Immune reactions in cattle after immunization with a Mycobacterium paratuberculosis vaccine and implications for the diagnosis of M. paratuberculosis and M. bovis infections

After immunization of four calves with a live modified Mycobacterium paratuberculosis vaccine the course of the humoral and cell mediated immune reactions was studied during a 2-year clinical investigation. Furthermore, the possibility of shedding of the vaccine strain and the influence of the vaccination on the tuberculin skin test was determined. In addition to standard procedures recently developed diagnostic methods (antibody enzyme-linked immunosorbent assay, interferon-gamma test, polymerase chain reaction) were used. A cell-mediated immune reaction, reflected in an increased, specifically induced, interferon-gamma production developed much earlier (1-2 weeks post-immunization) than humoral immunity (8-16 weeks post-gamma immunization). While the increase in antibody titres was transient, declining to extremely low levels 48-60 weeks post-immunization, cell-mediated immunity remained detectable until the end of the investigation. Spread of the vaccine strain into the body and shedding were never detected during the whole course of the study except for one colon site in one calf. As late as 2 years after vaccine application positive or doubtful skin reactions against M. bovis purified protein derivative were measured, reflecting possible interference of the immunization with the diagnosis of bovine tuberculosis. At the end of the investigation, a positive cell-mediated immune reaction was detected the control animal although clinical, pathological and bacteriological examinations gave no indication for a mycobacterial infection.     

Idiopathic skeletal muscle necrosis in bluegills

Skeletal muscle degeneration and necrosis in a wild population of bluegills (Lepomis macrochirus) were investigated. Hemorrhage and large areas of muscle necrosis were evident at necropsy. Histologically, muscle fibers were granular, vacuolated, and fragmented. Ultrastructural alterations included mitochondrial swelling, clumping and loss of actin and myosin fibrils, swelling of T tubules, and loss of continuity of the sarcolemma. An etiologic agent was not identified.     

Detection of Campylobacter jejuni strains in the water lines of a commercial broiler house and their relationship to the strains that colonized the chickens

Campylobacter jejuni is frequently present in the intestinal tract of commercial broiler chickens, and their drinking water has been proposed to be an initial source of bacteria for newly hatched chicks. We studied three sequential commercial broiler flocks raised in a house from which we had cultured C. jejuni from the nipple waters prior to placement of the first flock. Campylobacter cells were detected by immunofluorescence in the biofilm of the drinking nipples during the weeks when the flock was colonized with C. jejuni but not during weeks when the birds were negative. Campylobacter jejuni was isolated from the drinking water during the growth of the first flock and was present in the birds from all three flocks. Randomly amplified polymorphic DNA (RAPD)-polymerase chain reaction (PCR) typing with primer OPA11 indicated that seven distinct strains were present within the broiler house. One strain found in drinking water was similar to a strain found in birds in the second flock; however, RAPD-PCR with primer HLW85 showed that the strains were not identical. These results suggest that although the watering system is a potential source of C. jejuni in broiler flocks, the waterborne strain in this study was not detected in the birds.     

Predictive values of serum and bulk milk sampling for the presence of persistently infected BVDV carriers in dairy herds

The aim of this study was to examine whether it is possible to predict the presence of persistently infected (PI) animals with bovine viral diarrhoea virus on dairy farms in The Netherlands, based on a few blood samples of the herd, possibly in combination with a bulk milk test for antibodies. In 25 herds with, and 24 herds without, PI animal(s) the probabilities of obtaining at least x antibody positive animals out of a sample of n animals were calculated, with n varying from 3 to 7 and values for x that were considered were n, n - 1 to n - x. This probability, among animals 9-24 months old, ranged from 0.70 to 0.96 for herds with PI animals and from 0.13 to 0.37 for herds without. Using the result of bulk milk testing in addition did not add to the prediction. It was concluded that, due to the high percentage and large variation of antibody positive animals in herds without PI animals, it is not possible to predict the presence of PI animal(s) in dairy herds in The Netherlands using these methods.     

Classification of thermally modified wood by FT-NIR spectroscopy and SIMCA

Quality assessment of thermally modified wood has evolved as one of the major fields in the research on thermal modification of wood. This study investigates NIR spectroscopy in combination with the pattern recognition method of soft independent modeling of class analogies (SIMCA). Focus is put on identifying different treatment intensities of thermally modified samples of beech, ash, and Norway spruce. The results indicate that SIMCA classification based on NIR spectroscopy could be used for quality control of thermally modified wood. The method might be applicable for producers (pre-delivery checks) and customers (reception control). However, transfer from laboratory to industrial conditions needs further investigation.     

Clinical evaluation and prerelease management of American river otters in the second year of a reintroduction study

In the first year (1984) of a reintroduction study, 10 American river otters (Lutra canadensis) from Louisiana were transported to Oklahoma, held for 5 days for clinical evaluation, surgical implantation with intra-abdominal radiotelemetry devices, and then released in Oklahoma. Four of 10 otters released died within 32 days. Clinical evaluation indicated that respiratory tract disease, bacterial and parasitic infections, and inanition may have contributed to the death of these otters. In the second year (1985) of the study, an exotic feline diet was fed, and the holding period for 10 otters was increased to provide time for evaluation and treatment before surgery, postsurgical acclimation to Oklahoma, and reevaluation before release. Although the initial clinical findings on otters in the second year were similar to those found in the first year, otter body weights increased, and the prevalence and severity of clinical abnormalities decreased with treatment during the second-year holding period. Three of 10 second-year otters died during the holding period, and contributing causes of death were determined to be: trauma (hepatic hematoma), inanition, renal disease, pneumonia, salmonellosis (Salmonella anatum), and a retropharyngeal abscess (Klebsiella pneumoniae). Seven healthy otters were reintroduced into Oklahoma in 1985, and postrelease deaths were not experienced.