Novel adenovirus associated with necrotizing bronchiolitis in a captive reindeer (Rangifer tarandus).

Adenoviruses cause a range of major diseases across many diverse animal species including ruminants. They are classified into six genera in the family Adenoviridae. In deer species, two adenoviruses are currently recognized: deer adenovirus 1 in the Atadenovirus genus, and deer adenovirus 2 in the Mastadenovirus genus. Deer adenovirus 1 causes adenovirus haemorrhagic disease with high fatality in black-tailed and mule deer in North America. Conversely, deer adenovirus 2 was incidentally detected from a healthy white-tailed deer fawn, but experimentally it has been shown to cause pyrexia, cough and moderate to severe haemorrhage. Here, we detected a novel adenovirus, reindeer adenovirus 1, from lung lesions of a 5-year-old male reindeer (Rangifer tarandus). This animal presented with aspiration pneumonia and necrotizing bronchiolitis following a period of clinical weakness, nasal discharge and wasting. Histopathological examination of the lung revealed large intranuclear basophilic inclusions associated with the areas of necrotizing bronchiolitis. Next generation sequencing of the lung tissue identified a novel mastadenovirus with close similarity to deer adenovirus 2 and bovine adenovirus 3. To our knowledge, this is the first report of a deer mastadenovirus associated with necrotizing bronchiolitis in captive reindeer.

Perspectives in veterinary medicine: Description and classification of bronchiolar disorders in cats.

This Perspectives in Veterinary Medicine article seeks to define, describe putative causes, and discuss key diagnostic tests for primary and secondary bronchiolar disorders to propose a classification scheme in cats with support from a literature review and case examples. The small airways (bronchioles with inner diameters <2 mm), located at the transitional zone between larger conducting airways and the pulmonary acinus, have been overlooked as major contributors to clinical syndromes of respiratory disease in cats. Because the trigger for many bronchiolar disorders is environmental and humans live in a shared environment with similar susceptibility, understanding these diseases in pet cats has relevance to One Health. Thoracic radiography, the major imaging modality used in the diagnostic evaluation of respiratory disease in cats, has low utility in detection of bronchiolar disease. Computed tomography (CT) with paired inspiratory and expiratory scans can detect pathology centered on small airways. In humans, treatment of bronchiolar disorders is not well established because of heterogeneous presentations and often late definitive diagnosis. A review of the human and veterinary medical literature will serve as the basis for a proposed classification scheme in cats. A case series of cats with CT or histopathologic evidence of bronchiolar lesions or both, either as a primary disorder or secondary to extension from large airway disease or interstitial lung disease, will be presented. Future multi-institutional and multidisciplinary discussions among clinicians, radiologists, and pathologists will help refine and develop this classification scheme to promote early and specific recognition and optimize treatment.

Evaluation of a new chest physiotherapy technique in dogs with airway fluid accumulation hospitalized in an intensive care unit.

OBJECTIVE: To evaluate the feasibility, benefits, and adverse effects of prolonged slow expiration (PSE) and assisted cough (AC) as chest physiotherapy (CP) techniques in dogs with airway fluid accumulation. DESIGN: Prospective interventional study. SETTINGS: University teaching hospital. ANIMALS: Intervention group of 30 client-owned dogs and retrospective control group of 71 client-owned dogs. INTERVENTIONS: PSE was performed on dogs with evidence of airway fluid accumulation, identified based on physical examination and thoracic radiographs. AC was performed if spontaneous cough or swallowing were not evident. The PSE treatment was performed every 6 hours until normalization of respiratory status or hospital discharge. Animals were monitored for respiratory distress, discomfort, and SpO2 during the procedure. A retrospective control group was identified by computer search. MEASUREMENTS AND MAIN RESULTS: One hundred thirty-three sessions of CP were performed on 30 dogs. Discomfort frequency during physiotherapy was low (9%). The most commonly used position for CP was in lateral recumbency (95%) and this was well tolerated in most cases. There was no significant difference in the median SpO2 before and after CP sessions (P = 0.24). Sixty percent of sessions had a spontaneous cough or swallowing evident, 21% had successful AC performed, and no cough or swallowing occurred in the remaining (19%) sessions despite attempts of AC being made. The length of hospitalization was significantly longer in the intervention group (6 days vs 4) (P = 0.02). There was no difference in survival between the intervention (76.7%) and the control (57.7%) group (P = 0.055). CONCLUSIONS: PSE associated with AC are easily adaptable, well-tolerated techniques in dogs. The benefit of CP in dogs with airway fluid accumulation remains to be determined and it is hoped that future randomized controlled prospective studies may help answer this line of inquiry.

Respiratory syncytial virus genomic load and disease severity among children hospitalized with bronchiolitis: multicenter cohort studies in the United States and Finland.

BACKGROUND: We investigated whether children with a higher respiratory syncytial virus (RSV) genomic load are at a higher risk of more-severe bronchiolitis. METHODS: Two multicenter prospective cohort studies in the United States and Finland used the same protocol to enroll children aged <2 years hospitalized for bronchiolitis and collect nasopharyngeal aspirates. By using real-time polymerase chain reaction analysis, patients were classified into 3 genomic load status groups: low, intermediate, and high. Outcome measures were a length of hospital stay (LOS) of ≥3 days and intensive care use, defined as admission to the intensive care unit or use of mechanical ventilation. RESULTS: Of 2615 enrolled children, 1764 (67%) had RSV bronchiolitis. Children with a low genomic load had a higher unadjusted risk of having a length of stay of ≥3 days (52%), compared with children with intermediate and those with high genomic loads (42% and 51%, respectively). In a multivariable model, the risk of having a length of stay of ≥3 days remained significantly higher in the groups with intermediate (odds ratio [OR], 1.43; 95% confidence interval [CI], 1.20-1.69) and high (OR, 1.58; 95% CI, 1.29-1.94) genomic loads. Similarly, children with a high genomic load had a higher risk of intensive care use (20%, compared with 15% and 16% in the groups with low and intermediate genomic loads, respectively). In a multivariable model, the risk remained significantly higher in the group with a high genomic load (OR, 1.43; 95% CI, 1.03-1.99). CONCLUSION: Children with a higher RSV genomic load had a higher risk for more-severe bronchiolitis.

Histopathological and immunohistochemical findings of swine with spontaneous influenza A infection in Brazil, 2009-2010 / Achados histopatológicos e imuno-histoquímicos de suínos com infecção espontânea de influenza A no Brasil, 2009-2010

Swine influenza (SI) is caused by the type A swine influenza virus (SIV). It is a highly contagious disease with a rapid course and recovery. The major clinical signs and symptoms are cough, fever, anorexia and poor performance. The disease has been associated with other co-infections in many countries, but not in Brazil, where, however, the first outbreak has been reported in 2011. The main aim of this study was to characterize the histological features in association with the immunohistochemical (IHC) results for influenza A (IA), porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) in lung samples from 60 pigs submitted to Setor de Patologia Veterinária at the Universidade Federal do Rio Grande do Sul (SPV-UFRGS), Brazil, during 2009-2010. All of these lung samples had changes characterized by interstitial pneumonia with necrotizing bronchiolitis, never observed previously in the evaluation of swine lungs in our laboratory routine. Pigs in this study had showed clinical signs of a respiratory infection. Swine samples originated from Rio Grande do Sul 31 (52%), Santa Catarina 14 (23%), Paraná 11 (18%), and Mato Grosso do Sul 4 (7%). Positive anti-IA IHC labelling was observed in 45% of the cases, which were associated with necrotizing bronchiolitis, atelectasis, purulent bronchopneumonia and hyperemia. Moreover, type II pneumocyte hyperplasia, alveolar and bronchiolar polyp-like structures, bronchus-associated lymphoid tissue (BALT) hyperplasia and pleuritis were the significant features in negative anti-IA IHC, which were also associated with chronic lesions. There were only two cases with positive anti-PCV2 IHC and none to PRRSV. Therefore, SIV was the predominant infectious agent in the lung samples studied. The viral antigen is often absent due to the rapid progress of SI, which may explain the negative IHC results for IA (55%); therefore, IHC should be performed at the beginning of the disease. This study has shown how important a careful histological evaluation is for the diagnosis. Since 2009, a new histological feature of swine pneumonia in animals with respiratory clinical signs has been observed in samples from pigs with clinical respiratory disease submitted to SPV-UFRGS. In addition, the results proved the importance of histological evaluation for swine herd health management.

Influenza suína (IS) é uma doença altamente contagiosa, de curso rápido e pronta recuperação, causada pelo vírus influenza tipo A (SIV). Os principais sinais clínicos são tosse, febre, anorexia e baixo desenvolvimento. A doença está presente em outros países e, geralmente, está associada com outros agentes infecciosos. No Brasil, a primeira descrição ocorreu em 2011 e foi associada ao vírus H1N1 pandêmico (pH1N1). O principal objetivo deste estudo foi caracterizar as alterações histológicas em casos de doença respiratória suína sugestiva de IS e estudar a associação dessas alterações com os resultados de imuno-histoquímica (IHQ) anti-vírus da influenza A (SIV), anti-circovírus suíno tipo 2 (PCV2) e anti-vírus da síndrome reprodutiva e respiratória (PRRSV). Para tanto, foram estudadas amostras de pulmões de 60 suínos selecionadas dos materiais do arquivo do Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul (SPV-UFRGS), de casos de doença respiratória remetidos no período de 2009 a 2010 e que apresentavam alterações histopatológicas compatíveis com pneumonia viral causada pelo SIV. Todas as amostras apresentavam pneumonia intersticial e bronquiolite necrótica muito peculiar que não eram vistas antes na rotina do nosso laboratório. Trinta e uma amostras (52%) tiveram origem no estado do Rio Grande do Sul, 14 (23%) do Paraná, 11 (18%) de Santa Catarina e quatro (7%) do Mato Grosso do Sul. A IHQ para IA confirmou a presença do agente viral em 45% das amostras analisadas. Os achados histológicos mais significativos associados à IHQ positiva para IA foram bronquiolite necrótica, atelectasia, broncopneumonia purulenta e hiperemia. Por outro lado, as alterações histológicas dos pulmões estudados, mais significativamente associadas às IHQ negativa para IA foram hiperplasia dos pneumócitos tipo II, estruturas similares a pólipos em alvéolo e bronquíolo, hiperplasia de tecido linfoide associado a brônquios (BALT) e pleurite, que são alterações associadas a processos crônicos. Somente dois casos apresentaram marcação positiva na IHQ para PCV2 e nenhum pulmão foi positivo para PRRSV. Esses resultados sugerem que as lesões histológicas encontradas no presente estudo foram, predominantemente, causadas pelo SIV. Os casos negativos de IHQ para IA (55%) podem ser explicados pela ausência do antígeno viral nos tecidos estudados. Como o curso da doença é muito rápido, o teste de IHQ é mais indicado para diagnóstico no início da doença. Este estudo possibilitou demonstrar um conjunto de novas alterações histológicas pulmonares de suínos com problemas respiratórios, observadas em amostras pulmonares enviadas ao SPV-UFRGS a partir de 2009. O presente trabalho também reforça a importância de estudos histopatológicos dos casos de campo para auxiliar na monitoria da sanidade dos rebanhos suínos.

Bovine respiratory syncytial virus ISCOMs-Immunity, protection and safety in young conventional calves.

Bovine respiratory syncytial virus (BRSV) is a major cause of bronchiolitis and pneumonia in cattle and causes yearly outbreaks with high morbidity in Europe. Commercial vaccines against this virus needs improvement of efficacy, especially in calves with BRSV-specific maternally derived antibodies (MDA). We previously reported that an experimental BRSV-ISCOM vaccine, but not a commercial vaccine, induced strong clinical and virological protection in calves with MDA, immunized at 7-15 weeks of age. The aim of the present study was to characterize the immune responses, as well as to investigate the efficacy and safety in younger animals, representing the target population for vaccination. Four groups of five 3-8 week old calves with variable levels of BRSV-specific MDA were immunized s.c. twice at a 3 weeks interval with (i) BRSV immunostimulating complexes (BRSV-ISCOMs), (ii) BRSV-protein, (iii) adjuvant, or (iv) PBS. All calves were challenged with virulent BRSV by aerosol 2 weeks later and euthanized on day 6 after infection. The cellular and humoral responses were monitored as well as the clinical signs, the viral excretion and the pathology following challenge. Despite presence of MDA at the time of the immunization, only a minimum of clinical signs were observed in the BRSV-ISCOM group after challenge. In contrast, in all control groups, clinical signs of disease were observed in most of the animals (respiratory rates up to 76min(-1) and rectal temperatures up to 41°C). The clinical protection was associated to a highly significant reduction of virus replication in the upper and lower respiratory tract of calves, rapid systemic and local antibody responses and T helper cell responses dominated by IFNγ production. Animals that did not shed virus detectable by PCR or cell culture following challenge possessed particularly high levels of pulmonary IgA. The protective immunological responses to BRSV proteins and the ability to overcome the inhibiting effect of MDA were dependent on ISCOM borne antigen presentation.

Canine H3N8 influenza virus infection in dogs and mice.

An H3N8 influenza virus closely related to equine influenza virus was identified in racing greyhound dogs with respiratory disease in 2004 and subsequently identified in shelter and pet dogs. Pathologic findings in dogs spontaneously infected with canine influenza virus were compared with lesions induced in beagle and mongrel dogs following experimental inoculation with influenza A/canine/Florida/43/2004. BALB/c mice were inoculated with canine influenza virus to assess their suitability as an experimental model for viral pathogenesis studies. All dogs inoculated with virus developed necrotizing and hyperplastic tracheitis and bronchitis with involvement of submucosal glands as well as mild bronchiolitis and pneumonia. Viral antigen was identified in bronchial and tracheal epithelial cells of all dogs and in alveolar macrophages of several dogs. Many dogs that were spontaneously infected with virus also developed bacterial pneumonia, and greyhound dogs with fatal spontaneous infection developed severe pulmonary hemorrhage with hemothorax. Virus-inoculated BALB/c mice developed tracheitis, bronchitis, bronchiolitis, and mild pneumonia in association with viral antigen in airway epithelial cells and in type 2 alveolar epithelial cells. Virus was not detected in extrarespiratory sites in any animals. The results indicate that canine influenza virus infection consistently induces acute tracheitis and bronchitis in dogs. Mice may be a useful model for some pathogenesis studies on canine influenza virus infection.

Alveolar fibrosis and changes in equine lung morphometry in response to intrapulmonary blood.

Necropsy studies of horses suffering exercise-induced pulmonary haemorrhage (EIPH) have identified mild inflammatory lesions with evidence of alveolar fibrosis and bronchiolitis. These lesions were thought to be the result of viral infections that predisposed the affected regions of the lung to EIPH. We have shown previously that during erythrophagocytosis in the alveolar space, there is a prolonged period of macrophage influx and activation. This present study used morphometric analysis to quantify the effects of macrophage activity during erythrophagocytosis, on the alveolar cell population and physical structure of the alveolar walls. Segments of the bronchial tree were inoculated with either autologous whole blood or serum, at 15, 8, 3 days, 24 h and 30 min prior to euthanasia. Blood inoculation produced many significant changes in the alveolar morphometry including, increased numbers of alveolar macrophages, increased septal thickness, and a markedly increased percentage of collagen in the alveolar walls. Signs of chronic inflammation including increased macrophage activity and erythrophagocytosis coincided with increased alveolar macrophage numbers (10,688 +/- 1708 cells/mm3 to 30,957 +/- 6831 cells/mm3), septal thickness (4.1 +/- 0.4 microm to 6.1 +/- 0.5 microm) and alveolar septal collagen content (6.6 +/- 0.5% to 27.5 +/- 3.3%). The results suggest that intrapulmonary blood induces a macrophage dominated inflammatory response, septal thickening and the development of alveolar fibrosis. These changes are the probable cause of the observed alveolar fibrosis and bronchiolitis that was once suspected to be the originating cause of EIPH.

Bronchitis and bronchiolitis in a cat with cilia-associated respiratory bacillus-like organisms.

A 10-year-old male domestic shorthair cat died during anesthesia. Grossly, the lungs had multiple nodules corresponding to inflamed airways (bronchitis and bronchiolitis). Microscopically, cuffs and nodular aggregates of lymphocytes and plasma cells surrounded airways. Peribronchiolar fibrosis was also common. Globule leukocytes infiltrated the respiratory epithelium of noninflamed or mildly inflamed bronchi. Argyrophilic and filamentous organisms, consistent with cilia-associated respiratory bacillus-like organisms (CLO), were intermixed with cilia of respiratory epithelium. Ultrastructurally, CLO were longer and thinner than cilia and had a distinct trilaminar membrane, central electron-lucent areas, and no specialized external structures. Silver stained lung sections from 18 additional feline airways revealed similar bacilli in 2/9 normal lungs, 1/7 lungs with bronchitis and bronchiolitis, and 1/2 lungs with pneumonia. The significance of CLO in the pulmonary lesions was not determined.

A new model rat with acute bronchiolitis and its application to research on the toxicology of inhaled particulate matter.

The aim of the present study was to establish a useful animal model that simulates humans sensitive to inhaled particulate matter (PM). We have developed a new rat model of acute bronchiolitis (Br) by exposing animals to NiCl2 (Ni) aerosols for five days. Three days following the Ni exposure, the animals developed signs of tachypnea, mucous hypersecretion, and bronchiolar inflammation which seemed to progress quickly during the fourth to fifth day. They recovered from lesions after four weeks in clean air. To assess the sensitivity of the Br rats to inhaled particles, two kinds of PM of respirable size were tested with doses similar to or a little higher to the recommended threshold limit values (TLVs) for the working environment in Japan. Titanium dioxide (TiO2 = Ti) was chosen as an inert and insoluble particles and vanadium pentoxide (V2O5 = V), as a representative soluble and toxic airborne material. The Br rats exposed to either Ti or V were compared the pathological changes in the lungs and the clearance of particles to those in normal control or Br rats kept in clean air. The following significant differences were observed in Br rats: 1. delayed recovery from pre-existing lesions or exacerbated inflammation, 2. reductions in deposition and clearance rate of inhaled particles with the progress of lesions. The present results suggest that Br rats are more susceptible to inhaled particles than control rats. Therefore, concentrations of particulate matter lower than the TLVs for Japan, which have no harmful effects on normal lungs, may not always be safe in the case of pre-existing lung inflammation.

Gas exchange during exercise in standardbred trotters with mild bronchiolitis.

To investigate the gas exchange response during exercise in horses with mild bronchiolitis (MB), we studied 7 Standardbred trotters. In order to determine pulmonary gas exchange and red cell volume in relation to bodyweight (CV/BW), submaximal graded exercise tests were performed. VO2 was monitored from an open bias flow system without valves. Heart rate, respiratory rate and mean pulmonary and systemic artery pressures were measured. Cardiac output and alveolar ventilation were calculated. Arterial and mixed venous blood were drawn for blood gas analysis and pH measurements. Pulmonary gas exchange was assessed by conventional blood gas variables, and the ventilation-perfusion distribution was estimated using the multiple inert gas elimination technique. The dispersion of perfusion and ventilation distribution and the difference between measured arterial oxygen tension and that predicted on the basis of the amount of ventilation-perfusion mismatching and shunt were determined in order to reflect diffusion limitation. The results were compared, using analysis of variance, with data from an earlier study on healthy Standardbred trotters (LH) during a similar exercise test. No differences in pulmonary gas exchange were obtained between LH and MB. However, CV/BW, pulmonary artery mean pressure (PAP) and systemic arterial mean pressure (SAP) were significantly higher in MB than in LH. Lactate concentration, arteriovenous oxygen content differences C(av)O2[ and pH were significantly lower in MB horses than in LH. We conclude that Standardbred trotters with mild subclinical bronchiolitis can achieve an adequate gas exchange compared to healthy Standardbred trotters, during a graded exercise test; however, the significantly increased CV/BW in MB horses may be a compensatory mechanism for hypoxaemia during maximal work.

Ultrasound spirometry in the horse: a preliminary report on the method and the effects of xylazine and lobeline hydrochloride medication.

A new computerised ultrasound-based spirometry system according to Buess et al. (1995) modified by a double flow measurement facility was used to study pulmonary function in healthy horses and horses affected with subclinical and manifest chronic bronchiolitis (CB). The horses were first evaluated at rest without any medication. On another occasion all horses were tested following i.v. administration of xylazine (0.4 mg/kg) and following i.v. administration of lobeline hydrochloride (l.hy.; 0.2 mg/kg) to evaluate the effect of xylazine and l.hy. on different spirometric variables. Ultrasound-based spirometry proved to be an easily applicable method for lung function testing, even in difficult horses. However, there existed a pronounced physiological variation for all measured lung function parameters and no significant differences between healthy horses and horses with chronic bronchiolitis could be found except for the expiratory tidal volume (VTE p < 0.05). Individually, a marked decrease of variability from breath to breath following either xylazine and l.hy. administration could be observed for all parameters, except the flow-time-ratio (Tpef./ Texp.) and the flow-volume-ratio (Vpef./Vexp).

Verminous bronchitis and bronchiolitis in potoroid marsupials associated with a new Capillaria sp.

We describe verminous bronchitis and bronchiolitis in potoroid marsupials associated with a new species of Capillaria resident in the epithelial lining of bronchi and bronchioles. The parasites was associated with alveolar oedema and emphysema, and a mixed inflammatory cell exudate within and surrounding the airways.

Pulmonary gas exchange correlated to clinical signs and lung pathology in horses with chronic bronchiolitis.

Eight horses (mean weight 438 kg) with chronic obstructive pulmonary disease (COPD) were studied for clinical signs, ventilation/perfusion relationships (VA/Q) and lung morphology. Four horses were killed and necropsied after the study. In horses with COPD, minute ventilation was almost twice as high as normal, whereas PaO2 was significantly decreased. Cardiac output was normal, but pulmonary artery pressure and pulmonary vascular resistance were significantly increased. The VA/Q distribution was abnormal with an increased scatter of VA/Q ratios. However, shunt (VA/Q = 0) was increased in one horse only. Ventilation of dead space and high VA/Q regions (VA/Q greater than 10) were increased markedly and comprised 74 per cent of minute ventilation. On lung biopsy, all horses showed chronic bronchiolitis with epithelial hyperplasia and metaplasia. Diffuse acinar hyperinflation also was evident at necropsy. There was a significant inverse correlation between the respiratory rate and the fractional ventilation of normal VA/Q regions. Also, there was a significant agreement between the extent of bronchiolar epithelial hyperplasia in necropsy specimens of lungs and the degree of ventilation of high VA/Q regions and dead space. The findings suggest that hyperinflation of the lung due to obstructed airways may be the common denominator of increased ventilation of high VA/Q regions and dead space ventilation and of elevated pulmonary artery pressure in horses with COPD from chronic bronchiolitis.

Morphological investigations on the pathology of Dictyocaulus viviparus infections in cattle.

Morphological investigations of lungs obtained from cattle that had been experimentally infected with Dictyocaulus viviparus were carried out using a new fixation technique that excludes post-mortem changes in the samples. Light and electron microscopical investigation showed a substantial loss of ciliated epithelial cells in the bronchi, severely affecting the mucociliary clearance. Bronchiolitis, peribronchiolitis and cell-rich mucus caused bronchial atelectasis and consolidation of the related alveoli. Interlobular septa completely separated diseased from normal tissue. Clara cells contained abundant intraplasmatic glycogen. Alveolary walls were thickened and showed cellular infiltration, loss of functional epithelial cells and hyperplasia of alveolar type II cells. Increased connective tissue indicated an irreversible chronic decline in lung performance. Lung eosinophilia and the cytotoxic abilities of eosinophils are discussed as a cause of the changes in lung tissue after infection with D. viviparus.

Ultrastructural morphogenesis of 4-ipomeanol-induced bronchiolitis and interstitial pneumonia in calves.

The two objectives of this research were 1) to describe the ultrastructural morphogenesis of pulmonary damage and repair induced in calves after treatment with 4-ipomeanol and 2) to characterize infiltrating pulmonary inflammatory cells by bronchoalveolar lavage. Interstitial edema was observed as early as 4 hours after intravenous injection of 4-ipomeanol (5 mg/kg body weight) and progressed to severe alveolar edema by 72 hours. Damage to type I alveolar epithelial cells and terminal bronchiolar nonciliated cells included dilation of endoplasmic reticulum and perinuclear envelopes and was present at 4 hours after treatment. Necrosis and sloughing of these cells from basement membranes occurred at times from 12 to 96 hours after treatment. Alveolar capillary endothelial cells had mild dilation of endoplasmic reticulum at times from 12 to 72 hours after treatment. Necrosis of endothelial cells was not observed. Inflammatory cell infiltrates in bronchioles and alveoli were dominated by macrophages and neutrophils. Significant elevations (P less than 0.05) in numbers of neutrophils and macrophages were recovered by bronchoalveolar lavage at times from 24 to 96 hours after 4-ipomeanol-treatment. Hyperplasia of nonciliated bronchiolar epithelial cells and of type II alveolar epithelial cells were observed at 72 and 96 hours after treatment. The results indicate that type I alveolar epithelial cells and nonciliated bronchiolar epithelial cells are most susceptible to 4-ipomeanol-induced damage and necrosis in calves. 4-ipomeanol-induced pulmonary edema in calves occurs prior to ultrastructurally-demonstrable, mild, alveolar capillary endothelial cell damage.

An ultrastructural study of spontaneous chronic lung lesions in asymptomatic rabbits.

An electron microscopical study of chronic lung lesions in 12 clinically healthy, purpose bred laboratory rabbits (eight of which were free from infections with known respiratory pathogens but 4 of them carried a natural B. bronchiseptica infection) revealed focal chronic interstitial pneumonia, vascular changes and focal chronic bronchiolitis. In addition, severe endothelial changes and intravascular deposition of collagen were observed in septal capillaries. In type I pneumocytes and septal capillary endothelium we noticed numerous rounded structures, 70-90 nm in diameter, which consisted of a limiting two layer membrane enclosing an irregularly rounded electron-dense centre surrounded by a more electron-lucent halo. These structures appeared free in the cytoplasm, or they were attached to or apparently budding from membranes other than the plasmalemma. Particles located extracellularly were not found. Whether the structures described were involved in the genesis of the lesions found remains to be elucidated.

Studies on the pathogenesis and interspecies transmission of respiratory syncytial virus isolated from sheep.

Inoculation of lambs with an ovine isolate of respiratory syncytial virus (RSV) by a combined intranasal and intratracheal route resulted in mild respiratory tract illness, with respiratory tract lesions. Lung lesions were characterized by bronchitis and bronchiolitis, hyperplasia of bronchial and bronchiolar epithelium, peribronchiolar and perivascular accumulations of lymphocytes, alveolar septal thickening, and collapse. Respiratory syncytial virus was recovered from the respiratory tract of inoculated lambs, and RSV antigen was demonstrated by immunoperoxidase staining of bronchiolar and alveolar epithelial cell in pneumonic lesions of lambs euthanatized on post-inoculation days 5 and 6. Other primary respiratory tract pathogens were not isolated. Clinical signs of respiratory tract illness or respiratory tract lesions did not develop in the in-contact control lamb. Inoculation of the ovine RSV isolate into calves and deer fawns resulted in infection in both species, and at necropsy, pneumonic lesions were present. A mild to moderate respiratory tract illness developed in the calves, but clinical disease was not seen in the fawns. Lung lesions in fawns were similar to those seen in lambs; lesions in calves were characterized by collapse, scattered areas of parenchymal necrosis, and bronchiolitis. Respiratory syncytial virus was reisolated from the lower respiratory tract of inoculated calves and fawns, and immunoperoxidase-positive epithelial cells were seen in pneumonic lesions. Other primary respiratory pathogens were not detected. Respiratory syncytial virus infection was not demonstrable in control animals that were in contact with inoculated animals.(ABSTRACT TRUNCATED AT 250 WORDS)