Monday, February 17, 2014

Monday Medical: Can your cat get the stomach flu?

Zoonosis is the transmission of disease from animal to human.

Reverse zoonosis is a relatively new concept, and - as the term suggests - is the transmission of disease from human to animal.

We've heard a lot about this in the past few years.

Especially the fact that our pets can indeed catch the flu from us. Certain strains of influenza, most notably types H1N1 (also known as the swine flu) and H5N1, have been documented in dogs, cats, ferrets -- even a cheetah.

The cheetah: one of several animals known
to have caught disease from mankind.
Photo: Tom Rafferty
A little over a week ago, I came down with the stomach flu. As many of you know, stomach flu is technically not an influenza. And flu vaccines do not inoculate against it.

It's a virus. A norovirus, to be exact, in over half of the cases. Including mine.

(The remainder of all 'stomach flus' are caused by food-borne parasites or bacteria, according to the Centers for Disease Control - see link at bottom.)

So I began to wonder: do I need to worry about the cats getting this? Not only would it be terribly unpleasant for them, following around a vomiting cat all evening isn't much fun for me either!

Turns out there is cause for concern.

The first warning flag was when I learned that noroviruses belong to the virus family Caliciviridae. About now, any of you who work in a veterinary environment, or who volunteer or work in shelter environments are sitting up just a bit straighter, aren't you? I certainly did!

We see cats with calicivirus all the time. In fact, it's pretty contagious. Our shelter's policy is no free-roaming for any cat who's contracted the virus, since they can still "shed" it - meaning other cats can catch it - even after they're symptom-free. (They do eventually get their "get out of jail free" card back, in about a month.)

One of the staff at Wayside Waifs even joked with me about it, telling me I needed to carry around my own kennel card: "no roaming for 2 weeks"! That's the amount of time a human can continue to shed the stomach virus even after recovery. Oh joy, my husband says....

So norovirus is in the calici family, eh? I dug a bit further.

It seems several studies have been conducted since 2004 searching for indications that norovirus in humans is found in animals and vice versa. Then I came across this: in the January 27, 2010 edition of the magazine Veterinarian Microbiology, authors Koenig, Thiel and Wolf write:

"The close genetic relationship of noroviruses and sapoviruses found in animals and humans has raised the question whether these viruses have a zoonotic potential. ... Detection of human noroviruses in animals as well as simultaneous presence of animal and human viruses in bivalve molluscs suggest a risk of transmission. Furthermore, antibodies against animal noroviruses were detected in humans as well as antibodies against human noroviruses in swine."

No cases have been confirmed, but the above was cause enough for me to be extra careful around the felines in my family as well as the humans!

Faraday: Stay away from me, please, Mommy!
(photo taken well before I was sick, so he's safe :-)


CDC on norovirus
Avian H5N1 influenza in cats, Science, October 2004.
2009 Confirmed results: H1N1, USDA.
Zoonotic aspects of infections with noroviruses and sapoviruses, Veterinary Microbiology, January 2010.

Noroviruses and Sapoviruses in man and farm animals, Deutche tierarztliche Wochenschrift, August, 2004.
Animal Noroviruses, Veterinary Journal, London, England, October, 2008.

I am not a veterinarian, and the information provided here is not intended in any way as a substitute for professional veterinary care. Nor should it be used to self-diagnose for your pet. This information is for educational purposes and to provide you with reputable documentation you can use to pose informed questions of your own to the veterinarian of your choice.


  1. we are sure the cats thank you for your concerns. :) that is interesting that it is related to calici....

  2. That is scary to read that we can pass it backwards and forwards. Have a marvellous Monday.
    Best wishes Molly

  3. That's very interesting. I've got to read up on stomach flu since that term isn't used here often.

  4. That is a scary thing! And why our humans rush through the house and directly into the shower before touching any of us when they come home from the shelter. Calicivirus is evil!

  5. Interesting! And fortunately the humans here rarely get ill - usually only my human. And I steer clear of her when she gets sick. She is really unpleasant to be around when she is not well, and this is even more reason to avoid her!

  6. That is pretty darn interesting. I never thought that could happen but it makes sense that it might be transmitted. Thanks for the info.

  7. Interesting! A comprehensive list of ailments risking reverse zoonosis would be really handy... but probably really alarming, too.

  8. My hoomin washes her hands a lot when she goes to help at the animal shelter. She uses that purifier they have. :)

  9. We never knew that, great information. Love your sepia Sunday :) xxoxxxx

    Mollie and Alfie

  10. We will be VERY careful around TBT IF he ever gets all sicky!

  11. Thanks for this very informative post! Mom says we throw up enough without getting a stomach virus. We can't get out dad's mono can we? Hope not. Mom feels so fortunate that she hasn't gotten it. Purrs and paw-pats, Mauricio, Misty May, Lily Olivia, Fiona, Giulietta, Astrid, Lisbeth and Calista Jo

  12. That is inneresting. All summer TW had one of those food-borne viruses cos she ate the salad at Olive Garden. Since she can’t take antibiotics, she had to wait until probiotics cleared it out of her system.


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