The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

S.d. Carter - One of the best experts on this subject based on the ideXlab platform.

  • missing pieces of the puzzle to effectively control Digital Dermatitis
    Transboundary and Emerging Diseases, 2018
    Co-Authors: Karin Orsel, S.d. Carter, Jan K Shearer, P Plummer, J De Buck, R Guatteo, H W Barkema
    Abstract:

    Since the first report of bovine Digital Dermatitis (DD) in 1974, there is a large body of the literature published; however, effective prevention and control of the disease remain elusive. Although many aspects of the pathogenesis of DD have been investigated, even some of the most basic questions such as the aetiology of this disease remain under debate. Treponema spp. have been strongly associated with DD lesions and occur in abundance in advanced lesions; however, efforts to induce disease with pure cultures of these organisms have been largely underwhelming and inconsistent. Furthermore, although the disease has been presented for several decades, there is limited scientific evidence regarding effective treatment of DD. Apparent discrepancies between effectiveness in vitro and in vivo have challenged the scientific community to identify new potential treatment options. With no treatment resulting in a 100% cure rate, the current expectation is manageable control, but prospects for the eradication of the disease are unlikely using current approaches. In order to develop more effective approaches to control DD on-farm, there is a critical need for a deeper understanding regarding the causation, ecology, transmission and treatment of this disease. In this article, we attempt to provide insights into specific research needs related to DD in order to assist the industry, researchers, pharmaceutical companies and research sponsors with decision-making and identified research gaps.

  • survival of contagious ovine Digital Dermatitis codd associated treponemes on disposable gloves after handling codd affected feet
    Veterinary Record, 2017
    Co-Authors: J W Angell, S R Clegg, Roger Blowey, J S Duncan, Dai Grovewhite, S.d. Carter, Nicholas Evans
    Abstract:

    Both contagious ovine Digital Dermatitis (CODD) and bovine Digital Dermatitis (BDD) are causes of infectious lameness in sheep and cattle, respectively, and are strongly associated with the presence of specific treponemes, with three different cultivable phylogroups commonly isolated: Treponema medium , Treponema phagedenis and Treponema pedis . The aim of this study was to investigate the potential to transmit CODD-associated Treponema species via gloves used when handling visibly clinically affected animals. The feet of sheep with and without CODD were handled as part of routine examination with gloved hands. The gloves were then swabbed to detect the presence of treponemes immediately after handling. Detection methods included culture and isolation techniques together with DNA detection by PCR. In addition, the duration of survival in air was determined as well as the efficacy of common disinfectants to remove treponemes from gloves. In this study, we demonstrate that CODD-associated treponemes can survive on gloves used to handle the feet of CODD-affected sheep but may be removed effectively using common disinfectants. These data provide evidence of a potential route of transmission and identify a practical method to reduce this risk.

  • bovine Digital Dermatitis current concepts from laboratory to farm
    Veterinary Journal, 2016
    Co-Authors: Nicholas Evans, R D Murray, S.d. Carter
    Abstract:

    Bovine Digital Dermatitis (DD) is a severe infectious disease causing lameness in dairy cattle worldwide and is an important ruminant welfare problem that has considerable economic issues. Bovine DD is endemic in many regions worldwide and it is important to understand this major disease so that effective control strategies can be identified. There is substantial evidence that specific treponeme phylotypes play an important causative role in bovine DD. This review considers current research, including DD Treponema spp. investigations, associated DD pathobiology, and current and potential treatment and control options. Epidemiological data, alongside new microbiological data, help delineate important transmission routes and reservoirs of infection that allow effective interventions to be identified. Better on-farm housing hygiene, pasture access, routine footbathing and claw trimming with disinfected equipment need to be implemented to significantly reduce the incidence of DD. There is a paucity of peer reviewed research into both commonly used and novel treatments. In vitro antimicrobial susceptibility studies of DD treponemes and effective treatment of human treponematoses clearly indicate that antibiotics frequently selected for DD treatments are not the most efficacious. Whilst there are understandable concerns over milk withdrawal times in dairy cattle, more needs to be done to identify, license and implement more appropriate antibiotic treatments, since continued overuse of less efficacious antibiotics, applied incorrectly, will lead to increased disease recurrence and transmission. More research is needed into methods of preventing DD that circumvent the use of antibiotics, including vaccination and transmission blocking studies, to reduce or hopefully eradicate DD in the future.

  • isolation of Digital Dermatitis treponemes from cattle hock skin lesions
    Veterinary Dermatology, 2016
    Co-Authors: S R Clegg, N J Bell, Roger Blowey, Stuart Ainsworth, Jennifer Bell, S.d. Carter, N J Evans
    Abstract:

    Background: Bovine hock lesions present a serious welfare and production issue on dairy farms worldwide. Current theories suggest that trauma is an important factor in the formation of hock lesions, although infection may also play a role in increasing their severity and duration. Hypothesis: Digital Dermatitis (DD) lesions in dairy cows are strongly associated with specific treponeme bacteria which are opportunistic invaders of other skin regions. Hock lesions were tested to ascertain if they too contained treponemes. Animals: Swab and tissue samples were taken from hock lesions from two farms in South West England. Methods: Hock lesions were classified into two categories: open lesions, which were often bleeding and ulcerated, or were encrusted; and closed lesions, which were classified as hair loss with no skin breakage. PCR assays and bacterial isolation were used to detect treponemes in hock lesions. Results: All three phylogroups of Digital Dermatitis treponemes were detectable and isolated from open hock lesions only, with closed lesions showing no evidence of treponeme infection, either by PCR or bacterial culture. When analysed by 16S rRNA gene sequencing, the cultured treponeme DNA showed complete homology or was very similar to that found in foot lesions. Additionally, skin swabs from near the open hock wounds were also positive by PCR assay and isolation for the DD treponemes. Conclusions and clinical importance: Identification of the contribution of these infectious agents will allow for more optimal treatments to be developed that reduce the prevalence and healing times of both hock and DD lesions. © 2016 ESVD and ACVD.

  • detection and isolation of Digital Dermatitis treponemes from skin and tail lesions in pigs
    Research in Veterinary Science, 2016
    Co-Authors: S R Clegg, L E Sullivan, Roger Blowey, Jennifer Bell, S.d. Carter, Nicholas Evans
    Abstract:

    Pig skin lesions are common significant welfare issues, and can cause large economic losses, due to culling of severely affected animals or carcass condemnation at slaughter. It was considered that the treponemal bacteria associated with Digital Dermatitis (DD) lesions in cattle, sheep and goats may have a role in these pig lesions. Specific diagnostic PCR assays for three cultivable DD Treponema phylogroups were used to survey relevant porcine lesion samples. Using these assays, DD treponemes were detected in 88% (22/25), 72% (8/11) and 82% (14/17) of tail, ear and flank lesions, respectively. Mouth swabs from animals kept in enclosures with high prevalence of skin lesions were positive for the DD treponemes, but not in enclosures with low lesion prevalence. Culture of treponemes from skin lesions resulted in pure isolates of all three DD-associated phylogroups. This study shows a strong association of DD treponemes with a range of pig skin lesions.

Nicholas Evans - One of the best experts on this subject based on the ideXlab platform.

  • survival of contagious ovine Digital Dermatitis codd associated treponemes on disposable gloves after handling codd affected feet
    Veterinary Record, 2017
    Co-Authors: J W Angell, S R Clegg, Roger Blowey, J S Duncan, Dai Grovewhite, S.d. Carter, Nicholas Evans
    Abstract:

    Both contagious ovine Digital Dermatitis (CODD) and bovine Digital Dermatitis (BDD) are causes of infectious lameness in sheep and cattle, respectively, and are strongly associated with the presence of specific treponemes, with three different cultivable phylogroups commonly isolated: Treponema medium , Treponema phagedenis and Treponema pedis . The aim of this study was to investigate the potential to transmit CODD-associated Treponema species via gloves used when handling visibly clinically affected animals. The feet of sheep with and without CODD were handled as part of routine examination with gloved hands. The gloves were then swabbed to detect the presence of treponemes immediately after handling. Detection methods included culture and isolation techniques together with DNA detection by PCR. In addition, the duration of survival in air was determined as well as the efficacy of common disinfectants to remove treponemes from gloves. In this study, we demonstrate that CODD-associated treponemes can survive on gloves used to handle the feet of CODD-affected sheep but may be removed effectively using common disinfectants. These data provide evidence of a potential route of transmission and identify a practical method to reduce this risk.

  • bovine Digital Dermatitis current concepts from laboratory to farm
    Veterinary Journal, 2016
    Co-Authors: Nicholas Evans, R D Murray, S.d. Carter
    Abstract:

    Bovine Digital Dermatitis (DD) is a severe infectious disease causing lameness in dairy cattle worldwide and is an important ruminant welfare problem that has considerable economic issues. Bovine DD is endemic in many regions worldwide and it is important to understand this major disease so that effective control strategies can be identified. There is substantial evidence that specific treponeme phylotypes play an important causative role in bovine DD. This review considers current research, including DD Treponema spp. investigations, associated DD pathobiology, and current and potential treatment and control options. Epidemiological data, alongside new microbiological data, help delineate important transmission routes and reservoirs of infection that allow effective interventions to be identified. Better on-farm housing hygiene, pasture access, routine footbathing and claw trimming with disinfected equipment need to be implemented to significantly reduce the incidence of DD. There is a paucity of peer reviewed research into both commonly used and novel treatments. In vitro antimicrobial susceptibility studies of DD treponemes and effective treatment of human treponematoses clearly indicate that antibiotics frequently selected for DD treatments are not the most efficacious. Whilst there are understandable concerns over milk withdrawal times in dairy cattle, more needs to be done to identify, license and implement more appropriate antibiotic treatments, since continued overuse of less efficacious antibiotics, applied incorrectly, will lead to increased disease recurrence and transmission. More research is needed into methods of preventing DD that circumvent the use of antibiotics, including vaccination and transmission blocking studies, to reduce or hopefully eradicate DD in the future.

  • detection and isolation of Digital Dermatitis treponemes from skin and tail lesions in pigs
    Research in Veterinary Science, 2016
    Co-Authors: S R Clegg, L E Sullivan, Roger Blowey, Jennifer Bell, S.d. Carter, Nicholas Evans
    Abstract:

    Pig skin lesions are common significant welfare issues, and can cause large economic losses, due to culling of severely affected animals or carcass condemnation at slaughter. It was considered that the treponemal bacteria associated with Digital Dermatitis (DD) lesions in cattle, sheep and goats may have a role in these pig lesions. Specific diagnostic PCR assays for three cultivable DD Treponema phylogroups were used to survey relevant porcine lesion samples. Using these assays, DD treponemes were detected in 88% (22/25), 72% (8/11) and 82% (14/17) of tail, ear and flank lesions, respectively. Mouth swabs from animals kept in enclosures with high prevalence of skin lesions were positive for the DD treponemes, but not in enclosures with low lesion prevalence. Culture of treponemes from skin lesions resulted in pure isolates of all three DD-associated phylogroups. This study shows a strong association of DD treponemes with a range of pig skin lesions.

  • bovine ischaemic teat necrosis a further potential role for Digital Dermatitis treponemes
    Veterinary Record, 2016
    Co-Authors: S R Clegg, Roger Blowey, S.d. Carter, James P Stewart, D M Amin, Nicholas Evans
    Abstract:

    A recent outbreak of ischaemic teat necrosis (ITN) on mainland UK has resulted in large economic losses for dairy farmers. Typical cases start as an area of dry, thickened and encrusted skin on the medial aspect of the base of the teat, where the teat joins the udder, often with a fetid odour. The erosion spreads down the teat, often causing intense irritation, which in turn leads to more severely affected animals removing the entire teat. Due to the severity of ITN and the substantial economic costs to the industry, analyses were undertaken to ascertain if an infectious agent might be involved in the pathology. The study has considered a role for Digital Dermatitis (DD) treponemes in the aetiopathogenesis of ITN because, as well as being the prime bacteria associated with infectious lameness, they have been associated with a number of emerging skin diseases of cattle, including udder lesions. A high association between presence of DD-associated treponemes and incidence of ITN (19/22), compared with absence in the control population is reported. Furthermore, sequencing of the 16S rRNA gene of treponeme isolates supports the hypothesis that the identified treponemes are similar or identical to those isolated from classical foot DD lesions in cattle (and sheep). Further studies are required to allow effective targeted prevention measures and/or treatments to be developed.

  • Digital Dermatitis in beef cattle
    Veterinary Record, 2013
    Co-Authors: L E Sullivan, Roger Blowey, J S Duncan, Dai Grovewhite, S.d. Carter, Nicholas Evans
    Abstract:

    Digital Dermatitis (DD) is an ulcerative lesion of the bovine Digital skin (Cheli and Mortellaro 1974) which causes severe lameness in dairy cattle. The disease can have considerable economic impact through reduced reproductive performance, weight loss and the costs of treatment and control. The primary causative agents of DD in dairy cattle are considered to be spirochetal bacteria of the genus Treponema (Evans and others 2011). Recently, the disease has been identified to be polytreponemal in aetiology (Klitgaard and others 2008), and in the UK and USA, three phylotypes have been isolated from dairy cattle lesions (Evans and others 2008, Stamm and others 2002), and described as ‘ Treponema medium / Treponema vincentii -like’, ‘ Treponema phagedenis -­like’ and ‘ Treponema denticola / T putidum -like’ BDD spirochaetes (Evans and others 2008) with the latter now recognised as a new species, Treponema pedis (Evans and others 2009). DD has been reported in dairy cattle in nearly all countries where they are farmed, and the disease has spread to sheep in the UK (Harwood and others 1997). There have been anecdotal reports of DD lesions in beef cattle and of increased prevalence in recent years, but only the abattoir studies of Brown and others (2000) in southeast USA has actually reported the disease in beef cattle. There have been no definitive published case reports in the UK or elsewhere; these will be a …

R D Murray - One of the best experts on this subject based on the ideXlab platform.

  • bovine Digital Dermatitis current concepts from laboratory to farm
    Veterinary Journal, 2016
    Co-Authors: Nicholas Evans, R D Murray, S.d. Carter
    Abstract:

    Bovine Digital Dermatitis (DD) is a severe infectious disease causing lameness in dairy cattle worldwide and is an important ruminant welfare problem that has considerable economic issues. Bovine DD is endemic in many regions worldwide and it is important to understand this major disease so that effective control strategies can be identified. There is substantial evidence that specific treponeme phylotypes play an important causative role in bovine DD. This review considers current research, including DD Treponema spp. investigations, associated DD pathobiology, and current and potential treatment and control options. Epidemiological data, alongside new microbiological data, help delineate important transmission routes and reservoirs of infection that allow effective interventions to be identified. Better on-farm housing hygiene, pasture access, routine footbathing and claw trimming with disinfected equipment need to be implemented to significantly reduce the incidence of DD. There is a paucity of peer reviewed research into both commonly used and novel treatments. In vitro antimicrobial susceptibility studies of DD treponemes and effective treatment of human treponematoses clearly indicate that antibiotics frequently selected for DD treatments are not the most efficacious. Whilst there are understandable concerns over milk withdrawal times in dairy cattle, more needs to be done to identify, license and implement more appropriate antibiotic treatments, since continued overuse of less efficacious antibiotics, applied incorrectly, will lead to increased disease recurrence and transmission. More research is needed into methods of preventing DD that circumvent the use of antibiotics, including vaccination and transmission blocking studies, to reduce or hopefully eradicate DD in the future.

  • high level association of bovine Digital Dermatitis treponema spp with contagious ovine Digital Dermatitis lesions and presence of fusobacterium necrophorum and dichelobacter nodosus
    Journal of Clinical Microbiology, 2015
    Co-Authors: L E Sullivan, S R Clegg, J W Angell, Roger Blowey, J S Duncan, Jennifer Bell, Dai Grovewhite, S.d. Carter, Kerry Newbrook, R D Murray
    Abstract:

    ABSTRACT Contagious ovine Digital Dermatitis (CODD) is an important foot disease in sheep, with significant animal welfare and economic implications. It is thought that CODD emerged from bovine Digital Dermatitis (BDD) via treponemal bacteria. With wildlife species such as elk now suffering a CODD-like disease, it is imperative to clarify these disease etiologies. A large investigation into treponemal association with CODD is warranted. CODD lesions ( n = 58) and healthy sheep foot tissues ( n = 56) were analyzed by PCR for the three BDD-associated Treponema phylogroups and two other lameness-associated bacteria, Dichelobacter nodosus and Fusobacterium necrophorum. Spirochete culture was also attempted on CODD lesions. “Treponema medium/Treponema vincentii-like,” “Treponema phagedenis-like,” and Treponema pedis spirochetes were identified in 39/58 (67%), 49/58 (85%), and 41/58 (71%) of CODD lesions, respectively. One or more BDD-associated Treponema phylogroups were detected in 100% of CODD lesions. Healthy foot tissues did not amplify BDD-associated Treponema phylogroup DNA. D. nodosus and F. necrophorum were present in 34/58 (59%) and 41/58 (71%) of CODD lesions and 22/56 (39%) and 5/56 (9%) of healthy foot tissues, respectively. Thirty-two spirochetes were isolated from CODD lesions, with representatives clustering with, and indistinguishable from, each of the three BDD-associated Treponema phylogroups based on 16S rRNA gene comparisons. This study for the first time demonstrates a high-level association for BDD treponeme phylogroups in CODD and their absence from healthy tissues, supporting the hypothesis that BDD treponemes play a primary causative role in CODD and confirming that the specific PCR assays are an effective differential diagnostic tool for CODD.

  • host and environmental reservoirs of infection for bovine Digital Dermatitis treponemes
    Veterinary Microbiology, 2012
    Co-Authors: Nicholas Evans, Jennifer M Brown, R D Murray, Dorina Timofte, D R Isherwood, Jonathan M Williams, Kenneth Sherlock, Michael J Lehane, Richard Birtles
    Abstract:

    Bovine Digital Dermatitis (BDD) is a global infectious disease causing lameness of cattle and is responsible for substantial animal welfare issues and economic losses. The causative agents are considered to be spirochetal bacteria belonging to the genus Treponema, which have consistently been identified in BDD lesions worldwide. One potential means of controlling infection is the disruption of transmission; however, the infection reservoirs and transmission routes of BDD treponemes have yet to be elucidated. To address these issues, we surveyed for evidence of BDD treponeme presence in the dairy farm environment, in bovine tissues and in bovine gastrointestinal (GI) tract contents. A total of 368 samples were tested using PCR assays specific for each of three currently recognised, isolated phylotypes of BDD treponemes. All environmental samples, together with insects and GI tract content samples were negative for BDD treponeme DNA from the three phylotypes. However, we identified BDD treponemes in two non-pedal bovine regions: the oral cavity (14.3% of cattle tested) and the rectum (14.8% of cattle tested). Whilst only single phylotypes were detected in the oral cavity, two of the rectal tissues yielded DNA from more than one phylotype, with one sample yielding all three BDD treponeme phylotypes. Whilst it might be considered that direct skin to skin contact may be a major transmission route of BDD treponemes, further studies are required to characterise and determine the potential contribution of oral and rectal carriage to BDD transmission.

  • association between bovine Digital Dermatitis treponemes and a range of non healing bovine hoof disorders
    Veterinary Record, 2011
    Co-Authors: Nicholas Evans, Roger Blowey, Jennifer M Brown, R D Murray, Dorina Timofte, D R Isherwood, R J Paton, S.d. Carter
    Abstract:

    This study describes the association between bovine Digital Dermatitis (BDD) treponemes and three ‘non-healing’ bovine hoof horn lesions, namely, ‘toe necrosis’ (TN), ‘non-healing white line disease’ (nhWLD) and ‘non-healing sole ulcer’ (nhSU), which are disorders that involve penetration through the horn capsule to involve the corium. In this study, these non-healing disorders (n=44) were identified as foot lesions that exhibited a topical granular appearance, exuded a typical pungent smell, were severely painful to the animal involved, and typically originated from farms where BDD is endemic. Given the similarities between these ‘non-healing’ lesions and BDD, the authors subjected samples of diseased tissue to PCR assays to detect the presence of DNA of BDD treponemes. All the three characterised BDD treponeme groups were identified as present together in 84.2, 81.3 and 55.6 per cent of samples of TN (n=19), nhWLD (n=16) and nhSU (n=9), respectively. In contrast, healthy control horn samples from similar sites (n=16) were PCR-negative for the BDD treponemes. Hence, these non-healing hoof lesions were strongly associated with BDD treponemes. Samples from typical heel horn erosions (n=9) were also subjected to BDD treponeme PCR assays and no association could be identified between the BDD treponemes and this horn manifestation.

  • characterization of novel bovine gastrointestinal tract treponema isolates and comparison with bovine Digital Dermatitis treponemes
    Applied and Environmental Microbiology, 2011
    Co-Authors: Nicholas Evans, Jennifer M Brown, Richard Birtles, R D Murray, Anthony C Hart, Brian Getty, S.d. Carter
    Abstract:

    This study aimed to isolate and characterize treponemes present in the bovine gastrointestinal (GI) tract and compare them with bovine Digital Dermatitis (BDD) treponemes. Seven spirochete isolates were obtained from the bovine GI tract, which, on the basis of 16S rRNA gene comparisons, clustered within the genus Treponema as four novel phylotypes. One phylotype was isolated from several different GI tract regions, including the omasum, colon, rumen, and rectum. These four phylotypes could be divided into two phylotype pairs that clustered closest with each other and then with different, previously reported rumen treponemes. The treponemes displayed great genotypic and phenotypic diversity between phylotypes and differed considerably from named treponeme species and those recently reported by metagenomic studies of the bovine GI tract. Phylogenetic inference, based on comparisons of 16S rRNA sequences from only bovine treponemes, suggested a marked divergence between two important groups. The dendrogram formed two major clusters, with one cluster containing GI tract treponemes and the other containing BDD treponemes. This division among the bovine treponemes is likely the result of adaptation to different niches. To further differentiate the bovine GI and BDD strains, we designed a degenerate PCR for a gene encoding a putative virulence factor, tlyC, which gave a positive reaction only for treponemes from the BDD cluster.

Roger Blowey - One of the best experts on this subject based on the ideXlab platform.

  • survival of contagious ovine Digital Dermatitis codd associated treponemes on disposable gloves after handling codd affected feet
    Veterinary Record, 2017
    Co-Authors: J W Angell, S R Clegg, Roger Blowey, J S Duncan, Dai Grovewhite, S.d. Carter, Nicholas Evans
    Abstract:

    Both contagious ovine Digital Dermatitis (CODD) and bovine Digital Dermatitis (BDD) are causes of infectious lameness in sheep and cattle, respectively, and are strongly associated with the presence of specific treponemes, with three different cultivable phylogroups commonly isolated: Treponema medium , Treponema phagedenis and Treponema pedis . The aim of this study was to investigate the potential to transmit CODD-associated Treponema species via gloves used when handling visibly clinically affected animals. The feet of sheep with and without CODD were handled as part of routine examination with gloved hands. The gloves were then swabbed to detect the presence of treponemes immediately after handling. Detection methods included culture and isolation techniques together with DNA detection by PCR. In addition, the duration of survival in air was determined as well as the efficacy of common disinfectants to remove treponemes from gloves. In this study, we demonstrate that CODD-associated treponemes can survive on gloves used to handle the feet of CODD-affected sheep but may be removed effectively using common disinfectants. These data provide evidence of a potential route of transmission and identify a practical method to reduce this risk.

  • isolation of Digital Dermatitis treponemes from cattle hock skin lesions
    Veterinary Dermatology, 2016
    Co-Authors: S R Clegg, N J Bell, Roger Blowey, Stuart Ainsworth, Jennifer Bell, S.d. Carter, N J Evans
    Abstract:

    Background: Bovine hock lesions present a serious welfare and production issue on dairy farms worldwide. Current theories suggest that trauma is an important factor in the formation of hock lesions, although infection may also play a role in increasing their severity and duration. Hypothesis: Digital Dermatitis (DD) lesions in dairy cows are strongly associated with specific treponeme bacteria which are opportunistic invaders of other skin regions. Hock lesions were tested to ascertain if they too contained treponemes. Animals: Swab and tissue samples were taken from hock lesions from two farms in South West England. Methods: Hock lesions were classified into two categories: open lesions, which were often bleeding and ulcerated, or were encrusted; and closed lesions, which were classified as hair loss with no skin breakage. PCR assays and bacterial isolation were used to detect treponemes in hock lesions. Results: All three phylogroups of Digital Dermatitis treponemes were detectable and isolated from open hock lesions only, with closed lesions showing no evidence of treponeme infection, either by PCR or bacterial culture. When analysed by 16S rRNA gene sequencing, the cultured treponeme DNA showed complete homology or was very similar to that found in foot lesions. Additionally, skin swabs from near the open hock wounds were also positive by PCR assay and isolation for the DD treponemes. Conclusions and clinical importance: Identification of the contribution of these infectious agents will allow for more optimal treatments to be developed that reduce the prevalence and healing times of both hock and DD lesions. © 2016 ESVD and ACVD.

  • detection and isolation of Digital Dermatitis treponemes from skin and tail lesions in pigs
    Research in Veterinary Science, 2016
    Co-Authors: S R Clegg, L E Sullivan, Roger Blowey, Jennifer Bell, S.d. Carter, Nicholas Evans
    Abstract:

    Pig skin lesions are common significant welfare issues, and can cause large economic losses, due to culling of severely affected animals or carcass condemnation at slaughter. It was considered that the treponemal bacteria associated with Digital Dermatitis (DD) lesions in cattle, sheep and goats may have a role in these pig lesions. Specific diagnostic PCR assays for three cultivable DD Treponema phylogroups were used to survey relevant porcine lesion samples. Using these assays, DD treponemes were detected in 88% (22/25), 72% (8/11) and 82% (14/17) of tail, ear and flank lesions, respectively. Mouth swabs from animals kept in enclosures with high prevalence of skin lesions were positive for the DD treponemes, but not in enclosures with low lesion prevalence. Culture of treponemes from skin lesions resulted in pure isolates of all three DD-associated phylogroups. This study shows a strong association of DD treponemes with a range of pig skin lesions.

  • bovine ischaemic teat necrosis a further potential role for Digital Dermatitis treponemes
    Veterinary Record, 2016
    Co-Authors: S R Clegg, Roger Blowey, S.d. Carter, James P Stewart, D M Amin, Nicholas Evans
    Abstract:

    A recent outbreak of ischaemic teat necrosis (ITN) on mainland UK has resulted in large economic losses for dairy farmers. Typical cases start as an area of dry, thickened and encrusted skin on the medial aspect of the base of the teat, where the teat joins the udder, often with a fetid odour. The erosion spreads down the teat, often causing intense irritation, which in turn leads to more severely affected animals removing the entire teat. Due to the severity of ITN and the substantial economic costs to the industry, analyses were undertaken to ascertain if an infectious agent might be involved in the pathology. The study has considered a role for Digital Dermatitis (DD) treponemes in the aetiopathogenesis of ITN because, as well as being the prime bacteria associated with infectious lameness, they have been associated with a number of emerging skin diseases of cattle, including udder lesions. A high association between presence of DD-associated treponemes and incidence of ITN (19/22), compared with absence in the control population is reported. Furthermore, sequencing of the 16S rRNA gene of treponeme isolates supports the hypothesis that the identified treponemes are similar or identical to those isolated from classical foot DD lesions in cattle (and sheep). Further studies are required to allow effective targeted prevention measures and/or treatments to be developed.

  • high level association of bovine Digital Dermatitis treponema spp with contagious ovine Digital Dermatitis lesions and presence of fusobacterium necrophorum and dichelobacter nodosus
    Journal of Clinical Microbiology, 2015
    Co-Authors: L E Sullivan, S R Clegg, J W Angell, Roger Blowey, J S Duncan, Jennifer Bell, Dai Grovewhite, S.d. Carter, Kerry Newbrook, R D Murray
    Abstract:

    ABSTRACT Contagious ovine Digital Dermatitis (CODD) is an important foot disease in sheep, with significant animal welfare and economic implications. It is thought that CODD emerged from bovine Digital Dermatitis (BDD) via treponemal bacteria. With wildlife species such as elk now suffering a CODD-like disease, it is imperative to clarify these disease etiologies. A large investigation into treponemal association with CODD is warranted. CODD lesions ( n = 58) and healthy sheep foot tissues ( n = 56) were analyzed by PCR for the three BDD-associated Treponema phylogroups and two other lameness-associated bacteria, Dichelobacter nodosus and Fusobacterium necrophorum. Spirochete culture was also attempted on CODD lesions. “Treponema medium/Treponema vincentii-like,” “Treponema phagedenis-like,” and Treponema pedis spirochetes were identified in 39/58 (67%), 49/58 (85%), and 41/58 (71%) of CODD lesions, respectively. One or more BDD-associated Treponema phylogroups were detected in 100% of CODD lesions. Healthy foot tissues did not amplify BDD-associated Treponema phylogroup DNA. D. nodosus and F. necrophorum were present in 34/58 (59%) and 41/58 (71%) of CODD lesions and 22/56 (39%) and 5/56 (9%) of healthy foot tissues, respectively. Thirty-two spirochetes were isolated from CODD lesions, with representatives clustering with, and indistinguishable from, each of the three BDD-associated Treponema phylogroups based on 16S rRNA gene comparisons. This study for the first time demonstrates a high-level association for BDD treponeme phylogroups in CODD and their absence from healthy tissues, supporting the hypothesis that BDD treponemes play a primary causative role in CODD and confirming that the specific PCR assays are an effective differential diagnostic tool for CODD.

Dörte Döpfer - One of the best experts on this subject based on the ideXlab platform.

  • hot topic detecting Digital Dermatitis with computer vision
    Journal of Dairy Science, 2020
    Co-Authors: Preston Cernek, Kelly Anklam, Nathan Bollig, Dörte Döpfer
    Abstract:

    Digital Dermatitis (DD) is linked to severe lameness, infertility, and decreased milk production in cattle. Early detection of DD provides an improved prognosis for treatment and recovery; however, this is extremely challenging on commercial dairy farms. Computer vision (COMV) models can help facilitate early DD detection on commercial dairy farms. The aim of this study was to develop and implement a novel COMV tool to identify DD lesions on a commercial dairy farm. Using a database of more than 3,500 DD lesion images, a model was trained using the YOLOv2 architecture to detect the M-stages of DD. The YOLOv2 COMV model detected DD with an accuracy of 71%, and the agreement was quantified as "moderate" by Cohen's kappa when compared with a human evaluator for the internal validation. In the external validation, the YOLOv2 COMV model detected DD with an accuracy of 88% and agreement was quantified as "fair" by Cohen's kappa. Implementation of COMV tools for DD detection provides an opportunity to identify cows for DD treatment, which has the potential to lower DD prevalence and improve animal welfare on commercial dairy farms.

  • RESEARCH ARTICLE Altered Microbiomes in Bovine Digital Dermatitis Lesions, and the Gut as a Pathogen Reservoir
    2016
    Co-Authors: Martin Zinicola, Dörte Döpfer, Fabio Lima, Svetlana Lima, Vinicius Machado, Marilia Gomez, Charles Guard, Rodrigo Bicalho
    Abstract:

    Bovine Digital Dermatitis (DD) is the most important infectious disease associated with lame-ness in cattle worldwide. Since the disease was first described in 1974, a series of Trepone-ma species concurrent with other microbes have been identified in DD lesions, suggesting a polymicrobial etiology. However, the pathogenesis of DD and the source of the causative microbes remain unclear. Here we characterized the microbiomes of healthy skin and skin lesions in dairy cows affected with different stages of DD and investigated the gut micro-biome as a potential reservoir for microbes associated with this disease. Discriminant analy-sis revealed that the microbiomes of healthy skin, active DD lesions (ulcerative and chronic ulcerative) and inactive DD lesions (healing and chronic proliferative) are completely dis-tinct. Treponema denticola, Treponema maltophilum, Treponema medium, Treponema putidum, Treponema phagedenis and Treponema paraluiscuniculi were all found to be present in greater relative abundance in active DD lesions when compared with healthy skin and inactive DD lesions, and these same Treponema species were nearly ubiquitously present in rumen and fecal microbiomes. The relative abundance of Candidatus Amoebo

  • Altered microbiomes in bovine Digital Dermatitis lesions, and the gut as a pathogen reservoir.
    PloS one, 2015
    Co-Authors: Martin Zinicola, Dörte Döpfer, Svetlana Lima, Fabio S. Lima, V.s. Machado, Marilia Souza Gomez, Rodrigo C. Bicalho
    Abstract:

    Bovine Digital Dermatitis (DD) is the most important infectious disease associated with lameness in cattle worldwide. Since the disease was first described in 1974, a series of Treponema species concurrent with other microbes have been identified in DD lesions, suggesting a polymicrobial etiology. However, the pathogenesis of DD and the source of the causative microbes remain unclear. Here we characterized the microbiomes of healthy skin and skin lesions in dairy cows affected with different stages of DD and investigated the gut microbiome as a potential reservoir for microbes associated with this disease. Discriminant analysis revealed that the microbiomes of healthy skin, active DD lesions (ulcerative and chronic ulcerative) and inactive DD lesions (healing and chronic proliferative) are completely distinct. Treponema denticola, Treponema maltophilum, Treponema medium, Treponema putidum, Treponema phagedenis and Treponema paraluiscuniculi were all found to be present in greater relative abundance in active DD lesions when compared with healthy skin and inactive DD lesions, and these same Treponema species were nearly ubiquitously present in rumen and fecal microbiomes. The relative abundance of Candidatus Amoebophilus asiaticus, a bacterium not previously reported in DD lesions, was increased in both active and inactive lesions when compared with healthy skin. In conclusion, our data support the concept that DD is a polymicrobial disease, with active DD lesions having a markedly distinct microbiome dominated by T. denticola, T. maltophilum, T. medium, T. putidum, T. phagedenis and T. paraluiscuniculi. Furthermore, these Treponema species are nearly ubiquitously found in rumen and fecal microbiomes, suggesting that the gut is an important reservoir of microbes involved in DD pathogenesis. Additionally, the bacterium Candidatus Amoebophilus asiaticus was highly abundant in active and inactive DD lesions.

  • the effect of Digital Dermatitis on hoof conformation
    Journal of Dairy Science, 2015
    Co-Authors: A. Gomez, M T Socha, N B Cook, J Rieman, K A Dunbar, K E Cooley, Dörte Döpfer
    Abstract:

    Digital Dermatitis (DD) is the most prevalent cause of lameness of infectious origin in cattle. However, little is known about the effects of DD on hoof conformation (HC) during the clinical disease. The objectives of the present study were to (1) evaluate the changes in HC observed in feet affected with clinical DD lesions and (2) investigate the temporal relationship between DD and heel horn erosion (HHE). A longitudinal study was carried out including a cohort of 644 Holstein heifers. Digital Dermatitis, HC, and presence of HHE in the rear feet of each heifer were assessed during a period of 6 mo. A total of 1,979 feet evaluations were included in the data set, of which 157 corresponded to feet presenting DD lesions >20mm [mean (SD) size of 27.2 (8.2) mm]. Age, days of pregnancy, hip height, and girth circumference were also recorded at cow level. Significant HC changes were observed in DD-affected feet. Results standardized to a period of 90d of follow-up showed an increase in heel height [mean (95% CI) 3.4 (2.5, 4.4) and 2.8 (2.0, 3.7) mm] and claw angle [0.8 (0.2, 1.4) and 1.4 (0.7, 2.0) degrees] of the medial and lateral claws, respectively. In addition, an increase in depth of the interDigital cleft [3.2 (2.7, 3.7) mm] and on debris accumulation [14% (7, 21) of feet] was also observed. Feet affected with clinical DD lesions also experienced a 46% point increase in the presence of severe HHE. In the short term, HC changes returned to normal levels when clinical cure of DD was achieved after topical treatment. In conclusion, significant HC changes occur in heifers affected by clinical DD before lameness symptoms are detected. The transformation of the heel area in feet affected by DD likely promotes the creation of a local environment that favors the persistence of the disease and the occurrence of severe HHE. To avoid further hoof damage, active surveillance and early intervention to reduce HC changes are recommended to improve DD control programs. Successful restoration of HC can be achieved upon clinical cure of DD. The long-term effects in lifetime performance of the HC changes due to DD remain to be further investigated.

  • immune response against treponema spp and elisa detection of Digital Dermatitis
    Journal of Dairy Science, 2014
    Co-Authors: A. Gomez, M T Socha, N B Cook, Kelly Anklam, J Rieman, K A Dunbar, K E Cooley, Dörte Döpfer
    Abstract:

    Abstract The objective of this longitudinal study was to evaluate the immune response against Treponema spp. infection in dairy heifers affected with Digital Dermatitis (DD). In addition, the accuracy of an indirect ELISA detecting anti- Treponema IgG antibodies in identifying clinical DD status has been assessed. A cohort of 688 pregnant Holstein heifers was evaluated at least 3 times before calving during a period of 6 mo. Complete clinical assessment of DD presence on the back feet of each heifer and blood extraction were performed in a stand-up chute. Digital Dermatitis cases were characterized by the M-stage classification system and size and level of skin proliferation. An ELISA was performed on blood serum samples obtained from a subcohort of 130 heifers. For description purposes, the animals were classified by the number of clinical cases experienced during the study period as type I (no clinical cases were observed), type II (only 1 acute clinical case diagnosed), and type III (at least 2 acute clinical cases diagnosed). Multivariable repeated-measures models were used to evaluate the immune response against Treponema spp. infection. A binormal Bayesian model for the ELISA data without cut-point values was used to assess the accuracy of the ELISA as a diagnostic tool. Animals that never experienced a DD event throughout the study kept a constant low level of antibody titer. A 56% increase in mean ELISA titer was observed in heifers upon a first clinical DD case diagnosis. After topical treatment of an acute DD case with oxytetracycline, the antibody titer decreased progressively in type II heifers, achieving mean levels of those observed in healthy cows after a mean of 223 d. Surprisingly, antibody titer was not increased in the presence of M1 (DD lesion