Puppies and Parvo 

As we celebrate National Puppy Day (March 23rd), this month’s blog will highlight Parvovirus disease. As you can imagine, all of us at Somerset Veterinary Hospital LOVE puppies. What better way to start the day with a well puppy visit. The wiggles, the puppy breath, the baby barks – what’s not to love?  However, we also want our puppy owners to be aware of the continuing threat of Parvovirus for our most vulnerable patients.

Parvovirus first came on the scene in the 1970’s. Researchers believe that Canine Parvovirus was a mutation of Feline Panleukopenia. Parvovirus is a very hardy virus. It can survive in the environment for several months if the conditions are right. The virus is also very deadly. 90% of untreated parvoviral enteritis patients will succumb to the disease. Many die within 3 – 5 days. Luckily humans or cats do not contract this deadly virus. Also, we have a very effective vaccination for parvovirus. 

How does Parvovirus Spread?

Parvovirus is present in the environment. Dogs with no immunity can pick this up from other dogs that have no symptoms of the disease (carriers). They simply come in contact with the infected dogs’ stools or vomitus. 

Puppies that have not been vaccinated should be kept away from public spaces where dogs can frequent. This includes; parks, dog runs, kennels, groomers, etc. It is also a good idea to carry your new puppy when within the veterinary clinic. Stools are usually cleaned with an adequate disinfectant , but a good precaution. 

Parvo can be carried on shoes and clothing. Keep shoes picked up and away from unvaccinated puppies. 

Remember, parvo is not airborne. Your puppy cannot contract parvo from simply being in the same house with another dog. Symptomatic dogs do shed a larger number of virus particles and therefore, are more contagious. 

Prevention of Parvovirus

In 1980 a Modified live vaccination for Parvovirus emerged. Although the most prevalent variant of parvovirus has changed, this original vaccine still provides good protection to parvoviral enteritis. 

The vaccine has proven to be very effective in preventing parvoviral enteritis. However, maternal antibodies can block vaccine efficacy in puppies for several weeks. 

When a puppy is born and nurses from its mother, it receives important immunity from various diseases. For a variable number of weeks, the puppy will have good immunity to parvovirus but this immunity wanes. This is why a series of vaccinations is recommended. The problem is that we do not know when this immunity from the mother subsides enough to allow the puppy’s immune system to react to the vaccine. There remains a possible window in all puppy’s lives of susceptibility to parvo. This window is 2 – 5 weeks of age. This is a very important time to eliminate exposure to the virus. 

Hopefully, your puppy has received its initial vaccination before the puppy was transferred to its new home. The usual time for initial vaccination should be around 6 weeks. 

Boosters should occur at around 9, 12 and 15 weeks. This does not have to be exact. Your veterinarian will make recommendations for exact weeks. 

We also like to make sure that your puppy is not fighting off other infections or infestations which could make them more susceptible to parvovirus. Your puppy should be regularly wormed and have stool samples tested. 

Feeding your puppy a good quality puppy food will also help build his/ her immunity and improve his/ her response to vaccinations. 

Diagnosis

Fecal Eliza testing has made in-clinic testing of Parvovirus very simple. The test includes swabbing feces or more commonly, rectal swabs.  These tests are quite accurate – 98%! However, some patients will test negative early on in the disease. Others will be falsely positive, meaning the test is positive but the patient does not have Parvovirus. This is very rare. These results occur between 4 and 6 days of vaccination and are usually weakly positive. 

CBC – This is a blood test to look at the blood cells. Dogs with parvo may have a high white count. This is actually a good sign as the patient is fighting off the disease. As the disease progresses, sick patients often have a very large drop in white blood cells. As  you can imagine, the patient has less ability to fight the disease on her own. Red blood cell count is often decreased because puppies naturally have mild anemia. These patients start losing blood through the GI tract decreasing an already low red blood cell count. As disease progresses, these puppies may need a transfusion. 

Clinical signs of Canine Parvovirus

Clinical signs emerge about 7 – 14 days after infection with the virus. 

How to Treat Parvo?

Over 80% of parvovirus enteritis patients will get better with aggressive therapy. This is a virus so we cannot kill the virus with antibiotics. Our treatment plan includes supportive care as the patient heals itself by mounting an immune response. Some have at least some vaccination history and this helps them recover faster. 

Treatment in a hospital intensive care is one option for treatment. Your veterinarian will likely go over some plan which includes hospitalization. However, we have seen many patients do well with outpatient care. One study reports that 83% of dogs treated aggressively as outpatients survived. This often involves daily visits for fluids and injections but puppies are home with their families which is also less stressful.

Hydration – Keeping these puppies adequately hydrated is key. Usually they are vomiting so just relying on drinking water is not enough to adequately hydrate. As an in-patient, IVF are the best path to rehydration. This is a great way to deliver water and much needed electrolytes. However, if we are treating the patient as an outpatient, we will provide fluids subcutaneously. A large bolus of fluids is administered under the skin of the puppy (usually by the shoulder blades). This fluid will be absorbed slowly over the next 24 – 48 hours. This should be repeated daily to be effective. 

Antibiotics – Although Parvovirus is a virus, antibiotics help us prevent secondary infections. The parvovirus attacks the villi of the small intestine and allow intestinal bacteria to enter the blood stream. This is very important as many pups die of systemic bacterial infection. 

Canine parvovirus monoclonal antibody ( CPMA)  – This is a new therapy that is proving to work quite well. In a recent study no dogs died that received this medication within 4 days of exposure to parvovirus and had a positive test. Most patients still need intensive supportive care if receiving CPMA. 

Anti-emetics – These medications prevent vomiting and are of utmost importance in treating Parvoviral enteritis. This is usually administered as an injection. The injection does not usually help with nausea so your patient may receive additional antiemetics to help with nausea.

Nutritional therapy – Puppies need nutrition desperately.  However, with the constant vomiting, this is difficult and often they just refuse to eat for several days. Parenteral feeding ( through an IV) does not work with small animals and has horrible complications so this is not an option for us. Often hospitalized patients will have a feeding tube in order to administer small doses of nutrition into their stomach in the face of inappetence. 

Monitoring

In the hospital, patients are monitored closely so adjustments can be made in their therapy.  For our outpatients, we should also monitor daily. This will allow us to alter treatments or hospitalize if the patient is not responding well. 

Prognosis

As stated above, untreated patients do not do well.  Mortality rates are over 90 % for unvaccinated, untreated patients. However, patients which survive the first 3 – 4 days typically recover with treatment. Average hospitalization length is 79 hours but some have been known to be hospitalized for 7 -8 days.

In Conclusion

Good vaccinations, at scheduled times, by your veterinarian are the best way to prevent your puppy from getting Parvovirus. Fortunately, parvovirus is no longer a death sentence for puppies. This disease can cause a lot of suffering for puppies and treatment is expensive. Recognizing this disease early and treating aggressively will usually lead to a good outcome. Most patients go on to live normal lives. If you have any questions about preventing Parvovirus, please see your primary care veterinarian. If your puppy has some of the signs of parvovirus, please schedule an urgent care appointment or see an emergency veterinarian. The earlier the diagnosis, the better.