The internet has been buzzing with talk of an emerging and possibly deadly virus occurring in dogs. Concern about this virus is significant enough that even during a webinar I attended yesterday on using social media in veterinary medicine, dog circovirus received a mention. The Animal Medical Center’s Facebook friends have been discussing the virus and their concerns about their dogs, as well.
I had actually not heard of the circovirus group until recently, probably because the majority of circoviruses infect birds. Until this new virus was isolated from sick dogs in April, pigs were the only mammal known to be infected with a circovirus, which causes pneumonia, gastrointestinal signs, and systemic inflammation. The genome of a dog circovirus was reported back in 2012, but the authors of that paper do not report where the virus was found or if the virus made dogs sick.
Sick dogs in California
In April of this year, Emerging Infectious Diseases published an article, “Circovirus in Tissues of Dogs with Vasculitis and Hemorrhage.” In California, a young dog, sick with signs of vomiting and bloody diarrhea, died and was autopsied. Tests for typical diseases causing bloody diarrhea, parvovirus, Salmonella and Giardia, were negative. Researchers performed additional testing on the tissues, leading to the identification of a strain of dog circovirus. Fecal analysis of samples from both healthy dogs and sick dogs with signs similar to the dog in California found about 10% of fecal samples were positive for circovirus, but many dogs had other pathogens in their stool including coronavirus, Giardia and Salmonella. One common historical feature of these cases was group housing, such as a shelter or boarding kennel.
Sick dogs in Ohio
Last month, an astute veterinarian in Ohio treated several dogs, all with a history of staying at the same boarding kennel, and reported this cluster of cases to the Ohio Department of Agriculture. The dogs had strikingly similar signs to one another and to the dogs reported in Emerging Infectious Diseases: bloody diarrhea, vomiting, weight loss, lethargy and inflammation of the blood vessels. One dog had circovirus isolated from a fecal sample, and further testing is underway in one of the dogs that died to determine the cause of death.
Treat with common sense
Medical caution is indicated in this situation. Finding a virus in a sick patient does not automatically determine causality and much more research is necessary before circovirus infection can be added to the list of potential diagnoses for sick dogs. Our friends at the Veterinary Network News urge caution in attributing too many illnesses to this newly found virus.
The unknown can be scary. Since so little is known about dog circovirus, making rational recommendations is a hard task.