Canine coronavirus (CCV) is a highly contagious gastrointestinal disease that causes vomiting and diarrhea. It was first identified in 1971 in a group of military dogs in Germany. The virus has since been found in Europe, North America, and Australia and occurs throughout the world.
Coronaviruses occur in all kinds of animals and often look similar or cause similar signs. For instance, the canine coronavirus is closely related to the feline forms that cause feline enteric disease and notably sometimes mutates into feline infectious peritonitis. However, CCV causes disease only in wild and domestic dogs, including coyotes, wolves, and foxes.
All dogs are susceptible, but the signs are most severe in puppies and may develop suddenly. Studies have shown that more than 25 percent of pet dogs have been exposed to CCV. The disease by itself is rarely fatal and often is a mild disease with sporadic symptoms that you may not even notice.
But CCV can prove deadly when the puppy is already infected with intestinal parasites that compromise his health. In particular, dogs infected with both CCV and canine parvovirus at the same time have up to a 90 percent death rate.
Signs of Coronavirus Infection
Dogs usually are infected through contact with sick dogs or their droppings. A stressed pup may have reduced resistance to infection. The virus can remain in a recovered dog's body and continue to be shed for up to six months, so even well pups could continue to spread the infection.
Puppies explore their world by sniffing everything and then tend to lick their nose, and that's a prime way for them to become infected. Once the virus is swallowed, the infection develops within one to three days. Signs vary with adult dogs perhaps showing only vomiting one time (if at all), or a sudden bout of explosive diarrhea—typically yellow-green to orange liquid. Many adult dogs will show no signs, while others become rapidly sick and die. Most cases are seen in kennel situations.
Early signs include loss of appetite, rarely fever, and more often vomiting and depression. This is followed by loose to liquid diarrhea which may contain blood or mucus and has a characteristic foul odor. In puppies, life-threatening dehydration can develop quickly.
Progression of the Disease
CCV infects a specific part of the lining of the small intestine. The small intestine is lined with hill-shaped structures called villi that are covered with tiny hair-like projections (microvilli) that absorb nutrients. CCV infects the "hilltops" of the villi, compromising the body's ability to process food.
The "valley" portion which contains microvilli-producing crypt cells can completely replace the tips about every three or four days. For that reason, the virus tends to produce only a mild to moderate, usually self-limiting disease. In most cases, dogs will recover within seven to ten days. Some dogs may relapse three or four weeks following apparent recovery.
Diagnosis is made on the basis of symptoms. However, since vomiting and diarrhea can also point to other diseases, a definitive test may require further tests such as serum (blood) tests or antibody tests. There is no specific treatment for CCV, but supportive care helps speed recovery.
Adult dogs may not need medication but puppies require extra attention. Diarrhea in severe cases may continue for nearly two weeks and soft stool for even longer. Antibiotics may be indicated if the disease is severe to counter the possibility of secondary infection.
Treatment is mostly aimed at counteracting dehydration from fluid loss, vomiting, and preventing secondary bacterial infection. Fluid therapy helps combat the dehydration that often results from the vomiting and diarrhea, and antibiotics reduce the number of bacteria in the bowel so they do not infect the bloodstream through the compromised bowel lining. Medication is often prescribed to control diarrhea and vomiting.
Prevention of the disease is best managed by avoiding contact with infected animals and their droppings. Sanitary procedures, such as picking up the yard and kennel area, help a great deal. Preventative vaccinations are available and may be recommended for high-risk pups such as those exposed through kenneling or dog shows.
When you have more than one dog, be sure to quarantine the sick puppy during treatment and recovery, and take steps to keep him from infecting the other pets. Remember that even once he's gotten well, he may continue to shed infective virus for some time. So keep the other pets from making contact with his stool.