Morphological studies of esophageal papilloma naturally occurring in cattle

Esophageal papillomas naturally occurring in 35 cattle were examined by light and electron microscopy. The characteristic histological lesions noted were acanthosis and parakeratosis of the mucous membrane with formation of basophilic intranuclear inclusion bodies in cells of the stratum corneum. Electron microscopically, viral particles were observed in the strata spinosum and corneum, and larger aggregations of viral particles appeared to correspond to the histological inclusions. The virus particles had a hexagonal profile, measured 35-40 nm in diameter and were arranged in crystalline arrays in some nuclei. The viral particles had morphologic characteristics indistinguishable from those of other papilloma viruses. The inclusions were stained positively by immunohistochemical methods using anti-bovine papilloma virus serum.     

Cutaneous papilloma and multicentric squamous cell carcinoma in four-toed hedgehogs (Atelerix albiventris)

Skin lesions possibly caused by Papillomavirus infections in two four-toed hedgehogs are described. In case 1, there was a papillary mass on the right hind limb. Histologically, the mass was consistent with a viral papilloma. In the other case, multifocal papillary masses with erosions and ulcers were found throughout the body, mainly on the extremities. Histology showed continuative lesions composed of acanthosis, Bowenoid in situ carcinoma, and squamous cell carcinoma, with abrupt transitions between the lesions. In both cases, keratinocytes in the granular layer infrequently had features of koilocytes and intranuclear inclusion bodies, and immunohistochemical staining was positive for anti-human papillomavirus antibody. To the best of the authors’ knowledge, this is the first pathological documentation of possibly papillomavirus-associated skin lesions in four-toed hedgehogs.     

Epizootic outbreaks of gizzard erosion associated with adenovirus infection in chickens

Two outbreaks of gizzard erosion in slaughtered broiler chickens in Japan were examined pathologically and microbiologically. The prevalences of such lesions were 9%-11% and 4%-50% in the affected flocks. Affected chickens had no clinical signs. Group I fowl adenovirus (FAV) serotype 1 was isolated from gizzard lesions. Histologically, gizzard mucosa were necrotic. Intranuclear inclusion bodies were seen in the enlarged nuclei of degenerating epithelial cells of the gizzard. The keratinoid layer in the erosion was edematous and desquamated and contained degenerative cells. Moderate to marked inflammatory cell infiltration was observed in the lamina propria and perivascular connective tissue in the submucosa and muscle layer. Immunohistochemical staining showed evidence of FAV antigens in the intranuclear inclusion bodies within degenerating epithelial cells. Ultrastructurally, numerous viral particles were demonstrated in the inclusions.     

Adenoviral gizzard erosion in commercial broiler chickens

Pathologic and immunohistochemical changes caused by group I of the fowl adenovirus (FAV) serotype-1 99ZH strain, isolated from broiler chickens exhibiting gizzard erosion, were investigated in commercial broiler chickens. One hundred twenty-two chickens were inoculated with the strain by both oral and ocular routes at 1, 3, or 5 weeks of age and euthanatized for necropsy within 4-18 days of inoculation. Focal gizzard erosions were observed in the inoculated chickens of each age group. A histologically degenerative koilin layer, necrotic mucosa, intranuclear inclusion bodies in the glandular epithelial cells, inflammatory cell infiltrations in the lamina propria, submucosa, and a muscle layer were seen in the gizzards. Immunohistochemical staining showed evidence of FAV antigens in the intranuclear inclusion bodies. These findings were recognized regardless of their maternal antibody levels for FAV serotype-1. Gizzard lesions appeared later in the lower-dose-inoculated chickens than in the higher-dose-inoculated chickens. Numerous CD3-positive cells and IgY-positive plasma cells were seen in the gizzard lesions. In 5-week-old chickens the heterophil infiltrations in the lesions were milder than in younger chickens. Intranuclear inclusion bodies also were observed in the epithelial cells of the ileum or cecal tonsils of some chickens. Thus, this study shows that FAV-99ZH causes adenoviral gizzard erosion in broiler chickens without hepatic or pancreatic lesions and that cell infiltration is more severe than in dietary gizzard erosions.     

Filamentous Intranuclear Inclusion Bodies in Psittacine Birds. A Structural and Ultrastructural Study

This paper concerns a disease affecting a group of African grey parrots, which involves intranuclear inclusion bodies composed of filamentous material. The disease was characterized by either sudden death or death within 2–3 days from onset of non-specific symptoms. At necropsy, gross lesions included enlarged liver, mild hepatic congestion and focal necrosis. Samples from five birds were fixed in 10% formol and routinely processed for light and electron microscopy. In four birds, numerous hepatocytes displayed an enlarged nucleus, with peripheral margination of chromatin; the nucleus was partially or wholly filled by a basophilic inclusion body. In the remaining bird, inclusion bodies were acidophilic and completely filled the nucleus; nuclear enlargement was less evident than in the other birds. At ultrastructural examination, and in both types of IIB, nuclei contained looped filaments but no evidence of viral structures. However, virion-like structures were observed in the cytoplasm of some hepatocytes.     

Congenital cutaneous fibropapillomatosis without evidences of papillomavirus infection in a Holstein-Friesian calf

A male Holstein-Friesian calf was born with multiple, cauliflower-like, pale pink cutaneous masses on the head and limbs. On histopathological examination, the cutaneous masses were diagnosed as congenital cutaneous fibropapillomatosis. Those lesions involved focal proliferation of sebaceous gland in the dermis. There were no histological findings to suggest bovine papillomavirus infection, such as the presence of intranuclear inclusion bodies, large keratohyalin granules, and koilocytosis. Furthermore, papillomaviral antigens and DNA were not detected by immunohistochemistry and polymerase chain reaction, respectively. These results suggested that there was no association between these cutaneous lesions and bovine papillomavirus infection, and the lesions were considered as harmartomatous changes.     

Filamentous intranuclear inclusion bodies in psittacine birds. A structural and ultrastructural study.

This paper concerns a disease affecting a group of African grey parrots, which involves intranuclear inclusion bodies composed of filamentous material. The disease was characterized by either sudden death or death within 2-3 days from onset of non-specific symptoms. At necropsy, gross lesions included enlarged liver, mild hepatic congestion and focal necrosis. Samples from five birds were fixed in 10% formol and routinely processed for light and electron microscopy. In four birds, numerous hepatocytes displayed an enlarged nucleus, with peripheral margination of chromatin; the nucleus was partially or wholly filled by a basophilic inclusion body. In the remaining bird, inclusion bodies were acidophilic and completely filled the nucleus; nuclear enlargement was less evident than in the other birds. At ultrastructural examination, and in both types of IIB, nuclei contained looped filaments but no evidence of viral structures. However, virion-like structures were observed in the cytoplasm of some hepatocytes.     

Marble Spleen Disease of Pheasants in Ontario

Two outbreaks of marble spleen disease were observed in pen-raised pheasants in Ontario on the same farm in the summer of 1971 and in 1972. In both instances, a mortality of 3% per day lasted for approximately 14 days. Fifteen birds were necropsied and tissues removed and examined histologically and by electron microscopy. In addition splenic material was injected into adult pheasants. The gross lesions, characterized by enlarged greyish-white mottled spleens and acute congestion and oedema in the lungs, were identical to those described by previous authors. Histological examination of livers, lungs, spleens and proventriculi revealed some reticular-type cells which contained either an eosinophilic or a basophilic intranuclear inclusion. Electron microscopy of the affected spleens revealed cells with massive intranuclear accumulations of virus particles. Although transmission trials failed, the evident histological and electron microscopy lesions confirm the suggestion by other authors that this is a viral disease affecting the reticulo-endothelial system.     

Adenovirus group II-like infection in chukar partridges (Alectoris chukar)

Seven live 5-to-6-wk-old chukar partridges (Alectoris chukar) were examined because of increased lacrimation, swollen eyelids, and increased mortality. Gross lesions consisted of mildly enlarged and mottled white spleens, swollen eyelids with external scab formation, and watery intestinal contents. Microscopically, there were increased numbers of mononuclear phagocytic system cells in the spleen, some of which contained faintly staining basophilic intranuclear inclusion bodies, blepharoconjunctivitis, enteritis associated with coccidia and crop mycosis. Transmission electron microscopy of the spleen revealed icosahedral virus particles 65 to 75 nm in diameter, consistent with the morphology of adenovirus. Three out of seven chukars were positive for hemorrhagic enteritis virus by serology.     

Investigation of parrot papillomavirus in cloacal and oral papillomas of psittacine birds

Cloacal and oral papillomas from 27 psittacine birds of various species were examined for the presence of parrot papillomavirus by DNA in situ hybridization, DNA in situ polymerase chain reaction, and nested polymerase chain reaction. Parrot papillomavirus was detected in one oral papilloma from an African grey parrot by all three techniques. In addition, rare basophilic intranuclear inclusions were observed by light microscopy in tissue sections of the oral papilloma from this parrot. The remaining lesions were negative for parrot papillomavirus DNA. This study suggests that parrot papillomavirus may be involved in the development of papillomas in African grey parrots, but apparently is not responsible for development of similar lesions in unrelated species of psittacine birds.     

Fatal herpesvirus infection in commercial rabbits

Acute mortality occurred in two unrelated rabbitries. In the rabbits examined, an unidentified herpesvirus caused lesions that have not been reported previously in this species. The primary lesions were multifocal hemorrhagic dermatitis on the face and back, localized pneumonia, and severe splenic necrosis. Large eosinophilic, intranuclear inclusion bodies that were observed in tissue sections of skin, spleen, and lung were identified as herpes-like viral particles by electron microscopy, and herpesvirus was cultured on rabbit kidney cells. Intramuscular injection of tissue culture fluid containing virus resulted in mortality and severe illness in two seven-week-old domestic rabbits four and six days postinfection, respectively. The gross and microscopic lesions were reproduced and herpeslike viral inclusions were observed in skin lesions. Herpesvirus was recovered from lung, trachea, spleen, liver, and from the thigh muscle at the site of inoculation. The experimental infection also activated severe pasteurella septicemia. The herpesvirus isolate needs further characterization.     

Adenovirus enteritis in pigs

Experimental transmissions were done with adenovirus strain 6618 in hysterectomy-produced colostrum-deprived pigs. After an incubation period of 3 to 4 days, all inoculated animals had diarrhea. Histopathologically, many intranuclear inclusion bodies were present on short villi of the terminal parts of jejunum and ileum. With electron microscopy, the inclusion bodies were observed to contain numerous adenovirus particles. Immunoperoxidase-positive cells were seen on short villi of the terminal parts of jejunum and ileum. Adenovirus particles also were detected by negative staining of intestinal contents. In 1 pig (naturally occurring infection), adenovirus enteritis was studied by the aforementioned techniques. Similar intestinal lesions as described in the experimental pigs were observed.     

Epithelial intracytoplasmic herpes viral inclusions associated with an outbreak of duck virus enteritis.

Several muscovy ducks from a free-roaming flock of 65 muscovy and mallard ducks died over a 3-week period. Three muscovy ducks were necropsied. Gross and microscopic changes were compatible with duck virus enteritis, and the virus was isolated. In addition to intranuclear viral inclusion bodies in several tissues, intracytoplasmic inclusion bodies were present in esophageal and cloacal epithelium. By electron microscopy, the membrane-bound intracytoplasmic inclusions were found to contain enveloped herpesvirus, and nuclei contained herpes viral nucleocapsids.     

Parvovirus-like enteropathy in Missouri turkeys

A viral enteric disease of young turkeys characterized by stunting of affected birds, diarrhea, and increased mortality is described. Eosinophilic intranuclear inclusion bodies were found in the absorptive epithelial cells of the ileum. Electron microscopy of formalin-fixed tissue revealed that the intestinal inclusions contained numerous loosely packed 15-to 20-nm hexagonal particles. The size, shape, and intranuclear location have been used to tentatively identify these particles as parvoviruses.     

Evidence for papillomaviruses in ocular lesions in cattle

Negatively stained preparations of various ocular lesions, generally considered to be precursors to bovine ocular squamous cell carcinoma, were subjected to electron microscopic examination for viruses. Lesions examined included five conjunctival plaques, an acanthotic lesion from an eyelid, 15 conjunctival papillomas, two papillomas of the eyelid and two keratinised elongated proliferative lesions of the eyelid (cutaneous horns). Eight lesions contained particles that resembled papillomaviruses. These consisted of a conjunctival plaque, five conjunctival papillomas, a papilloma of the eyelid and one of the samples of cutaneous horn. The particles were present in small numbers and were found only after prolonged search. The finding of these particles suggests that papillomavirus may be involved in the aetiology of bovine ocular squamous cell carcinoma.     

Pathologic study of specific-pathogen-free chicks and hens inoculated with adenovirus isolated from hydropericardium syndrome.

The mortality and pathology caused by serotype 4 adenovirus, isolated from chickens with hydropericardium syndrome (HPS) in Japan, was investigated in specific-pathogen-free (SPF) chickens. One-day-old to 15-mo-old SPF chickens were inoculated intramuscularly, orally, and intranasally with liver homogenates from HPS chickens or isolated serotype 4 adenovirus. There were no clinical signs before death. The mortality rate in all groups of 1-day-old chicks was 100%, irrespective of the inoculum or inoculation route. Four-week-old chickens inoculated with liver homogenate also had a 100% mortality rate. Five-week-old chickens inoculated with cell culture of HPS adenovirus had a 40% mortality rate. The mortality rates of 7-mo-old hens inoculated with liver homogenates intramuscularly and orally were 75% and 25%, respectively. In 15-mo-old hens inoculated with liver homogenates intramuscularly, the mortality rate was 70%. Gross lesions were hydropericardium and swelling and congestion of the liver with occasional petechial hemorrhages. Histologically, the liver had diffuse or multifocal hepatic necrosis and hemorrhage with intranuclear inclusion bodies noted within hepatocytes. In the spleen, macrophages containing erythrocytes and yellow pigment were prominent in the red pulp. In the lung, a moderate diffuse macrophage infiltration was noted throughout the lung parenchyma, and these macrophages contained yellow pigment. In the pancreas of the chicks inoculated at 1 day old, there was multifocal necrosis of glands with intranuclear inclusion bodies. Intranuclear inclusion bodies were seen also in the gizzard, proventriculus, duodenum, cecum, kidney, and lung of the chicks inoculated at 1 day old. Immunohistochemically, the intranuclear inclusion bodies of various organs showed positive reactions against group I avian adenovirus. Adenovirus was recovered from the liver of chickens with HPS. This study indicates that HPS adenovirus is able to reproduce HPS lesions and mortality in SPF chicks and even adult chickens and that it is a highly pathogenic strain.     

Respiratory herpesvirus infection in two Indian Ringneck parakeets.

A flock of Indian Ringneck parakeets (Psittacula krameri manillensis) was imported to the United States from Australia. Soon after, 1 parakeet suddenly died, and a second parakeet died after a 2-day course of illness, which consisted of anorexia, lethargy, emaciation, and dyspnea. At necropsy, the affected birds had diffuse consolidation and red discoloration of the lungs, as well as thickened, congested air sacs. The microscopic examination revealed multifocal, necrotizing bronchitis, parabronchitis, and interstitial pneumonia. The lumen of the affected airways contained numerous, large syncytial cells with up to 15 nuclei. The nuclei of these syncytial cells often contained large, eosinophilic inclusion bodies, consistent with herpesvirus. The epithelium of the trachea and air sacs was hypertrophied and contained syncytial cells with intranuclear inclusion bodies similar to the bronchi. In addition, a few intranuclear inclusion bodies were also present in the epithelial cells that line the air capillaries. On ultrastructural examination, the nuclei of degenerating epithelial cells contained clusters of viral nucleocapsid proteins and unenveloped, icosahedral, viral particles that were approximately 90 nm in diameter. In addition, some epithelial cells contained clusters of enveloped viral particles approximately 105 nm in diameter, within the cytocavitary network. These lesions are characteristic of those caused by respiratory herpesvirus of parakeets.     

A necrotizing pneumonia in lambs caused by pseudorabies virus (Aujesky''s disease virus).

An outbreak of pseudorabies occurred in sheep housed with swine in the same building. Although the sheep and swine were not in physical contact, the lambs and ewes were exposed to air from the sows' section. Three dead lambs were submitted to the Iowa State University Veterinary Diagnostic Laboratory for necropsy. Grossly there were pulmonary congestion and multifocal pulmonary hemorrhages. Microscopic lesions were severe acute multifocal necrotizing bronchopneumonia with necrotizing vasculitis and intranuclear inclusion bodies within the neurons of the parabronchial ganglia. Bacterial cultures were negative for pathogenic agents; pseudorabies virus was isolated from ovine brain tissue. Viral antigen was demonstrated in the neurons of the parabronchial ganglia by immunoperoxidase staining. Electron microscopy revealed nucleocapsids in the parabronchial ganglionic neurons which contained basophilic intranuclear inclusion bodies. Viral DNA prepared from the ovine pseudorabies virus isolate was found by restriction endonuclease analysis to be related to the Indiana Funkhauser strain of pseudorabies virus.     

Conjunctival swab cytology from a guinea pig: it's elementary!

Three 3-month-old guinea pigs (Cavia porcellus) were evaluated for purulent ocular discharge. Conjunctival swabs were obtained for cytologic evaluation of Wright's-Giemsa-stained preparations. The specimen from the most severely affected guinea pig consisted primarily of karyolytic neutrophils and small lymphocytes. Epithelial cells occasionally were observed that contained intracytoplasmic coccoid basophilic organisms, 0.5-1.5 microm in diameter. The intraepithelial inclusions were most consistent with Chlamydia sp elementary and reticulate bodies. Specimens from the other 2 guinea pigs had a similar inflammatory response, but organisms were not observed. Polymerase chain reaction (PCR) analysis of a conjunctival swab from the most severely affected guinea pig was positive for C psittaci, which also is referred to as Chlamydophila caviae, immunotype 8, formerly known as the guinea pig inclusion conjunctivitis strain of C psittaci. Chlamydial conjunctivitis is a common problem in guinea pig populations, with C caviae being specific for this species. Cytologic identification of elementary or reticulate bodies within epithelial cells is diagnostic for the organism in Giemsa-stained preparations. However, PCR is an important complementary tool when organisms are not observed and for accurate classification of the Chlamydia species.     

Isolation of circovirus from lesions of pigs with postweaning multisystemic wasting syndrome.

Postweaning multisystemic wasting syndrome (PMWS), an apparently new disease, has been recognized in swine herds in western Canada. Young pigs with this disease have progressive weight loss, tachypnea, dyspnea, and jaundice, accompanied by interstitial pneumonia, lymphadenopathy, hepatitis, and nephritis. We examined more than 400 pigs from more than 70 herds in Alberta, Saskatchewan, and Manitoba with cases of PMWS. A small virus was isolated from a range of tissues from 8 of 8 affected pigs examined. The agent was identified as a circovirus-like virus using electron microscopy, immunohistochemical staining with porcine and rabbit immune serum, and in situ hybridization. Immunohistochemical examination of tissues from more than 100 affected pigs has revealed widespread viral antigen, often contained in circovirus-like inclusion bodies, in lesions from numerous organs. Although Koch's postulates remain to be fulfilled, these results demonstrate a high degree of association between the presence of the circovirus-like virus and PMWS in affected swine.