Identification of Brucella abortus genes in elk (Cervus elaphus) using in vivo-induced antigen technology (IVIAT) reveals novel markers of infection.

Elk in the Greater Yellowstone Area are a major reservoir for brucellosis, which represents an obstacle to eradication of the disease in domestic livestock. Furthermore, immune responses to Brucella abortus infection in the wild host are not well-understood. In this regard, in vivo-induced antigen technology (IVIAT) was employed to identify novel B. abortus antigens expressed during infection in elk. Sera collected from sero-positive Wyoming elk were pooled and absorbed against in vitro-grown cultures of B. abortus. Approximately 35,000 E. coli clones, expressing B. abortus DNA, were then screened by colony immunoblot, yielding ten genes with immuno-reactive products, to include seven proteins secreted beyond the inner membrane. Three products, an outer membrane protein (D15), malate dehydrogenase (Mdh), and an ion transporter (AfuA), were examined by Western blot against individual elk serum samples. Sero-reactivity was significantly more frequent for both Mdh and D15 in naturally infected animals, compared to vaccinated and uninfected elk, indicating that antibody to these two antigens is a predictor of natural infection. Cross-reactivity of all three proteins was next examined with serum samples from confirmed brucellosis-positive cattle. While variable patterns of reactivity were seen with the antigens, the sample group was equivalently reactive to AfuA and Mdh, compared to elk, suggesting that these antigens are commonly expressed during infection in both hosts. We conclude that the application of IVIAT to B. abortus may not only facilitate the identification of serologic markers for brucellosis in elk, but may provide further insight into biological processes of the pathogen in different hosts.

Sonographic evaluation of urinary bladder wall thickness in normal dogs.

Urinary bladder wall thickness was evaluated by ultrasonography in 16 normal dogs. Sterile saline solution was administered via urinary catheters to control the degree of bladder distention. Bladder wall thickness was measured on static ultrasound images in 4 locations and at 3 degrees of bladder distention (minimal, mild, and moderate). Four randomized distention sequences with 3 distentions per sequence were performed on each dog and the data were analyzed using Williams' balanced Latin square. Mean bladder wall thickness was 2.3 mm in minimally distended bladders (0.5 ml/kg saline), 1.6 mm in mildly distended bladders (2 ml/kg saline) and 1.4 mm in moderately distended bladders (4 ml/kg saline). Mean bladder wall thickness increased significantly with increasing body weight and with decreasing bladder distention. The caudoventral measurement location produced a statistically significant smaller measurement, with a difference of 0.3 mm. Sex did not affect bladder wall thickness. Distention sequence and repetition of distentions did not affect bladder wall thickness.

Clinical and immunohistochemical characterization of thymic lymphosarcoma in a heifer.

A 2-year-old Holstein heifer with a swollen brisket, jugular vein distention, muffled heart sounds, tachycardia, and free gas bloat was examined. Thymic lymphosarcoma was suspected based on a negative agar gel immunodiffusion test for bovine leukemia virus, presence of atypical lymphocytes in pleural fluid, and detection of a mass in the thoracic inlet. Right-sided cardiac catheterization was performed, and markedly increased jugular venous pressures (41 mm Hg) with a pressure gradient of 29 mm Hg immediately cranial to the heart indicated constriction of the cranial vena cava. Immunohistochemical staining of formalin fixed, paraffin-embedded tissue sections of the tumor using a rabbit antihuman T cell, CD3 polyclonal antibody confirmed that the neoplastic lymphocytes were of thymic origin.

Radiographic anatomy and technique for arthrography of the cubital joint in clinically normal dogs.

A technique for arthrography of the cubital joint in clinically normal large-breed dogs was developed with the objective of improving visualization of the articular margin of the medial coronoid process. A lateral approach to the cubital joint for injection of contrast medium was selected. Arthrography of 24 cubital joints was performed by using 14 dogs. Twelve combinations of iodinated contrast medium, consisting of various concentrations (3) and volumes (4), were used. Two sets of arthrograms for each of the 12 combinations of contrast medium were obtained. Five radiographic views were used for each set. All arthrograms were examined by 3 evaluators, and each articular surface received a numerical rating for how well it could be seen in each view. Results of the evaluation indicated that low volumes of contrast medium were preferable to high volumes, with 2 ml providing the best visualization. Concentration of iodine seemed less important than did volume. The numerical ratings also indicated that the articular margin of the coronoid process was clearly observed a maximum of only 24% of the time on a slightly supinated mediolateral projection. The articular margins of the head of the radius, trochlea humeri, and trochlear notch were well visualized > 90% of the time. Arthrography of the cubital joint was technically easy to perform, and complications were not encountered, but arthrographic anatomy of the cubital joint is complex. Potential uses for arthrography of the cubital joint include diagnosis of osteochondrosis, intraarticular fragments, and joint capsule ruptures.

Comparison of radiologic imaging techniques for diagnosis of fragmented medial coronoid process of the cubital joint in dogs.

Thirty cubital joints from 16 dogs suspected of having a fragmented medial coronoid process were examined. Four breeds accounted for 87.5% of the cases: German Shepherd Dog (25%), Labrador Retriever (25%), Rottweiler (18.75%), and Golden Retriever (18.75%). Seventy-five percent of the dogs were male. Mean age of affected dogs was 13.6 months. Plain-film radiography, xeroradiography, linear tomography, arthrography, and computed tomography were performed on each cubital joint prior to surgical exploration of the joint. Three reviewers evaluated each diagnostic study and independently determined whether a fragment from the medial coronoid process could be seen. The consensus opinion was compared with the finding at surgery. Abnormalities of the medial coronoid process were detected in 25 of 30 joints at surgery. Fragmented coronoid process was found in 17 of 30 joints, and wear lesions were observed in 8 of 30 joints. Computed tomography had the highest accuracy (86.7%), sensitivity (88.2%), and negative-predictive value (84.6%) of the 5 imaging modalities evaluated (P < 0.05). Specificity and positive-predictive value of all imaging techniques were high. There was no significant difference between the diagnostic ability of plain-film radiography, xeroradiography, or linear tomography of the cubital joint. The combination of plain-film radiography and linear tomography provided an improvement in accuracy, approaching that of computed tomography.

Quantity, analysis, and lethality of European and Africanized honey bee venoms.

Venom from Africanized honey bees (derived mainly from Apis mellifera scutellata) was compared with venom from domestic, European bees by study of lethality, immunological cross-reactivity, venom yield, isoelectric focusing (IEF) patterns, and melittin titers. The LD50s of European and Africanized bee venom by iv injection in mice were similar. In venom neutralization experiments, Africanized bee venom was mixed with antibodies from a beekeeper exposed only to European bees and used to challenge mice. Survival times of mice given these mixtures were significantly prolonged, indicating that human serum antibodies to European bee venom neutralized the lethal effects of Africanized bee venom. Reservoirs from Africanized bees contained less venom than European bees (94 and 147 micrograms venom/bee, respectively) and Africanized bee venom had a lower melittin content. The IEF patterns of venom from individual European bees varied considerably, as did IEF patterns of individual Africanized bees. Pools of venom from 1,000 bees of each population of A. mellifera showed noticeable but less obvious electrophoretic differences. The findings suggest that multiple stinging, and not increased venom potency or delivery, is the cause of serious reactions from Africanized bee attacks.

New spiroplasmas from insects and flowers: isolation, ecology, and host association.

Eight spiroplasma strains from insects and one from spring flowers failed to react with antisera specific for any of the 11 described spiroplasma groups, with sera directed against spiroplasma Group I subgroups, or with sera directed against two unnumbered groups previously reported to occur in tabanid flies. Strains, all from Maryland, were isolated from the hemolymph of the spotted cucumber beetle Diabrotica undecimpunctata and the lampyrid beetle Ellychnia corrusca, and the guts of the cantharid beetles Cantharis bilineatus and C. carolinus. Other strains were obtained from a tabanid fly, Tabanus gladiator and from the firefly Photuris pennsylvanica in Maryland and from the mosquito Culex tritaeniorhynchus in Taiwan. An isolate from pooled Cicadulina bipunctella leafhoppers in Syria apparently represented a unique group. A single isolate from spring flowers in Oklahoma also appeared to be unrelated to existing groups or subgroups. One-way deformation tests using sera prepared against known beetle and tabanid spiroplasmas showed each of the above strains to be unique. Although these results strongly indicate that the nine strains studied are representatives of unique new spiroplasma groups, the formal designation of new groups awaits fulfillment of recently proposed criteria.