J. Hoorens

Pathology of Experimental CV777 Coronavirus Enteritis in Piglets. I. Histological and Histochemical Study

Sixteen cesarean-derived colostrum-deprived piglets were infected oronasally with CV777 coronavirus on the second or third day of life. Two uninfected piglets were controls. They were killed at 96 and 120 hours after birth. After an incubation period of 22 to 36 hours, all principals showed severe diarrhea. The principals were killed between 12 and 120 hours after infection. Exfoliation of enterocytes was seen first in the piglet killed 24 hours after infection (two hours after the diarrhea began). From that time on, shortening and fusion of villi was present in all small intestinal parts. Affected cells showed vacuolation. The histochemical study showed that infected piglets had decreased activity of all four enzymes studied. The light microscope showed no lesions in the absorptive colonic epithelium. The significance of the lesions in relation to intestinal dysfunction is discussed, and lesions are compared to those of transmissible gastroenteritis and porcine rotavirus infection.

Pathology of Experimental CV777 Coronavirus Enteritis in Piglets. II. Electron Microscopic Study

Sixteen cesarean-derived, colostrum-deprived piglets were infected oronasally with CV777 coronavirus on the second or third day of life. Two uninfected piglets were controls. After an incubation period of 22 hours to 36 hours, all principals showed severe diarrhea. The piglets were killed at different time intervals. Viral particles were found in the jejunal villous epithelial cells from 18 hours after infection until four days after the beginning of diarrhea. In the colonic epithelial cells, viral particles and degenerative lesions were found only in the piglet killed 36 hours after onset of diarrhea. Degenerative lesions in the enterocytes began at 18 hours after infection and were most pronounced in the jejunum at the onset of clinical signs. From 24 hours on after the onset of clinical signs, three cell types were found: degenerated virus-containing enterocytes; cuboidal cells; and columnar, highly vacuolated cells containing lipid droplets.

Sequential Pathological Study of Experimental Porcine Adenovirus Enteritis

The sequential enteric lesions of experimental porcine adenovirus strain 6618 infection were studied in 18 hysterotomy-derived, colostrum-deprived piglets, by histology, transmission electron microscopy, and an immunoperoxidase technique. Viral particles could be seen in altered epithelial cells of the lower small intestine from 24 hours until 16 days after inoculation. With the immunoperoxidase technique, viral antigen could be found in epithelial cells at 45 days after challenge. Destruction of epithelial cells and shortening of villi could be related directly to the presence of the virus. Histology of the lower jejunum and ileum, which demonstrates intranuclear inclusion bodies, is proposed as a useful diagnostic technique.

Spontaneous and experimental myofibrillar hypoplasia and its relation to splayleg in newborn pigs

Abstract The relation of myofibrillar hypoplasia to clinical splayleg was studied. A strain of Belgian Landrace sows was selected for this study because they produced pigs which had no myfibrillar hypoplasia. Myofibrillar hypoplasia could nevertheless by induced experimentally in these animals by dexamethasone treatment of the sows during late pregnancy. The lesion was observed without clinical signs and was compared to the myofibrillar hypoplasia in clinical cases of splayleg. The differences between these 2 groups may account for the appearance of clinical signs. These differences included the maturity of the myofibrils and the degree of autophagosomal glycogen breakdown.

Malacoplakia-like lesion in the lymph node of a pig.

Abstract Among 112 mandibular and mesenteric lymph nodes with tuberculosis-like lesions from slaughtered pigs, one tuberculous lymph node had a malacoplakia-like granulomatous lesion; no similar lesion has been recorded before in animals.

An Electron Microscopic Study of Experimentally-induced HEV Encephalitis

A gnobiotic piglet, was inoculated intracerebrally with hemagglutinating encephalomyelitis virus (strain VW572). Mononuclear cells formed vascular cuffs and were disseminated in the brain parenchyma. A few neurons were surrounded by the same kind of cells. Virus particles morphologically similar to Coronavirus particles were found in the cytoplasm of both chromatolytic light neurons and hyperchromic dark neurons. The particles were in vesicles of distended endoplasmic reticulum and in the hypertrophied Golgi apparatus.

Dual adenovirus and distemper virus pneumonia in a dog

A case of simultaneous infection of the lungs of a dog with canine distemper virus (CDV) and canine adenovirus (CAV) is described. The techniques employed are histological stains, immunoperoxidase technique, and transmission electron microscopy. Two viruses are shown to infect the same cells. The significance of dual infection of the same cells is discussed in comparison with literature data on in vitro experiments.

Immunoperoxidase study of adenovirus pneumonia in dogs.

The pathology of adenovirus pneumonia in 16 dogs is described. Clinically, these dogs had been severely ill, with severe dyspnoea and listlessness, but only faint coughing. Histopathological lesions could be associated directly with the presence of adenovirus antigens in the lungs of these dogs by using an unlabelled immunoperoxidase technique on paraffin tissue sections. The lesions were focal and located in alveoli and bronchioles. Infected cells were mostly alveolar macrophages and less frequently type 1 and 2 pneumocytes and bronchiolar epithelial cells. Infiltrating neutrophils and lymphocytes were not observed to be infected. This type of pneumonia appears to be a fairly well defined clinical and pathological entity in kennel dogs.