Sera of weaned puppies from a hysterectomy-derived, specific pathogen free (SPF) closed dog colony did not contain antibodies against a TGE-associated virus or a serologically related one, but sera from puppies and older dogs from open kennels did. The higher antiviral titers in serum of older dogs suggested that these animals had suffered either persistent or recurrent infections. Seventy-two puppies had no contact with swine, indicating that the virus was able to propagate independently of contact with swine.
