Laboratory investigation of a naturally occurring outbreak of arthrogryposis-hydranencephaly in Texas sheep

An epizootic of abortions, weak lambs, stillbirths, and congenital arthrogryposis-hydranencephaly occurred in a sheep flock in West Texas. The outbreak began during the first week of January 1987 and continued through the third week of February 1987. Lambs born after February 1987 were not affected. A high incidence of antibodies to Cache Valley virus (Texas 7856 isolate) was demonstrated in the ewes' serum and in precolostral serum from affected lambs. No virus was isolated from tissues and body fluids of the affected lambs. The clinical, pathological, and immunological features of the epizootic were similar to those reported in Akabane virus infection in sheep. Although serological findings strongly suggest Cache Valley virus as the etiological agent of this outbreak, transmission studies are needed.     

Immune response to pulmonary injection of Pasteurella haemolytica-impregnated agar beads followed by transthoracic challenge exposure in goats

A method of inducing Pasteurella haemolytica serotype 1 (Ph1) lung infection in goats, using low numbers of bacteria and without impairing host immunity, was developed. Two trials were conducted. Results of trial 1, using 10 principals (Ph1 agar beads) and 6 controls (agar beads alone), indicated that Ph1 organisms imbedded in agar beads could survive host lung defenses for 32 days. Results of trial 2 indicated that lung immunity in the inoculated goats (principals) was high and they were more protected than controls against a transthoracic challenge of Ph1 (1.18 x 10(7) colony-forming units) injected into a lung of each goat on posttreatment day 35. When comparing challenge-exposed principals with controls, the controls developed rectal temperatures above normal for a longer time, duration of anorexia was longer, and signs of depression were seen. The controls developed large areas of consolidated lung tissue, more Ph1 isolates were recovered from nasal turbinates and lung tissue, and higher Ph1 concentrations were found in the lungs. The serum Ph1 indirect hemagglutination antibody titers in the principals of both trials increased, compared with titers in controls. Principal goats in trial 2 had higher Ph1 indirect hemagglutination antibody titers after injection of Ph1-impregnated agar beads and less severe lung lesions after challenge exposure than did controls. The small pneumonic consolidated lesions in the principals, compared with extensive lesions in controls after Ph1 challenge exposure, indicated a high degree of immunity after exposure to Ph1 organisms imbedded in agar beads.     

Immunodiffusion test antigen from bluetongue virus-infected newborn mouse brains

Three methods of extracting bluetongue virus (BTV)-infected newborn mouse brains to prepare immunodiffusion (ID) test antigen were used. The most readily readable and reproducible results were obtained with fluorocarbon-extracted brains homogenized in 8.5% sucrose. Mouse brain- and reference cell culture-derived antigens gave a line of identity with anti-BTV serum. Extracts of noninfected brains were nonreactive. ID tests on field-collected bovine sera, comparing the two types of antigen, resulted in only 73% agreement due to a greater sensitivity of cell culture-derived antigen. A 70.5% agreement resulted when comparing mouse brain-derived antigen in ID tests with complement fixation tests, the latter being least sensitive. ID test results with sera from experimental sheep gave 95.9% agreement between cell culture- and mouse brain-derived antigens. Between ID, which detects antibody to the BTV common or group antigen, and virus neutralization, which detects type-specific antibody, the agreement was 71.4% with postchallenge sera. Data from pre- and postinjection sera, however, indicate the possible activity in Texas of viruses other than International BTV Types 10, 11, 13, and 17.     

Visuospatial skills are better predictors than dexterity for basic ultrasonographic and fluoroscopic skills in veterinary students

Radiological skills including ultrasonography and fluoroscopy, require a combination of manual dexterity and visuospatial skill to develop competency. The ability to detect veterinary students with an interest in radiology but who are deficient in these skills, may permit more individual adaptations to training programs, allowing for students training in radiology to achieve maximal potential. The objective of this cohort study was to investigate whether innate dexterity and visuospatial skill could be used to predict performance of basic ultrasound and fluoroscopic skills in veterinary students. Fifty veterinary students from the Ontario Veterinary College completed three tests of visuospatial ability, two tests of manual dexterity, a three‐dimensional mouse task, an ultrasound skill‐testing task, and a fluoroscopic skill‐testing task. Students who reported chopstick use completed the non‐dominant hand ultrasound task significantly faster than students who did not (P = 0.001). There was a significant positive association between scores on the Mental Rotations Test and time to complete the non‐dominant hand ultrasound task (P = 0.011) and fluoroscopy task (P = 0.029). No variables were associated with time to complete the dominant hand ultrasound task. The results of this study suggest that visuospatial skill, as assessed by the Mental Rotations Test, is a better predictor of baseline ultrasound and endovascular fluoroscopy skill than dexterity, with the exception of reported chopstick use, in veterinary students. Visuospatial skills can be developed and may be useful to include in the veterinary curriculum for students that are deficient, or students entering a field such as diagnostic imaging.     

p62/SQSTM1 expression in canine mammary tumours: Evolutionary notes

Recent studies highlighted the role of autophagy as a cardinal regulatory system for homeostasis and cancer‐related signalling pathways. In this context, the deregulated expression of p62 – Sequestosome1 (p62/SQSTM1) – a protein acting both as an autophagy receptor and signalling hub, has been associated with tumour development and chronic inflammation. Multiple clinical studies test drugs targeting autophagy, and even more research is on the way to clinical trials. However, no comparative investigations have been carried out to identify adequate preclinical models to assess p62‐based medicine. In veterinary oncology the role of p62 in cancer‐related pathways has been largely ignored. We compared p62 sequences in multiple organisms and found that canine p62 significantly diverges from the humans and from other animals sequences. Then, we chart by immunohistochemistry the expression levels of p62 in canine mammary tumours. A total of 66 tumours and 10 non‐neoplastic mammary samples were examined. The expression of p62 was higher in normal tissue and adenomas than carcinomas, with lowest levels of p62 protein detected in high grade carcinomas. In all cases examined the tumour stroma appeared to be p62‐negative. Taken together our results would suggest that in dogs the association between p62 expression and cancer cells overturns that reported in human breast carcinoma, where p62 accumulates in malignant cells as compared to normal epithelium. Thus, at least in canine mammary tumours, p62 should be not considered a tumour‐rejection antigen for an anti‐cancer immunotherapy.