Parvovirus, or parvo, is a highly contagious viral disease that can cause severe illness in dogs. Puppies and dogs that have not been fully vaccinated against parvo are at greatest risk of contracting the disease. Parvo has an incubation period of 4-14 days. Once symptoms develop, most dogs will start showing improvement within 3-6 days. However, it usually takes a full two weeks for the infection to completely run its course.
What are the stages of a parvo infection?
There are three main stages of parvo infection:
- Incubation period – This lasts 4-14 days from the time of exposure to the virus to when symptoms first appear. During this time, the virus is multiplying rapidly in the dog’s system.
- Acute illness – The acute illness phase lasts about 7-10 days. Dogs will exhibit symptoms like vomiting, diarrhea, lethargy, fever and weight loss. Severely affected dogs can suffer from bloody diarrhea and sepsis. Dehydration and electrolyte imbalances are common. This is the most critical period, when intensive treatment and supportive care are needed.
- Recovery period – Dogs who survive the acute illness will enter the recovery phase. Their condition will start improving within 3-6 days. However, shedding of the virus in the feces can continue for up to 2 weeks after symptoms end. Complete recovery can take up to a month.
What is the typical parvo timeline?
Here is a look at the typical timeline of how parvo progresses in dogs:
- Day 1: Exposure to parvovirus. The dog comes into contact with parvo in the environment or from another infected dog. The virus enters the body and starts reproducing.
- Days 4-14: Incubation period. The dog appears normal but the virus is multiplying and spreading in the intestines, lymph nodes and bone marrow.
- Days 15-17: Prodromal phase. The dog starts becoming lethargic. Fever develops. Vomiting and diarrhea may occur.
- Days 18-24: Acute illness. Severe vomiting and bloody diarrhea. Dehydration, electrolyte imbalances, sepsis, weight loss. Requires intensive vet care and hospitalization.
- Days 25-35: Recovery phase. Dog’s condition starts improving. Still shedding virus in feces. Appetite returns and energy increases.
- Weeks 5-8: Full recovery. Dog regains weight and returns to normal energy levels. Virus shedding ends.
So in summary, the acute phase of parvo lasts about 7-10 days. But it takes around 2 weeks from the onset of symptoms for the infection to completely run its course.
What factors influence parvo’s duration?
There are several factors that can affect the duration and severity of a parvo infection:
- Vaccination status – Unvaccinated and incompletely vaccinated puppies are at greatest risk of severe, prolonged parvo infections.
- Age – Younger puppies (<16 weeks old) often have more severe infections that take longer to resolve.
- Breed – Some breeds like Rottweilers, Dobermans and Labradors seem more susceptible to complications.
- Health status – Dogs with weaker immune systems or other health issues may suffer more severe disease.
- Virulence of virus strain – More aggressive virus strains can cause more severe clinical signs.
- Treatment – Early and aggressive vet care can shorten recovery time.
Additionally, the presence of secondary infections, sepsis, dehydration and electrolyte imbalances can all prolong the illness and delay recovery.
When is a dog with parvo no longer contagious?
Dogs with parvo stop shedding the virus in their feces about 2 weeks after symptoms end. So a dog is generally considered non-contagious around 3-4 weeks after the onset of symptoms.
However, in some cases virus shedding can persist for up to 6 weeks after recovery. Puppies tend to shed the virus for longer than adult dogs.
To be safe, dogs recovering from parvo should be kept isolated from uninfected dogs for at least 3-4 weeks. The environment should be thoroughly disinfected as the parvovirus is very hardy and can persist in the environment for months.
Some tips to prevent disease transmission:
- Isolate recovering dogs for at least 20 days beyond resolution of symptoms.
- Disinfect kennels, bowls, bedding etc. with bleach.
- Quarantine any new dogs before introducing into the home.
- Wash hands and change clothes after handling affected dogs.
Only once repeat fecal tests come back negative for the virus over a 2 week period can the dog be considered non-contagious to others.
What is the mortality rate of parvo?
The mortality rate of parvo refers to the percentage of dogs who die from the infection. With aggressive veterinary treatment, the overall mortality rate is 10-20%. However, in untreated cases or dogs who develop severe complications, the mortality rate can be as high as 91%.
Factors that increase the risk of death include:
- Young age (especially puppies <16 weeks)
- Lack of vaccination
- Delay in starting treatment
- Severe dehydration and electrolyte imbalances
- Prolonged vomiting and diarrhea
- Breed susceptibility (e.g. Rottweilers)
- Secondary infections
- Sepsis and septic shock
- Intestinal bleeding and perforation
With prompt veterinary care, most dogs can recover from parvo infection. Supportive therapies like fluid therapy, anti-nausea medication, antibiotics and nutritional support help manage symptoms and prevent complications until the infection runs its course.
Conclusion
In summary, here are the key points on the duration and mortality of canine parvovirus infections:
- Parvo incubation period is 4-14 days.
- Acute illness lasts about 7-10 days.
- Shedding of virus can persist up to 2 weeks after recovery.
- Total duration is about 2 weeks, but complete recovery can take 4-6 weeks.
- Puppies, unvaccinated and immune-compromised dogs tend to have more severe, prolonged infections.
- With treatment, mortality rate is 10-20%, but can exceed 90% without prompt vet care.
- Supportive treatment and preventing complications is key to recovery.
Knowing what to expect with parvo’s duration and survival rate can help dog owners be prepared and vigilant in getting prompt veterinary care when needed. Vaccination remains the best prevention against this devastating disease.