Investigations ongoing in dog illnesses, deaths

Published on October 16, 2013
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A recently discovered circovirus is no longer suspected as a cause of illnesses and deaths among dogs in Ohio. 

The Ohio Department of Agriculture has been investigating possible connections among at least 12 dogs that developed similar clinical signs, including four that died, since August, in the Cincinnati and Akron areas. The department received reports that clinical signs included vomiting and diarrhea connected with vasculitis, weight loss, and lethargy. 

Department investigators considered research published in April (Emerg Infect Dis 2013;19:534-541) that describes a novel circovirus first found in a dog in California that had hemorrhagic gastroenteritis, necrotizing vasculitis, and granulomatous lymphadenitis. The article, “Circovirus in tissues of dogs with vasculitis and hemorrhage,” indicates it is unclear whether the circovirus causes disease, but it should be considered in dogs with unexplained vasculitis. 
Officials with Michigan State University announced in October that the circovirus had been found in two dogs that were coinfected with other organisms. One was coinfected with parvovirus, and details on the second dog were not immediately available. 
Erica Hawkins, a spokeswoman for the Ohio Department of Agriculture, said samples from 12 to 15 dogs considered to be part of the potential outbreak in Ohio were tested for the presence of the circovirus, and only two were positive. And she noted that the scientific article published in April indicated the circovirus has been found in healthy dogs. 
Dr. Thomas P. Mullaney, acting director of the Diagnostic Center for Population and Animal Health at the MSU College of Veterinary Medicine, said merely finding the circovirus told investigators nothing about the cause of the disease. The diagnostic center planned further investigations using in situ hybridization, through which investigators can look for the virus in microscopic lesions.
Dr. Mullaney said coinfection with the novel circovirus and other pathogens may cause disease in dogs in the same manner that coinfection with porcine circovirus type 2 and other pathogens can cause disease in pigs.
The university announced that, once more common disease causes are excluded, veterinarians should consider circovirus to be a possible factor in dogs with clinical signs including vomiting, diarrhea, ascites, pleural effusion, hypovolemic shock, bicavitary hemorrhage, and disseminated intravascular coagulation.