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 and perivascular accumulations of lymphocytes, alveolar septal thickening, and collapse. Respiratory synctial virus was recovered from the respiratory tract of inoculated lambs, and RSV antigen was demonstrated by immunoperoxidase staining of bronchiolar and alveolar epithelial peroxidase staining of bronchiolar and alveolar epithelia cells 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 synctial 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. We concluded that an ovine RSV isolate, when inoculated in a severe challenge regime, caused mild primary pneumonia in lambs and lesions similar to those described in epizootics of naturally occurring ovine respiratory tract disease. Also, the ovine RSV caused lower respiratory tract lesions in infected calves and deer.

The fungal flora of the hair and underlying skin from 2 sites was examined qualitatively in 20 horses free of skin or ocular disease. Fungi were isolated from both the hair and the underlying skin of all 20 horses. Twenty-two genera regarded commonly as saprophytes were identified and an additional 2 fungi resembled the perfect state of the cutaneous pathogenic genera Microsporum and Trichophyton. Cladosporium spp, Penicillium spp, and Rhizopus spp were the most frequently isolated saprophytes. In general, similar fungi were isolated from the hair and underlying skin, and differences were not noted in isolates from the saddle and rump regions.

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).

Adherence of Streptococcus dysgalactiae isolates from cattle and S equi isolates from horses to their respective host epithelial cells was compared with the adherence of S pyogenes to human epithelial cells. The adherence was quantitatively determined by use of fluorescein-labeled streptococci. All 3 streptococcal species adhered selectively to their respective host cells. The mechanism of adherence was evaluated by binding studies with adhesive plasma protein, fibronectin. Although all 3 streptococcal species bound fibronectin, S dysgalactiae and S equi interacted preferentially with a 210-kilodalton (kD) C-terminal fragment of fibronectin, whereas S pyogenes bound only a 29-kD N-terminal fragment. A synthetic peptide Gly-Arg-Gly-Asp-Ser, representing the host cell attachment site of fibronectin, partially inhibited the binding of fibronectin and of its 210 kD fragment to S dysgalactiae, but not to S equi. The binding of fibronectin and its 29-kD fragment to S pyogenes was not inhibited by Gly-Arg-Gly-Asp-Ser. These differences in binding activities corresponded to the ability of fibronectin to mediate the adherence of the streptococci to the epithelial cells: fibronectin strongly inhibited the adherence of S pyogenes and S equi to the epithelial cells, but only weakly inhibited that of S dysgalactiae.

Hybridomas were selected for secretion of monoclonal antibodies directed against pseudorabies virus (PRV) glycoproteins. Each monoclonal antibody was capable of neutralizing PRV in vitro in the presence of complement. This panel of antibodies was used in passive immunization studies to protect mice and swine from PRV-induced mortality. The most protective antibody in mice was 3A4, specific for PRV glycoprotein gp50, which afforded as high as 100% protection. Although antibody 3A4 was partially protective in swine, antibody 3D11, which is specific for PRV glycoprotein gIII, afforded greater protection-83% protection when ascitic fluid was used and 100% protection when immunoglobulin concentrated from cell cultures was used at a dose of 150 mg/pig. These studies demonstrated that monoclonal antibodies may be useful for short-term prophylaxis against PRV-induced disease and that antibody directed against either PRV gylcoprotein gIII or gp50 is sufficient to protect animals from PRV-induced mortality.

Relative pathogenicity of 151 Escherichia coli isolates from 36 calves with bacteremia after necropsy was studied by measurement of the LD50 after mice were inoculated IP with E coli isolates. Study of virulence factors and markers revealed that the pathogenicity of E coli was associated with the production of hydroxamate siderophores and with resistance to serum bactericidal effects. Production of colicins, including colicin V, and of surface antigen 31A was correlated with virulence. The close association between phenotypic expression of virulence factors and markers was consistent with a hypothesis of a localization of genes coding for virulence factors and markers on the same plasmid.

Epizootic hemorrhagic disease virus was isolated from cattle and sheep in northeastern Colorado during July and August 1984. The isolates were identified as serotype 2 by plaque-inhibition serotyping, genome electropherotyping, and protein analysis.

A study was undertaken to investigate the combined effects of fasting and different diets on interferon (IFN) production and virus replication measured in nasal secretions of calves inoculated with a vaccine strain of infectious bovine rhinotracheitis virus. Four groups of calves were inoculated intranasally with infectious bovine rhinotracheitis virus. Two groups were inoculated 24 hours after onset of a 3-day fast; upon refeeding, 1 group was fed a maintenance diet (M diet) of hay, and the other was fed a higher energy diet (HE diet) of hay and concentrate. Nonfasted control groups were fed the M diet or the HE diet. Overall IFN production was highest (P less than 0.01) in nonfasted calves fed the M diet throughtout the study and lowest in nonfasted calves fed the HE diet. Fasted calves refed the HE diet produced consistently and significantly more IFN than did nonfasted calves fed this diet. Fasted calves refed the M diet, however, produced significantly less IFN, compared with control calves fed the M diet throughout the study. Overall mean virus excretion was similar in all groups; therefore, the amount of virus replication per se did not account for the differences in IFN production, nor did greater IFN production result in less virus excretion. Serum cortisol concentrations and immune responses were not significantly affected by fasting or diet.

Using an avidin-biotin-peroxidase complex immunoperoxidase staining method, respiratory syncytial virus (RSV) antigen was demonstrated in glutaraldehyde-fixed, parraffin-processed lung sections from calves with induced RSV pneumonia. The virus also was detected in formalin-fixed, paraffin-processed lung sections from calves with naturally occurring RSV pneumonia. Specific immunoperoxidase staining was detected within the cytoplasm of epithelial cells and syncytia in small bronchi, bronchioli, and alveoli. Staining also was detected within exudates in airway lumina and in mononuclear and multinucleate cells within alveolar lumina. Optimal intensity of staining was achieved by proteolytic enzyme treatment of lung sections, using 0 .1% pronase and overnight incubation in diluted primary antiserum. The distribution of antigen had a close correlation with presence of lesions. Antigen-staining patterns were similar in lung tissue from calves with naturally occurring and induced RSV disease.

Thirty-four preweaning pigs with induced enteropathogenic Escherichia coli diarrhea were treated with electroacupuncture, traditional acupuncture, or neomycin. In the group treated with electroacupuncture, points GV-1, bilateral ST-36, and Bai-hui were stimulated electrically. In the group treated with traditional acupuncture, points GV-1, bilateral ST-36, BL-20, bulb points, bilateral ear tip, and Shan-gen were used. Acupuncture points CV-12 and bilateral ST-25 also were treated with moxibustion (applying heat generated by a burning herb, Artemisia argyi). Hemoacumpuncture also was applied to Shan-gen, bilateral ear tip, and bulb points. Pigs in the third group were given neomycin orally. Five pigs were inoculated with E coli, but were not treated and served as nontreated controls. At postinoculation day 5, 60% of control pigs and greater than 80% of pigs in treated groups recovered from diarrhea. However, at postinoculation day 3, recovery rates for pigs in the control and group treated with electroacupuncture were only 20 and 27.3%, respectively; whereas pigs treated with acupuncture or neomycin attained 81.8 and 71.4% of recovery rates, respectively. Seemingly, traditional acupuncture, but not electroacupuncture, was effective in controlling induced E coli diarrhea in pigs at its early stage.