There are two significant strains of canine coronavirus (the respiratory group 2 strain, and the enteric group 1 strain) produce vastly different symptoms. The canine respiratory coronavirus (CRCoV) is a part of the kennel cough complex and is spread in kennel-like situations where dogs have high contact with one another or infected surfaces. It is genetically related to the bovine and human coronaviruses that cause respiratory infections and the common cold in people. Dogs that catch it have mild symptoms such as cough, sneezing, and nasal discharge.
Other dogs present without any clinical signs, yet they shed the virus that can then infect other dogs. When combined with bacteria (Bordetella; Streptococcus), veterinarians will usually prescribe antibiotics to treat the bacterial infection. Currently, no vaccine exists for the CRCoV strain of coronavirus. If it did, most dogs would not need this vaccine except when the pet was at high risk for exposure and illness from the kennel cough complex.
Unlike canine respiratory coronavirus, a vaccine exists against canine enteric coronavirus (CCV), but it does not cross-protect against the respiratory strain. Is the vaccine for CCV really necessary? Let’s first review the facts about CCV.
What is canine enteric coronavirus?
Canine enteric coronavirus causes diarrhea. Along with an orange diarrhea, dogs generally may experience lethargy and decreased appetite. By itself, the symptoms generally clear up within a few days. In many cases, dogs have absolutely no symptoms.
How is it spread?
Enteric coronavirus is spread by infected feces, food/water bowls or direct contact with another infected dog. Remember, it is a completely different strain than the respiratory strain of coronavirus. The CRCoV does not mutate in the gut to become the enteric CCV.
The best remedy to limit exposure is to keep the environment sanitary and not put dogs in such close quarters.
How to manage it?
In many instances, withholding food for approximately 24 hours and then reintroducing it slowly will help clear it up. Also, CCV is inactivated by heat when ambient temperatures are at or above 85 degrees F. Intravenous fluids may be needed to restore fluid levels and balance electrolytes. Definitely contact your veterinarian.
Is that all?
No. Just like respiratory coronavirus, enteric coronavirus becomes an issue when a secondary bacterial or other gut infection occurs. In this instance, a veterinarian may prescribe fluids, supportive care and antibiotics.
Enteric coronavirus can also become a major problem when it is commingled with parvovirus. In fact, the symptoms often lead pet caregivers to believe it is the latter. Since parvovirus can be life-threatening, especially in puppies, we want to definitely vaccinate against it. Remember – by itself – coronavirus is a mild infection.
Do veterinarians vaccinate against coronavirus?
It really depends on the veterinarian. Well-informed veterinarians – like those who follow the American Animal Hospital Association (AAHA) and World Small Animal Veterinary Association (WSAVA) guidelines – do not routinely vaccinate against CCV coronavirus.
AAHA position: Neither the MLV vaccine nor the killed CRCoV vaccines have been shown to significantly reduce disease caused by a combination of CRCoV and CPV-2. Only CPV-2 vaccines have been shown to protect dogs against a dual-virus challenge.
WSAVA position: Not Recommended. CCV infections are usually subclinical or cause mild clinical signs. Prevalence of confirmed CCV disease does not justify use of currently-available vaccines. There is no evidence that existing vaccines would protect against pathogenic variants of CCV. Variant strains of this virus have been reported to cause severe systemic disease in adult dogs and puppies in various parts of the world, but it is unclear whether the available vaccines would protect against these variants. The identification of coronavirus with a test kit does not necessarily mean it is the cause of disease.
Although CCV can be isolated commonly, the WSAVA Vaccination Guidelines Group (VGG) remains unconvinced that CCV is a significant primary enteric pathogen in the adult dog. No studies have satisfied Koch’s postulates for this infectious agent.
“Canine Respiratory Coronavirus FAQ.” American Veterinary Medical Association, Apr. 2008. Web. 30 July 2017. https://www.avma.org/public/PetCare/Pages/Canine-Respiratory-Coronavirus-FAQs.aspx.
Day, M.J. “Guidelines for the Vaccinations of Dogs and Cats.” (2016): n. pag. World Small Animal Veterinary Association. Web. 30 July 2017. https://www.wsava.org/sites/default/files/WSAVA%20Vaccination%20Guidelines%202015%20Full%20Version.pdf.
Welborn, Link et al. “2011 AAHA Canine Vaccination Guidelines.” (2011): n. pag. American Animal Hospital Association. Web. https://www.aaha.org/public_documents/professional/guidelines/caninevaccineguidelines.pdf.