Experimental Viral Pneumonia in Guinea Pigs: An Ultrastructural Study

Abstract

Abstract. Homogenized lung tissue was used to experimentally reproduce lethal viral pneumonia in guinea pigs. The resultant lesions corresponded with those of the spontaneous disease. Pneumonia with necrotic bronchiolar epithelium accompanied by basophilic intranuclear inclusion bodies was the primary finding. With transmission electron microscopy, numerous viral particles were found-mainly within the nucleus of pulmonary epithelial cells but also within the cytoplasm and in extracellular space. The appearance of viral particles, in particular their paracrystalline and crystalline deposition within the nucleus, indicates that our experimentally induced pneumonia was caused by an adenovirus.Acute or subacute Dneumonia is a common cause of from areas which appeared macroscopically altered or unal-_ _ have been isolated from diseased lungs of guinea pigs has been fOUnda3' We rePofled sudden death in guinea with pneumonia, but evidence of a dylate buffer (4 x 30 minutes) and dehydration in increasing pigs which were used for diagnosis of human tubercu-Semithin sections stained with toluidine blue and sections losis. l 7 Histologic and electron microscopic examina-embedded in paraffin were assessed by light microscopy. tion revealed pneumonia with signs of a viral infection. Sections for electron microscopy were prepared after orientation with semithin sections, and ultrathin sections were cut Lungs usually were bacteriologicdly. Intranu-with an ultramicrotome. Uranyl acetate and lead citrate were particles Observed by used to contrast sections before examination with an electron electron microscopy indicated an adenoviral infection. microscoDe. bodies andSince this disease is becoming more commonY3~ l4 we reproduced it experimentally to verify the infectious eti~logy.'~ Results of the clinical, macroscopic, and etiologic investigations have been reported.14 Electron microscopic changes in the lungs of experimentally infected guinea pigs are described. Materials and MethodsElectron microscopic examination was done on lungs from newborn guinea pigs (Cavia porcellus) which were infected intranasally in a third in vivo passage with homogenized lung.'4 The guinea pigs originated from a breeding colony with no spontaneous infection. In all four in vivo passages, the control bacteriologic examination of passaged lung homogenate remained negative; all samples were sterile. The Results Symptoms of experimental infection were similar to those of spontaneous disease. At necropsy, pneumonia was characterized by distinct red solid zones within the tips of the lobes and hilus. Compensatory emphysema and hemorrhages were observed in the remaining pulmonary tissue. No significant lesions were found in other organs. Semithin tissue sections from pneumonic regions revealed purulent necrotizing bronchitis and bronchiolitis. Inflammation sometimes involved the entire bronchiolar wall. Peribronchiolar space was infiltrated massively by mononuclear cells. Individual --experimental procedure, clinical signs, and attempts to pas-necrotic f...

Reovirus infection in rat lungs as a model to study the pathogenesis of viral pneumonia

“…The more extensive type I cell destruction may have been a function of the greater number of neutrophils recruited into the lungs of T3D-infected rats. Neutrophils release proteolytic enzymes in response to infection that can, in turn, have a detrimental effect on the lung tissue (19). Although type I epithelial cell destruction was primarily a direct result of viral infection, recruited neutrophils may have contributed to epithelial damage in T3D-infected rats.…”

Erkrankungen des Meerschweinchens aus Sicht der Pathologie

“…Entgegen den Ergebnissen von Brennecke (2), Breuer (3) und Naumann et al (35) waren in unserer Studie die Tiere wie bei Feldman (10) vorwiegend männlichen Geschlechts. Die lichtmikroskopischen Veränderungen entsprachen den in der Literatur beschriebenen Befunden (2,3,10,11,17,21,22,23,35). Entsprechend den Angaben anderer Untersucher (3, 10) konnten zwei verschiedene Typen von Viruspartikeln festgestellt werden.…”

“…Entsprechend den Angaben anderer Untersucher (3, 10) konnten zwei verschiedene Typen von Viruspartikeln festgestellt werden. Auch wurden in dieser Untersuchung kristallähnliche Fasern gefunden (17,21,22).…”

Adenovirus pneumonia in guinea pigs

“…The pulmonary lesions in these cases resembled those in other descriptions of adenovirus pneumonia in guinea pigs. Previous reports [2][3][4][6][7] suggest that cavian adenovirus pneumonia is a disease of low morbidity but often high mortality, with affected animals often found dead or sometimes showing premonitory respiratory distress. Young guinea pigs are most susceptible, although the virus appears not to be highly contagious, and clinical disease is often precipitated by stress.…”