Ovine footrot: new approaches to an old disease

Footrot is a bacterial disease that has substantial economic and welfare impacts in sheep and can be difficult to manage. Research is focussed on reducing the impact that footrot has on farmers and their flocks and better understanding the aetiology of the disease. Key areas of current research include, developing better vaccines, deploying tailored vaccines in a specific and targeted fashion on individual farms, analysing and developing better farm management practices to suit specific sheep farming environments, elucidating the virulence genes and bacterial population dynamics that drive footrot and using genetic testing in combination with selective breeding to produce stock that are more resilient to disease.     

Ovine Johne's disease in New Zealand

Abstract

Extract

Cambendazole, isopropy1 2-(4-thiazoly1)-5-benzimidazolecarbamate, has been reported to be a highly efficient anthelmintic against gastro-intestinal nematodes of cattle (Egerton et al., 1970 Egerton, J. R., Eary, C. H., Lanza, G. R., Wombolt, T. H. and Campbell, W. C. 1970. The efficacy of cambendazole against gastro-intestinal nematodes of cattle. Res. vet. Sci., 11: 495–499.  [Google Scholar]; Baker and Walters, 1971 Baker, N. P. and Walters, G. T. 1971. Anthelmintic efficacy of cambendazole in cattle. Ant. J. vet. Res., 14: 29–33.  [Google Scholar]; Ciordia and McCampbell, 1971 Ciordia, J. and McCampbell, H. C. 1971. Anthelmintic efficacy of four dose levels of cambendazole in cattle. Proc. helm. Soc. Wash., 38: 40–42.  [Google Scholar]; Benz, 1971a Benz, G. W. 1971a. Anthelmintic activities of cambendazole in calves. Am. J. vet. Res., 32: 399–403.  [Google Scholar], b Benz, G. W. 1971b. Activity of cambendazole against gastro-intestinal nematodes of calves: Single vs. two therapeutic treatments. J. Parasit., 57: 286–288.  [Google Scholar]; Restani, 1971 Restani, R. 1971. Research on the anthelmintic activity of cambendazole against some nematodes of cattle. Vet. Italiana, 22: 137–139.  [Google Scholar]). Efficacy against the cattle lungworm, Dictyocaulus viviparus, has also been reported as high (Rubin, 1972 Rubin, R. 1972. Efficacy of cambendazole against lungworm (Dictyocaulus vivipams) of cattle. Am. J. vet. Res., 33: 425–426.  [Google Scholar]; Gibbs and Gupta, 1972 Gibbs, H. C. and Gupta, R. P. 1972. The anthelmintic activity of cambendazole in calves and lambs. Can. J. comp. Med., 36: 108–115.  [Google Scholar]; Baker et al., 1972 Baker, N. F., Walters, G. T., Hjerp, G. A. and Fisk, R. A. 1972. Experimental therapy of Dictyocaulus viviparis infection in cattle with cambendazole. Am. J. vet. Res., 33: 1127–1130.  [Google Scholar]). This paperreports the results of four controlled critical efficacy trials with cambendazole against naturally acquired nematode infections in cattle.     

Immunity and mastitis. Some new ideas for an old disease.

The biggest challenge for host immune defense against mastitis-causing bacteria in dairy cows is to quickly recruit large enough numbers of opsonizing molecules and mature neutrophils into milk such that intramammary pathogens are cleared before they multiply significantly and the inflammatory response gets out of control. Currently, this challenge is best facilitated when established mastitis control procedures are practiced on the farm, including proper hygiene, milking procedures, and regular administration of approved mastitis vaccines. However, mastitis is still a significant problem. New animal functional genomics research is beginning to allow scientists to solve the puzzle of mastitis susceptibility. Results of this type of research offer the hope of giant leaps toward a clear identification of molecular genetic variation and potential gene targets for therapies and immune manipulations that could significantly reduce the risk of clinical mastitis in traditionally susceptible cows.     

New techniques for an old disease: sarcoptic mange in the Iberian wolf

Sarcoptic mange, a parasitic skin infection caused by the burrowing mite Sarcoptes scabiei, has been reported in over 100 mammals, including humans. In endangered species, mange causes conservation concerns because it may decimate isolated populations and contribute to extinction. The Iberian Peninsula still maintains one of the largest wolf (Canis lupus) populations in Europe. In Iberia, sarcoptic mange is endemic in red foxes (Vulpes vulpes) and the first confirmed wolf mange cases were recently reported. However, knowledge on S. scabiei in wolves is scarce because of the sampling difficulties inherent to research on scarce species. In order to describe wolf mange epidemiology and to infer conservation implications, this study combined traditional laboratory techniques with the revision of wolf carcass pictures taken by field biologists and original information obtained by camera trapping. A total of 125 necropsies and 8783 camera-trap days allowed insights into wolf mange epidemiology between 2003 and 2010. Living Sarcoptes mites were detected in 19% of the fresh carcasses. Alopecic (delayed) type IV hypersensitive response reactions were observed, while parakeratotic lesions were infrequent. The number of mites isolated per wolf ranged from 1 to 78, and had a negative correlation with the percentage of alopecic skin. No effect by sex on mange prevalence was found. Yearlings showed a lower probability to present mange-compatible lesions than pups or adults. Wolves with mange-compatible lesions had a lower kidney fat index than apparently healthy ones. ELISA testing of 88 sera yielded an antibody prevalence of 20%. Photo-trapping recorded mange-compatible lesions since 2003 with a peak in 2008. The percentage of wolves with mange-compatible lesions registered in camera-traps during 1 year correlated with the percentage of red foxes with lesions in the previous year. This is the first large survey on sarcoptic mange in the Iberian wolf. Necropsy data, with alopecia as the main feature and a slight effect on body condition, and trends derived from camera trapping coincided in showing a rather low prevalence and an apparently stable situation of the disease and its host, suggesting that this parasite is currently not a major threat for this wolf population. However, more information is needed in order to assess the effect of mange on aspects such as pup survival.     

Comparison of a New Braid Fixation System to an Interlocking Intramedullary Nail for Tibial Osteotomy Repair in an Ovine Model

Objectives— To compare bone healing of tibial osteotomy repaired with Nitinol wire braid and hardened steel rods (Braid system) and polymethylmethacrylate bone cement with an interlocking intramedullary (IM) nail fixation in an ovine model.
Study Design— In vitro and in vivo experimental study.
Animals— Adult female sheep (n=22).
Methods— Using sheep tibia, a middiaphyseal transverse osteotomy was performed in the right tibia, which were then randomly assigned to the Braid system group or IM nail group (n=5). The left tibia were used as controls. The torsional properties of tibial constructs were compared. The study was repeated in vivo in 12 sheep and mechanical properties and bone healing were evaluated at 12 weeks.
Results— In vitro, there was no significant difference in torsional stiffness between the groups. In vivo, operative time for the Braid system group was significantly shorter than the IM nail group. At 12 weeks, there were no significant differences in maximum torque and torsional stiffness between IM nail and Braid system groups nor were there significant radiographic or histologic differences between the groups.
Conclusions— The Braid system might decrease operative time for repair of transverse middiaphyseal tibial fractures and result in similar bone healing at 12 weeks after surgery compared with an interlocking IM nail repair.
Clinical Relevance— A Nitinol Braid system may be a treatment option for transverse midshaft tibial fractures.     

Ovine progressive pneumonia (Maedi-Visna): an emerging respiratory disease of sheep in Ethiopia

A serological study was done to assess the role of Maedi-Visna (MV) infection in sheep from flocks with high respiratory tract disease morbidity in Ethiopia. Of 105 sheep examined from central Ethiopia 78 (74%) were positive for MV-infection. However, antibodies to the virus were not detected in 48 sheep and 70 goats from elsewhere in Ethiopia. The infection was detected in all breeds of sheep examined (Awassi, Hampshire, Corriedale, indigenous Menz breeds and their crosses) but with a significant breed difference (chi 2 = 20, p < 0.001) varying from 48% in imported Awassi sheep to 92% in the indigenous Menz sheep. This suggests that Menz sheep are more susceptible to infection, which may support the observation of a higher incidence of clinical disease in these sheep compared to exotic breeds and their crosses. It also supports recent studies indicating that MV is becoming one of the most important respiratory tract diseases in sheep in central Ethiopia. Our findings indicate that MV was introduced into Ethiopia via sheep imported into the central highlands and that it now constitutes an important emerging disease is discussed. Measures to control the disease are suggested.     

The molecular mechanisms of scrapie encephalopathy and relevance to human neurodegenerative disease.

We have investigated alterations in the structure and function of nuclei isolated from normal and pathological brains in a number of neurodegenerative diseases including scrapie and Alzheimer's disease. Here we summarize both general and specific changes in chromatin structure, gene expression, and neuropathological features for each encephalopathy and compare them in terms of their molecular biological similarities and differences. While both scrapie and Alzheimer's disease share a number of common alterations in genomic organization and gene activity during the pathogenic process, each neurological disease appears to operate on fundamentally different mechanisms.     

老病毒新流行——浅谈猪圆环病毒（PCV2）感染

自从1991年加拿大报道猪断奶后衰竭综合症(PMWS)以来,美国、英国、丹麦、意大利、墨西哥、匈牙利等国以及日本、泰国和我国皆有此病的发生流行报告。据文献资料介绍在二、三十年前即有此病的报道,虽然PCV广泛分布于许多国家的猪群中,猪群血清阳性率可达20%-80%不等,但是,实际上只有相对较小比例的猪或猪群发病,存在大量隐性感染。近些年来,引起PMWS的发病流行,往往与同时感染了PRRSV(猪繁殖呼吸综合症病毒),或是PPV(细小病毒)、PRV(伪狂犬病毒)等因素有关。目前知道与圆环病毒感染有关的疾病,还有猪皮炎和肾病综合症、猪间质性肺炎…     

Immune-mediated disease in the old English sheepdog.

Immunological data are reported from 19 cases of immune-mediated disease recorded in the old English sheepdog breed in Western Australia between 1978 and 1989. The conditions included autoimmune haemolytic anaemia (seven), idiopathic thrombocytopenia (one), Evans' syndrome (five), multiple myeloma (two), systemic lupus erythematosus (one), discoid lupus erythematosus (one) and hypothyroidism (two). The most consistent serological findings were raised serum IgG (60 per cent), depressed serum IgM (60 per cent) and the presence of multiple autoantibodies (anti-red blood cell 78 per cent, antinuclear antibody 44 per cent, rheumatoid factor 19 per cent). An underlying, breed-related disorder of immune regulation may account for these observations.     

Simulation of the options for a national control programme to eradicate scrapie from Great Britain

Because of the risk to public health posed by the potential presence of bovine spongiform encephalopathy (BSE) in sheep, there are plans to eradicate transmissible spongiform encephalopathies (TSEs) from the British sheep population. We used a mathematical model for the spread of scrapie between sheep flocks to assess the efficacy of five control strategies at eradicating the infection from the national flock. These range from ram-genotyping schemes through whole-flock genotyping with selective culling to whole-flock slaughter. The impact of control was considered under three scenarios for the long-term dynamics of scrapie in GB: two in which scrapie is ultimately eliminated (with different median extinction times) and one in which scrapie remains endemic. Results suggested that it is feasible to eradicate scrapie from the British sheep flock, but that any national control programme will take decades to eliminate the disease and be costly. The most-effective strategy, measured in terms of the probability of eradication and time taken for eradication, was predicted to be whole-flock culling, which was effective under all three scenarios for the long-term dynamics of scrapie. Strategies involving whole-flock genotyping with selective culling were also effective, though they were predicted to take longer to eradicate scrapie than whole-flock culling. Ram-genotyping schemes were effective in some instances, but not for the scenario where scrapie remained endemic in the national flock. At low levels of reporting of clinical disease (<20%) the probability of eradication within 100 years was predicted to be <100% and, consequently, low levels of reporting could compromise the effectiveness of a control programme. Moreover, the predicted time taken to eradicate scrapie would increase markedly if the reporting compliance decreased.     

Feline experimental models for control of periodontal disease.

Feline periodontal disease has many elements in common with human and canine disease. Anatomic, physiologic, microbiologic, and immunologic differences between the three species make it impossible to predict with certainty whether successful approaches to controlling and treating canine oral disease will also prove successful in cats. We have developed methods for reproducible, quantitative evaluation of feline dental plaque and calculus. Our studies demonstrated that feline plaque accumulation peaks at 1 week after prophylaxis and that calculus peaks at 4 weeks after prophylaxis. These methods should be adequately sensitive to document control of plaque and calculus accumulation by efficacious chemical or antimicrobial agents.