Coronavirus In Your Puppy

Ron Hines DVM PhD

  A Science-Based Vaccination Schedule For Your Dog

Parvovirus Infection In Your Dog

Diarrhea episodes are common in puppies. Sometimes it is due to the things they eat and chew. (read here) But sometimes it is due to organisms that have taken up residence in your dog’s digestive tract. The most serious of them is the canine parvovirus. Read about canine parvovirus here. Another much less lethal virus, the enteric (=confined to the intestines) coronavirus of dogs is another.

When the enteric form of canine coronavirus is acting alone, diarrhea lasts only a few days – if any symptoms occur at all. Your puppy might be uncomfortable and have a tummy ache for a time. It might pass soft stools, and occasionally some true diarrhea that messes up your house. When coronavirus is the culprit, stools rarely if ever contain blood. Your pup’s appetite might decrease for a few days as well. When symptoms are more severe, it is usually because your dog was coinfected with other intestinal pathogens (even parvovirus) and/or intestinal parasites at the same time. Environmental and nutritional stress tend to accentuate symptoms. The coronavirus of dogs is a distant relative of the coronavirus of cats – the nasty one that sometimes mutates into FIP, and of course, COVID-19 that affects us. 

Canine coronavirus is highly contagious. When diarrhea occurs, it generally begins 1-4 days after exposure to the stool of a carrier dog. Few of the dogs that are most likely to spread coronavirus to your dog show any signs that they are ill. These recovered or resistant dogs are thought to be able to continue shedding this canine coronavirus intermittently for almost 6 months. (read here)

Where Might My Dog Catch Coronavirus?

Your dog is most likely to catch coronavirus at locations where lots of dogs congregate. Doggy daycare centers, dog parks, grooming establishments, dog shows, mass vaccination clinics and animal shelters. The more crowded the animals, the poorer the sanitation, the more likely it is that cross infection will occur. It is common in puppy mill puppies and pups supplied by large commercial dog-breeding operations (more than 3 breeding dams). The canine coronavirus can infect a dog of any age. But most dogs will have already been exposed and immune to this virus by the time they are one year old or are already immune to the virus through vaccination. As I mentioned, the virus causes inflammation of the upper intestines (enteritis). These irritated intestines move more rapidly to expel their food contents, produce the diarrhea. Something I will mention frequently as I go along is that coronavirus of dogs rarely if ever acts alone. It usually produces enteritis and diarrhea as one player among many players who have taken up residence in your dog – all at the same time. (read here) The older studies that attributed a sick dog’s symptoms to coronavirus did not check for these more recently discovered pathogens. The most recently discovered ones I know of are the astroviruses.  (read here)  

A fatty (phospholipid) protective envelope surrounds each coronavirus. Unlike the parvovirus that has no envelope but is highly stable in the environment, coronavirus are quite easy to kill with bleach, ammonia or hydrogen peroxide; as well as with dish and laundry detergents that effectively dissolves their fatty protective phospholipid coating.

Respiratory Coronavirus Of Dogs

The AVMA put out an advisory in 2008 regarding a “new” coronavirus that had the ability to cause severe respiratory (lung) infections in dogs. That advisory and similar warnings from the AKC, proved to be exaggerated. More recent studies found that respiratory coronavirus of dogs (CRCoV) is a different virus from the traditional intestinal coronavirus of dogs (CCoV). It also found that this newly discovered coronavirus was a much closer relative to the varieties that cause respiratory problems in pigs and cows than it was to the coronavirus associated with diarrhea in young dogs. (read here) Pfizer sponsored a study of this respiratory form. (read here) If the coronavirus portion of the vaccines that your dog receives has any protective properties against CRCoV remains unknown. 

What Tests Can My Veterinarian Run To Diagnose Coronavirus?

University and large commercial veterinary diagnostic laboratories can check your dog’s stool for coronavirus. They can also run blood antibody tests that tell them if your dog was ever exposed to the virus. However, those tests are rarely run on samples from individual pets. They are generally reserved for scientific studies or animal shelters facing an unacceptable number of canine diarrhea cases. See Cornell test offerings here

What Treatment Might My Dog Require?

There is no specific treatment for a dog with a digestive tract coronavirus infection. TLC and whatever supportive care that is indicated are usually all that are required. In a typical mild case, the diarrhea resolves in a few days without any medications being dispensed. Many veterinarians would suggest oral fluids (e.g. electrolytes) and a bland diet that you give in small amounts throughout the day. Others might suggest withholding food for 24 hours. Both are valid approaches. But still other veterinarians might send you home with a basket full of products, i/d™, a/d™ or EN™ dog food, Pro-Pectalin®, probiotics like Proviable-KP™, etc, etc. I do not believe that any of those products are likely to speed your dog’s coronavirus recovery, but one always feels better when doctors dispense things. Antibiotics would be counterproductive since they kill no virus but do kill off the protective bacteria that normally reside in your dog’s intestines. Should the diarrhea be severe, the primary treatments would be to correct dehydration and electrolyte imbalances. The rest would be selected by your veterinarian from the same treatment options available for parvovirus infections. You can read about those medications and options in detail here.

Vaccines Available Against Coronavirus Infection

There are currently two I am acquainted with: Boehringer Ingelheim’s Recombitek Corona MLV®, a weakened (attenuated) live virus product and Zoetis’ Vanguard CV®  which is a killed (inactivated) product. Both companies, plus Merck, incorporate coronavirus in their “8-way” formulas marketed to protect dogs against everything. I never recommend them because I believe that the more ingredients a vaccine contains, the more likely it is to confuse the dog’s immune system. None of the vaccines currently on the market claim to provide complete (“sterile”) protection against coronavirus. (read here + the product inserts).

The American Animal Hospital Association, AAHA no longer recommends coronavirus-containing vaccines, based on their opinion that the disease is usually mild or subclinical and that it generally occurs in dogs 6 weeks of age or younger – too young to be successfully vaccinated. The central pharmacy at the Vet School, University of California, Davis no longer stocks coronavirus-containing vaccines. Their rational is: “It is not possible to reproduce disease with coronavirus unless the dog is immunosuppressed with steroids. Antibodies do not correlate with resistance to infection and the length of time these vaccines might make a dog resistant to coronavirus is unknown.” (see here) Nevertheless, some boarding kennels and other commercial establishments might still insist that your dog receive a coronavirus-containing vaccination before they provide their services.

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