Home Parvo

Parvo in Dogs

By the Dog Health Handbook team · Updated · Fact-checked against current veterinary references (see sources)

Key takeaways

  • Parvo is a highly contagious virus causing vomiting and often bloody diarrhea.
  • Puppies 6 weeks to 6 months and unvaccinated dogs are most at risk.
  • Most dogs survive with prompt treatment; untreated parvo is nearly always fatal.
  • The virus lasts months outdoors. Clean with a parvo-killing disinfectant.
  • Finish the puppy vaccine series with the last dose at 16 weeks or older.

Table of Contents

Research How dogs get it Risk Signs Treatment Cleaning Prevention FAQ Sources

Viruses and Vaccines Quicklinks

Parvo Parvo Symptoms Parvo Treatment Distemper DHPP Vaccine Vaccination Schedule Kennel Cough Dog Flu

Parvo (canine parvovirus) is a highly contagious virus that attacks a dog's intestines and immune system. It causes vomiting, severe and often bloody diarrhea, and life-threatening dehydration.1,2 It spreads through infected feces, directly or on shoes, hands, bowls and ground, and it can survive in the environment for months to years.1,3,4 Puppies between 6 weeks and 6 months and unvaccinated dogs are most at risk.1,3 With prompt veterinary care, most dogs survive, but untreated parvo is nearly always fatal.4,5,2 A full course of vaccines, with the last puppy dose at 16 weeks or older, is the best protection.6,3

Call your vet right away if a puppy or unvaccinated dog has:

  • Vomiting or diarrhea, especially if it's bloody. Any puppy or unvaccinated dog with these signs should be tested for parvo.2
  • Sudden lethargy, loss of appetite or fever4,7
  • Weakness, pale gums, a cold body or collapse, which can be signs of shock. This is an emergency.5,8

Call ahead and say you suspect parvo, so the clinic can keep your dog away from other patients.5

What the Research and Guidelines Say

  • Cases have fallen, but parvo is still deadly. A 2026 study of 78,977 US cases found parvo diagnoses fell by more than 85% from 2010 to 2022, but 43.6% of dogs with known outcomes died or were put to sleep within 14 days.9
  • Puppies make up most cases. In the same study, about 46% of cases were puppies 8 to 16 weeks old, and vaccination history wasn't documented for more than 90%.9
  • Treatment works. Published studies report survival of roughly 70% to 90% with prompt supportive care, and higher with intensive hospital care.1,4,10
  • The first days are the most dangerous. In a study of over 5,000 shelter dogs, 80% of deaths happened in the first 5 days of treatment, and survival rose to 96.7% after that.10

How Dogs Get Parvo

Dogs catch parvo by swallowing the virus from infected feces, either by direct contact or from contaminated ground, shoes, hands, clothing, bowls, leashes and kennels. Even trace amounts of feces can carry it.1,3 Infected dogs start shedding the virus about 4 to 5 days after exposure, often before they look sick, and keep shedding for about 10 days to 2 weeks after they recover.1,2 The virus is very hardy: it can last at least 2 months indoors and many months, possibly years, outdoors in shady, moist places.1,11 People can't catch canine parvovirus, but they can carry it between dogs.5,7

Which Dogs Are at Risk

  • Puppies from about 6 weeks to 6 months, especially before they've finished their vaccines1,3
  • Unvaccinated or incompletely vaccinated dogs of any age1,2
  • Breeds including Rottweilers, Doberman Pinschers, pit bull-type dogs, German Shepherds and English Springer Spaniels1,3
  • Dogs with intestinal parasites or other infections, which can make illness more severe1

Maternal antibodies from the mother protect young puppies at first but can also block vaccines, which leaves a window of risk at around 3 to 5 months of age.12,13

Signs and Timeline

Signs usually start 5 to 7 days after exposure, but the range is 2 to 14 days.1,4 Early signs are lethargy, poor appetite and fever, followed within 1 to 2 days by vomiting and diarrhea that is often bloody, foul-smelling and watery.4,2,5 About 1 in 4 dogs with parvo doesn't have bloody diarrhea, so its absence doesn't rule parvo out.1 See parvo symptoms in dogs and puppies.

Diagnosis and Treatment

A quick fecal test at the clinic can confirm parvo, though it can be negative very early, so your vet may repeat it.4,1 There's no antiviral cure. Treatment mainly supports the dog while the immune system fights it: IV fluids, anti-nausea medicine, nutrition and antibiotics to prevent secondary infection.1,2 A canine parvovirus monoclonal antibody, an injection that neutralizes the virus, was conditionally approved in the US in 2023 and fully approved in December 2025.14,15,2 When hospital care isn't affordable, a vet-supervised outpatient plan can still save most dogs.16,17 See parvo treatment.

Cleaning Your Home and Yard

  • Remove all feces and dirt first, then wash with detergent and water. Disinfectants don't work well through organic matter.18,19
  • Use a disinfectant that kills parvo, such as accelerated hydrogen peroxide, potassium peroxymonosulfate or fresh, in-date household bleach diluted 1 part to 30 parts water (never weaker), and keep the surface wet for about 10 minutes.1,2,18,19
  • Don't rely on everyday cleaners, including quaternary ammonium ("quat") disinfectants, which aren't reliable against parvo.1,20
  • Wash bedding and fabrics on hot with bleach where safe, and dry on high heat.11,8
  • Keep unvaccinated dogs off contaminated outdoor areas, which can't be fully disinfected and may stay infectious for 7 months or longer, especially in shady, damp spots. Sunlight and drying help.8,11,1

Prevention

Vaccinate puppies every 2 to 4 weeks from 6 to 8 weeks of age, with the last puppy dose at 16 weeks or older, then give a booster and keep up adult vaccines.6,3,21 Until a puppy has finished the series, avoid dog parks, pet stores, classes, kennels and other places where dogs gather.3 Most parvo in "vaccinated" dogs happens when the series stopped too early.22,13 See the DHPP vaccine and the dog vaccination schedule.

Frequently Asked Questions

What are the first signs of parvo?

Lethargy, poor appetite and fever, followed within a day or two by vomiting and diarrhea.

Can a dog survive parvo?

Yes. Most dogs survive with prompt veterinary treatment. Without treatment, it's nearly always fatal.

Can a vaccinated dog get parvo?

It's rare after a complete series. Most cases are in puppies who haven't finished their vaccines.

Can humans get parvo from dogs?

No. Canine parvovirus doesn't infect people, but people can carry it on hands, shoes and clothing.

How long does parvo last?

Dogs are usually sick for about 5 to 10 days. Dogs that survive the first 3 to 4 days usually recover within about a week.

Ask Our Team a Question

Help Others by Sharing Your Dog Health Related Question or Story!

Have a Question, Request or Want to Share a Story that could help others? Our team will answer questions for free!

Please include information such as your dog's medical history, age, sex, breed, symptoms, diet, changes in behavior and medications. Providing pictures by uploading them below can also be of help.

We will do our best to get back to you quickly (it depends on how many questions we receive each day). If you do require an immediate response we suggest using this online dog veterinary service that is available now.

[ ? ]

Upload 1-4 Pictures or Graphics (optional)[ ? ]

 

Click here to upload more images (optional)

Author Information (optional)

To receive credit as the author, enter your information below.

(first or full name)

(e.g., City, State, Country)

Submit Your Contribution

  •  submission guidelines.


(You can preview and edit on the next page)

Sources and further reading

This article was rewritten and fact-checked on October 22, 2026 against current veterinary references and specialist guidelines:

  1. Gallagher A. Canine Parvovirus Infection (Parvoviral Enteritis in Dogs). Merck Veterinary Manual, reviewed and updated June 2025.
  2. Cornell Richard P. Riney Canine Health Center. Parvovirus: Transmission to treatment. Cornell University College of Veterinary Medicine, updated April 2024.
  3. American Veterinary Medical Association. Canine parvovirus. AVMA pet owner resources, accessed October 2026.
  4. Defarges A, Blois S, Hall EJ, Gibson TWG, Mitchell KD. Disorders of the Stomach and Intestines in Dogs (Canine Parvovirus). Merck Veterinary Manual (pet owner version), reviewed May 2018, updated June 2026.
  5. PDSA. Parvovirus in dogs and puppies. PDSA Pet Health Hub, January 2023.
  6. Squires RA, Crawford C, Marcondes M, Whitley N. 2024 Guidelines for the Vaccination of Dogs and Cats, compiled by the Vaccination Guidelines Group (VGG) of the WSAVA. Journal of Small Animal Practice, 2024.
  7. Malmanger E. Parvo in Dogs: Symptoms, Treatment, and Prevention. PetMD, updated October 2026.
  8. Evason M, Stull J. Canine Parvovirus: Information for Dog Owners. AKC Canine Health Foundation fact sheet, June 2018.
  9. Morrison J, George CM, Kollasch TM, Pattee JC, Ryan WG, Moore GE. Canine parvovirus cases (2010-2023): a retrospective study of 78,977 cases demonstrates declining incidence, but mortality risk remains. Journal of the American Veterinary Medical Association, 2026 (reported by dvm360, September 2026).
  10. Horecka K, Porter S, Amirian ES, Jefferson E. A Decade of Treatment of Canine Parvovirus in an Animal Shelter: A Retrospective Study. Animals, 2020.
  11. Ferrell E. Parvovirus in a Home Environment. University of Wisconsin Shelter Medicine Program, 2019.
  12. Crawford C. Diagnosis and management of parvoviral outbreaks. University of Florida shelter medicine teaching slides, 2025.
  13. Ellis J, Marziani E, Aziz C, Brown CM, Cohn LA, Lea C, Moore GE, Taneja N. 2022 AAHA Canine Vaccination Guidelines. Journal of the American Animal Hospital Association, 2022.
  14. American Veterinary Medical Association. Canine parvovirus treatment receives conditional approval. AVMA News, May 2023.
  15. dvm360. USDA grants full approval for novel canine parvovirus therapy. dvm360, December 2025.
  16. Venn EC, Preisner K, Boscan PL, Twedt DC, Sullivan LA. Evaluation of an outpatient protocol in the treatment of canine parvoviral enteritis. Journal of Veterinary Emergency and Critical Care, 2017.
  17. ASPCApro. Canine Parvovirus Outpatient Treatment Research Summaries. ASPCA professional resources, 2025.
  18. Commonwealth of Massachusetts. Parvovirus Cleaning and Disinfection. Mass.gov guidance document, accessed October 2026.
  19. Cavalli A, Marinaro M, Desario C, Corrente M, Camero M, Buonavoglia C. In vitro virucidal activity of sodium hypochlorite against canine parvovirus type 2. Epidemiology and Infection, 2018.
  20. Doyle E. Shelter snapshot: What to put in the spray bottle. dvm360, 2017.
  21. AAHA Canine Vaccination Task Force. Recommendations for core and noncore canine vaccines. 2022 AAHA Canine Vaccination Guidelines, updated September 2025.
  22. Weese JS. Parvovirus in vaccinated dogs? Northern Ontario. Worms & Germs Blog, Ontario Veterinary College, September 2023.

About this article

Last updated : fully rewritten using the Merck Veterinary Manual, Cornell, the AVMA, AAHA and WSAVA guidelines, shelter-medicine programs and a 2026 study of 78,977 US cases, plus International Veterinary Information Service (IVIS) proceedings and research published 2022 to 2026.

This page is for general information and is not a substitute for an exam by your veterinarian.