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Experimentally induced digital dermatitis, sheep (passage of digital dermatitis using material from digital dermatitis lesions induced in sheep). Fig. 21. Ballooning degeneration of keratinocytes and neutrophilic infiltrate. Hematoxylin and eosin (HE). Fig. 22. Irregular acanthosis and hyperkeratosis. HE. Fig. 23. Erosion and ulceration with neutrophilic infiltrates. HE. Fig. 24. Large numbers of spirochetes found deep in the stratum corneum. Steiner and Steiner silver stain. Inset: higher magnification of spirochetes (black arrows).
Source publication
Digital dermatitis is an infectious cause of lameness primarily affecting cattle but also described in sheep, goats, and wild elk. Digital dermatitis is a polymicrobial infection, involving several Treponema species and other anaerobic bacteria. Although the exact etiology has not been demonstrated, a number of bacterial, host, and environmental fa...
Similar publications
The serum concentration of certain acute phase proteins significantly increases during various pathological conditions in cattle. The aim of this study was to determine the influence of claw disorders etiology on the concentrations of two major acute phase proteins in dairy cattle: haptoglobin (Hp) and serum amyloid protein A (SAA). Fifty dairy cow...
Citations
... In both DD and CODD, increased severity of lesions is associated with marked increases in Treponema numbers, diversity, and depth of invasion [9][10][11][12][13]. Three species of Treponema: T. phagedenis, T. pedis and T. medium, have been identified globally in association with DD, both geographically across the globe, associated with hoof lesions in multiple hosts (goats, sheep, cattle, elk, bison, Mediterranean buffalo), and persists in DD transmission animal models [13][14][15][16][17][18]. Other Treponema species that have been isolated from DD lesions less frequently or identified by bacterial 16S DNA sequencing include: T. refringens, T. brennaborense, T. denticola or T. dentocolalike, T. lecithinolyticum, T. putidum, and un-named lesscharacterized phylotypes (PT1, PT2, PT3, PT8, PT13) [14,[19][20][21][22]. Bacterial population differences between studies may reflect variations influenced by climate, geography, or husbandry practices. ...
... PCR for Treponema medium, Treponema pedis, Treponema phagedenis, Treponema vincentii, Treponema denticola, Treponema brennaborense and Fusobacterium necrophorum was performed on n = 158, including healthy, lesion and contralateral samples, in a two-stage nested PCR assay as previously described [1,17,18]. Positive controls were genomic DNA purified from each respective bacterial species. Details on bacterial strains, PCR primers and amplification conditions are given in supplementary material 5 (Table S1). ...
Background
Treponeme-Associated Hoof Disease (TAHD) is a polybacterial, multifactorial disease affecting free-ranging wild elk (Cervus canadensis) in the Pacific Northwest. Previous studies have indicated a bacterial etiology similar to digital dermatitis in livestock, including isolation of Treponema species from lesions. The lesions appear to progress rapidly from ulcerative areas in the interdigital space or along the coronary band to severe, ulcerative, necrotic, proliferative lesions under-running the hoof wall, perforating the sole, and contributing to hoof elongation, deformity, and overgrowth. Eventually the lesions undermine the laminal structure leading to sloughing of the hoof horn capsule. The objective of this study was to characterize the bacterial communities associated with hoof lesions, which were categorized into 5 stages or disease grade severities, with 0 being unaffected tissue and 4 being sloughed hoof capsule. We also wanted to determine if the etiology of TAHD through morphological changes was dominated by Treponema, as observed in hoof diseases in livestock.
Results
The bacterial 16S rRNA gene was sequenced from 66 hoof skin biopsy samples representing 5 lesion grades from samples collected by Washington Department of Fish and Wildlife as part of a voluntary hunter program. Analysis of the relative abundance of bacterial sequences showed that lesions were dominated by members of the bacterial phyla Proteobacteria, Firmicutes, Spirochaetes, Bacteroidetes and Actinobacteria. In lesion samples, members of the genus Treponema, Porphyromonas, and Mycoplasma increased with lesion severity. Association analysis indicated frequent identification of Treponema with Porphyromonas, Bacteroides and other anaerobic Gram-positive cocci.
Conclusions
The bacterial 16S rRNA gene sequencing confirmed the presence of Treponema species at all stages of TAHD lesions, treponeme specie-specific PCR and histopathology, indicating that the morphological changes are a continual progression of disease severity with similar bacterial communities. Association and abundance of these other pathogenic genera within lesions may mean synergistic role with Treponema in hoof disease pathogenesis. Characterizing bacteria involved in lesion development, and their persistence during disease progression, provides evidence for science-based management decisions in TAHD infected elk populations.
... Wraps in our study were designed to increase the contact time of the foot with soil-inoculum mixture, increasing the duration of exposure to infectious material. Although our objective in using the wrap was not to create an anaerobic environment as in digital dermatitis experimental challenge studies in cattle [10,23] and sheep [24], the wrap may have aided in maintaining moisture and reducing oxygen that further promoted lesion development and progression; lesions on wrapped feet in our study progressed to grade III, while lesions on unwrapped feet were transient and none progressed beyond grade I. Because only wrapped feet were abraded, however, our model limits our ability to distinguish the role of wraps from abrasions in the progression of lesion development. ...
Treponeme-associated hoof disease (TAHD) is a debilitating disease of free-ranging elk (Cervus canadensis) in the northwestern U.S. While treponemes are associated with lesions, the etiology and transmissibility between elk are unknown. Our objective was to determine whether the disease can be environmentally transmitted to captive elk. Four individually housed treatment elk and 2 control elk were challenged with soil mixed with inoculum prepared from free-ranging elk hooves from TAHD-positive elk or autoclaved hooves from normal elk, respectively. The inoculum for each group was applied to the interdigital space and added to pre-existing soil in each pen. Eight challenges were conducted at 1-4-week intervals and lesion development was assessed during a 138-day challenge period that was followed by a 170-day monitoring period to document lesion progression. All treatment elk, but no control elk, developed gross and histologic lesions consistent with TAHD. Treponema phylotypes similar to those in bovine digital dermatitis in cattle were detected using 16S rRNA gene amplicon sequencing from lesions in all treatment elk, but no control elk, during the challenge period. Lesions progressed from ulcerations in the interdigital space to extensive ulceration and underrunning of the hoof capsule by 35 and 173 days following the initial inoculation, respectively. Lameness in treatment elk was correlated with lesion development (R = 0.702, p≤0.001), and activity of infected elk was reduced during the challenge (p≤0.001) and monitoring periods (p = 0.004). Body condition was significantly lower in treatment than control elk 168 days following the initial inoculation (p = 0.05) and at each individual elk's study endpoint (p = 0.006). Three of 4 treatment elk were euthanized when they reached humane endpoints, and one elk recovered. These results provide direct evidence that TAHD is a transmissible infectious disease in elk. As such, actions that reduce transmission risk can support disease management and prevention.
... Due to the high experimental costs, research on bovine foot rot has transitioned from the original in vivo experiments (Wilson-Welder et al., 2018;Gomez et al., 2012) to a single-layer cell model in vitro. However, the latter approach can not reflect the cellular processes in vivo due to the lack of multi-cell interactions (Maboni et al., 2017). ...
Background
Fusobacterium necrophorum is the main pathogen inducing bovine foot rot. The infected site is often accompanied by a strong inflammatory response, but the specific inflammatory regulatory mechanism remains unclear.
Aim
A cow skin explants model was established to elucidate the mechanism of F. necrophorum bacillus causing foot rot in cows, and to provide reference for future clinical practice.
Methods
Cow intertoe skin explants were cultured in vitro, and F. necrophorum bacteria solution and nuclear factor-κB (NF-κB) inhibitor BAY 1-7082 were added to establish an in vitro infection model. Hematoxylin and eosin staining, terminal - deoxynucleotidyl transferase mediated nick end labeling, and immunohistochemistry were used to detect the pathological changes of the skin explants infected with F. necrophorum, the degree of tissue cell apoptosis, and the expression of the apoptosis-related protein Caspase-3, respectively. RT-qPCR, Western blot, and ELISA were used to detect the activation of the NF-κB pathway and inflammatory cytokines by F. necrophorum.
Results
The intertoe skin structure of cows infected with F. necrophorum changed with different degrees of inflammation, and the degree of tissue cell apoptosis was significantly increased (P < 0.01). In addition, infection with F. necrophorum significantly increased the phosphorylation level of IκBα protein and up-regulated the expression level of NF-κB p65. The high expression and transcriptional activity of NF-κB p65 significantly increased the expression and concentration of the inflammatory cytokines TNF-α, IL-1β, and IL-8, thus inducing the occurrence of an inflammatory response. However, inhibition of NF-κB p65 activity significantly decreased the expression of inflammatory factors in the intertoe skin of cows infected with F. necrophorum.
Conclusion
F. necrophorum activates NF‐κB signaling pathway by increasing the expression of TNF‐α, IL‐1β, IL‐8 and other inflammatory factors, leading to foot rot in dairy cows.
... sheep, hoof diseases of American elk, and proliferative pododermatitis (canker) of horses. 2,10,12,14,21,34,35,38,44,45,50 To date, Treponema spp. have not been identified in keratoma lesions. ...
Keratoma is an aberrant keratin mass thought to originate from epidermal horn-producing cells interposed between the stratum medium of the hoof wall and the underlying third phalanx. The cause is unknown, although the presence of keratomas is frequently associated with chronic irritation, focal infection, or trauma. A total of 167 donkeys with keratomas were presented in this study. The diagnosis of a keratoma was based on clinical signs, radiography, and histopathologic examination. Surgical excision was attempted on all donkeys with lameness unless euthanasia was advised. Histopathologic examination, including Giemsa, periodic acid Schiff, and Young’s silver special histochemical stains, was performed and showed the presence of fungal hyphae and spirochete bacteria within the degenerate keratin. Polymerase chain reaction (PCR) for treponeme bacteria was performed on 10 keratoma lesions and 9 healthy pieces of hoof (controls). All healthy donkey tissues were negative for the 3 recognized digital dermatitis (DD) treponeme phylogroups, whereas 3 of 10 (30%) donkey keratoma samples were positive for one of the DD treponeme phylogroups. Routine fungal culture and PCR for fungi were performed on 8 keratoma lesions and 8 healthy pieces of hoof (controls). Keratinopathogenic fungi were detected in 1 of 8 (12.5%) keratomas, while only non-keratinopathogenic, environmental fungi were detected in 8 control healthy hoof samples. This is the first time the DD treponemes phylogroup and keratinopathogenic fungi have been detected in keratomas. Further studies are required to assess the significance of this finding.
... Successful induction of DD has also been reported in sheep. Wilson-Welder et al. [27] inoculated crossbred sheep with bovine derived DD inoculum and achieved an 88% induction over a 28-day protocol, and contagious ovine digital dermatitis was induced in 15 of 30 experimental sheep [28]. Most recently, Wilson-Welder et al. [29] using lesion material obtained from wild elk induced treponeme-associated hoof disease in sheep by way of a sheep DD model. ...
... Prolonged moisture and an anaerobic environment were not maintained for the duration of the experiment. These conditions are essential for DD induction in experimental models as demonstrated by Gomez et al. [25], Krull et al. [26], and Wilson-Welder et al. [27]. Additionally, the most common risk factors identified for the natural development of DD are wet and muddy pen conditions [12,34]. ...
Background
Digital dermatitis (DD) is a multifactorial infectious disease affecting the skin on feet of cattle causing erosion and inflammation above the heel bulbs. Some cases of DD cause lameness and significantly impact animal welfare and productivity. While DD has emerged as a concern for the beef industry, key information regarding early detection and its impact on cattle behaviour is lacking. The primary objective of this study was to determine if an established DD experimental model for dairy calves could be used to induce DD lesions in beef calves. A secondary objective was to describe changes in behaviour and pain associated with induction of DD lesions. Eight beef calves acquired from a single cow-calf operator were enrolled in the study. Upon enrolment, calves were evaluated and determined to be free of foot lesions. Within the experimental environment, calves were housed in individual pens and assigned to two groups (mock-inoculated and inoculated). Both hind feet of each calf were enrolled. Within calf, inoculation protocol was consistent, and a 28-day experimental protocol was employed. Two days prior to inoculation, both hind feet of each calf were abraded (area above the heel bulbs and below the dewclaws), moistened, and wrapped to facilitate an anaerobic condition. Feet were inoculated with macerated DD lesion material or mock inoculum and remained wrapped until clinical signs of DD or protocol endpoint.
Results
After a period of 14 to 18 days post inoculation, three of five inoculated calves developed clinical signs (lameness), and upon close inspection, DD lesions were present on at least one hind foot. Two of five inoculated calves did not develop lesions within 28 days. Zero of three mock-inoculated calves developed DD. Treponema spp. were detected by quantitative polymerase chain reaction from biopsies of induced lesions. Measurements of behaviour prior to disease induction were numerically different between DD affected and mock-inoculated calves.
Conclusions
An experimental infection model established for dairy cattle was used to successfully induce acute DD lesions in three of five inoculated beef calves. This model can provide a framework to study intervention protocols and to evaluate the impact of DD on behaviour and pain.
... To study hoof diseases in controlled settings, various models of naturally occurring hoof diseases have been used. Most involve housing animals with wet bedding, using boots, bandages, or a system of wraps to macerate the skin and hold bacterial cultures or lesion material in place (11)(12)(13)(14)(15). Recently, cell-based models have even been proposed but appear to be limited to evaluating pathogenesis of a single bacterial species at a time (16,17). ...
... Most involve housing animals with wet bedding, using boots, bandages, or a system of wraps to macerate the skin and hold bacterial cultures or lesion material in place (11)(12)(13)(14)(15). Recently, cell-based models have even been proposed but appear to be limited to evaluating pathogenesis of a single bacterial species at a time (16,17). Models for DD of cattle have been developed using lengthy macerations (12) or initial abrasion of the skin to provide bacterial inoculum for a site for penetration and lesion production (13,15). All models require extensive handling of the animal and their feet. ...
... Fortunately, a sheep model of bovine DD provides a viable alternative to large animal models (15). In comparison to larger animal models, sheep are easier to handle, are less expensive to maintain, and previous work has demonstrated that Treponemadriven bovine DD can be reproduced in a sheep model (15). ...
A hoof disease among wild elk (Cervus elaphus) in the western United States has been reported since 2008. Now present in Washington, Oregon, Idaho, and California, this hoof disease continues to spread among elk herds suggesting an infectious etiology. Causing severe lesions at the hoof-skin junction, lesions can penetrate the hoof-horn structure causing severe lameness, misshapen hooves, and in some cases, sloughed hooves leaving the elk prone to infection, malnutrition, and premature death. Isolated to the feet, this disease has been termed treponeme-associated hoof disease due to the numerous Treponema spp. found within lesions. In addition to the Treponema spp., treponeme-associated hoof disease shares many similarities with digital dermatitis of cattle and livestock including association with several groups of anaerobic bacteria such as Bacteroides, Clostridia, and Fusobacterium, neutrophilic inflammatory infiltrate, and restriction of the disease to the foot and hoof tissues. To determine if there was a transmissible infectious component to this disease syndrome, elk lesion homogenate was used in a sheep model of digital dermatitis. Ten animals were inoculated with lesion material and lesion development was followed over 7 weeks. Most inoculated feet developed moderate to severe lesions at 2- or 4-weeks post-inoculation timepoints, with 16 of 18 feet at 4 weeks also had spirochetes associated within the lesions. Histopathology demonstrated spirochetes at the invading edge of the lesions along with other hallmarks of elk hoof disease, neutrophilic inflammatory infiltrates, and keratinocyte erosion. Treponema-specific PCR demonstrated three phylotypes associated with elk hoof disease and digital dermatitis were present. Serum of infected sheep had increased anti-Treponema IgG when compared to negative control sheep and pre-exposure samples. Analysis of the bacterial microbiome by sequencing of the bacterial 16S rRNA gene showed a community structure in sheep lesions that was highly similar to the elk lesion homogenate used as inoculum. Bacteroidies, Fusobacterium, and Clostridia were among the bacterial taxa overrepresented in infected samples as compared to negative control samples. In conclusion, there is a highly transmissible, infectious bacterial component to elk treponeme-associated hoof disease which includes several species of Treponema as well as other bacteria previously associated with digital dermatitis.
... There are no other CODD experimental transmission studies for direct comparison; however, anecdotal evidence on CODD transmission in the field and experimental studies of induction of FR and BDD suggest that the time to disease induction in our study was surprisingly long. For example, in a study where BDD lesion material was directly inoculated onto abraded and wet bandaged sheep's feet (37), lesions consistent with BDD were observed after 28 days in the sheep. Experimental induction of FR in other studies report a lag of 7 days to the onset of FR when scarification of feet was combined with continued exposure to wet bedding and accumulation of fecal matter (38). ...
Contagious ovine digital dermatitis (CODD) is a severe and common infectious foot disease of sheep and a significant animal welfare issue for the sheep industry in the UK and some European countries. The etiology and pathogenesis of the disease are incompletely understood. In this longitudinal, experimental study, CODD was induced in 18 sheep, and for the first time, the clinical lesion development and associated microbiological changes in CODD affected feet are described over time, resulting in a completely new understanding of the etiopathogenesis of CODD. The majority of CODD lesions (83.9%) arose from pre-existing interdigital dermatitis (ID) and/or footrot (FR) lesions. All stages of foot disease were associated with high levels of poly-bacterial colonization with five pathogens, which were detected by quantitative PCR (qPCR): Treponema medium, Treponema phagedenis, Treponema pedis, Dichelobacter nodosus, and Fusobacterium necrophorum. Temporal colonization patterns showed a trend for early colonization by T. phagedenis, followed by F. necrophorum and D. nodosus, T. medium, and then T. pedis, D. nodosus was present at significantly higher predicted mean log10 genome copy numbers in FR lesions compared to both ID and CODD, while Treponema species were significantly higher in CODD and FR lesions compared to ID lesions (p < 0.001). Treatment of CODD-affected sheep with two doses of 10 mg/kg long acting amoxicillin resulted in a 91.7% clinical cure rate by 3 weeks post-treatment; however, a bacteriological cure was not established for all CODD-affected feet. The study found that in an infected flock, healthy feet, healed CODD feet, and treated CODD feet can be colonized by some or all of the five pathogens associated with CODD and therefore could be a source of continued infection in flocks. The study is an experimental study, and the findings require validation in field CODD cases. However, it does provide a new understanding of the etiopathogenesis of CODD and further supportive evidence for the importance of current advice on the control of CODD; namely, ensuring optimum flock control of footrot and prompt isolation and effective treatment of clinical cases.
... Whilst we are confident in our observations and consider this a key paradigm in the pathogenesis of infectious foot disease, there is still a possibility that naturally occurring field cases could deviate from those observed in this experiment. However, as we did not manually abrade or macerate tissue as described in other digital dermatitis infection models [21][22][23] it could be considered that the circumstances of disease induction described here are the most relevant to natural disease induction in the field thus far. ...
Background
Contagious Ovine Digital Dermatitis (CODD) is an emerging and common infectious foot disease of sheep which causes severe welfare and economic problems for the sheep industry. The aetiology of the disease is not fully understood and control of the disease is problematic. The aim of this study was to investigate the polybacterial aetiopathogenesis of CODD and the effects of antibiotic treatment, in a longitudinal study of an experimentally induced disease outbreak using a 16S rRNA gene amplicon sequencing approach.
Results
CODD was induced in 15/30 experimental sheep. During the development of CODD three distinct phenotypic lesion stages were observed. These were an initial interdigital dermatitis (ID) lesion, followed by a footrot (FR) lesion, then finally a CODD lesion. Distinct microbiota were observed for each lesion in terms of microbial diversity, clustering and composition. Porphyromonadaceae, Family XI, Veillonellaceae and Fusobacteriaceae were significantly associated with the diseased feet. Veillonellaceae and Fusobacteriaceae were most associated with the earlier stages of ID and footrot rather than CODD. Following antibiotic treatment of the sheep, the foot microbiota showed a strong tendency to return to the composition of the healthy state. The microbiota composition of CODD lesions collected by swab and biopsy methods were different. In particular, the Spirochaetaceae family were more abundant in samples collected by the biopsy method, suggesting that these bacteria are present in deeper tissues of the diseased foot.
Conclusion
In this study, CODD presented as part of a spectrum of poly-bacterial foot disease strongly associated with bacterial families Porphyromonadaceae, Family XI (a family in Clostridiales also known as Clostridium cluster XI), Veillonellaceae and Fusobacteriaceae which are predominately Gram-negative anaerobes. Following antibiotic treatment, the microbiome showed a strong tendency to return to the composition of the healthy state. The composition of the healthy foot microbiome does not influence susceptibility to CODD.
Based on the data presented here and that CODD appears to be the severest end stage of sheep infectious foot disease lesions, better control of the initial ID and FR lesions would enable better control of CODD and enable better animal welfare.
... It is very common in the northern coastal region of Germany for sheep to graze in late autumn and winter on pastures that have been previously used for grazing cattle, or fertilised by slurry. BDD is highly prevalent in the cattle herds in that region [37], and this may represent an important disease transmission route [38]. Introduction of CODD might also have been caused by visitors to the dyke or the farm. ...
Abstract Contagious ovine digital dermatitis (CODD) is a significant disease of the ovine foot characterised by severe lameness and progressive separation of the hoof horn capsule from the underlying tissue. Similar to bovine digital dermatitis (BDD), pathogenic members of the genus Treponema including the Treponema medium phylogroup, Treponema phagedenis phylogroup and Treponema pedis are frequently found together in CODD lesions. To date, CODD was only described in Ireland and the United Kingdom. In northern Germany, cases of an unusually severe lameness presented in a sheep flock that had been affected by footrot for several years. These cases were non-responsive to conventional footrot therapies, with some sheep exhibiting substantial lesions of the claw horn that resulted in horn detachment. Lesion swab samples were collected from both clinically affected and asymptomatic animals. In all clinically affected sheep, CODD-associated Treponema phylogroups were detected by polymerase chain reaction. This is the first report of CODD in Germany and mainland Europe, indicating a wider geographic spread than previously considered. In cases of severe lameness attributed to claw lesions in sheep that fail to respond to footrot treatment, CODD should be considered irrespective of geographic location.
... Whilst we are con dent in our observations and consider this a key paradigm in the pathogenesis of infectious foot disease, there is still a possibility that naturally occurring eld cases could deviate from those observed in this experiment. However, as we did not manually abrade or macerate tissue as described in other digital dermatitis infection models (43)(44)(45) it could be considered that the circumstances of disease induction described here are the most relevant to natural disease induction in the eld thus far. ...
Background: Contagious Ovine Digital Dermatitis (CODD) is an emerging and common infectious foot disease of sheep which causes severe welfare and economic problems for the sheep industry. The aetiology of the disease is not fully understood and control of the disease is problematic. The aim of this study was to investigate the polybacterial aetiopathogenesis of CODD and the effects of antibiotic treatment, in a longitudinal study of an experimentally induced disease outbreak using a 16S rRNA gene amplicon sequencing approach.
Results: CODD was induced in 15/30 experimental sheep. During the development of CODD three distinct phenotypic lesion stages were observed. These were an initial interdigital dermatitis (ID) lesion, followed by a footrot (FR) lesion, then finally a CODD lesion. Distinct microbiota were observed for each lesion in terms of microbial diversity, clustering and composition. Porphyromonadaceae, Familiy XI, Veillonellaceae and Fusobacteriaceae were significantly associated with the diseased feet. Veillonellaceae and Fusobacteriaceae were most associated with the earlier stages of ID and footrot rather than CODD. Following antibiotic treatment of the sheep, the foot microbiota showed a strong tendency to return to the composition of the healthy state. The microbiota composition of CODD lesions collected by swab and biopsy methods were different. In particular, the Spirochaetaceae family were more abundant in samples collected by the biopsy method, suggesting that these bacteria are present in deeper tissues of the diseased foot.
Conclusion: In this study, CODD presented as part of a spectrum of poly-bacterial foot disease strongly associated with bacterial families Porphyromonadaceae, Family XI (a family in Clostridiales also known as Clostridium cluster XI), Veillonellaceae and Fusobacteriaceae which are predominately Gram-negative anaerobes. Following antibiotic treatment, the microbiome showed a strong tendency to return to the composition of the healthy state. The composition of the healthy foot microbiome does not influence susceptibility to CODD.
Based on the data presented here and that CODD appears to be the severest end stage of sheep infectious foot disease lesions, better control of the initial ID and FR lesions would enable better control of CODD and enable better animal welfare.
