Angiostrongylus vasorum infection in dogs: continuing spread and developments in diagnosis and treatment

Disease caused by Angiostrongylus vasorum is increasingly diagnosed in dogs, as the geographic range of the parasite increases along with awareness among clinicians. Diagnosis, treatment and prevention are not always straightforward, although recent developments offer hope for improved options in future. Understanding of the epidemiology and pathogenesis remains poor. This paper provides an overview of the current state of knowledge of this parasitic disease, focussing on the most recent developments and advances.     

A survey of helminth control practices on sheep farms in Great Britain and Ireland

A telephone survey of 600 farmers throughout Great Britain and Ireland was conducted in order to characterise helminth control practices, and identify factors correlated with perceived anthelmintic failure. Overall, 93% of surveyed farmers routinely treated their sheep against nematodes, 67% against liver fluke and 58% against tapeworms. Anthelmintic resistance in nematodes was perceived by farmers to be present on 10% of farms. Farmers who dosed ewes at mating were more likely to have observed anthelmintic failure, than those who were aware of national guidelines on parasite control. However, objective assessment of anthelmintic efficacy had only been undertaken on 19% of farms. Ewes were treated at mating and lambing on 63% and 62% of farms, respectively. On average, lambs were treated 3.6 times annually, depending on geographical region and on dates of lambing and finishing. Although 'quarantine' treatments were widely administered to bought-in stock, these were appropriately applied in only 3% of cases. This study provides baseline data against which the impact of future anthelmintic information campaigns can be assessed; it will facilitate the development of rational, farm-level mathematical models in support of sustainable parasite control, and will aid in the design of farm management practices that prolong the effective lifespan of novel classes of anthelmintic.     

Comparison of the Biobullet versus traditional pharmaceutical injection techniques on injection-site tissue damage and tenderness in beef subprimals

The incidence and severity of injection-site lesions has decreased since the development of the Beef Quality Assurance program. The objective was to evaluate the route of administration and the pharmaceutical product on the impact on tenderness, collagen concentration, and lesion occurrence in muscles of chucks and rounds. A total of 144 yearling steers (initial BW = 383 +/- 29.4 kg) were selected and transported to Oklahoma State University. Steers were blocked into 2 groups of 72 based on initial BW and were randomly allocated, within block, into pens of 6 head per pen (12 pens per block). Each pen was randomly assigned an injection protocol. On May 19, 2006 (d 0), steers were administered one of the following treatment injections: a standard Biobullet containing 100 mg of ceftiofur sodium (Naxel, Pfizer Inc., New York, NY); a traditional needle and syringe dose of ceftiofur sodium; a standard Biobullet containing BallistiVac infectious bovine rhinotracheitis (IBR; Titanium 5, SolidTech Animal Health, Newcastle, OK); a traditional needle and syringe dose of IBR; a traditional needle and syringe dose of Vira Shield 5 (Grand Laboratories Inc., Freeman, SD); a standard placebo Biobullet; or a traditional needle and syringe dose of sterile water. Percentage of samples with an identifiable lesion did not differ by drug administered or injection method. Warner-Bratzler shear force values of lesion center cores in chucks tended to be different (P = 0.07) from cores from the control steaks and at 2.54 and 5.08 cm away from the lesion center. Lesion centers from the Biobullet-BallistiVac IBR had a Warner-Bratzler shear force value of 7.01 kg, which was greater (P < 0.05) than values for lesion centers from chucks injected with a Biobullet-placebo (6.27 kg) or needle-ceftiofur sodium (5.08 kg). No significant differences (P > 0.10) were observed in the total collagenous connective tissue in samples extracted from the chuck or round. The comparison of lesion site and control (nonlesion site) samples for lipid concentration showed no significant difference (P > 0.10) among treatments in the round. It was concluded the Biobullet did not create a greater occurrence of lesions in the muscles of the chuck and round. The Biobullet is not an appropriate injection method for the round of beef cattle because it caused tissue damage similar to a needle injection. However, the Biobullet can be used effectively in neck (chuck) applications without additional negative effects on tenderness.     

Prediction of chicken embryo lethality with the avian Escherichia coli traits complement resistance,colicin V production,and presence of the increased serum survival gene cluster (iss)

Differentiating between virulent and avirulent avian Escherichia coli isolates continues to be a problem for poultry diagnostic laboratories and the study of colibacillosis in poultry. The ability of a laboratory to conduct one simple test that correlates with virulence would simplify studies in these areas; however, previous studies have not enabled researchers to establish such a test. In this study, the occurrence of certain phenotypic and genotypic traits purported to contribute to avian E. coli virulence in 20 avian E. coli isolates was correlated with the results of embryo challenge studies. This analysis was undertaken in an effort to determine which trait(s) best identified each avian E. coli isolate as virulent or avirulent. Traits selected were complement resistance, production of colicin V (ColV), motility, type F1 pili expression, presence of the temperature-sensitive hemagglutinin gene (tsh), and presence of the increased serum survival genetic locus (iss). ColV production, complement resistance, and presence of the iss genetic element were the three traits most highly correlated with high embryo lethality. A logistic regression model was used to predict the embryo lethality results on the basis of the most frequent isolate characteristics. Results indicate that ColV, complement resistance, and if are significant predictor variables for the percentage of embryo lethality resulting from challenge with a specific avian E. coli isolate. However, no single trait has the ability to predict virulent isolates 100% of the time. Such results suggest the possibility that the embryo lethality assay may prove to be the one test needed to determine if an avian E. coli isolate is virulent.     

Primary degenerative joint disease of the shoulder in a colony of beagles

Shoulder joints of 149 Beagles over 8 years old at the time of death (mean age, 13.8 years +/- 3.21), were examined radiographically throughout their life-times for the frequency of degenerative joint disease (DJD). Clinical histories revealed no underlying cause for DJD. The shoulder joints of a subgroup of 18 dogs were examined at necropsy, and thin sections of the joints were evaluated radiographically and histologically. Serial clinical radiographic studies indicated that normal shoulder joint development during the first year of life was followed by the appearance of subchondral bone sclerosis and bony remodeling of normal joint contour, and by the formation of periarticular osteophytes and enthesiophytes. All changes were progressive with age and typical for DJD in dogs. Bilateral involvement was common. Evaluation of specimens obtained at necropsy revealed: articular cartilage change with roughening of the surface layer, degeneration and death of superficial chondrocytes, exposure of deeper layers of chondrocytes that had proliferated with fissuring of the damaged cartilage, total cartilage loss with polishing of the exposed subchondral bone, mixed patterns of subchondral bone sclerosis and osteoporosis, change in contour of the articular surfaces, and formation of periarticular osteophytes and enthesiophytes. Joint capsule thickening, synovitis, pannus formation, and synovial chondroma formation were observed. Because of the available clinical information, in addition to the typical changes of DJD, it was thought that the changes were primary. Instability appeared to play a role in the pathogenesis of the joint disease described; however, it was not clear whether the instability caused abnormal forces on healthy cartilage or whether the primary cartilage wear caused the instability.