Fatal coronavirus infection in puppies following canine parvovirus 2b infection.

Abstract

Canine coronavirus (CCV) belongs to the Coronaviridae family, which includes enveloped and pleomorphic viruses 60–220 nm in diameter, helical nucleocapsids, and petal (club-shaped) peplomeres, which are widely spaced on the envelope, resembling a solar corona.1,12 CCV was first isolated in 1971 from military dogs in Germany suffering from gastroenteritis.3 Subsequently, additional cases have been reported that were usually mild and selflimiting, unless complicated by canine parvovirus (CPV) infection.2,7,8,10,14 Coronaviral disease in dogs is extremely variable. Although adult dogs generally have no or mild clinical signs and usually recover after a brief period of illness, pups with secondary bacterial infections, parasites, or other viruses may suffer severe, even fatal, disease.1,8,10 Infected dogs shed CCV in the feces for 6–9 days, but shedding can be prolonged in some animals.1,9 The most likely mode of transmission is by the fecal–oral route. The main target of CCV is the small intestinal epithelium, where a lytic infection results in desquamation and shortening of duodenal and jejunal villi. Pathologic changes have been observed mainly in experimentally infected dogs and are characterized by dilated intestinal loops filled with watery ingesta and feces, congested or edematous mucosa, and edematous mesenteric lymph nodes.1,8,9,13,14 Microscopic changes are characterized by atrophy and fusion of intestinal villi, a deepening of crypts, and increased cellularity of the lamina propria.8,9 In this report, we describe the clinical, virologic, and histopathologic findings observed in littermate pups that died with signs of severe hemorrhagic enteritis 15 days following recovery from a CPV-2b infection. The presence of parvovirus-like intranuclear inclusions in intestinal epithelial cells .2 weeks following recovery from CPV-2b infection and the presence of pulmonary lesions were unexpected, and the CCV infection may have been complicated by infection with another agent such as the minute virus of canines (MVC, canine parvovirus 1). In the initial disease episode, 4/4 Corso (Italian breed) pups, 45 days old, developed hemorrhagic gastroenteritis. CPV. 2b was the only virus detected by laboratory examination, which included hemagglutination (HA) tests on fecal suspensions, viral isolation attempts in A-72 cell cultures,