How Can a Dog Get Parvo Twice? (Yes, It’s Possible!)
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These days most puppies are vaccinated against canine parvovirus (a.k.a. parvo or CPV), but those who aren’t run a high risk of contracting the serious disease. Once their puppies recover, pet owners often ask, “Can dogs get parvo twice?”
While it is theoretically possible for a dog to get parvo twice, in reality very few are at risk of getting sick more than once. Approximately 0.001% of dogs are genetically unable to mount an immune response to natural infection or a vaccine. In the unlikely event that they survive the first illness, these dogs could get parvo again.
Thankfully, normal puppies who survive the infection will never get sick from parvo again. CPV infection survivors are immune to the disease for at least 20 months after recovering and possibly for life.
Even if a CPV survivor’s antibody levels later decrease, he would not develop symptoms even if he is infected with the disease. A re-infected dog is also not likely to spread the virus in his feces the way he did the first time. (2)
How Can a Dog Get Parvo Twice?
It is possible, in rare cases, for a dog to get parvo twice. A small subset of dogs cannot develop any immunity to parvo whether it’s in the form of a vaccine or a natural infection.
We call these unfortunate dogs parvo non-responders. An estimated 1 in 1000 dogs has a genetic mutation that prevents them from developing immunity after vaccination (1).
Rottweilers were considered a high-risk breed for parvovirus non-response in the past. Some Rotties were genetically unable to mount an immune response to a parvo vaccine or a natural infection. Rottweiler parvo non-responders have been virtually eliminated in the U.S. Rottie population today, but they still exist in Europe.
Another thing to keep in mind is just because a dog has a positive parvo test sometime after recovering doesn’t mean he will become symptomatic again. Dogs who are immune to parvo can still have enough of the virus in their feces to make a parvo test turn positive. In this case, the virus is just passing through and isn’t causing any problems.
Testing positive for parvo twice is not the same as getting sick from parvo twice.
Is Your Dog a Parvo Non-Responder?
If you want to make sure your dog is not a parvo non-responder, your vet can test your puppy a couple of weeks after his last parvo inoculation to see if he has produced a strong immune response. If his antibody level is above the lab’s recommended number, he’s is likely immune to parvo.
A high parvo titer is not a guarantee that he will never get the disease, but the chances are extremely low. On the other hand, a low titer doesn’t necessarily mean your dog has no immunity to parvo. The test your vet can do to check for antibodies only detects a response by one part of the immune system when in reality, several forms of immunity protect against parvo.
Even dogs with a low antibody level may still be protected due to different parts of the immune system being activated if they’re re-infected with parvo. For that reason, antibody titers are not always easy to interpret. If they’re high, your dog should be safe from parvo. If they’re low, he’s probably still safe but it’s impossible to say for sure.
Parvo Immunity Lasts a Long Time in Dogs
Most dogs have a strong and long-lasting immune response to parvo vaccines and natural infection. Vaccines are so good these days that most vets don’t recommend vaccinating against parvo more frequently than every 3 years after the puppy series and 1-year booster.
The duration of immunity to parvo after the proper initial vaccination is known to be much longer than we previously believed. Schulz et al. showed in a 2010 study that dogs who hadn’t been vaccinated for at least 9 years still had adequate immunity to parvovirus.
And once they’re immune, not much can disturb a dog’s ability to resist parvovirus infection. The immune response to a parvo infection or vaccination is so strong that it doesn’t even go down when dogs receive chemotherapy treatment (3).
Watch out, Mom! I might give you something you don’t want.
Can Vaccinated Adult Dogs Get Parvo from a Puppy?
Although it’s not common, a vaccinated adult dog can get sick from canine parvovirus.
There are several reasons for this:
- No vaccine is 100% effective.
- If the vaccine wasn’t stored properly it could have been ineffective.
- If the vaccine wasn’t given at the right time(s) it could fail to protect against parvo infection (i.e. last dose is given at less than 16 weeks of age). Remember, it’s not the number of vaccines that is important. It’s the pup’s age at the time the final puppy inoculation is given. The last puppy parvo injection should be given at 16 to 20 weeks of age.
- If a dog was sick with another disease when a parvo shot was given, it might not mount an adequate immune response to the parvo virus.
- A few dogs have a genetic mutation that doesn’t react properly to a parvo inoculation.
If you have a puppy or dog who is sick with parvoviral enteritis, it’s a good idea to be cautious and keep all dogs and cats away from him while he is sick. But vaccinated animals have a very low risk of getting sick with parvo even when sharing a home and yard with a sick dog.
Can Cats Get Parvo from Dogs?
Canine parvovirus types 2a and 2b are similar to the feline parvovirus (a.k.a. feline panleukopenia or feline distemper).
The most common strain of canine parvovirus in North American is strain 2b (4).
Unvaccinated cats can get a symptomatic feline parvo infection from an infected dog. So keep any unprotected kitties away from your sick pup!
If your cat or kitten has received the recommended core feline vaccines (usually a combo shot called FVRCP), she should be protected from getting parvo from a dog.
How Long Should a Dog With Parvo Be Isolated?
An animal that is infected with parvo continues to shed viral particles in its stool for months. We don’t know how infectious it is to other dogs, but we must assume that it is. There is no easy way to know for sure when a dog is not passing parvovirus anymore.
The best bet is to keep the recovered dog away from an unvaccinated dog or puppies as long as possible. Ask your vet for advice on what to do in your particular situation.
The reality is that parvovirus infection is best prevented by vaccinating dogs, not by avoiding the virus. So vaccinate the unvaccinated A.S.A.P.!
As long as the other dogs and puppies in your family are fully vaccinated, their risk of getting sick from parvo is very low. It’s still a good idea to keep a dog who’s sick with parvo isolated from all the dogs in the home until he’s feeling better.
Keep Your Other Dogs from Getting Parvo
If one of your dogs gets sick with this virus, the first thing to do is figure out if any of your other dogs have not been vaccinated properly against parvovirus. Dogs under 6 months of age are the most susceptible, but an unvaccinated adult dog can also get sick.
Separate all unvaccinated dogs from the infected dog immediately. Don’t let the sick dog share the same yard or any areas of the home. If you’re treating your dog at home, keep him isolated in one room until he is free from symptoms and all dogs have been vaccinated.
I recommend you set up a puppy playpen in the isolation room like the one below and line it with disposable potty pads (click for link to Amazon, opens in new page). Get more potty pads than you think you need because you’re going to need them!
Clean up all bloody diarrhea, parvo poop and vomit from the home and yard. Viral particles passed in body fluids and stool can persist in the environment for months. Make sure to clean with 1:30 bleach: water solution or a parvo-killing cleaner like Rescue (click for link to Amazon) to kill parvovirus in your home and yard.
You must allow the bleach/water solution to have a 10-minute contact time with surfaces contaminated with virus-infected feces before rinsing or it might not be effective. If you’re using a commercial cleaner like Rescue, follow the directions on the label carefully for mixing and usage.
Bathe all exposed dogs immediately to remove any potentially infectious material from their coat and skin. Contact your vet about vaccinating any unvaccinated dogs in the household.
Your family’s dogs should be kept away from dogs outside the household for at least 7 days, 14 days if you want to be extra cautious, to see if they develop symptoms of parvo. This is especially important if any of them are unvaccinated for parvo. But even an asymptomatic, vaccinated dog could shed enough virus in their stool to infect dogs outside the home.
I tell my clients to avoid bringing an unvaccinated puppy or into the area occupied by a dog with parvo symptoms for at least a year. If you must use the same facilities do some extreme cleaning with hot water and bleach or Rescue several times before bringing susceptible dogs in.
The best bet is to only adopt dogs and puppies who have been fully vaccinated before bringing them to a place that housed a dog with parvo.
What to Do After a Dog Has Survived Parvo
Most of the dogs and puppies who get sick with parvo will recover from vomiting and diarrhea within 5 to 10 days. Once a dog with parvo starts eating, they usually make a rapid return to health with no long-term consequences.
Some dogs who recover from parvo have chronic gastrointestinal problems or just an extra sensitive intestinal tract. If you notice this, you might try giving him a course of probiotic supplements (click to see the one I recommend on Amazon.com) and feeding highly digestible food for a few months.
Read my article about Probiotic Supplements for Dogs
Do Dogs Need Parvo Vaccination After Recovering?
Dogs and puppies who have survived parvovirus illness probably don’t need to get any more parvo vaccines to stay protected. The reality is that most of them do end up getting more parvo vaccines. That’s because most vet clinics carry only combination vaccines that have distemper and parvo components (plus or minus other things).
As far as we know, it won’t harm your dog to get the parvo vaccine even if he has recovered from parvo. It’s a matter of convenience to give the combo vaccine since it’s a bit difficult to source and stock vaccines without a parvovirus component.
If you feel strongly about not over-vaccinating your dog, work with your vet to find a quality vaccine product that doesn’t contain a parvo component.
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References
- Day, M. J., BSc, BVMS(Hons), PhD, DSc, DECVP, FASM, FRCPath, FRCVS. (2013). How I Treat: Serology for Decision-Making in Core Vaccination. In World Small Animal Veterinary Association World Congress Proceedings. University of Bristol, UK: School of Veterinary Sciences. Retrieved November 17, 2020.
- Greene CE, Decaro N: Canine Viral Enteritides. Infectious Diseases of the Dog and Cat, 4th ed. Elsevier 2012 pp. 67-75.
- Henry, C. J., McCaw, D. L., Brock, K. V., Stoker, A. M., Tyler, J. W., Tate, D. J., & Higginbotham, M. L. (2001). Association between cancer chemotherapy and canine distemper virus, canine parvovirus, and rabies virus antibody titers in tumor-bearing dogs. Journal of the American Veterinary Medical Association, 219(9), 1238-1241.
- Mochizuki, M., Horiuchi, M., Hiragi, H., San Gabriel, M. C., Yasuda, N., & Uno, T. (1996). Isolation of canine parvovirus from a cat manifesting clinical signs of feline panleukopenia. Journal of Clinical Microbiology, 34(9), 2101-2105.
- Schultz, R. D., Thiel, B., Mukhtar, E., Sharp, P., & Larson, L. J. (2010). Age and long-term protective immunity in dogs and cats. Journal of comparative pathology , 142, S102-S108.
Last update on 2023-03-29 / Affiliate links / Images from Amazon Product Advertising API