Chronic bovine brucellosis is characterized by persistent infection of the mammary gland. The interaction of live Brucella abortus with bovine mammary gland macrophages was studied in vitro. Opsonization of smooth B abortus strain 2308 and rough strain 45/20 was required for phagocytosis by mammary gland macrophages. When opsonized with specific antiserum, strains 2308 and 45/20 stimulated a considerable oxidative burst when phagocytized by mammary gland macrophages. Intracellular survival rates for strain 2308 were significantly higher than those for strain 45/20. After being phagocytized, B abortus localized in phagosomes and phagolysosomes of mammary gland macrophages.

Feline immunodeficiency virus (FIV; formerly, feline T-lymphotropic lentivirus) is a typical lentivirus resembling human and simian immunodeficiency viruses in morphologic features, protein structure, and reverse transcriptase enzyme. It is antigenically dissimilar, however. The virus is tropic for primary and permanent feline T-lymphoblastoid cells and Crandell feline kidney cells. The virus did not grow in other permanent feline non-lymphoblastoid cells that were tested or in lymphoid and non-lymphoid cells from man, dogs, mice, and sheep. During short term inoculation studies in cats, the feline immunodeficiency-like syndrome found in nature was not experimentally induced, but a distinct primary phase of infection was observed. Fever and neutropenia were observed 4 to 5 weeks after inoculation; fever lasted several days, and neutropenia persisted from 1 to 9 weeks. Generalized lymphadenopathy that persisted for 2 to 9 months appeared at the same time. Antibodies to FIV appeared 2 weeks after inoculation and then plateaued. Virus was reisolated from the blood of all infected cats within 4 to 5 weeks after inoculation and persisted indefinitely in the face of humoral antibody response. Virus was recovered from blood, plasma, CSF and saliva, but not from colostrum or milk. Contact transmission was achieved slowly in one colony of naturally infected cats, but not between experimentally infected and susceptible specific-pathogen-free cats kept together for periods aslong as 4 to 14 months. The infection was transmitted readily, however, by parenteral inoculation with blood, plasma, or infective cell culture fluids. In utero and lactogenic transmission were not observed in kittens born to naturally or experimentally infected queens. Lymphadenopathy observed during the initial stage of FIV infection was ascribed to lymphoid hyperplasia and follicular dysplasia. A myeloproliferative disorder was observed in 1 cat with experimentally induced infection.

Pig epizootic diarrhea virus cannot be grown in cell culture; for its characterization, intestinal perfusate material from a pig infected with the strain CV777 had to be used. In isopyknic sucrose gradients, a peak of virus-specific ELISA activity was detected at a density of 1.17 g/ml. Using immunoprecipitation of radioiodinated-purified virus material followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, 3 proteins of low molecular weight (20,000 to 32,000 daltons [D] were found; after blotting nitrocellulose and glycoprotein identification with concanavalin A and horseradish peroxidase, 1 of the proteins (23,000 D) gave a signal. Another protein of 58,000 D was encountered, which was the only protein binding an RNA probe. Finally, a protein of 85,000 D was visible, associated with minor bands of about 110,000 and 135,000 D in most experiments. Using the concanavalin A-blotting technique, the same bands were visualized. The demonstration of a polydisperse cluster of proteins from 20,000 to 32,000 D (of which at least 1 is glycosylated), of glycosylated proteins from 85,000 to 135,000 D, and of an RNA-binding protein of 58,000 D is taken as structural evidence that pig epizootic diarrhea virus should be classified with the Coronaviridae, irrespective of the apparent lack of an antigenic relationship with other members of that family.

The sense of smell in dogs infected with canine distemper virus (CDV) was examined by use of EEG olfactometry, behavioral olfactometry, and electro-olfactography. Infection with CDV was confirmed by a direct immunofluorescence technique in 8 active cases and was suggested by clinical history compatible with canine distemper 10 to 26 weeks earlier in 6 cases. Pathologic alterations of the olfactory mucosa in 3 clinically affected dogs was examined by light microscopy. Infection with CDV was found to be associated with anosmia and lack of recorded responses on electro-olfactogram in 8 of 8 dogs with clinical signs of acute distemper from naturally acquired infections. Anosmia was found in 5 of 6 dogs that had recovered from acute distemper 10 to 26 weeks earlier. The sixth dog had hyposmia, with abnormalities on the electro-olfactogram. Histologic examination was not performed on the 6 dogs that had recovered. Histologic lesions observed at necropsy in 3 dogs that had had clinical signs of acute distemper were those of subacute purulent rhinitis and atrophy of the olfactory epithelium. Altered olfactory function could be explained by mucopurulent exudate blocking odors from olfactory receptors in the acutely affected dogs, but alteration of olfactory function in the dogs that had recovered without clinical evidence of rhinitis could not be explained.

Eighteen 4-day-old gnotobiotic pigs were orally inoculated with porcine enteric calicivirus-like virus (C strain). Seven additional gnotobiotic pigs served as noninoculated controls. Mild diarrhea developed in all inoculated pigs by postinoculation day (PID) 3 and persisted for 3 to 7 days. Severe diarrhea developed in 2 inoculated pigs between PID 4 and 5. Twelve inoculated and 7 control pigs were euthanatized over a 7-day period. Small intestinal mucosal smears were stained with a fluorescein-conjugated anti-porcine enteric calicivirus-like virus serum. Immunofluorescence was observed in villous epithelial cells (primarily in the duodenum or jejunum) of all inoculated pigs, except for 1 pig euthanatized at PID 7. Villus length was determined in histologic sections of the small intestinal specimens from control and inoculated pigs. Statistically significant (P less than 0.01) villus atrophy was found in the duodenum and/or jejunum of inoculated pigs at PID 3 to 7. These observations were confirmed by scanning electron microscopy, which revealed shortening, blunting, fusion, or absence of villi in the duodenum and jejunum of inoculated pigs at PID 3 to 7. Lesions were not seen in control pigs. Calicivirus-like particles were detected by immune electron microscopy in the large intestinal contents and feces of inoculated pigs from PID 1 to 7.

In an anatomic and radiologic study of the clavicle of 50 adult dogs of 10 breeds, the clavicle had ossified in 96% of the dogs. The clavicles studied had various shapes, and each clavicle was attached to the caudomedial part of the clavicular intersection of the bradiocephalic muscle, to the mastoid part of the cleidocephalic muscle, and to 4 radiating bands of connective tissue fasciculi. One band was attached to the caudal border of the scapula and fascia deep to the latissimus dorsi muscle, 1 was attached to the manubrium of the sternum, and 1 each was attached to the epimysia of the superficial pectoral and sternocephalic muscles. We concluded that, during movements of the thoracic limb, the clavicle and the 4 fasciculated connective tissue bands associated with it stabilize the position of the brachiocephalic muscle with relation to the crest of the greater tubercle of the humerus. Also, the fasciculated band attached to the caudal border of the scapula provides protection for nerves from the brachial plexus and axillary blood vessels that supply the thoracic limb.

Lymphocytes from 5 clinically normal lambs and 5 lambs affected with ovine hereditary chondrodysplasia (spider syndrome) were cultured, G-banded, and karyotyped. Fifty metaphase karyotypes and one heterogram were evaluated for chromosome number and morphologic features. All lambs had normal diploid (2n) chromosome numbers of 54,XX or 54,XY, and there were no apparent differences in the morphologic features of the chromosomes.

The umbilical arteries urachus, and umbilical vein were scanned ultrasonographically in 13 clinically normal foals that ranged in age from 6 hours to 4 weeks. Sonograms were obtained using a 7.5-MHz sector scanner transducer placed across the midline of the ventral portion of the foal's abdominal wall. The umbilical vein was scanned from the umbilical stalk to its entrance into the hepatic parenchyma. The mean (+/- SD) diameter of the umbilical vein was 0.61 +/- 0.20 cm immediately cranial to the umbilical stalk, 0.52 +/- 0.19 cm midway between the umbilicus and liver, and 0.6 +/- 0.19 cm at the liver. The urachus and umbilical arteries were scanned from the umbilical stalk to the apex of the urinary bladder and had a mean total diameter of 1.75 +/- 0.37 cm at the bladder apex. The umbilical arteries also were scanned along either side of the bladder and had a mean diameter of 0.85 +/- 0.21 cm. These measurements and the ultrasonographic appearance of the internal umbilical structures from clinically normal foals can be used as references to diagnose abnormalities of the umbilical structures in neonatal foals.

Concentrations of serum IgA, IgG, and IgM were determined for 829 adult Beagles from a commercial kennel in which several IgA-deficient dogs had been identified previously (index kennel). These values were compared with measurements of 100 adult dogs from another Beagle kennel (control kennel). After adjustment for differences in the ages and gender of the dogs, dogs from the index kennel had significantly (P less than 0.0001) lower IgA concentrations (mean, 46 mg/dl). Regardless of kennel, males had significantly (P less than 0.01) higher IgA concentrations than did females. Dogs in the control kennel had significantly (P less than 0.04) higher IgG concentrations (mean, 2,649 mg/dl) than did dogs in the index kennel (mean 2,478 mg/dl), and female dogs in the control kennel had significantly (P less than 0.05) higher IgM concentrations (mean, 189 mg/dl) than dogs of either sex in the index kennel (mean, 162 mg/dl) or male dogs in the control kennel (mean, 163 mg/dl). For both sexes, concentrations of IgA, IgG, and IgM increased with age.

The effect of T-2 toxin, a radiomimetic immunosuppressive agent, on resistance to the facultative intracellular bacterial pathogens Listeria monocytogenes (strain EGD), Mycobacterium bovis (BCG Copenhagen 1331), and Salmonella typhimurium was determined. Female Swiss ICR mice were given a single dose of T-2 toxin (4 mg/kg of body weight) by gastric gavage. On the seventh day after toxin administration, the mice were infected by intraperitoneal inoculation with L monocytogenes, S typhimurium, or M bovis. Mice given the toxin also were exposed to respirable droplet nuclei containing L monocytogenes or M bovis. The effect of the toxin on the course of infection was monitored by observing mortality or by enumeration of bacteria in te spleen or lungs of infected mice. The toxin increased resistance to infection with L monocytogenes initiated by intraperitoneal inoculation, but reduced resistance to M bovis infection initiated by intraperitoneal inoculation. The toxin had no appreciable effect on the course of salmonellosis or on resistance to infection initiated by inhalation of L monocytogenes or M bovis aerosols. Therefore, it was concluded that T-2 toxin does not necessarily reduce resistance to infection in mice. The toxin's effect on the course of in vivo bacterial infections depends on the nature of the infective agent and the route of inoculation.