitoring. As with humans, most cats with colds recover on their own at home in a week or two.
For cats with more pronounced symptoms, antibiotics may be prescribed as part of feline herpesvirus treatment. Antibiotics don’t treat the viral infection, per se. They help prevent the development of bacterial infections that often occur secondary to the viral infection. I usually prescribe antibiotics early in the course of the illness in kittens because they are so fragile.
Some cats get pretty sick from the herpesvirus and may require additional measures, including hospitalization. Cats with severe nasal congestion may have a poor appetite because they cannot smell their food. These cats may require appetite stimulants and/or syringe feeding until the congestion resolves. Cats who won’t drink may require either subcutaneous (under the skin) or intravenous fluid therapy to maintain hydration.
Although viral upper respiratory infections commonly cause conjunctivitis (inflammation of the tissues around the eyes; in humans we often call this “pink eye”), feline herpesvirus is notorious for its ability to cause more severe eye problems, in particular, corneal ulcers. The cornea is loaded with pain receptors, and cats with corneal irritation from the herpesvirus are uncomfortable. To prevent permanent damage to the eyes, corneal ulcers that occur due to the feline herpesvirus require treatment, usually with antiviral eye drops. This is labor-intensive, as most antiviral drops need to be administered four to six times daily to be maximally effective. As you might imagine, cats do not enjoy this.
Although most cats conquer their viral respiratory infection on their own, persistent cases may benefit from antiviral medications. The antiviral drug famciclovir, given twice daily, has been shown to be safe and effective in both adult cats and kittens. When given at the proper dosage, therapeutic levels of famciclovir will be achieved in the tears as well as the bloodstream, which helps speed the resolution of any symptoms involving the eyes.
Antiviral medications can be expensive, unfortunately, and achieving the proper dose using famciclovir tablets can be tricky. Having the medication compounded into a flavored liquid may allow for more accurate dosing; however, famciclovir has a bitter taste that can be difficult to mask.
Cats with feline herpesvirus infection often have nasal congestion, and increasing the humidity is a good tool in feline herpesvirus treatment. Take the cat into the bathroom and run the hot water in the shower so that the bathroom gets very steamy. Let the cat sit in the steamy bathroom for 10 or 15 minutes, twice daily. Most of my clients are happy to do this for their cat, and many feel that it is helpful. Nasal and ocular discharge, when it dries, can irritate the skin beneath it.
Gently wipe away nasal or eye discharge that accumulates with a moist tissue. Because cats with copious nasal discharge may have an impaired sense of smell, I advise clients to feed their cat very tasty, strong-smelling food. Herpes viruses stay in the body forever, and once the symptoms have resolved, cats remain lifelong carriers. The virus stays dormant in the body but may periodically re-emerge when the cat’s immune system is suppressed. During these times, cats may show symptoms again and may be contagious to other cats.
Many veterinarians were (and still are) prescribing the amino acid lysine as adjunct therapy for feline herpesvirus treatment, believing that lysine speeds the resolution of the infection and may help prevent future infections. However, several clinical studies have shown that lysine is not effective for the prevention or the treatment of feline herpesvirus infection, and many veterinarians have stopped prescribing it. Personally, I’m on the fence.
Despite the lack of scientific evidence, I have a few clients who swear by it, telling me that the moment they stop giving lysine, the symptoms return. Veterinary lysine products are available in many forms, and the oral gel and the chicken liver-flavored treats are quite palatable. While it is certainly not one of my first-line treatments, if a client wants to give lysine a try, I won’t discourage it, especially if the cat enjoys the taste of it.
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Dr. Arnold Plotnick is the founder of Manhattan Cat Specialists, a feline-exclusive veterinary practice on Manhattan’s upper west side. He is also an author of The Original Cat Fancy Cat Bible. Dr. Plotnick is a frequent contributor to feline publications and websites, including his own blog, Cat Man Do. He lives in New York City with his cats, Mittens and Glitter.
Editor’s note: This article originally appeared in Catster magazine. Have you seen the new Catster print magazine in stores? Or in the waiting area of your vet’s office? Click here to subscribe to Catster and get the bimonthly magazine delivered to your home.