Over the last few months, I have received multiple questions related to feline upper respiratory infections. Rather than address them separately, I decided to give you a nice summary here, so pay attention. It’s a complicated and frustrating problem for vets and people owned by cats alike. Here’s why.
What are the common symptoms of feline upper respiratory infections?
-sneezing
-coughing
-discharge from eyes and nose
-conjunctivitis
-oral and nasal ulcerations
-fever
-loss of appetite
-loss of energy
What organisms cause these infections?
– there are several, which is part of the reason they are so difficult to manage
– feline herpes virus (rhinotracheitis)
– only survives for 18 hours outside host
– many infected cats remain carriers for life
– carriers may intermittently shed later in life at times of stress/illness
– carriers are sources of infections for other cats
– since it is a virus, antibiotics are not effective
– some say approx 1/3 of all cats are carriers of feline herpes virus
– calici virus
– most cats do finally clear the virus after several months
– many do remain contagious for months even though the illness has improved
– some remain carriers for life
– the virus can remain active for up to 10 days outside the host cat
– only bleach, not normal laundering, will kill it
– since it is a virus, antibiotics are not effective
– these two viruses account for a majority of infections, close to 90%
– don’t worry- these viruses are only infectious to other cats
Other possible causes of feline upper respiratory infections include:
– mycoplasma
– chlamydophila (formerly known as chlamydia)
– bordetella
-these account for generally less than 10% of feline upper respiratory infections
-these can be responsive to antibiotics, such as doxycycline, however, doxycycline can not be safely used in young, growing animals (such as kittens), complicating the treatment even further
More crappy news:
– infections may be caused by multiple organisms, which can obviously complicate treatment/recovery
– to further complicate it, there is no simple test to determine which organism is causing the illness, and some cats are infected simultaneously with multiple organisms
OK, so how do these illnesses spread?
-airborne (sneezing, coughing)
-fomites (objects carrying the organism such as bedding, toys, grooming utensils, and your clothes and hands that have been contaminated)
-crowded conditions (such as shelters and breeders) increase the likelihood of outbreaks
-stress or illness may induce a carrier cat (herpes virus) to show signs or begin shedding again
So, why are these illnesses so common?
– they are highly contagious
– 90% are viral, so there is no direct treatment available except for time
– carrier cats with no symptoms of illness can shed the infectious organisms for months
(calicivirus) or years (herpesvirus)
– stress (changes in household including new people, pets, construction, or moving) or other
illnesses may cause carrier cats to begin intermittently shedding for weeks (herpes virus)
– some organisms (calicivirus, remember?) can last for days outside of the host on bedding, toys,
etc, and aren’t deactivated by non-bleach detergents
Why are they so hard to treat?
– weren’t you paying attention?
– 90% of them are caused by viruses so like the common cold or flu, there is no effective direct treatment other than nursing care and time
– there is no simple testing to determine what is causing the infection, so treatment has to be aimed at the most likely causes and the symptoms
– there is no easy way to determine if and when a cat has ceased shedding the organism and is no longer contagious
– generally the time of exposure to illness is 2-7 days, so in crowded situations, many cats can get sick very quickly
– active illness generally lasts 7-10 days regardless of treatment
– upper respiratory infections can result in secondary pneumonia, which can be life threatening
Well this sucks. How can I prevent an upper respiratory infection in my household?
– short answer, you can’t
– many cats become carriers (therefore infected and/or contagious) before they reach your house
– many cats that are carriers/contagious are not showing any symptoms of illness at the time of
adoption
– many cats that are carriers/contagious remain so for weeks, months, or even a lifetime, even in
the absence of obvious symptoms of illness
– there is no simple test to determine if your cat is infected, contagious, or a carrier of an
upper respiratory infection
Well that sucks too. So what can I do to prevent infection?
– short answer, again, you really can’t (have you been paying attention?)… but…
– vaccinate- herpes and calicivirus are part of the feline “distemper” vaccination and vaccinated cats are less likely to develop illness if exposed or may have less severe symptoms if they do become sick
– isolate new cats (not just obviously sick ones)- just remember, some cats are carriers for months or for life, and do not show obvious signs of illness, so this will not be 100% effective
(this is also a good idea in general- intestinal parasites are also very contagious, so until you have had an exam by a veterinarian and a stool check for parasites, you should never allow new cats to come in direct contact with other cats in the house, especially sharing litter boxes)
– wash all materials in bleach that have come into contact with a sick cat (not entirely practical or possible, considering your carpet, furniture, and hands are likely included in that)
– try to minimize stress and be aware stress or illness may cause a carrier cat to become sick again and/or begin shedding the infectious organism again, for weeks or months
Well crap. My cat has an upper respiratory infection… what should I do?
– If you have multiple cats, separate the sick cat as soon as you notice symptoms. Even though this will not likely prevent the spread of infection at that point, it may help minimize it.
– Make sure all other cats’ vaccinations are up to date.
– Have the sick cat examined by a veterinarian, especially if there is lethargy, loss of appetite, severe congestion or conjunctivitis, or coughing. While the underlying organism may not be directly treatable, many of the symptoms can be managed with medications such as anti-histamines, decongestants, eye medications, immune supplements, and appetite stimulants. Your vet may also be able to give you tips about home care (such as steamy shower therapy for congestion.) It is also smart to determine if there are signs of secondary pneumonia, which may require antibiotic treatment to prevent severe or even fatal infections. Kittens, due to their immature immune systems, are especially susceptible to severe complications due to upper respiratory infections.
– Never give any over the counter medications to your cat without a veterinarian’s recommendation. Many over the counter medications are toxic to cats. Also, cats and esp kittens require very small doses of the medications they can safely take.
So it sounds like there really isn’t any way to be positive my cat will never be exposed to an upper respiratory infection… is there any good news?
– Yes! Most cats with upper respiratory infections are able to successfully overcome the signs of illness and do not have any obvious long term health problems. But remember, some may remain carriers for months or even a lifetime. So, although respiratory infections are almost impossible to contain and prevent, in otherwise healthy cats, they are usually nothing more than annoying outbreaks (much like a common cold or flu in people) that do not impact the cat’s overall quality of life in the long run. What makes them different from the common cold and flu is the fact that many cats remain chronically infected carriers for months or years even after recovering from the signs of the infection.
I told you. It snot fun.
DC MetroVet 
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