URIs are very common in cats, especially those adopted from the animal shelter or from pet stores.  Any place where there are a lot of cats in close proximity you have an increased risk of getting a URI.  There are several different bacterial and viral URIs that cats can get and treating each is a little different.

This is likely the most common URI we see in cats.  The most common signs are:

• Conjunctivitis or red, swollen and watery eyes
• Yellow or green discharge from the eyes
• Corneal ulcers (squinting, holding eyes shut, cloudy eyes)
  
• Sneezing, with or without discharge from the nose
• Fever
  

We usually treat any cat with conjunctivitis like it has herpesvirus.  To get a definitive diagnosis we do a conjunctival scraping and send the tissue in for PCR, where the lab isolates the virus.  Treatment includes topical eye drops if there is corneal ulceration, antibiotics to help prevent secondary infections, fluids to treat dehydration, and L-lysine supplementation.  L-lysine is an amino acid that decreases replication of herpesvirus. We also make sure the cats continue to eat (their appetite is directly linked to their sense of smell so if they have too much nasal congestion their appetite drops) as not eating for even 3 days can potentially cause liver failure.  Once infected with herpesvirus, these cats remain carriers for life and will have flare-ups of their symptoms from time to time, especially during periods of stress.  Sometimes L-lysine supplementation is continued daily for the entire lifetime of the cat to help control symptoms.  Though highly contagious to other cats, Feline Herpesvirus cannot be transmitted to dogs or people.  We vaccinate kittens with a minimum of 3 vaccinations to protect against herpesvirus, and adult cats receive yearly boosters as well.

This is the other most common URI in cats.  This viral infection has similar symptoms to herpesvirus with a few differences:

• Sneezing, nasal discharge, watery eyes, and fever are still present
  
• Corneal ulcers are not usually seen
• Ulcers are present in the back of the mouth or on the gums

Treatment for calicivirus infections is usually symptomatic with antibiotics given to prevent secondary bacterial infections and fluids are given if the cat is dehydrated.  It is important to keep cats eating during the course of their illness - it is common for cats with severe congestion or oral ulcers to not want to eat.  We make sure they eat in the hospital to prevent liver failure.  This virus is highly contagious to other cats and bleach is needed to disinfect any surfaces or bedding.  Though these cats remain infected for life, they do not seem to have the problems with recurrent flare-ups like cats infected with herpesvirus.

Chlamydophila felis, Bordetella bronchiseptica, and Mycoplasma are the most common bacteria that cause URIs in cats.  The symptoms will look the same as with the viral URIs but treatment with antibiotics will usually give a much faster recovery.  The good news is that there is one antibiotic that can treat all 3 on these bacteria fairly well.  We try not to use it in young kittens though as it can cause staining of the teeth, but there are other antibiotics that work well.  Fluids for dehydration and making sure the cats eat is also important.  Recovery from a bacterial URI is permanent and there should be no relapse as long as the kitten or cat is no longer exposed to any more carriers.