Virulent Systemic Feline Calicivirus
Guest Post by Dr. Fern Crist
Virulent Systemic Feline Calicivirus – What Do We Really Know?
When Ingrid called me to tell me that Amber was making occasional odd gagging noises as if something was stuck in her throat, but that she seemed fine otherwise, I was certainly not expecting Amber to die within ten days.
Two days later, Ingrid told me Amber’s appetite was decreased, and she was throwing up a little bit, gagging a little more but still seemed generally fine. My brain went on yellow alert, but not red. After all, Amber was still eating and keeping nearly all of it down. Her abdomen was not painful. Most such events resolve on their own, and since Amber gets very stressed with hospital visits, the benefits of getting her checked out had to be weighed against the stress of the hospital visit. It seemed wiser to “just watch” for a little longer.
But after a few more days of “she’s not worse but she’s not better either,” I hit my limit of “let’s keep an eye on it,” so into the hospital we went.
I didn’t think of calicivirus right away when I first examined her. I could hear that her airway was narrowed at some point in her throat, and like Ingrid, I thought she might have a foreign body stuck there. Cats will sometimes vomit a little if they cough hard enough, so the occasional little “urp” didn’t concern me too much at the time. She had no fever, and her labwork and x-rays showed nothing significant. We decided to look down her throat and hope we could pull out an offending object.
It wasn’t until I saw her larynx that I first thought, fleetingly, of calici. The edges of her larynx were very swollen and her air passage narrowed at that point. We passed tubes down her trachea and esophagus anyway to be sure, and found no foreign body. The only real finding we had was laryngeal edema (swelling around the larynx), which can be caused by allergic reactions, many viruses, and a host of other things. Laryngeal edema is quite often a transient problem in the cat, for which a cause is never identified, but in nearly all cases the cats recover as long as the edema is treated. We treat strenuous breathing when present because it can lead to the potentially fatal development of lung edema. So we gave her steroids and fluids, the standard approach for acute laryngitis. Having seen such cases before, I fully expected her to be much better the next day.
When she wasn’t, I began to seriously consider other possibilities. And here’s where the calici comes in.
Feline calicivirus (FCV) is an important and largely preventable respiratory disease in cats. It is included in what we consider the “core” vaccination protocol for every cat. If you’ve ever seen the inside of the mouth of a cat with regular old calici, you’ll understand why. It’s nasty, very difficult to treat, and some cats are even euthanized because of the terrible pain it causes them. And that’s the “good” calicivirus.
Calicivirus is an RNA virus (a virus that has ribonucleic acid as its genetic material). RNA viruses can mutate (change) easily, which means that new strains pop up from time to time. It likes to set up shop in cat mouths and noses, and is then passed on through pretty much any body fluid. Calici does not die quickly when exposed to air, so it can be transmitted by such normal actions as petting one cat and then petting another. Virus shedding is common in cats with no symptoms at all. Cats with symptoms can have any combination of fever, conjunctivitis, ulcerations in the mouth, sneezing and snotting, and often feel totally miserable. Some cats will develop inflammation in the joints, kidneys, or other organs. This creates a variability of symptoms that makes diagnosis tough, and again, this is for the “good” calicivirus.
In 1998, a particularly nasty strain of calicivirus was described in California. There have been a number of similar occurrences since, which appear to be arising independently. What this implies about the mutating ability of the calici virus is just plain scary. These hot strains have been designated “Virulent Systemic Feline Calici Virus” (VS-FCV), although it is misleading to give them all one name, since each is probably a new and different mutation of the virus. They do have characteristics in common, however. Their mortality rate is much higher than that of the usual variety, reported to be as high as 67%. Most of the affected cats are obviously very sick. Many develop swelling (edema) in the legs and face, because inflammation of the vessels allows circulatory fluids to escape. Major organs can be hit hard, including the lungs, pancreas, liver, and GI tract. Often multiple organs fail, leading to death. Adult cats are typically hit harder than kittens.
To date, there have been fewer than 20 documented outbreaks that I am aware of. These occurred in California, Nevada, Pennsylvania, Massachusetts, Indiana, Tennessee, North Carolina, and the United Kingdom. They have been verified by genetic analysis, possible because these mutants are genetically different from the garden-variety calici. In each case, the outbreak was contained and over quickly. And to date, there have been no outbreaks reported in Virginia. But here’s the problem: we really don’t know how many times this has happened. We wouldn’t, because the less dramatic cases would not get the attention and research that the horrendous outbreaks have. Most likely, a lesser problem would be treated symptomatically and never diagnosed. Cats get sick every day with diseases that we never identify. Most of them just get better; but some of them die. Unless there are many victims who are simultaneously very ill, a mutant viral event probably will not be recognized for what it is.
Since a successful parasite does not kill its host, it is nearly inevitable that eventually, a less virulent form of “virulent calicivirus” will appear. And being less fatal, it will be much harder to spot. A quieter calici mutation might not resemble the popularly reported VS-FCV strain as much as we’d expect. An affected cat might, for instance, have only one or two organ systems affected enough to be a problem, and may or may not have swelling of the face and limbs, and may or may not have oral ulcers. After all, the definition of a mutation is that is different.
With Amber, the unusual combination of laryngeal edema with pancreatic or GI dysfunction is what led me to ask whether calici might be the culprit. Initially, there was no edema or fever, but we eventually saw both. We had multiple organ failure, including cardiac; we had effusion in the chest and abdomen; evidence of pancreatic involvement; and we found no other explanation. Amber had a positive PCR (polymerase chain reaction) test for calici, but that does not necessarily mean that calici caused her disease process. We did not do a genetic analysis. It might have been just an ordinary calicivirus which had nothing to do with her disease. We’ll never know for sure.
Had I considered calici sooner, could I have done more to help her? I believe the answer is definitively yes. There are antiviral drugs purported to help in these cases; I might have used those. I might have hospitalized her earlier in the process, and maybe kept her from going past the point of no return with drugs to suppress immune-mediated damage. Monitoring in the hospital would have allowed faster intervention as different systems were affected. Her surprise development — a hidden heart condition which had never shown up on Amber’s regular bi-annual check ups, but was revealed by the combination of disease, steroids and fluid therapy — would have been detected earlier and managed better. She might have survived, and she might not have. But she would, perhaps, have had a better chance.
Ingrid asked me to write this article in hopes that we can help make cat owners and veterinarians alike more aware that mutant caliciviruses are capable of creating disease scenarios such as Amber’s, and that this may be more common than we realize. Mutant caliciviruses don’t have to be the total train-wrecks reported in the news. Having the possibility of calici in our heads earlier in the process may save some lives.
This is not an alarm call, and it is not intended to inspire fear. You should not lock yourself in your house, nor avoid the vet, or anywhere else where another cat might be found. You should not give up adopting kittens. Diseases will continue to appear, as they have throughout history, and though most never affect most cats, some cats will get sick, and in rare cases, the outcome will be devastating.
But if you see symptoms similar to Amber’s, perhaps this story will encourage you to wonder whether it could possibly be a case of a more-than-commonly virulent strain of calicivirus. If the answer is yes and you intervene early, your cat may have a better chance than Amber did.
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PS:
I should mention that there is a vaccine available labeled for protection against the virulent calicivirus. This vaccine was developed from one of the mutant strains; however, since each mutation arises independently, there is no way to know if it would be protective against any new mutation. It is a killed vaccine, requiring the use of an adjuvant, which we think may play a role in the rise of injection site tumors; and it is a new product, so time has not yet shown if there may be other risks with it. We don’t even really know how prevalent virulent strains are at this time. So – would I vaccinate my cat against VS-FCV? Absolutely not. In my mind, the risk of vaccinating with a product as new as this, with such questionable efficacy, far outweighs any benefit likely to accrue.
Dr. Crist, that was a wonderful article and explains very well the virus. You sound like a wonderful person and it is so great that Ingrid has you as a good friend.
It is so scary all the disease that these cats and all animals can get and we just can’t vaccinate them against everything.
The amazing thing to me is all the feral cats that live around me, not with me, are all just fine and have had no shots. The ones that live with me have had some shots.
I appreciate your honesty about the treatment of Amber. I do the same thing here, if someone has a little something wrong, my famous words, oh lets just wait another day. And like you said, it usually works. I have one cat that I just cannot catch and she gets all kinds of things wrong with her, and I prepare myself that she is going to die, and darned if she doesn’t get better.
Sorry to to go so long.
Marg,
Thank you from the bottom of my heart for your compassionate comment.
I am always grateful when my clients or readers appreciate that we vets are not emotionally removed from the outcomes of the these events. I can recall one night, many years ago in my prior life as an emergency vet, when I saw 15 cases in a 16 hour shift: several were euthanized, several died despite all our efforts, two were DOA – and only one went home alive. I went home that day and sobbed my heart out.
Thirty years ago in vet school, a professor told us that the humbling reality of medicine is this: 85% of patients get better on their own (regardless of any treatment we prescribed,) 5% die despite anything we can do, 5% get better because we actually helped them, and 5% die because of something we did. The evolution of medicine is the slow and tiny improvement in those numbers.
The first maxim of medicine is “do no harm.” More often than not, the best thing to do is nothing at all. I strongly believe that our own bodies are MUCH better at healing than we are at helping. Many times, the best thing we can do is get out of the way and let the cat do what the cat does best – survive. But not always.
My honesty is, I hope, a reflection of the good medical practice of critical case review. If doctors are to improve as we practice, we must be ready to look back and see where we could have done better. If our egos (or our fear of getting sued) get in the way of that, we cannot learn.
Again, my thanks.
Dr. Crist, I’m glad to read these details that I can keep on hand for future cases. I’ve had unnamed viruses sicken one or another of my cats four times through the years to varying degrees though each survived, and each time it happened I remembered the horrible cases of friends who had lost cats. We do need to be vigilant when symptoms appear and persist, and I wish there was a central place to track things so that we might have a greater understanding of these sorts of viruses and be able to respond better.
This is a very helpful post. I will definitely pay closer attention to any of these symptoms than I would have before.
Mason
Thoughts in Progress
Very interesting and useful post. It’s good to know there is a vaccine.
I’m glad everyone is finding the article helpful. It was difficult for Fern to write (as you can tell from her comment), difficult for me to read and edit, and it’s still difficult to read. But if even one cat can be saved by making people aware that this virus is out there, it will have been worthwhile.
Layla, there may be a vaccine, but it’s probably not very effective. It is very much like the human flu vaccine – each season’s vaccine only protects against the prior season’s flu strain. In this case, the vaccine only protects against the known strain of VS-FCV, not the mutations.
Dr Fern…I knew you would ‘pen’ an excellent article and you did not disappoint! Working in a cat hospital and also breeding cats, I have been concerned about this disease for some time, but like you, still can’t bring myself to vaccinate for it due to the ‘mutation’ factor.
One interesting thing that I read on the UC Davis Shelter Medicine site, that I must have missed before is that adult cats are more often affected than kittens. After what Ingrid went through, I too am now watching my cats more closely for any symptoms like what Amber began with, though I know it can vary.
Interesting side note, in 1998 my mom (who lives in Oregon) adopted a kitten through a veterinary clinic that broke with VS-FCV, I don’t even recall if they performed a verifying test, but they were sure that is what it was…it started with a cough and then progressed to the the ear tips and paw swelling etc and was compassionately euthanised.
The clinic was in a panic and saw no cat patients for quite some time after that…I recall UC Davis was helping them with their protocol in the face of the situation.
[...] us posted as Amber had begun with puzzling but non-specific symptoms, and we later learned it was a feline calicivirus. That was a little too recent for my comfort. I also remembered other friends who had suddenly lost [...]
[...] May 13, I had to let Amber go after a brief, sudden illness. Less than a year and a half after I lost Buckley, I was faced with grieving yet [...]
Interesting fact about petting another cat and transmitting the virus-This has been a great article-thank you for your time and information. Is it fair to say that if your cat is never exposed to the virus they will not contact it?
Esme, I’m glad the article was helpful. I’m not sure what you’re asking though. If you’re asking whether previous exposure to the virus (such as through a vaccine) provides immunity, the answer is maybe – it depends on whether the virus the cat was exposed to has mutated or not. If that doesn’t answer your question, please let me know!
A truly wonderful, honest piece. It’s hard not to think “what if” but just remember that you and Ingrid both meant the best and wanted the best for Amber. Your hearts were in the right place.
T
Thanks, Tamar. Both Fern and I have to frequently remind ourselves that we made the best decisions we could at any given moment in time. It’s hard not to secondguess yourself after something like this.
[...] in the face of symptoms that don’t point to any one disease, yet the clock is ticking. Virulent Systemic Feline Calicivirus | The Conscious Cat consciouscat.net When Ingrid called me to tell me that Amber was making occasional odd gagging [...]
We just lost our Tortie Sunshine this past Saturday. She had a variety of little symptoms over the course of a few months and each and of themselves, caused alarm and most of them I wrote off to behavioral. The final chapter of her life started with a runny nose with considerable clear discharge at times, then sneezing, then blood in her stool and blood in her sneezes. Each symtom was treated vigorously, the running nose stopped, the blood in her stool stopped, then she had total renal failure. One day she was fine and the next day I saw blood in her cat box, then blood spots throughout the house. She was treated aggressively and with passion by our vets but we lost the battle. She was dehydrated and we administered fluids into her tissues at home 3 times a day (my wife is a nurse). The last day she had what looked like an airway obstruction or some episode that made her violently pass out for about 20 mins. Then we awakened but just rested her head in my hand. The vet met me 20 mins later at the hospital and we gave her peace and rest. Could this have been that virus….??? I will always ask myself if I could have reacted quicker or done more could we have saved her. She was only 6 years old and part of our day to day lives.
I’m so sorry about Sunshine, Ron – my heart goes out to you and your wife. From your description of her disease progression, it’s certainly possible that it was VS-FCV. It’s almost a year after Amber died, and I’m still second-guessing myself over whether we did enough, whether I stopped care too soon, whether she would have survived if I had gotten her to the vet’s sooner. I know better – these kinds of questions are not helping anything, but I think they’re an inevitable part of the grieving process. In the end, I think I made the right decision by letting her go. It’s what she would have wanted.
For you, the loss is still so fresh and raw, it’ll take some time for you to come to terms with it. I hope that you, too, can eventually feel at peace with your decision. Be gentle with yourself, it’s such a difficult time.
Thank you for your kind words! We are putting together a photo book and our fun memories of Sunshine so we can go back from time to time and remember specifics. Thank you again.
[...] had to let Amber go after a brief, sudden illness last May, I wasn’t prepared for the depth of my grief. It hadn’t even been a year and [...]
Please give me guidance…
I have a healthy 2nd old cat. Two months ago I adopted two kittens from a breeder. While I kept these kittens in quarantine I observed that they just weren’t clearing the URI they came with.
I had a blood test done, came back neg. for FIP/FIV. I also had a PCR done which came back positive for: Bordetella, Calici and Mycroplasma.
I have been advised by my vet to return them to the breeder, it now appears that this breeder will not answer my efforts to contact him. The other option is to “put them down”. My question to you
is: If these were your kittens, what would you do?
Thankyou, I am so in love with these two little guys I just can think straight!
I’m so sorry about your kittens, Doreen. You’re in a very tough position, and my heart goes out to you.
As I’m sure you know, it’s not unusual for kittens to have chronic URI’s, and just because they can’t clear the virus doesn’t necessarily mean that they have the virulent form of the calici virus. The following link provides one of the most thorough explanations of the virulent form of the virus: http://sheltermedicine.com/shelter-health-portal/information-sheets/feline-calicivirus-virulent-systemic-feline-calicivirus-vs-
I honestly don’t know what I would do if I were in your situation. I’m pretty sure that I couldn’t choose euthanasia, but at the same time, I’d worry about the older cat. I’d probably get another veterinary opinion to start with. Perhaps it’ll provide some additional information you don’t have yet that will help you make the next decision.
Wow, interesting to read this. I am going through similar symptoms with my cat. She started gagging every so often on Christmas night and making some murmuring noises and now even snoring. I took her to the vet her lung Xray was clear. She continued to gag another day so I took her back he recommended me to a specialist. They found a small mass on her larynx and then did a CT scan but found nothing else. Now waiting for the Biopsy results which are supposed to come in January 3rd,2012 meanwhile she is still gagging especially after she eats. The vet thinks it may just be a Trauma as he said he saw some blood in the tissue he biopsied. Should I call him and tell him that he should check for Virulent Systemic Feline Calicivirus? I hate this waiting game – and I just want to make her better and be sure that this waiting isn’t costing us time
I’m sorry to hear your cat is having such a hard time. Since they found an actual mass on her larynx, I’m guessing it’s something else and not VS/FCV, especially if you’re not seeing any of the other symptoms generally associated with the virulent form of the virus. I know the waiting is hard, and it certainly couldn’t hurt to ask whether your vet thinks it could be calici. Best wishes to your cat for a quick recover, whatever it may be!
Thanks- I was a little worried when I read your cat had the same symptoms- the coughing- yet clear X-rays. Guess we’ll see. I just lost her brother 6 months ago to kidney disease. As they were trying to fix that it turned out he had a bad heart to there wasn’t anything that could be done. So I understand your loss and am very sorry for it.
Thanks, Mike. I’m sorry for your loss, too. I’m hoping for a good report from you after you get the biopsy results this week.
Ingrid, I hate myself at this point (almost severely depressed). Back in December 2011 our So MS Humane Society had a fire. I opted to help one of the sick cats with an URI. I told them I was worried about the five cats I had at home. They told me it would be just fine and I kept them Isolated from the others. This past weekend the sneezes began (still isolated). All of my cats are ill and the shelter cat seems just fine in its room in a kennel. I am sickened that my life one month ago was challenging enough and then this. I have them all on Clavomox now BUT with six cats the expense is outrageous. I have an extremely small home that was partially rebuilt after losing it to Katrina (no sympathy card here it happens just explaining). I have a 14 yr daughter who threatens if I put them down she will hate me. I have to work as a single parent from her birth, and it is taking an hour and a half to prep all six (the one in the kennel too) twice a day. I have to keep my job which I am always late now. I wish I would have never brought this cat into my home. I am sorry but true. I am sickened and cannot understand how this can happen. Do you have any suggestions in helping my others survive this trial. I am not sure how much more I can take as my child is very selfish and thinks I am overeacting and has never helped me in general so I am on my wits end and I am very serious and I am not joking. I am scared I fear that they need more help. I am trying though,but need help with this. Any advise besides going to a shrink?
Betty, I am so sorry. That’s an awful lot to deal with all at once.
Depending on how sick your cats are, they may need more support than just Clavamox. I understand that resources are an issue. If you click through on the link below, you’ll find a list of organizations that may be able to help with veterinary expenses. Talk to your vet as well – many vets are willing to work with clients in terms of setting up payment arrangements. See if your humane society can help out. There are always options, it’s just hard to see them when you’re in the thick of it the way you are.
http://www.humanesociety.org/animals/resources/tips/trouble_affording_pet.html