Abstract. Sixty-one of 68 sets of bovine lungs from which only Haemophilus somnus was isolated had microscopic lesions of purulent bronchiolitis and bronchopneumonia. In 37 of 6 1 lungs, the bronchiolar exudates were markedly necrotic with accompanying necrosis of the adjacent bronchiolar epithelium. Bronchiolitis obliterans was prominent in 23 of 28 lungs affected with chronic lesions with abscesses present in seven. Alveolar filling with inflammatory cells (neutrophils with fewer macrophages) was limited to peribronchiolar alveoli in 25 of 6 1 lungs and was multifocal to diffuse in the other 36. Lesions in the remaining lungs (7 of 68) were classified as fibrinous pneumonia with bronchiolitis (2), fibrinous pleuritis (2), suppurative interstitial pneumonia with vasculitis (2), and diffuse congestion ( 1). 30, 1983, all submissions of bovine tissues to the Iowa State University Veterinary Diagnostic Laboratory from which Haemophilus somnus was isolated were selected for review. In addition, 25 bovine submissions from which only Pasteurella hemolytica was isolated from pneumonic lung tissue were included in the review for comparison. Whenever parafin-embedded lung tissue was available, 6 pm sections were cut, mounted on glass slides, and stained with hematoxylin and eosin (HE) by standard methods. Lung tissues for histologic examination were selected from pneumonic cranial ventral lobes, and in a few cases, additional lung tissue was selected from less affected or nonaffected caudal lobes. Each lung section was examined, and histologic changes were described and subsequently classified according to the major lesions. Lung is used throughout to mean one or both lungs from a single animal.The decision to attempt demonstration or isolation of other microbial agents was made by the diagnostician in charge of the submitted sample based on the referring veterinarian's request, the samples and their condition, and the available examination procedures. Therefore, all samples were not subjected to identical microbiologic procedures. Bacteriologic isolation attempts were the most standardized and were done on all lungs. All fresh lungs were swabbed with sterile cottontipped swabs, and these swabs were plated on unsupplemented 5% bovine blood agar and brain heart infusion agar supplemented with 10% bovine whole blood and 0.5% yeast extract. Inoculated 5% bovine blood agar plates were incubated at 37°C for 24 to 48 hours in normal atmosphere and duplicate plates were incubated in reduced oxygen environments. The inoculated brain heart infusion agar plates were incubated in moist chambers containing 10% CO, at 37°C for a minimum of 48 hours. Bacterial identification was done by standard procedures.Attempts to demonstrate the presence of viral and mycoplasma1 agents was by direct fluorescent antibody examination of sections of frozen lung or other appropriate tissues for infectious bovine rhinotracheitis and bovine virus diarrhea viruses and for Mycoplasma bovis and Mycoplasma dispar or by inoculation of susceptible cell cul...

A 10-month-old male Rottweiler dog from Ottawa, Illinois, had persistent diarrhea for 2 months. After the diarrhea stopped, the dog developed multiple cutaneous abscesses all over its body, particularly in the hind limbs. The limbs were swollen, hot, and painful. A skin biopsy was fixed in 10% formalin solution. The dog died, and the carcass was frozen until necropsy. No other history was available.Portions of liver, unspecified lymph node, lungs, kidney, and skin from the frozen-thawed carcass were fixed in 10% formalin solution. Paraffin-embedded sections of tissues were cut at 5 pm and stained with hematoxylin and eosin (HE). Paraffin-embedded sections from the biopsy specimens of skin were deparaffinized and reacted with Toxoplasma gondii antiserum and Neospora caninum antiserum with an avidinbiotin complex (ABC) immunohistochemical staining method? To further identify the protozoon, biopsy specimens of skin were deparaffinized and processed for transmission electronmicroscopy.Severe necrotizing fibrinosuppurative dermatitis was evident in the sections of skin (Figs. 1, 2). Numerous neutrophils, fewer eosinophils and macrophages, and abundant edema and fibrin expanded extensive areas of deep dermis and occasionally extended into superficial dermis and subcutaneous fat. Multifocal areas of dermal connective tissue and rare hair follicles were necrotic. Capillaries and venules were markedly congested. Many of them contained fibrin thrombi, and the walls of some were disrupted and infiltrated by neutrophils. Hemorrhage had occurred in some areas. A focally extensive area of epidermal necrosis and ulceration overlain by a fibrinohemorrhagic crust was present.A 1-cm-diameter focus of necrosis and fibrinosuppurative inflammation was present in the lung. Alveolar septa in this area were necrotic. Numerous neutrophils, fewer macrophages, and abundant fibrin filled alveoli and expanded re-

A 4-month-old male Rottweiler dog from Ottawa, Illinois, an initial body temperature of 40 C, weakness in left foredied 5 days after becoming ill following entrapment in icy and both rear limbs, and a horizontal nystagmus in both pond water for 30 minutes. The attending veterinarian noted eyes. The dog was unable to rise, had a pronounced nystagmus, and, in spite of antibiotic and corticosteroid adminisFrom the Zoonotic Diseases Laboratory, Livestock and Poultry tration, died.Sciences Institute,