Acute and chronic bovine pulmonary edema and emphysema in Uruguay / Edema e enfisema pulmonar agudo e crônico em bovinos do Uruguai

An outbreak of pulmonary edema and emphysema with acute and chronic cases is reported in a farm in Uruguay. In a herd of 40 Hereford steers, 20 died. The deaths began four days after a change of paddock, from an old pasture of Avena sativa to a lush growing pasture of the same grass. Acutely affected animals showed severe dyspnea, sialorrhea, cough, and subcutaneous edema, and died within 72 hours. Chronically affected steers showed dyspnea, respiratory noises, weight loss, and intolerance to exercise. The deaths began four days after the change of paddock. Ten days after the first death, the steers were withdrawn from the pasture, but continued dying throughout the following 40 days. Twenty animals died and six were necropsied. Grossly, the lungs were diffusely armed and glistening, with reddish and crepitant cut surface, and presented alveolar septae sharply distended by edema and emphysema. There was subpleural emphysema with air blebs distributed across the pleural surface. Presence of Dictyocaulus viviparus was observed in three steers. In some animals, the trachea was diffusely reddish with presence of pink foam; in some others, there was bloody liquid in the tracheal lumen. Histologic examination showed severe diffuse alveolar and interstitial emphysema, hyaline membranes adhered to the alveolar wall, thickening of the interlobular septae with proliferation of type II pneumocytes, and moderate-to-severe multifocal histiocytic, neutrophilic and eosinophilic infiltrate. In the trachea, there was submucosal hemorrhage and moderate multifocal eosinophilic and lymphocytic infiltrate. The steers with chronic signs presented similar lung lesions, but multifocal pulmonary fibrosis and cardiac dilatation were also observed. The diagnosis of acute bovine pulmonary emphysema and edema (ABPE) was based on the occurrence of the disease after introduction of the herd in a lush green pasture, on the characteristic gross and histologic lesions, and on the absence of other toxic or infectious agents causing similar lesions. Cattle raisers should be alert to the risks of occurrence of this disease after the introduction of the herds into paddocks with green and lush pastures.(AU)

Descreve-se um surto de edema e enfisema pulmonar com casos agudos e crônicos em bovinos em uma criação semi-intensiva no Uruguai. De um lote de 40 novilhos da raça Hereford morreram 20. As mortes começaram quatro dias após uma mudança de alimentação, de uma pastagem mais velha de Avena sativa, para uma pastagem recentemente plantada de aveia que estava em brotação. Os animais afetados apresentaram sinais clínicos agudos de dispneia, sialorreia, tosse e alguns desenvolveram edema subcutâneo, morrendo em até 72 horas. Outros novilhos mais cronicamente afetados apresentaram dispneia, ruídos respiratórios, perda de peso e intolerância ao exercício. As mortes começaram quatro dias após a mudança de pastagens. Dez dias após a primeira morte, os novilhos foram retirados do pasto, mas morreram ainda durante 40 dias mais. Ao total, morreram vinte animais e seis foram necropsiados. Nas necropsias dos animais mortos na fase aguda os pulmões estavam difusamente armados e brilhosos e ao corte de coloração avermelhada e crepitante, com os septos alveolares acentuadamente distendidos por edema e enfisema. Havia enfisema subpleural caracterizado por bolhas de ar distribuídas pela superfície pleural. Em três bovinos havia ainda presença de Dictyocaulus viviparus. Alguns animais apresentaram a traqueia difusamente avermelhada com espuma de coloração rósea ou liquido sanguinolento livre na luz traqueal. Histologicamente havia edema e enfisema alveolar e intersticial difuso severo, membranas hialinas espessas aderidas à parede alveolar, espessamento dos septos interlobulares com proliferação de pneumócitos tipo II e infiltrado inflamatório histiocítico, neutrofílico e eosinofílico multifocal moderado a severo. Na traqueia havia hemorragias na submucosa e infiltrado eosinofílico e linfocítico multifocal. Os novilhos com sinais crônicos apresentaram lesões pulmonares semelhantes, entretanto, foram observadas também, fibrose pulmonar multifocal e dilatação cardíaca. O diagnóstico de EEPAB baseou-se na ocorrência da doença após a introdução do rebanho em uma pastagem viçosa em brotação, nas características macroscópicas e histológicas e na ausência de outros agentes tóxicos ou infecciosos que causam lesões semelhantes. Se alerta para os riscos da ocorrência desta enfermidade, quando houver mudanças de pastagens.(AU)

Pathogenesis and pathology of bovine pneumonia.

Pneumonia is a major cause of death and economic losses to the cattle industry. Recognizing the patterns of pneumonic lesions and understanding the pathogenesis of the various types of pneumonia are important for correct diagnosis and interpretation of the lesions. Bacterial pneumonias consist of bronchopneumonia, fibrinous pneumonia, and pleuropneumonia as well as caseonecrotic, aspiration, and tuberculous pneumonias. Two major patterns of interstitial pneumonia are recognized in cattle, and verminous pneumonia is associated with Dictyocaulus viviparus infection.

Bovine atypical interstitial pneumonia.

Bovine atypical interstitial pneumonia (AIP) is a multifaceted disease with several known causes or clinical presentations. Multiple causal agents and management practices have been associated with development of the condition. The sporadic incidence and development of disease in a variety of circumstances argues against a common infectious agent, although cases of AIP are often complicated with bacterial, viral, or mycoplasmal organisms. Lesions develop and progress as a basic response of the lung to injury. Metabolic activation of naturally occurring xenobiotic compounds such as 3-methyl indole, perilla ketone, and 4-ipomeanol produce a clinical syndrome that is indistinguishable from naturally occurring AIP. Pulmonary injury is mediated by formation and activation of intermediate electrophilic compounds that covalently bind to cellular proteins and nucleic acids and ultimately cause cell death. Clara cells (nonciliated bronchiolar) and type I alveolar epithelial cells are primarily responsible for metabolism and activation of these naturally occurring xenobiotics.

Bovine atypical interstitial pneumonia associated with the ingestion of damaged sweet potatoes (Ipomoea batatas) in Northeastern Brazil.

Atypical interstitial pneumonia in cattle associated with the ingestion of damaged sweet potatoes is reported in the State of Paraíba, Northeastern Brazil. The sweet potatoes were severely damaged by Myzus tersicae, and had an obvious fungal infection. Eighteen milking cows, 1 bull and 1 steer were fed approximately 400 kg of the sweet potatoes. Six days after consumption 13 cows were affected with labored abdominal breathing, extended and lowered head, coughing, expiratory grunt, salivation and protruded tongue. Six animals died and the others recovered in 4-7 d. At necropsy lungs were distended and did not collapse when the thorax was opened. Bullous emphysema and gelatinous exudates were observed in the interlobular, peribronchial and subpleural tissues. Microscopically, the lungs had severe edema and emphysema, congestion, and alveolar epithelial cell hyperplasia. The sweet potatoes were cultured but Fusarium spp was not isolated, probably because a zigomycete fungus covered the plates in 48 h of incubation.

Atypical pneumonia associated with ryegrass staggers in calves.

A group of 6- to 8-month-old calves developed head tremors, stiff gait, and staggering after consuming ryegrass straw that contained 3,711 micrograms of lolitrem-B/ kg. Signs were consistent with ryegrass staggers syndrome. At necropsy, all calves examined had atypical interstitial pneumonia, with marked emphysema and bullae. Infectious organisms and pneumotoxins were not identified. Experimentally, feeding the same ryegrass straw to age-matched calves induced similar neurologic signs, but did not result in pneumonic lesions. The high concentration of lolitrem-B in the straw or other, undefined factors, such as feed changes, may have contributed to the atypical interstitial pneumonia in the naturally exposed calves.

Association of bovine respiratory syncytial virus with atypical interstitial pneumonia in feedlot cattle.

Thirty-three cattle with fatal respiratory tract disease were examined for gross and histologic lesions and for the presence of viral and bacterial agents in the lungs. Fifteen cattle had lesions characteristic of atypical interstitial pneumonia (AIP), and 18 had other respiratory tract diseases, including infectious bovine rhinotracheitis, shipping fever pneumonia, bronchopneumonia, pulmonary abscess, and edema of the trachea. Gross necropsy findings in the cattle with AIP were uncollapsed and emphysematous lungs; histopathologic findings included interstitial edema, thickening of alveolar walls, hyaline membrane formation, and hyperplasia of type-II pneumonocytes. The infective agents found in the lungs of the 33 cattle included bovine respiratory syncytial virus, bovine herpesvirus type 1, Pasteurella sp, mycoplasmas, and Corynebacterium pyogenes. Bovine respiratory syncytial virus was detected by use of immunofluorescence and immunoperoxidase on lung tissue sections; bovine herpesvirus type 1 was detected by these techniques and by isolation of the virus. Bovine respiratory syncytial virus was significantly (P = 0.01) associated with lesions of AIP (11 of 15), compared with those of other respiratory tract diseases (5 of 18).

Ultrastructural pathology of 3-methylindole-induced pneumotoxicity in cattle. I. Glycogen accumulation in the alveolar type II cells and tubular myelin accumulation in the alveoli.

3-Methylindole (3MI) was orally administered as a single dose of 0.1-0.2 gm/kgm which then produced acute pulmonary edema in cattle. Electronmicroscopic examination of lung tissue collected after 72 hours revealed vesiculation and desquamation of alveolar type I cells as well as hyperplasia of the alveolar type II cells. Hyaline membrane formation, along with massive accumulation of tubular myelin in the alveolar spaces, was observed. Pulmonary capillaries were occluded with microthrombi and leukocytes infiltrated the interstitium as well as the alveoli. Accumulation of large aggregates of glycogen in the alveolar type II cells were the most unusual changes seen in the experimental animals. It is suggested that accumulation of tubular myelin is a structural manifestation of surfactant inactivation by the plasma proteins. Furthermore, the disease process may be complicated by a compositional or quantitative defect in the surfactant produced by the alveolar type II cells, which are pathologically loaded with glycogen.

Effects of 4-ipomeanol, a product from mold-damaged sweet potatoes, on the bovine lung.

Cattle given intraruminal administration of 4-ipomeanol, a furanoterpenoid originally obtained from sweet potatoes infected with Fusarium solani (F. javanicum), developed a respiratory syndrome clinically and histologically indistinguishable from atypical interstitial pneumonia. There were edema and emphysema in the lungs and mediastinum. The maximum nonlethal oral dose of 4-ipomeanol was estimated to be between 7.5 and 9 mg/kg of body weight.

Bovine allergic pneumonitis: an acute outbreak associated with mouldy hay.

An outbreak of acute bovine atypical interstitial pneumonia is reported in association with feeding mouldy hay. Results of serological investigation and of provocation challenge indicated a hypersensitivity pneumonitis due to allergens of Micropolyspora faeni. Macroscopic and microscopic pulmonary changes were predominantly those of oedema and emphysema. These lesions were contrasted with more chronic changes reported in allergic pneumonitis of housed cattle.

Atypical interstitial pneumonia in yearling feedlot cattle.

During each week of 1974, we surveyed, for illnesses and deaths, a constantly changing population of yearling feedlot cattle that, for the year, totaled 407,000 animals. From 3,943 fatalities, 1,988 necropsies were made; of this number, 106 (5.3%) had atypical interstitial pneumonia. The death rate was higher during summer and fall than during the other seasons and was evenly distributed throughout each of the 4 stages of fattening. Gross pulmonary lesions involved both lungs and were prominent throughout the caudal (diaphragmatic) lobes. Epithelialization, hemorrhage, fibrin, hyaline membranes, emphysema, bronchiolitis, and interstitial edema were common, whereas chromatin strands, bronchiolar edema, interstitial emphysema, and obliterating bronchiolitis were less common histopathologic features.

Acute respiratory distress in cattle.

The term "fog fever" was originally used identify a disease of adult cattle grazing lush pastures in the autumn. Unfortunately, the name has subsequently been applied to other respiratory disorders which occurred under different epidemiological circumstances, so that the name "fog fever" has lost much of its original specificity and become almost synonymous with "acute respiratory distress". The pulmonary lesions in 151 cattle, of all ages, with acute respiratory distress are described in this report. While most of the animals were referred as examples of "fog fever", in only 43 of the 151 cases were the clinical signs, epidemiology and post mortem findings consistent with that disease. Twelve other pulmonary disturbances were encountered in the other animals and the pathology of these conditions has bee described.