Fatal Disease in Nursing Puppies Associated with Minute Virus of Canines

Abstract

Thirteen cases of a previously undescribed parvoviral infection affecting puppies ranging in age from 5 to 21 days is described. The cases were originally thought to represent an unusual pathologic manifestation of canine parvovirus-2 (CPV-2) infection. However, failure to confirm CPV-2 infection in any of the cases suggested a different parvovirus was involved. Minute virus of canines (MVC) was subsequently isolated from a case by using the Walter Reed Canine Cell Line, the only cell line which will support the growth of MVC. The pathologic and virologic findings for these 13 cases are described in this report.

Minute Virus of Canines (MVC, Canine Parvovirus Type-1): Pathogenicity for Pups and Seroprevalence Estimate

“…The differences between the reported field cases 6 and experimental findings reported here are notable; clinical signs in experimentally infected pups consisted mostly of only mild to moderate respiratory distress. Only 2 of the experimentally infected pups died or appeared moribund.…”

“…Similar lesions were also observed in canine fetuses that had been inoculated directly with MVC; 4 myocardial lesions were not seen in pups in the present study. Severe bronchopneumonia also was noted in some of the fatal field cases, 6 but pulmonary lesions were not emphasized despite the clinical signs of respiratory distress noted in most pups. In the reported field cases, lung lesions were not prominently featured, possibly because the primary focus was on the intestinal tract, where signs were most prominent and parvoviral particles had been observed by electron microscopy.…”

“…Microscopic examination of the small intestine, especially the duodenum and jejunum, may reveal crypt epithelial hyperplasia, single cell necrosis of crypt cells 8 and amphophilic intranuclear inclusion bodies at the tips of villi. 6 Histopathologic examination of lung sections should include a search for inclusion bodies, especially in the bronchial epithelium. More extensive diagnostic work would include IFA tests for MVC viral antigen, especially in the small intestine and affected areas of the lung.…”

“…5 Recently, 13 cases of a fatal disease of nursing pups similar to parvovirus infection was reported. 6 Electron microscopic examination revealed parvovirus particles in the intestinal contents, but isolation attempts in canine or feline cell lines, hemagglutination by fecal extracts, and indirect fluorescent antibody (IFA) tests for CPV-2 were negative. The prominent signs in the field cases were vomiting, diarrhea, dyspnea, or sudden death.…”

Molecular characterization ofCanineminute virusassociated with neonatal mortality in a litter of Jack Russell terrier dogs

“…24 Natural outbreaks of CnMV-associated neonatal mortality have been reported only sporadically, and last reports date back to the 1990s. 2,18,20,25 Puppies infected less than 4 weeks of age often had mild or vague symptoms preceding their rapid death; others displayed depression, loss of appetite, acute myocarditis, respiratory distress, and/or enteritis. 7 A certain role in CnMV pathogenesis may be played by virus-induced immunosuppression due to reduction of monocyte phagocytosis.…”