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Bailey S.S.,University of Bristol | Crawshaw T.R.,Animal Health and Veterinary Laboratories Agency Starcross | Smith N.H.,Animal Health and Veterinary Laboratories Agency Weybridge | Palgrave C.J.,University of Bristol
Veterinary Journal | Year: 2013

Mycobacterium bovis, the causative agent of bovine tuberculosis (TB), infects a wide range of wild and domestic mammals. Despite a control programme spanning decades, M. bovis infection levels in cattle in Great Britain (GB) have continued to rise over recent years. As the incidence of infection in cattle and wildlife may be linked to that in swine, data relating to infection of pigs identified at slaughter were examined in this study. Between 2007 and 2011, almost all M. bovis-infected pigs originated from farms in the South-West and West-Midland regions of England. The data suggest that pigs raised outdoors or on holdings with poor biosecurity may be more vulnerable to infection with M. bovis. In the majority of cases, the same strains of M. bovis were found in pigs and cattle, despite that fact that direct contact between these species was rarely observed. Genotyping and geographical mapping data indicated that some strains found in pigs may correlate better with those present in badgers, rather than cattle. In consequence, it is proposed that pigs may represent a useful sentinel for M. bovis infection in wildlife in GB. Given the potential implications of this infection for the pig industry, and for the on-going effort to control bovine TB, the importance of understanding the epidemiology and pathogenesis of M. bovis infection, as well as monitoring its prevalence, in pigs should not be underestimated. © 2013. Source

Hope J.,Animal Health and Veterinary Laboratories Agency Weybridge
Current Topics in Microbiology and Immunology | Year: 2013

Bovine spongiform encephalopathy (BSE) is a protein misfolding disease of cattle which belongs to the group of transmissible spongiform encephalopathies (TSEs) or prion diseases. This group also includes scrapie in sheep and goats, chronic wasting disease (CWD) of cervids and Creutzfeldt-Jakob disease (CJD) humans. The first case of BSE was recognised in England in 1986 as a progressive, neurological condition where affected animals behaved abnormally, exhibited anxiety, ataxia, hypersensitivity to touch and noise and poor body condition. Spongiform change was observed in the brain stem of cattle at postmortem and its similarity to scrapie in sheep stimulated biochemical investigation and transmission studies which confirmed it as a novel prion disease of cattle. Epidemiological analysis of the initial cases of disease implicated a common extended source of infection, likely to be related to feed, and stimulated a series of control measures designed to restrict feeding of mammalian-derived protein to ruminants in various parts of the United Kingdom and to prevent the use of various bovine offals in feed or food production. This article outlines the rise and fall of the incidence of BSE in the UK and Europe, its classification as a zoonotic disease with the emergence of variant CJD, the implications of it as a prion disease and challenge its diagnosis and control continues to represent worldwide. © 2012 Springer-Verlag Berlin Heidelberg. Source

Lofthouse E.K.,Animal Health and Veterinary Laboratories Agency Weybridge
PloS one | Year: 2013

The Mycobacterium tuberculosis complex includes bovine and human strains of the tuberculosis bacillus, including Mycobacterium tuberculosis, Mycobacterium bovis and the Mycobacterium bovis BCG vaccine strain. M. bovis has evolved from a M. tuberculosis-like ancestor and is the ancestor of the BCG vaccine. The pathogens demonstrate distinct differences in virulence, host range and metabolism, but the role of metabolic differences in pathogenicity is poorly understood. Systems biology approaches have been used to investigate the metabolism of M. tuberculosis, but not to probe differences between tuberculosis strains. In this study genome scale metabolic networks of M. bovis and M. bovis BCG were constructed and interrogated, along with a M. tuberculosis network, to predict substrate utilisation, gene essentiality and growth rates. The models correctly predicted 87-88% of high-throughput phenotype data, 75-76% of gene essentiality data and in silico-predicted growth rates matched measured rates. However, analysis of the metabolic networks identified discrepancies between in silico predictions and in vitro data, highlighting areas of incomplete metabolic knowledge. Additional experimental studies carried out to probe these inconsistencies revealed novel insights into the metabolism of these strains. For instance, that the reduction in metabolic capability observed in bovine tuberculosis strains, as compared to M. tuberculosis, is not reflected by current genetic or enzymatic knowledge. Hence, the in silico networks not only successfully simulate many aspects of the growth and physiology of these mycobacteria, but also provide an invaluable tool for future metabolic studies. Source

Alexander D.J.,Animal Health and Veterinary Laboratories Agency Weybridge
Avian Pathology | Year: 2011

Newcastle disease (ND) is a devastating disease of poultry that has to some extent been neglected by those working in the field in the past 10 to 15 years while attention has been focused on the emergence and spread of highly pathogenic avian influenza caused by a H5N1 subtype virus. During 2000 to 2009 in the European Union (EU) member states, ND viruses virulent for chickens have been detected in wild birds, domesticated pigeons and poultry. Based on these isolations it appears that the epizootic in racing pigeons caused by the variant viruses termed pigeon avian paramyxovirus type 1, which form the genetic group 4b(VIb) first seen in Europe in 1981, continued during 2000 to 2009, and the virus is probably enzootic in racing pigeons in some EU countries. This virus appears to have spread regularly to wild birds, especially those of the Columbidae family, and has been the cause of significant outbreaks in poultry. Other avian paramyxovirus type 1 viruses responsible for ND outbreaks in the EU during 2000 to 2009 have been those from genetic groups 5b(VIIb) and 5d(VIId). There is evidence that the former may well represent spread from a wild bird source and these viruses have also been isolated from wild birds, while the latter represents continuing spread from the East. Future legislation or recommendations aimed at the control and eradication of ND will need to encompass these three sources of virulent ND viruses. © 2011 Copyright Crown Copyright (Animal Health and Veterinary Laboratories Agency). Source

Wooldridge M.,Animal Health and Veterinary Laboratories Agency Weybridge
OIE Revue Scientifique et Technique | Year: 2012

The concern over antibiotic-resistant bacteria producing human infections that are difficult to treat has led to a proliferation of studies in recent years investigating resistance in livestock, food products, the environment and people, as well as in the mechanisms of transfer of the genetic elements of resistance between bacteria, and the routes, or risk pathways, by which the spread of resistance might occur. The possibility of transfer of resistant genetic elements between bacteria in mixed populations adds many additional and complex potential routes of spread. There is now considerable evidence that transfer of antimicrobial resistance from food-producing animals to humans directly via the food chain is a likely route of spread. The application of animal wastes to farmland and subsequent leaching into watercourses has also been shown to lead to many potential, but less well-documented, pathways for spread. Often, however, where contamination of water sources, processed foods, and other environmental sites is concerned, specific routes of circulation are unclear and may well involve human sources of contamination. Examination of water sources in particular may be difficult due to dilution and their natural flow. Also, as meat is comparatively easy to examine, and is frequently suspected of being a source of spread, there is some bias in favour of studying this vehicle. Such complexities mean that, with the evidence currently available, it is not possible to prioritise the importance of potential risk pathways and circulation routes. Source

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