Collateral vessel development after chronic bilateral common carotid artery occlusion in the dog

The functional response to occlusion of arteries supplying the head has been found to be much less severe in th dog than in man, indicating that a more significant collateral development occurs in the dog. To document the anatomic response to chronic occlusion of vessels supplying the head, patterns of collateral vessel growth and development were studied by corrosion casting in adult mongrel dogs 8 weeks after bilateral ligation of the common carotid artery. Dissection of the casts revealed two consistent and bilateral anastomotic connections: (i) internal carotid artery to maxillary artery (anastomotic artery) and (ii) internal carotid artery to ascending pharyngeal artery. Also present in all of the casts was a connection between one common carotid artery and both vertebral arteries, which has been designated as the deep collateral vessel. Significant collateral connections did not occur between the orbital vessels or between analogous vessels of the right and the left sides.     

Comparison of a serum indirect fluorescent antibody test with two Western blot tests for the diagnosis of equine protozoal myeloencephalitis.

A serum indirect fluorescent antibody test (IFAT) was compared with a Western blot (WB) and a modified Western blot (mWB) for diagnosis of equine protozoal myeloencephalitis (EPM). Using receiver-operating characteristic (ROC) analysis, the area under the curve of the IFAT was greater than the areaunder the curves of the WB and the mWB (P = 0.025 and P = 0.044, respectively). There was no statistically significant difference between the areas under the curves of the WBs (P > 0.05). On the basis of an arbitrarily chosen cut-off titer for a positive test result of 1:80 for the IFAT and interpreting weak positive WB results as positive test results, the sensitivities and 95% confidence intervals (CI) of all 3 tests were identical and equal to 88.9% (51.8-99.7%). The specificities and 95% CIs of the IFAT, WB, and mWB test were 100% (91-100%), 87.2% (72.6-95.7%), and 69.2% (52.4-83%), respectively. The overall accuracy of the IFAT was shown to be better than that of the WBs and, therefore, the test has potential for use in the diagnosis of EPM caused by Sarcocystis neurona.     

Serosurvey of Babesia canis, Babesia gibsoni and Ehrlichia canis in pound dogs in California, USA

The seroprevalence of three canine tick-transmitted parasites, Babesia gibsoni, Babesia canis and Ehrlichia canis, was estimated in selected regions of California. Blood smears and sera were obtained from 971 dogs in seven animal shelters: four in Los Angeles County, one in Yolo County, one in El Dorado County in California and one in Minden, Nevada. Seroprevalence in Los Angeles County shelters were 0–13%, 0–2.6% and 0% for B. canis, B. gibsoni and E. canis, respectively. Seroprevalences of the same three parasites in Yolo County and El Dorado County Shelters were 0% except for a 1% seroprevalence of B. canis in dogs from Yolo County Shelter.

Potential risk factors (breed, age, sex and evidence of ticks on the dogs) for B. canis seropositivity were evaluated. Dogs 3 years of age or older had a significantly higher risk (odds ratio 5.04) of being seropositive to B. canis compared with dogs less than 1 year old. Breed, sex and evidence of ticks were not associated with seropositive reactions to B. canis. Of 29 coyotes captured in Los Angeles County, three (10.3%) were seropositive for B. gibsoni, with titers of 1280 to 2560. This study indicated that dogs in Los Angeles County were at higher risk of being seropositive and potentially infected with canine babesial parasites than dogs in Yolo and El Dorado Counties. Movement of chronically infected dogs from Los Angeles County into other areas could contribute to the spread of these important pathogens.     

Different Culture Media Requirements of IVF and Nuclear Transfer Bovine Embryos

Important differences exist between in vitro fertilized (IVF) and nuclear transfer (NT) bovine embryos. Studies have shown that although in vitro development is comparable, post-implantation survival is greatly reduced in NT embryos. In this study, we compare serum and bovine serum albumin (BSA) supplementation during oocyte maturation and embryo culture of IVF and NT embryos. In experiment 1, oocytes and embryos were randomly distributed into different treatment groups consisting of synthetic oviductal fluid (SOF) medium supplemented with either serum, fatty acid-free BSA (FAF) or fraction V BSA during maturation and/or culture to assess IVF embryo development. In experiment 2, oocytes were matured in SOF + serum or SOF + FAF and reconstructed embryos were cultured in SOF + FAF to assess NT embryo development. Among the IVF treatment groups, a greater number of blastocysts were observed in the steer serum (SER) group (IVM and IVC in SOF + serum) on day 6; however, no significant differences were seen in blastocyst development from day 8 onwards. Hatching frequencies on days 8 and 9 were significantly greater in groups with serum, with the exception of FAF (IVM and IVC in SOF + FAF) on day 9. For the NT treatment groups, the presence of serum during IVM resulted in a higher proportion of MII oocytes and increased blastocyst development and hatching rates were compared with supplementation of FAF. These results indicate that both serum and FAF provide comparable embryo development for IVF but not for NT bovine embryos.     

First isolation of EBLV-2 in Germany

In Europe, rabies in bats is caused by European Bat Lyssavirus (EBLV) type 1 (EBLV-1) or type 2 (EBLV-2) which form two distinct genotypes (gt 5 and 6) within the genus Lyssavirus of the family of Rhadoviridae. Spill-over infections of EBLV in humans have caused fatal rabies encephalitis and highlighted the relevance of this wildlife disease for public health. The vast majority of the 831 European bat rabies cases reported between 1977 and 2006 were identified as EBLV-1. Only few virus isolates originating from Switzerland, The Netherlands and the United Kingdom were characterized as EBLV-2. Here we report the first EBLV-2 case detected in Germany in a Daubenton's bat (Myotis daubentonii) in August 2007. The bat showed clinical signs of disorders of the central nervous system and subsequently tested positive for rabies. The virus was isolated and characterized as EBLV-2 based on its antigen pattern and by nucleotide sequencing. Phylogenetic analysis indicated an association to EBLV-2 isolates from Switzerland which correlates with the origin of the bat close to the Swiss border.     

A systematic representation of crop rotations

Crop rotations are allocations by growers of crop types to specific fields through time. This paper aims at presenting (i) a systematic and rigorous mathematical representation of crops rotations; and (ii) a concise mathematical framework to model crop rotations, which is useable on landscape scale modelling of agronomical practices. Rotations can be defined as temporal arrangements of crops and can be classified systematically according to their internal variability and cyclical pattern. Crop sequences in a rotation can be quantified as a transition matrix, with the Markovian property that the allocation in a given year depends on the crop allocated in the previous year. Such transition matrices can represent stochastic processes and thus facilitate modelling uncertainty in rotations, and forecasting of the long-term proportions of each crop in a rotation, such as changes in climate or economics. The matrices also permit modelling transitions between rotations due to external variables. Computer software was developed that incorporates these techniques and was used to simulate landscape scale agronomic processes over decadal periods.