Bovine Tuberculosis Risk Factors for British Herds Before and After the 2001 Foot-and-Mouth Epidemic: What have we Learned from the TB99 and CCS2005 Studies?

Over the last couple of decades, the UK experienced a substantial increase in the incidence and geographical spread of bovine tuberculosis (TB), in particular since the epidemic of foot-and-mouth disease (FMD) in 2001. The initiation of the Randomized Badger Culling Trial (RBCT) in 1998 in south-west England provided an opportunity for an in-depth collection of questionnaire data (covering farming practices, herd management and husbandry, trading and wildlife activity) from herds having experienced a TB breakdown between 1998 and early 2006 and randomly selected control herds, both within and outside the RBCT (the so-called TB99 and CCS2005 case-control studies). The data collated were split into four separate and comparable substudies related to either the pre-FMD or post-FMD period, which are brought together and discussed here for the first time. The findings suggest that the risk factors associated with TB breakdowns may have changed. Higher Mycobacterium bovis prevalence in badgers following the FMD epidemic may have contributed to the identification of the presence of badgers on a farm as a prominent TB risk factor only post-FMD. The strong emergence of contact/trading TB risk factors post-FMD suggests that the purchasing and movement of cattle, which took place to restock FMD-affected areas after 2001, may have exacerbated the TB problem. Post-FMD analyses also highlighted the potential impact of environmental factors on TB risk. Although no unique and universal solution exists to reduce the transmission of TB to and among British cattle, there is an evidence to suggest that applying the broad principles of biosecurity on farms reduces the risk of infection. However, with trading remaining as an important route of local and long-distance TB transmission, improvements in the detection of infected animals during pre- and post-movement testing should further reduce the geographical spread of the disease.

The badger; a monograph,

Mode of access: Internet.

Imperfect Creatures : Vermin, Literature, and the Sciences of Life, 1550-1750 /

Plagues of pests have always been a part of recorded history, but they hold special significance in the early modern period. 'Imperfect Creatures' is the first full-length study to investigate the shifting, unstable, but foundational status of “vermin” as creatures and category in the early modern literary and scientific imagination.

Improving diagnosis and oral vaccination strategies against bovine tuberculosis

In this work peptide antigens [ESAT-6,p45 in water (1ml, 1mg/ml)] have been adsorbed onto 10mg inorganic substrates (hydroxyapatite (MHA P201;P120, CHA), polystyrene, calcium carbonate and glass microspheres) and in vitro release characteristics were determined. The aim of formulation was to enhance the interaction of peptides with antigen presenting cells and to achieve rapid peptide release from the carrier compartment system in a mildly acidic environment. Hydroxyapatite microparticle P201 has a greater surface area and thus has the largest peptide adsorption compared to the P120. CHA gave a further higher adsorption due to larger surface area than that available on microparticles. These particles were incorporated into the BOVIGAMTM assay to determine if they improve the sensitivity. After overnight incubation the blood plasma was removed and the amount of IFN-g in each plasma sample was estimated. CHA and MHA P201 gave a significantly higher immune response at low peptide concentration compared to the free peptide, thus indicating that these systems can be used to evaluate Tuberculosis (TB) amongst cattle using the BOVIGAMTM assay. Badgers are a source of TB and pass infection to cattle. At the moment vaccination against TB in badgers is via the parenteral route and requires a trained veterinary surgeon as well as catching the badgers. This process is expensive and time consuming; consequently an oral delivery system for delivery of BCG vaccines is easier and cheaper. The initial stage involved addition of various surfactants and suspending agents to disperse BCG and the second stage involved testing for BCG viability. Various copolymers of Eudragit were used as enteric coating systems to protect BCG against the acidic environment of the stomach (SGF, 0.1M HCl pH 1.2 at 37oC) while dissolving completely in the alkaline environment of the small intestine (SIF, IM PBS solution pH 7.4 at 37oC). Eudragit L100 dispersed in 2ml PBS solution and 0.9ml Tween 80 (0.1%w/v) gave the best results remaining intact in SGF loosing only approximately 10-15% of the initial weight and dissolving completely within 3 hours. BCG was incorporated within the matrix formulation adjusted to pH 7 at the initial formulation stage containing PBS solution and Tween 80. It gave viability of x106 cfu/ml at initial formulation stage, freezing and freeze-drying stages. After this stage the matrix was compressed at 4 tons for 3 mins and placed in SGF for 2 hours and then in SIF until dissolved. The BCG viability dropped to x106 cfu/ml. There is potential to develop it further for oral delivery of BCG vaccine.

Assessment of different formulations of oral Mycobacterium bovis Bacille Calmette-Guerin (BCG) vaccine in rodent models for immunogenicity and protection against aerosol challenge with M-bovis

Bovine tuberculosis (bTB) caused by infection with Mycobacterium bovis is causing considerable economic loss to farmers and Government in the United Kingdom as its incidence is increasing. Efforts to control bTB in the UK are hampered by the infection in Eurasian badgers (Metes metes) that represent a wildlife reservoir and source of recurrent M. bovis exposure to cattle. Vaccination of badgers with the human TB vaccine, M. bovis Bacille Calmette-Guerin (BCG), in oral bait represents a possible disease control tool and holds the best prospect for reaching badger populations over a wide geographical area. Using mouse and guinea pig models, we evaluated the immunogenicity and protective efficacy, respectively, of candidate badger oral vaccines based on formulation of BCG in lipid matrix, alginate beads, or a novel microcapsular hybrid of both lipid and alginate. Two different oral doses of BCG were evaluated in each formulation for their protective efficacy in guinea pigs, while a single dose was evaluated in mice. In mice, significant immune responses (based on lymphocyte proliferation and expression of IFN-gamma) were only seen with the lipid matrix and the lipid in alginate microcapsular formulation, corresponding to the isolation of viable BCG from alimentary tract lymph nodes. In guinea pigs, only BCG formulated in lipid matrix conferred protection to the spleen and lungs following aerosol route challenge with M. bovis. Protection was seen with delivery doses in the range 10(6)-10(7) CFU, although this was more consistent in the spleen at the higher dose. No protection in terms of organ CFU was seen with BCG administered in alginate beads or in lipid in alginate microcapsules, although 10(7) in the latter formulation conferred protection in terms of increasing body weight after challenge and a smaller lung to body weight ratio at necropsy. These results highlight the potential for lipid, rather than alginate, -based vaccine formulations as suitable delivery vehicles for an oral BCG vaccine in badgers.

Caracterização da diversidade parasitária em carníveros silvestres e implicações na conservação

Recolher dados para actualizar os conhecimento da diversidade parasitária dos mesocarnívoros mais abundantes nas regiões do sul de Portugal e relacionar a dispersão parasitária, a conservação e a saúde humana constituíram os principais objetivos deste estudo. Raposas (Vulpes vulpes), sacarrabos (Herpestes ichneumon), fuinhas (Martes foina), ginetes (Genetta genetta) e texugos (Meles meles) atropelados foram os carnívoros-hospedeiros em estudo. Um grupo de raposas caçadas foi também considerado parte da amostra. A informação geo-referenciada de todos os animais serviu para executar a análise espacial. Realizaram-se necrópsias meticulosas e procedeu­ se à recolha, identificação e preservação dos parasitas encontrados. Pela primeira vez em Portugal é registada a presença do parasita da gineta Ancytostoma martinezi. A correlação entre os factores humanos e ambientais e, a riqueza de espécies foi determinada estatisticamente. Densidade populacional, disponibilidade de égua, tipo de uso de solo e distância mínima às sedes de concelho não apresentaram uma relação estatisticamente significativa com a infecção parasitária das raposas. Os resultados obtidos relativamente à presença de parasitas zoonóticos nos animais silvestres em estudo fomentam o trabalho multidisciplinar entre a Biologia da Conservação e as ciências médicas. ABSTRACT; The aim of this study was to collect data in order to update the information related to the parasitic diversity of the predominant mesocarnívores in the southern regions of Portugal and to establish relationships between the parasite dispersal, conservation and human health. Road killed foxes (Vulpes vulpes), mongoose (Herpestes ichneumon), stone marten (Martes foina), common genets (Genetta genetta) and euroasian badgers (Meles meles) were the considered carnivore-hosts. A sample of hunted foxes was also regarded.AD the animals had geo-reference information, ultimately used for spatial analysis. Thorough necropsies were performed and macroparasites collected, identified and preserved. For the first time in Portugal Ancylostoma martinezi, a common genets parasite.is recorded. Statistical species richness and correlation between human and environmental factors were determined. Human population density, water drainage, soil use, minimum distance to head council cities and the infection status of foxes proved no significant statistical relation. Results obtained on zoonotic parasites present in wild animals enhance the necessity of multidisciplinary work between Biology conservation and medical sciences.

An inter-laboratory validation of a real time PCR assay to measure host excretion of bacterial pathogens, particularly of Mycobacterium bovis

Advances in the diagnosis of Mycobacterium bovis infection in wildlife hosts may benefit the development of sustainable approaches to the management of bovine tuberculosis in cattle. In the present study, three laboratories from two different countries participated in a validation trial to evaluate the reliability and reproducibility of a real time PCR assay in the detection and quantification of M. bovis from environmental samples. The sample panels consisted of negative badger faeces spiked with a dilution series of M. bovis BCG Pasteur and of field samples of faeces from badgers of unknown infection status taken from badger latrines in areas with high and low incidence of bovine TB (bTB) in cattle. Samples were tested with a previously optimised methodology. The experimental design involved rigorous testing which highlighted a number of potential pitfalls in the analysis of environmental samples using real time PCR. Despite minor variation between operators and laboratories, the validation study demonstrated good concordance between the three laboratories: on the spiked panels, the test showed high levels of agreement in terms of positive/negative detection, with high specificity (100%) and high sensitivity (97%) at levels of 10(5) cells g(-1) and above. Quantitative analysis of the data revealed low variability in recovery of BCG cells between laboratories and operators. On the field samples, the test showed high reproducibility both in terms of positive/negative detection and in the number of cells detected, despite low numbers of samples identified as positive by any laboratory. Use of a parallel PCR inhibition control assay revealed negligible PCR-interfering chemicals co-extracted with the DNA. This is the first example of a multi-laboratory validation of a real time PCR assay for the detection of mycobacteria in environmental samples. Field studies are now required to determine how best to apply the assay for population-level bTB surveillance in wildlife.