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detection and serogrouping ofdichelobacter nodosusinfection using direct pcr from lesion swabs to support outbreak-specific vaccination for virulent footrot in sheep.virulent footrot is an economically significant disease in most sheep-rearing countries. the disease can be controlled with vaccine targeting the fimbriae of virulent strains of the essential causative agent,dichelobacter nodosushowever, the bacterium is immunologically heterogeneous, and ten distinct fimbrial serogroups have been identified. ideally, in each outbreak the infecting strains must be cultured and serogrouped so that the appropriate serogroup-specific mono- or bi-valent vaccine can ...201829436426
direct serogrouping of dichelobacter nodosus from victorian farms using conventional multiplex polymerase chain reaction.dichelobacter nodosus is the causative agent of footrot in sheep. ovine footrot is a major problem in australia that results in large economic losses and a represents a very significant animal welfare issue. d. nodosus is divided into 10 serogroups (a-i, m), based on sequence variation in the type iv fimbriae gene, fima. control of the bacteria is possible through use of serogroup-specific vaccination, however traditional identification of the serogroups of d. nodosus on infected sheep is time-c ...201829415761
sheep and farm level factors associated with footrot: a longitudinal repeated cross-sectional study of sheep on six farms.footrot is an ovine foot disease of infectious origin and a cause of serious welfare and economic compromise in affected animals and flocks. the development of footrot in sheep is associated with the infectious agentdichelobacter nodosus, which may invade as a primary pathogen, but the risk of disease is increased following damage to the interdigital skin of the foot. in this study, we used data from six farms in north wales collected between june 2012 and october 2013 to model the dynamic chang ...201829363571
pooling of interdigital swab samples for pcr detection of virulent dichelobacter nodosus.virulent ovine foot rot is a contagious foot disease. given the development and validation of a real-time pcr to detect dichelobacter nodosus isolates that contain the virulence-associated protease genes aprv2 and aprb2, the diagnosis of foot rot has made considerable progress. we evaluated pooling methods to reduce the number of samples during a foot rot control program. samples of individual feet were compared to a 4-feet sample of the same sheep. all further analyses based on 4-feet samples ( ...201829105601
a financial cost-benefit analysis of eradicating virulent footrot.in 2008, virulent footrot was detected in sheep in south-west norway. footrot is caused by dichelobacter nodosus, and the outbreak was linked to live sheep imported from denmark in 2005. a large-scale program for eradicating the disease was implemented as a joint industry and governmental driven eradication project in the years 2008-2014, and continued with surveillance and control measures by the norwegian food safety authority from 2015. the cost of the eradication program including surveillan ...201728992932
a genome-wide significant association on chromosome 2 for footrot resistance/susceptibility in swiss white alpine sheep.footrot is one of the most important causes of lameness in global sheep populations and is characterized by a bacterial infection of the interdigital skin. as a multifactorial disease, its clinical representation depends not only on pathogen factors and environmental components but also on the individual resistance/susceptibility of the host. a genetic component has been shown in previous studies; however, so far no causative genetic variant influencing the risk of developing footrot has been id ...201728983925
a novel 3d skin explant model to study anaerobic bacterial infection.skin infection studies are often limited by financial and ethical constraints, and alternatives, such as monolayer cell culture, do not reflect many cellular processes limiting their application. for a more functional replacement, 3d skin culture models offer many advantages such as the maintenance of the tissue structure and the cell types present in the host environment. a 3d skin culture model can be set up using tissues acquired from surgical procedures or post slaughter, making it a cost ef ...201728959685
artificial infection of sheep with multiple strains of dichelobacter nodosus to induce footrot.to establish multiple strains of dichelobacter nodosus in two flocks of sheep and to assess the virulence of five of these strains.201728749020
epidemiological and economic evaluation of alternative on-farm management scenarios for ovine footrot in switzerland.footrot is a multifactorial infectious disease mostly affecting sheep, caused by the bacteria dichelobacter nodosus. it causes painful feet lesions resulting in animal welfare issues, weight loss, and reduced wool production, which leads to a considerable economic burden in animal production. in switzerland, the disease is endemic and mandatory coordinated control programs exist only in some parts of the country. this study aimed to compare two nationwide control strategies and a no intervention ...201728560223
within-flock population dynamics of dichelobacter nodosus.footrot causes 70-90% of lameness in sheep in great britain. with approximately 5% of 18 million adult sheep lame at any one time, it costs the uk sheep industry £24-84 million per year. the gram-negative anaerobe dichelobacter nodosus is the causative agent, with disease severity influenced by bacterial load, virulence, and climate. the aim of the current study was to characterize strains of d. nodosus isolated by culture of swabs from healthy and diseased feet of 99 ewes kept as a closed flock ...201728484704
mathematical modeling of ovine footrot in the uk: the effect of dichelobacter nodosus and fusobacterium necrophorum on the disease dynamics.dichelobacter nodosus is a virulent, invasive, anaerobic bacterium that is believed to be the causative agent of ovine footrot, an infectious bacterial disease of sheep that causes lameness. another anaerobe, fusobacterium necrophorum, has been intimately linked with the disease occurrence and severity. here we examine data from a longitudinal study of footrot on one uk farm, including quantitative pcr (qpcr) estimates of bacterial load of d. nodosus and f. necrophorum. the data is at foot level ...201728461081
reducing exposure to pathogens in the horse: a preliminary study into the survival of bacteria on a range of equine bedding types.to compare the rate of growth of four microbial strains that cause disease in the horse, on four commonly used types of bedding. the moisture-holding capacity of each bedding type was also tested.201727659898
sample pooling for real-time pcr detection and virulence determination of the footrot pathogen dichelobacter nodosus.dichelobacter nodosus is the principal cause of ovine footrot and strain virulence is an important factor in disease severity. therefore, detection and virulence determination of d. nodosus is important for proper diagnosis of the disease. today this is possible by real-time pcr analysis. analysis of large numbers of samples is costly and laborious; therefore, pooling of individual samples is common in surveillance programs. however, pooling can reduce the sensitivity of the method. the aim of t ...201728343363
a distinct bacterial dysbiosis associated skin inflammation in ovine footrot.ovine footrot is a highly prevalent bacterial disease caused by dichelobacter nodosus and characterised by the separation of the hoof horn from the underlying skin. the role of innate immune molecules and other bacterial communities in the development of footrot lesions remains unclear. this study shows a significant association between the high expression of il1β and high d. nodosus load in footrot samples. investigation of the microbial population identified distinct bacterial populations in t ...201728338081
evaluation of genotypic and phenotypic protease virulence tests for dichelobacter nodosus infection in sheep.dichelobacter nodosus is a fastidious, strictly anaerobic bacterium, an obligate parasite of the ruminant hoof and the essential causative agent of virulent ovine footrot. the clinical disease results from a complex interplay between pathogen, environment and host. sheep flocks diagnosed with virulent but not benign footrot in australia may be quarantined and required to undergo a compulsory eradication program, with costs met by the farmer. virulence of d. nodosus is at least partially dependen ...201728202796
elimination of virulent strains (aprv2) of dichelobacter nodosus from feet of 28 swiss sheep flocks: a proof of concept study.virulent ovine footrot caused by dichelobacter nodosus is an endemic disease worldwide. it is associated with severe pain, impaired animal welfare and economic losses. the competitive real-time pcr for the differentiation of virulent aprv2 and benign aprb2 strains of dichelobacter nodosus provides an objective, rapid and sensitive diagnostic tool for footrot surveillance, especially as it enables early detection of subclinical carriers of virulent strains. the aim of this study was to evaluate t ...201627687922
nuclear magnetic resonance-based serum metabolic profiling of dairy cows with footrot.footrot is a debilitating and contagious disease in dairy cows, caused by the gram-negative anaerobe dichelobacter nodosus. (1)h-nmr (nuclear magnetic resonance)-based metabolomics has been previously used to understand the pathology and etiology of several diseases. the objective of this study was to characterize serum from dairy cows with footrot (n=10) using (1)h-nmr-based metabolomics and chemometric analyses. (1)h-nmr spectroscopy with multivariate pattern recognition (principal component a ...201627320815
ovine footrot: new insights into bacterial colonisation.ovine footrot is characterised by interdigital dermatitis (id) and by the separation of the skin and hoof horn (under-running footrot). dichelobacter nodosus is the essential pathogen causing footrot; the role of other microorganisms in this disease remains unclear. the aims of this study were (i) to investigate the colonisation of d nodosus, fusobacterium necrophorum and treponema species in biopsies from the ovine interdigital skin of healthy, id and footrot-affected feet and (ii) to character ...201627317761
identification and characterization of dichelobacter nodosus serogroup h from ovine footrot in india.a total of 56 foot swabs were collected from inter digital spaces of sheep with footrot lesions were screened for 16 rrna of dichelobacter nodosus by pcr. out of the 56 samples, 38(67.85%) were found to be positive. all the positive samples were subjected to multiplex pcr targeting fima gene for identification of serogroups of d. nodosus. serogroup h was found along with serogroup b in 12 (55.26%) samples and with serogroup i in 8 (22.2%) samples. the serogroup h was identified for the first tim ...201627259362
cloning, expression, and functional characterization of serine protease aprv2 from virulent isolate dichelobacter nodosus of indian origin.a gene encoding an extracellular protease from dichelobacter nodosus was characterized and expressed in e. coli rosetta-gami (de3). the nucleotide sequence analysis revealed an orf of 1427 bp ecoding 475 amino acids long protein of calculated molecular weight 50.6 kda and pi value 6.09. the phylogenetic analysis showed relatedness to subtilisin-like serine proteases of peptidase s8 family. the amino acid sequence analysis showed presence of n-terminal pre-peptide (1-23 aa), pro-peptide (24-160 a ...201627168406
survival of the ovine footrot pathogen dichelobacter nodosus in different soils.dichelobacter nodosus (d. nodosus) is the causative agent of footrot in sheep; one of the most important health and welfare issues of sheep worldwide. for control programmes to be effective, it is essential that the transmission cycle of d. nodosus is understood and bacterial reservoirs in the environment are better defined. this study evaluated the survival of d. nodosus in different soils using soil microcosms. cultivation independent and dependent methods were used to detect d. nodosus over 4 ...201626746387
drug target identification and prioritization for treatment of ovine foot rot: an in silico approach.ovine foot rot is an infection of the feet of sheep, mainly caused by dichelobacter nodosus. in its virulent form, it is highly contagious and debilitating, causing significant losses in the form of decline in wool growth and quality and poor fertility. current methods of treatment are ineffective in complete eradication. effective antibiotic treatment of foot rot is hence necessary to ensure better outcomes during control phases by reduction in culling count and the possibility of carriers of t ...201627379247
high-level association of bovine digital dermatitis treponema spp. with contagious ovine digital dermatitis lesions and presence of fusobacterium necrophorum and dichelobacter nodosus.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 a ...201525740778
a case report of lameness in two dairy goat herds; a suspected combination of nutritional factors concurrent with treponeme infection.two dairy goat farms with high level of lameness in lactating animals were presented for further investigation. farm 1 and farm 2 presented with 37 and 67% morbidity, respectively. both farms had an all year round indoor system, feeding ad libitum concentrate with forage available at all times.201526673897
experimental infection of cattle with ovine dichelobacter nodosus isolates.dichelobacter nodosus is the main causative agent of ovine footrot, and there are strong indications that the bacterium can be transferred to cattle grazing on the same pasture as sheep. the aim of this study was to investigate if benign and virulent d. nodosus strains isolated from sheep can be transferred to the interdigital skin of cattle under experimental conditions. further, we wanted to observe the impact of such infection on bovine foot health, and test the effect of topical chlortetracy ...201526407552
draft genome sequence of dichelobacter nodosus atcc 25549, strain vpi 2340 [11342], a bacterium causing footrot in sheep.we report a draft genome sequence for dichelobacter nodosus atcc 25549, strain vpi 2340 [11342], a causative agent of ovine footrot. the draft genome shares ~98% gene similarity with the available genome of d. nodosus strain vcs1703a but is differentiated by extensive gene duplication and the absence of 13 particular genes.201526404593
the detection of dichelobacter nodosus and fusobacterium necrophorum from ovine footrot in kashmir, india.in a study conducted, a total of 450 swab samples from footrot lesions of naturally infected sheep were collected in all the ten districts of the kashmir valley and were examined for the presence of dichelobacter nodosus (d. nodosus) and fusobacterium necrophorum (f. necrophorum), in order to determine if f. necrophorum was associated with ovine footrot. the detection of f. necrophorum and d. nodosus was carried out by polymerase chain reaction targeting the leukotoxin (lkta) and 16s rrna genes, ...201526159406
association of treponeme species with atypical foot lesions in goats.five uk goat farms with high levels of lameness (prevalence 14-67 per cent) were investigated. on two farms (farms 1 and 2), the animals presented with typical footrot lesions. the remaining three farms (farms 3, 4 and 5) presented with infected lesions on the foot that did not resemble footrot. these lesions were observed to start from the white line or sole but the interdigital space was rarely affected. swabs were processed by pcr to assess the presence of dichelobacter nodosus and three spec ...201525977404
the role of the environment in transmission of dichelobacter nodosus between ewes and their lambs.dichelobacter nodosus (d. nodosus) is the essential causative agent of footrot in sheep. the current study investigated when d. nodosus was detectable on newborn lambs and possible routes of transmission. specific qpcr was used to detect and quantify the load of d. nodosus in foot swabs of lambs at birth and 5-13 h post-partum, and their mothers 5-13 h post-partum; and in samples of bedding, pasture, soil and faeces. d. nodosus was not detected on the feet of newborn lambs swabbed at birth, but ...201525953734
a molecular epidemiology of treponemes in beef cattle digital dermatitis lesions and comparative analyses with sheep contagious ovine digital dermatitis and dairy cattle digital dermatitis lesions.bovine digital dermatitis (bdd) is an infective foot disease commonly reported in dairy cattle where treponema are considered as the primary causative infectious agents. there still remains little definitive information on the etiology of bdd in beef cattle suggesting further investigations are warranted. beef bdd lesions (n=34) and healthy beef foot tissues (n=38) were analysed by pcr for three bdd-associated treponema phylogroups and also for dichelobacter nodosus and fusobacterium necrophorum ...201525937315
a two-component regulatory system modulates twitching motility in dichelobacter nodosus.dichelobacter nodosus is the essential causative agent of footrot in sheep and type iv fimbriae-mediated twitching motility has been shown to be essential for virulence. we have identified a two-component signal transduction system (twmsr) that shows similarity to chemosensory systems from other bacteria. insertional inactivation of the gene encoding the response regulator, twmr, led to a twitching motility defect, with the mutant having a reduced rate of twitching motility when compared to the ...201525891425
characterisation of dichelobacter nodosus and detection of fusobacterium necrophorum and treponema spp. in sheep with different clinical manifestations of footrot.the aim of this study was to determine the proportion of dichelobacter nodosus, fusobacterium necrophorum and treponema spp. in sheep with different clinical manifestations of footrot compared to healthy sheep both at flock and individual level. the second aim was to characterise d. nodosus with respect to virulence, presence of inta gene and the serogroups. swab samples (n=1000) from footrot-affected (n=10) and healthy flocks (n=10) were analysed for the presence of d. nodosus, f. necrophorum a ...201525796133
identification and characterization of serogroup m dichelobacter nodosus from sheep with virulent footrot.as part of an outbreak-specific footrot vaccination field trial a total of 1282 footrot lesion samples were collected from 2 sheep flocks on king island, tasmania. breeding rams were shared between the two flocks, suggesting a common source of infection. all samples were tested for dichelobacter nodosus. a total of 1047 d. nodosus isolates were obtained in pure culture (490 from 670 lesion samples from flock 1, and 557 from 612 lesion samples from flock 2) were tested by agglutination and pcr te ...201525669597
phylogenetic analysis of dichelobacter nodosus serogroup-specific fima gene from ovine footrot in andhra pradesh.identification of different serogroups of dichelobacter nodosus prevailing in the region and to understand the degree of genetic heterogeneities among the different isolates of d. nodosus.201527047136
infectious lameness among migratory sheep and goats in north-west india, with particular focus on anaerobes.various bacterial species, particularly dichelobacter nodosus, fusobacterium necrophorum, trueperella pyogenes (previously arcanobacterium pyogenes) and treponema spp., have been implicated in infectious conditions manifesting in lameness in sheep and goat populations. the current study reports the causes of infectious lameness in the north-western himalayan region, particularly himachal pradesh (hp), where no such study has been conducted in the past. among a total surveyed population of 27,586 ...201527044157
outbreak of severe foot rot associated with benign dichelobacter nodosus in an alpine ibex colony in the swiss prealps.an outbreak of foot rot occurred in the ibex colony "vanil noir" in switzerland from may to december 2014. this article describes field observations and the analyses carried out on the limbs of 3 animals submitted for postmortem examination. disease signs observed in the field included lameness, poor body condition and overgrown hooves. macroscopic examination of selected limbs revealed severe lesions in all of them, including interdigital inflammation with ulceration and malodorous exudation. h ...201526753343
first study of pathogen load and localisation of ovine footrot using fluorescence in situ hybridisation (fish).analysis of bacterial populations in situ provides insights into pathogen population dynamics and potential reservoirs for disease. here we report a culture-independent study of ovine footrot (fr); a debilitating bacterial disease that has significant economic impact on sheep farming worldwide. disease begins as an interdigital dermatitis (id), which may then progress to separation of the hoof horn from the underlying epidermis causing severe footrot (sfr). dichelobacter nodosus is the causative ...201525742734
investigation of immunity in sheep following footrot infection and vaccination.ovine footrot is a major disease affecting sheep welfare and production. the anaerobic gram-negative bacterium dichelobacter nodosus is the essential transmitting agent. monovalent or bivalent vaccines induce high levels of d. nodosus antibodies and are the basis of several successful footrot treatment, control and eradication programs. due to the rapid rate of disease transmission within a flock, the presence of therapeutic vaccination non-responders has major implications for a control program ...201425454866
genomic evidence for a globally distributed, bimodal population in the ovine footrot pathogen dichelobacter nodosus.footrot is a contagious, debilitating disease of sheep, causing major economic losses in most sheep-producing countries. the causative agent is the gram-negative anaerobe dichelobacter nodosus. depending on the virulence of the infective bacterial strain, clinical signs vary from a mild interdigital dermatitis (benign footrot) to severe underrunning of the horn of the hoof (virulent footrot). the aim of this study was to investigate the genetic relationship between d. nodosus strains of differen ...201425271288
differential expression of toll-like receptors and inflammatory cytokines in ovine interdigital dermatitis and footrot.footrot is a common inflammatory bacterial disease affecting the health and welfare of sheep worldwide. the pathogenesis of footrot is complex and multifactorial. the primary causal pathogen is the anaerobic bacterium dichelobacter nodosus, with fusobacterium necrophorum also shown to play a key role in disease. since immune-mediated pathology is implicated, the aim of this research was to investigate the role of the host response in interdigital dermatitis (id) and footrot. we compared the expr ...201425124770
dynamics and impact of footrot and climate on hoof horn length in 50 ewes from one farm over a period of 10 months.footrot, including interdigital dermatitis, is caused by dichelobacter nodosus cause the majority of lameness in sheep in the uk. lame sheep often have overgrown hoof horn but recent evidence has indicated that trimming overgrown hoof horn increases recovery time, and that routine foot trimming of the flock does not reduce the prevalence or incidence of lameness. the objectives of this study were to investigate the temporal associations between hoof horn length, footrot and climate. fifty multip ...201424973007
contagious ovine digital dermatitis: an emerging disease.the novel sheep disease, contagious ovine digital dermatitis (codd) was first described in the uk in 1997. the disease is characterised by severe lameness associated with initial inflammation at the coronary band, followed by progressive separation of the hoof capsule from the underlying tissue. on microbiological examination, treponeme bacteria have been frequently isolated from cases of codd, including treponemes phylogenetically identical to those associated with bovine digital dermatitis (bd ...201424973004
a recently introduced dichelobacter nodosus strain caused an outbreak of footrot in norway.in 2008, an outbreak of ovine footrot occurred in norway. dichelobacter nodosus isolates collected between 2008 and 2011 have been characterised. isolates defined as virulent by the gelatin gel test (gg-test) were only found in sheep in rogaland county, where the severe cases of footrot were registered. the majority (96%) of the virulent isolates belonged to serogroup a. it is suspected that they represent a newly introduced strain, and the aim of the present study was to investigate whether the ...201424886510
multiple locus vntr analysis highlights that geographical clustering and distribution of dichelobacter nodosus, the causal agent of footrot in sheep, correlates with inter-country movements.dichelobacter nodosus is a gram-negative, anaerobic bacterium and the causal agent of footrot in sheep. multiple locus variable number tandem repeat (vntr) analysis (mlva) is a portable technique that involves the identification and enumeration of polymorphic tandem repeats across the genome. the aims of this study were to develop an mlva scheme for d. nodosus suitable for use as a molecular typing tool, and to apply it to a global collection of isolates. seventy-seven isolates selected from reg ...201423748018
footrot vaccines and vaccination.research on footrot in small ruminants, which is caused by dichelobacter nodosus, has led to development of vaccines and their application for control, treatment and eradication of the disease in sheep. footrot vaccines have evolved over decades to contain monovalent whole cell, multivalent recombinant fimbrial, and finally mono or bivalent recombinant fimbrial antigens. initially whole cell vaccines made against the few known serogroups of d. nodosus were found to be inefficient in control of t ...201424736003
a longitudinal study of the role of dichelobacter nodosus and fusobacterium necrophorum load in initiation and severity of footrot in sheep.footrot is an infectious bacterial disease of sheep that causes lameness. the causal agent is dichelobacter nodosus. there is debate regarding the role of fusobacterium necrophorum in disease initiation. this research used an observational longitudinal study of footrot, together with quantitative pcr (qpcr) of bacterial load of d. nodosus and f. necrophorum, to elucidate the roles of each species in the development of disease. all feet of 18 a priori selected sheep were monitored for five weeks ...201424703249
cross-infection of virulent dichelobacter nodosus between sheep and co-grazing cattle.dichelobacter nodosus is the main aetiological agent of ovine footrot and the bacterium has also been associated with interdigital dermatitis is cattle. the aim of this study was to investigate possible cross-infection of virulent d. nodosus between sheep and co-grazing cattle. five farms, where sheep previously diagnosed with virulent d. nodosus were co-grazing with cattle for different periods of time, were included. the study sample consisted of 200 cows and 50 sheep. all cows were examined f ...201424698131
field studies on the elimination of footrot in sheep through whole flock treatments with gamithromycin. 201424477473
simultaneous detection and discrimination of virulent and benign dichelobacter nodosus in sheep of flocks affected by foot rot and in clinically healthy flocks by competitive real-time pcr.ovine foot rot caused by dichelobacter nodosus is affecting sheep worldwide. the current diagnostic methods are difficult and cumbersome. here, we present a competitive real-time pcr based on allelic discrimination of the protease genes aprv2 and aprb2. this method allows direct detection and differentiation of virulent and benign d. nodosus from interdigital skin swabs in a single test. clinically affected sheep harbored high loads of only virulent strains, whereas healthy sheep had lower loads ...201424452162
molecular genetic analysis of dichelobacter nodosus proteases aprv2/b2, aprv5/b5 and bprv/b in clinical material from european sheep flocks.dichelobacter nodosus, the etiological agent of ovine footrot, exists both as virulent and as benign strains, which differ in virulence mainly due to subtle differences in the three subtilisin-like proteases aprv2, aprv5 and bprv found in virulent, and aprb2, aprb5 and bprb in benign strains of d. nodosus. our objective was a molecular genetic epidemiological analysis of the genes of these proteases by direct sequence analysis from clinical material of sheep from herds with and without history o ...201424332828
a longitudinal study of the risks for introduction of severe footrot into sheep flocks in the south west of norway.in 2008, ovine footrot was detected in norway for the first time since 1948. by december 2012 it had spread to 99 flocks, all in the county of rogaland in the south west of norway, and 42% of which were located in the municipality of rennesøy in rogaland. the aim of this study was to investigate risk factors for contracting severe footrot in flocks of sheep. a flock was considered positive for severe footrot based on positive virulence test or by clinical signs in addition to a positive pcr test ...201424315430
interdigital dermatitis, heel horn erosion, and digital dermatitis in 14 norwegian dairy herds.the aim of this study was to assess infectious foot diseases, including identification and characterization of dichelobacter nodosus and treponema spp., in herds having problems with interdigital dermatitis (id) and heel horn erosion (e) and in control herds expected to have few problems. we also wanted to compare diseased and healthy cows in all herds. the study included 14 dairy herds with a total of 633 cows. eight herds had a history of id and e, and 6 were control herds. all cows were score ...201324140335
non-specificity of primers used for pcr based serogrouping of dichelobacter nodosus and identification of a novel d. nodosus strain.the present study records the first case of non-specificity of typing primers developed by dhungyel et al. a strain of dichelobacter nodosus (jks-20g) isolated from ovine footrot in kashmir, india, showed specificity for serogroup c and g primers. the fima sequence of the strain turned out to be closer to serogroup g than c. the nucleotide sequence showed maximum homology of 92% with that of serotype g1 strain 238 and 95% with partial sequence available for serotype g2 strain vcs 1004. however, ...201323542117
outbreak-specific monovalent/bivalent vaccination to control and eradicate virulent ovine footrot.footrot is a contagious disease of small ruminants which is caused by the bacterium dichelobacter nodosus. in its virulent form there are severe economic losses and a very significant animal welfare issue. sheep and goats can be vaccinated for treatment and prevention of the disease. there are 10 different serogroups of d. nodosus (a-i and m) and immunity is serogroup-specific. when all 10 serogroups are presented together in a vaccine, protection persists for only a few months due to "antigenic ...201323395621
an evaluation of the ability of dichelobacter nodosus to survive in soil.dichelobacter nodosus is the causative agent of footrot in sheep. the survival of the bacterium in soil is of importance for the epidemiology of the disease. the investigation evaluates the survival of d. nodosus in soil with and without added hoof powder stored under different temperatures.201323343097
characterisation of dichelobacter nodosus isolates from norway.an outbreak of ovine footrot in norway in 2008, the first reported since 1948, prompted action to investigate norwegian isolates of dichelobacter nodosus. a total of 579 isolates from 124 different farms were characterised. these included 519 isolates from sheep, 52 isolates from cattle and 8 isolates from goats. the potential virulence of the isolates was assessed by the gelatin gel test (gg-test) and the elastin agar test, that test the heat stability and elastase activity of bacterial proteas ...201323332560
comparative study of the commonly used virulence tests for laboratory diagnosis of ovine footrot caused by dichelobacter nodosus in australia.footrot in sheep and goats is expressed as a spectrum of clinical entities ranging from benign, which is a self limiting interdigital dermatitis to highly virulent, in which severe under running of the horn of the hoof occurs. interactions between the host, the virulence of the causative strain of dichelobacter nodosus and environmental conditions determine the severity of the disease. clinical diagnosis of virulent footrot, which a notifiable disease in some states of australia, is not always s ...201323084506
secretion of tcpf by the vibrio cholerae toxin-coregulated pilus biogenesis apparatus requires an n-terminal determinant.type iv pili are important for microcolony formation, biofilm formation, twitching motility, and attachment. we and others have shown that type iv pili are important for protein secretion across the outer membrane, similar to type ii secretion systems. this study explored the relationship between protein secretion and pilus formation in vibrio cholerae. the toxin-coregulated pilus (tcp), a type iv pilus required for v. cholerae pathogenesis, is necessary for the secretion of the colonization fac ...201323564177
prevalence of ovine footrot in the tropical climate of southern india and isolation and characterisation of dichelobacter nodosus.the present communication records the first determination of the prevalence of footrot in the unexpected situation of the tropical climate of andhra pradesh and tamil nadu, two states in southern india where the maximum temperature rises to 42 degrees c. in total, 73 outbreaks of footrot in nellore brown sheep were investigated in 11 districts of andhra pradesh and one district of tamil nadu during the period march 2009 to march 2011.the overall prevalence of ovine footrot was 15%, with severity ...201324761738
fusobacterium necrophorum, and not dichelobacter nodosus, is associated with equine hoof thrush.the aim of this study was to determine which of the two species, fusobacterium necrophorum or dichelobacter nodosus, are associated with hoof thrush in horses. fourteen hoof samples, collected from eight horses with thrush and 14 samples collected from eight horses with healthy hooves, were examined for the presence of f. necrophorum, fusobacterium equinum and d. nodosus. only isolates with phenotypic characteristics representing fusobacterium could be cultured. total dna extracted from the 28 h ...201322909990
bovine digital dermatitis: possible pathogenic consortium consisting of dichelobacter nodosus and multiple treponema species.bovine digital dermatitis (dd) is a multifactorial disease involving at least one or more treponemal species. virulent phylotypes of treponema and other infectious agents contributing to disease etiology still remain to be identified. this study addressed these questions by analyzing the prevalence and distribution of seventeen phylotypes of treponema in dd lesions by fluorescent in situ hybridization (fish) applying species/phylotype-specific oligonucleotide probes. in situ hybridization for di ...201222698300
possible cross-infection of dichelobacter nodosus between co-grazing sheep and cattle.the aim of this study was to investigate possible cross-infection of dichelobacter nodosus in norwegian farms practising co-grazing of sheep and cattle.201222458248
impact of footrot vaccination and antibiotic therapy on footrot and contagious ovine digital dermatitis.footrot and contagious ovine digital dermatitis (codd) are common causes of foot disease of sheep in the uk. the study reported here is a split flock randomised treatment trial undertaken on a group of 748 fattening lambs on a uk sheep farm affected by codd and footrot. the sheep were randomly assigned to one of two treatment protocols. in protocol a, all sheep were given two doses of footrot vaccine (footvax, msd), plus targeted antibiotic therapy (long-acting amoxicillin, betamox la, norbrook ...201222266683
the aprv5 subtilase is required for the optimal processing of all three extracellular serine proteases from dichelobacter nodosus.dichelobacter nodosus is the principal causative agent of ovine footrot and its extracellular proteases are major virulence factors. virulent isolates of d. nodosus secrete three subtilisin-like serine proteases: aprv2, aprv5 and bprv. these enzymes are each synthesized as precursor molecules that include a signal (pre-) peptide, a pro-peptide and a c-terminal extension, which are processed to produce the mature active forms. the function of the c-terminal regions of these proteases and the mech ...201223112874
development and comparison of a real-time pcr assay for detection of dichelobacter nodosus with culturing and conventional pcr: harmonisation between three laboratories.ovine footrot is a contagious disease with worldwide occurrence in sheep. the main causative agent is the fastidious bacterium dichelobacter nodosus. in scandinavia, footrot was first diagnosed in sweden in 2004 and later also in norway and denmark. clinical examination of sheep feet is fundamental to diagnosis of footrot, but d. nodosus should also be detected to confirm the diagnosis. pcr-based detection using conventional pcr has been used at our institutes, but the method was laborious and t ...201222293440
infection dynamics of digital dermatitis in first-lactation holstein cows in an infected herd.digital dermatitis (dd) refers to painful lesions primarily affecting the skin in the interdigital region of dairy cattle. the purpose of this study was to evaluate the dynamics of dd in 39 cows, observed at approximately 3-d intervals, for the first 6 mo of lactation. specifically, the study aimed at evaluating different levels of dd susceptibility in cows, identifying the bacterial colonization of the interdigital skin, and exploring the relationship between clinical dd diagnosis and laborator ...201222939796
determination of prevalence and economic impact of ovine footrot in central kashmir india with isolation and molecular characterization of dichelobacter nodosus.the present study determines the prevalence, economic impact of virulent footrot in central kashmir, india, along with isolation and molecular characterization of dichelobacter nodosus (d. nodosus) where so far no such work has been carried out. over all 12.54% prevalence of footrot was recorded in central kashmir with highest (15.84%) in district srinagar, and least (10.89%) in district budgam, while it was 13.28% in district ganderbal. overall economic impact of footrot was estimated to the tu ...201121397709
ovine pedomics: the first study of the ovine foot 16s rrna-based microbiome.we report the first study of the bacterial microbiome of ovine interdigital skin based on 16s rrna by pyrosequencing and conventional cloning with sanger-sequencing. three flocks were selected, one a flock with no signs of footrot or interdigital dermatitis, a second flock with interdigital dermatitis alone and a third flock with both interdigital dermatitis and footrot. the sheep were classified as having either healthy interdigital skin (h) and interdigital dermatitis (id) or virulent footrot ...201121430786
prevalence of footrot in swedish slaughter lambs.abstract:201121492433
implications of host genetic variation on the risk and prevalence of infectious diseases transmitted through the environment.previous studies have shown that host genetic heterogeneity in the response to infectious challenge can affect the emergence risk and the severity of diseases transmitted through direct contact between individuals. however, there is substantial uncertainty about the degree and direction of influence owing to different definitions of genetic variation, most of which are not in line with the current understanding of the genetic architecture of disease traits. also, the relevance of previous result ...201121527777
the pathogenesis of ovine footrot.ovine footrot is a contagious and debilitating disease that is of major economic significance to the sheep meat and wool industries. the causative bacterium is the gram negative anaerobe dichelobacter nodosus. research that has used a classical molecular genetics approach has led to major advances in our understanding of the role of the key virulence factors of d. nodosus in the disease process. d. nodosus strains produce polar type iv fimbriae and extracellular serine proteases. mutagenesis of ...201121596496
s1 pocket of a bacterially derived subtilisin-like protease underpins effective tissue destruction.the ovine footrot pathogen, dichelobacter nodosus, secretes three subtilisin-like proteases that play an important role in the pathogenesis of footrot through their ability to mediate tissue destruction. virulent and benign strains of d. nodosus secrete the basic proteases bprv and bprb, respectively, with the catalytic domain of these enzymes having 96% sequence identity. at present, it is not known how sequence variation between these two putative virulence factors influences their respective ...201121990366
Identification of two new serotypes within serogroup B of Dichelobacter nodosus.The present study records the strain-specific molecular typing system for Dichelobacter nodosus (D. nodosus) based on genetic analysis of fimA locus. Based on the study two new serotypes B5 and B6 are reported within the serogroup B. Out of 200 swab samples collected randomly from foot lesions of footrot affected sheep from all the districts of Kashmir, India, 122 (61.0%) detected positive for D. nodosus. Serogroup B was predominantly prevalent in 83.60% of positive samples. Restriction fragment ...201122197966
plasmid-mediated florfenicol resistance in mannheimia haemolytica isolated from cattle.the aim of this study was to analyse a florfenicol-resistant mannheimia haemolytica isolated from a calf to determine the genetic basis of its florfenicol-resistance. the antimicrobial susceptibility and plasmid content of the isolate were determined. a florfenicol resistant plasmid carrying the flor gene was identified by pcr and transformed into escherichia coli jm109 and hb101 strains. the plasmid was then mapped and sequenced completely. the isolate was resistant to chloramphenicol, florfeni ...201122019290
ultrahigh resolution and full-length pilin structures with insights for filament assembly, pathogenic functions, and vaccine potential.pilin proteins assemble into type iv pili (t4p), surface-displayed bacterial filaments with virulence functions including motility, attachment, transformation, immune escape, and colony formation. however, challenges in crystallizing full-length fiber-forming and membrane protein pilins leave unanswered questions regarding pilin structures, assembly, functions, and vaccine potential. here we report pilin structures of full-length dnfima from the sheep pathogen dichelobacter nodosus and ftpile fr ...201122027840
detection and diversity of a putative novel heterogeneous polymorphic proline-glycine repeat (pgr) protein in the footrot pathogen dichelobacter nodosus.dichelobacter nodosus, a gram-negative anaerobic bacterium, is the essential causative agent of footrot in sheep. currently, depending on the clinical presentation in the field, footrot is described as benign or virulent; d. nodosus strains have also been classified as benign or virulent, but this designation is not always consistent with clinical disease. the aim of this study was to determine the diversity of the pgr gene, which encodes a putative proline-glycine repeat protein (pgr). the pgr ...201120655152
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 fa ...201020926208
the subtilisin-like protease aprv2 is required for virulence and uses a novel disulphide-tethered exosite to bind substrates.many bacterial pathogens produce extracellular proteases that degrade the extracellular matrix of the host and therefore are involved in disease pathogenesis. dichelobacter nodosus is the causative agent of ovine footrot, a highly contagious disease that is characterized by the separation of the hoof from the underlying tissue. d. nodosus secretes three subtilisin-like proteases whose analysis forms the basis of diagnostic tests that differentiate between virulent and benign strains and have bee ...201021124876
footrot on a sheep breeding farm in the himalayan state of jammu and kashmir.in the present study ovine footrot was detected clinically on a sheep farm in the himalayan state of jammu and kashmir. dichelobacter nodosus was confirmed by culture and polymerase chain reaction (pcr) using species-specific 16s ribosomal rna primers. when cultured, the organism appeared as flat colourless colonies having a fine granulated structure with irregular margins, and showing characteristic gram-negative rods with swollen ends. detection by pcr from cultured bacteria resulted in amplif ...201021309465
understanding the molecular epidemiology of the footrot pathogen dichelobacter nodosus to support control and eradication programs.the gram-negative anaerobe dichelobacter nodosus is the primary etiologic agent of ovine footrot. few studies of the genetic diversity and epidemiology of d. nodosus have been done, despite the economic cost and welfare implications of the disease. this study examined a large collection of australian isolates; 735 isolates from footrot-infected sheep from 247 farms in western australia (wa) were tested by pulsed-field gel electrophoresis (pfge), and a subset of 616 isolates was tested by infrequ ...201020071558
crystallization of the virulent and benign subtilisin-like proteases from the ovine footrot pathogen dichelobacter nodosus.dichelobacter nodosus is the principal causative agent of ovine footrot, a disease of significant economic importance to the sheep industry. d. nodosus secretes a number of subtilisin-like serine proteases which mediate tissue damage and presumably contribute to the pathogenesis of footrot. strains causing virulent footrot secrete the proteases aprv2, aprv5 and bprv and strains causing benign footrot secrete the closely related proteases aprb2, aprb5 and bprb. here, the cloning, purification and ...201020208163
diagnostic sampling strategies for virulent ovine footrot: simulating detection of dichelobacter nodosus serogroups for bivalent vaccine formulation.dichelobacter nodosus is a slow-growing anaerobic bacterium that is the causative agent of virulent ovine footrot. vaccination targeted at up to two specific serogroups can eliminate those serogroups from infected flocks, but requires identification of serogroups present in infected flocks. serogroups can be identified using slide agglutination or polymerase chain reaction (pcr) methods. the objectives of this project were to use stochastic simulation modeling to estimate the efficacy of samplin ...201020303191
footrot and interdigital dermatitis in sheep: farmer satisfaction with current management, their ideal management and sources used to adopt new strategies.the aims of this research were to identify management practices that sheep farmers currently use to treat and prevent footrot in sheep and whether they consider that these are successful management tools and to find out how sheep farmers would ideally like to manage footrot in their flock. over 90% of lameness in sheep in the uk is caused by dichelobacter nodosus, which presents clinically as interdigital dermatitis (id) alone or with separation of hoof horn (fr). a questionnaire was sent to 265 ...201020594602
a within farm clinical trial to compare two treatments (parenteral antibacterials and hoof trimming) for sheep lame with footrot.from observational studies, farmers who use parenteral antibacterials to promptly treat all sheep with footrot (fr) or interdigital dermatitis (id) have a prevalence of lameness of < 2% compared with a prevalence of 9% lameness reported by farmers who treat lame sheep by trimming affected feet. we tested the hypothesis that prompt treatment of sheep lame with naturally developing fr or id with parenteral and topical antibacterials reduces the prevalence and incidence of lameness with these condi ...201020627343
identification of two new dichelobacter nodosus strains in germany.the multi-strain anaerobe dichelobacter nodosus causes footrot, a contagious disease of the digits of ruminants that occurs worldwide. eleven d. nodosus-like isolates from footrot lesions of sheep in germany were investigated by pcr amplification of the variable region of the d. nodosus fimbrial (fima) gene. in six isolates, fima pcr amplicons of a size suggestive of d. nodosus were generated. single-strand conformational polymorphism (sscp) analysis of the amplicons revealed three banding patte ...201019285440
evolution of oxidative/nitrosative stress biomarkers during an open-field vaccination procedure in sheep: effect of melatonin.melatonin has been shown to exert immunomodularory properties with broad application in veterinary medicine. in previous work we have described that subcutaneous coadministration of melatonin to seeps vaccinated against two stumps of a1 and c strains of dichelobacter nodosus enhanced both the antibody titer and serum igg levels to a1 and c strains of d. nodosus compared to vaccinated animals not treated with melatonin. following a similar protocol here we have investigated the effect of a higher ...201019631992
deletion of the c-terminus of polynucleotide phosphorylase increases twitching motility, a virulence characteristic of the anaerobic bacterial pathogen dichelobacter nodosus.the gram-negative anaerobe dichelobacter nodosus is the causative agent of footrot in sheep. different strains of d. nodosus cause disease of differing severities, ranging from benign to virulent. virulent strains have greater twitching motility and secrete proteases that are more thermostable than those secreted by benign strains. we have identified polynucleotide phosphorylase (pnpase) as a putative virulence regulator and have proposed that pnpase expression is modulated by the adjacent integ ...201019895640
proteomic profiling of ovine serum by seldi-tof ms: optimisation, reproducibility and feasibility of biomarker discovery using routinely collected samples.the diagnosis of infectious diseases in animals may be enhanced by study of the serum proteome in which myriad components are influenced by physiological and pathological processes. surface-enhanced laser desorption/ionisation time-of-flight mass spectrometry (seldi-tof ms) has the capacity to detect known and unknown immunologically relevant molecules in the serum proteome. optimum combinations of proteinchip array surfaces, energy absorbing molecules, sample dilutions and instrument settings w ...201018775566
variation in fusobacterium necrophorum strains present on the hooves of footrot infected sheep, goats and cattle.footrot is a disease of sheep, goats and cattle that causes losses in production and raises welfare issues world-wide. the disease is characterised by destruction of the hard keratin of the hoof leading to lameness, and both dichelobacter nodosus (d. nodosus) and fusobacterium necrophorum (f. necrophorum) are thought to be involved in the etiology of this disease. while a lot is known about the genetic diversity of d. nodosus, very little is known about variation in f. necrophorum, especially as ...200919019570
melatonin enhances the immune response to vaccination against a1 and c strains of dichelobacter nodosus.melatonin has been shown to exert immunomodulatory properties with broad application in veterinary medicine. here we have investigated the effect of exogenous melatonin in the improvement of the immune response to administration of an immune-preparation of two stumps of a1 and c strains of dichelobacter nodosus in sheep. subcutaneous administration of melatonin enhanced plasma levels of melatonin from days 42 to 120. administration of melatonin to vaccinated animals enhanced both the titer of an ...200919166891
effect of parenteral selenium administration to sheep on prevalence and recovery from footrot.insufficient intake of selenium (se) is common in many regions, and can contribute to increased susceptibility to and prolonged recovery from infectious diseases.200919192142
melatonin, as an adjuvant-like agent, enhances platelet responsiveness.melatonin exerts immunomodulatory actions that enhance the magnitude and quality of immune responses specific for certain antigens; this has raised the possibility of using melatonin to design novel vaccine adjuvant systems. the present study investigated the effect of subcutaneous slow-release melatonin implants and subcutaneous melatonin injections on the responsiveness of circulating platelets in sheep after vaccination against dichelobacter nodosus (a1 and c serotypes), the bacterium that ca ...200919196436
dichelobacter nodosus, fusobacterium necrophorum and the epidemiology of footrot.footrot is a debilitating disease of sheep resulting in lameness, production losses and suffering. to study the basic bacteriology of the disease, a survey was initiated across commercial farms and non-commercial research flocks to compare the bacteriology of symptomatic footrot infected sheep with healthy asymptomatic sheep. of the 80 farmers initially contacted, 14 collected hoof swabs and returned the swabs by post. following dna extraction, species-specific pcr was used to identify if dichel ...200919239925
the detection of dichelobacter nodosus and fusobacterium necrophorum from footrot lesions in new zealand goats. 200919248838
serological diversity and virulence determination of dichelobacter nodosus from footrot in india.one hundred and twenty-eight swab samples from footrot lesions of naturally infected sheep were examined for presence of dichelobacter nodosus (d. nodosus). the detection of d. nodosus was carried out by polymerase chain reaction (pcr), directly from swabs or after isolation, using 16s rdna specific primers. the isolation of the bacterium was carried out anaerobically on trypticase-arginine-serine (tas) agar containing 4% hoof powder. serogrouping of the d. nodosus was accomplished with multiple ...200919272343
[structural and functional specificity of the dichelobacter nodosus pili. synthesis of the protein pilin of d. nodosus in various bacterial recombinant strains].the ovine foot rot is a severe infectious disease of sheep. dichelobacter nodosus is an essential pathogen of this disease. an obligatory anaerobic gram-negative rod-shaped microorganism has slow rate of accumulating bacterial density and fastidious growth requirements. this causes obstacles to vaccine production and makes it difficult to diagnose the disease. the diagnosis in this case is more expensive. fimbriae (or pili) are one of the major factors of virulence of d. nodosus. their antigenic ...200920050159
modulation of inter-vaccination interval to avoid antigenic competition in multivalent footrot (dichelobacter nodosus) vaccines in sheep.virulent footrot is a significant disease of sheep in most sheep farming countries; a strain/serogroup of the anaerobic bacterium dichelobacter nodosus is the essential transmitting agent. commercial multivalent footrot vaccines containing nine fimbrial serogroups (a through i) of d. nodosus produce relatively low and short term antibody responses due to antigenic competition, in contrast to higher and longer responses provided by monovalent or bivalent vaccines. the latter were important compon ...200919853681
the intd mobile genetic element from dichelobacter nodosus, the causative agent of ovine footrot, is associated with the benign phenotype.the gram-negative anaerobic pathogen dichelobacter nodosus is the principal causative agent of footrot in sheep. the inta, intb and intc elements are mobile genetic elements which integrate into two trna genes downstream from csra (formerly glpa) and pnpa in the d. nodosus chromosome. csra homologues act as global repressors of virulence in several bacterial pathogens, as does polynucleotide phosphorylase, the product of pnpa. we have proposed a model in which virulence in d. nodosus is controll ...200919327404
detection of fusobacterium necrophorum and dichelobacter nodosus in lame cattle on dairy farms in new zealand.lameness in the dairy industry in new zealand causes a problem in lost production, animal welfare and associated costs. to understand what bacteria may be present on the hooves of lame dairy cattle in this grass-fed system, samples were scraped from lame dairy cows and examined for the presence of fusobacterium necrophorum (f. necrophorum) and dichelobacter nodosus (d. nodosus) using the polymerase chain reaction (pcr). the pcr primers were designed to detect the presence of the lkta gene, which ...200919409584
comparative genomic analysis of ten streptococcus pneumoniae temperate bacteriophages.streptococcus pneumoniae is an important human pathogen that often carries temperate bacteriophages. as part of a program to characterize the genetic makeup of prophages associated with clinical strains and to assess the potential roles that they play in the biology and pathogenesis in their host, we performed comparative genomic analysis of 10 temperate pneumococcal phages. all of the genomes are organized into five major gene clusters: lysogeny, replication, packaging, morphogenesis, and lysis ...200919502408
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