The canine circovirus and its clinical relevance

The authors in this literature review summarize the most important knowledge about canine circovirus. Circoviruses are small, non -enveloped, highly resistant, circular single -stranded DNA viruses belonging to the family Circoviridae. Circo-viruses have been widely detected in pigs, dogs and other carnivores, as well as in various avian and fish species. Among the widely studied porcine circoviruses are porcine circovirus 1 (PCV1), PCV2, PCV3, and the recently described PCV4. PCV2 was first identified in Canada in the early 1990s. It was first reported in Hungary in 1999. Diseases caused by PCV2 include PCV2 systemic disease (formerely known as postweaning multisystemic wasting syndrome), PCV2 reproductive disease, porcine dermatitis and nephropathy syndrome and also subclinical infection. The canine circovirus was first identified in the United States in 2012. Later the presence of the virus was described worldwide, both in healthy dogs and dogs showing clinical symptoms. Tne review also gives insights into the clinical signs caused by canine circovirus. If the infection is detected In clinically ill animals, the clinical signs mostly include gastrointestinal symptoms, such as diarrhea and vomiting. Its pathological role, however, has yet to be fully clarified to date, and it is often detected together with other gastrointestinal viruses, especially canine protoparvovirus (canine parvovirus 2, CPV2), and furthermore canine herpesvirus, canine distemper virus, canine coronavirus and more rarely with viruses that cause respiratory diseases such as canine parainfluenza virus, canine adenovirus. Canine circovirus infection may influence the prognosis and severity of parvovirus disease. Not least, the present review includes essential information about canine circovirus infection in wild carnivores based on the latest literature data. Canine circovirus has also been detected in wild animals, mostly in red foxes (Vuples vulpes), gray wolves (Canis lupus), arctic foxes (Vulpes lagopus) living on the Norwegian island of Svalbard, and European badgers (Meles meles).