Successful experimental challenge of dogs with canine parvovirus-2.

Withholding food from dogs for 24 hours prior to, and for 48 hours following oral challenge with a gut mucosal homogenate of canine parvovirus-2, was a successful means of reproducing gastroenteric signs of canine parvovirus-2 infection. Twenty-one of 24 dogs, which had previously received various vaccine preparations of mink enteritis virus or were unvaccinated, and which were starved at challenge, developed soft or liquid feces with large or without large clots of mucus. Altered feces were most frequent on postexposure day 11. Seven dogs passed frank blood in their stools on one or more occasions and seven dogs vomited sporadically. Pyrexia was noted in 71.6% of the dogs on postexposure day 6 and lymphopenia was detected on postexposure day 5 or 6 in 50% of the dogs monitored. In contrast, four dogs not starved at the time of challenge remained free of gastrointestinal signs apart from one dog which passed a soft stool with scant mucus on one day, postexposure day 6. Also four dogs vaccinated with a killed canine parvovirus-2 vaccine preparation and subsequently starved at the time of challenge, remained clinically healthy. Apart from these last mentioned four dogs, all others shed canine parvovirus-2 in their feces following challenge.