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Contagious ovine digital dermatitis (CODD) causes a severe, infectious foot disease and lameness of sheep, is common within the UK and is now also emerging in other countries. As well as causing severe animal welfare issues, huge economic losses emerge from the disease due to weight loss/lack of weight gain, and veterinary treatments. CODD lesion progress is measured, with a scoring system from 1 (early lesions) to 5 (healed). Here, using samples from an experimental flock infected by natural means, samples were taken from CODD stage 5 lesions, post treatment, and subjected to bacterial isolation and MLST using previously published methods. Sequences were compared to others from the same flock, and those from previous studies. All CODD 5 lesions produced viable Treponema spp. bacteria. High levels of variation of bacteria were seen, with 12 sequence types (STs) for T. medium phylogroup (11 new), 15 STs for T. phagedenis phylogroup (9 new) and six T. pedis STs, of which two were new. This study shows that CODD stage 5 lesions still contain viable bacteria, representing all three known pathogenic Treponema spp. phylogroups, and these may thus play a role in disease transmission and epidemiology despite appearing healed after treatment. The high level CODD treponeme variability within an infected flock where sheep were bought from different sources, as might occur in common agricultural practice, may suggest reasons as to why the bacterial disease is difficult to treat, control and eradicate, and adds further complexity to the polybacterial pathogenesis of these lesions.

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Treponeme-associated foot disease has been described in cattle with digital dermatitis and sheep with contagious ovine digital dermatitis. In this study, severe foot lesions in dairy goats associated with digital dermatitis treponemes (i.e. Treponema medium, Treponema phagedenis and Treponema pedis) were characterized macroscopically, radiographically and histologically. The main macroscopic foot lesion was of extensive solar ulceration with or without exophytic papilliform hyperkeratosis. Radiographically, the distal phalanx and distal sesamoid bones were severely damaged and remodelled. Histologically, the lesion was categorized as a chronic lymphoplasmacytic, suppurative and ulcerative pododermatitis. Immunohistochemistry identified the spirochaetal microorganisms located extracellularly in the superficial horn. Study limitations mean that the treponeme bacteria could not be considered the sole or causal agents in the cases described.

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Pressure sores cause severe pain and discomfort in hospitalized people and in farmed cattle and are often infected with unknown bacteria. Pressure sores occur on the upper legs of 6-10% of recumbent cattle and are generally considered to be caused by constant pressure, commonly on bony areas of the limbs. This study analyzed pressure sores taken from the upper limbs of 14 cattle using isolation in culture and nested polymerase chain reaction (PCR) to detect treponemes associated with digital dermatitis (DD). A 100% association of DD treponemes with the pressure sores was demonstrated, but treponemes were shown not to be part of the normal skin microbiota. Immunohistochemistry showed an association of DD treponemes with lesions and particularly with the hair follicles in lesions, identifying the bacteria deep within wounds, thereby suggesting that they could contribute to lesion pathogenesis. The bacteria isolated from the pressure sore lesions were similar or identical on analysis of the 16S rRNA gene to those found in DD foot lesions in cattle, suggesting the same bacteria can infect multiple lesions. Indeed, the results of this study suggest that these spirochaetal bacteria may be expanding in host range and in their ability to colonize different tissues and contribute to a range of disease manifestations in farm animals.

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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.

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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. Spirochete culture was attempted on all BDD lesion samples. One or more BDD-associated Treponema phylogroups were detected in 100% of beef BDD lesions. "Treponema medium/Treponema vincentii-like", "Treponema phagedenis-like" and Treponema pedis spirochetes were identified in 27/34 (79%), 31/34 (91%) and 24/34 (71%) of BDD lesions, respectively. No BDD-associated treponeme DNA was amplified from beef healthy foot tissues. D. nodosus and F. necrophorum were present in 24/34 (71%) and 15/34 (44%) of lesions and 10/38 (26%) and 12/38 (32%) of healthy foot tissues, respectively. Twenty spirochetes were isolated from beef BDD lesions; 19 were representatives of the three BDD-associated Treponema phylogroups. One spirochete isolate shared less than 97% 16S rRNA gene similarity to the three cultivable BDD-associated Treponema phylogroups and therefore may represent a novel taxa of Treponema. Upon comparison, sheep contagious ovine digital dermatitis (CODD), dairy cattle and beef cattle BDD lesions appear to have extremely similar bacteriological data and therefore provides evidence of a shared etiopathogenesis posing concerns for cross-species transmission.

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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.

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A UK dairy goat herd was assessed after reports of a severe lameness problem of unknown aetiology. A lameness prevalence estimate was produced and individual clinical examination of 15 randomly selected lame goats was performed. Fifteen animals had foot lesions closely resembling contagious ovine digital dermatitis (CODD) in sheep. Eight of the goats examined presented with typical CODD lesions and seven showed what appeared to be a more severe CODD with under-running of the sole. Ten biopsy samples were obtained from the foot lesions and tested by PCR for the three previously isolated digital dermatitis (DD) Treponema phylogroups and culture of treponemes was attempted. Ninety per cent of the biopsy samples were positive for Treponema medium/Treponema vincentii-like spirochaetes and Treponema phagedenis-like DD spirochaetes and 80per cent were positive for Treponema pedis. Spirochaetes were successfully isolated from 50 per cent of lesion samples. Three isolates were identified as belonging to the T. phagedenis-like spirochaetes and two were identified as T. pedis. The frequent isolation of similar treponemes to those isolated from bovine digital dermatitis and CODD lesions and the identification of these DD-associated phylotypes in the vast majority of lesions support the hypothesis that this novel foot condition is associated with infection by DD treponemes, and given the similarities to CODD, it suggests a causal role.

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Since 2008, a large increase in the numbers of cases of lameness have been seen in wild North American elk (Cervus elaphus) from Washington State, USA. The most recent cases manifested as foot lesions similar both clinically and pathologically to those seen in digital dermatitis (DD) in cattle and sheep, a disease with a bacterial etiopathogenesis. To determine whether the same bacteria considered responsible for DD are associated with elk lameness, lesion samples were subjected to bacterial isolation studies and PCR assays for three phylogroups of relevant DD treponemes. The DD treponemes were isolated from lesional tissues but not from control feet or other areas of the diseased foot (including the coronary band or interdigital space), suggesting that the bacteria are strongly associated with DD lesions and may therefore be causal. In addition, PCR analysis revealed that all three unique DD treponeme phylotypes were found in elk hoof disease, and in 23% of samples, all 3 DD-associated treponemes were present in lesions. Sequence analysis of the 16S rRNA gene showed that the elk lesion treponemes were phylogenetically almost identical to those isolated from cattle and sheep DD lesions. The isolates were particularly similar to two of the three culturable DD treponeme phylotypes: specifically, the Treponema medium/Treponema vincentii-like and Treponema phagedenis-like DD spirochetes. The third treponeme culturable phylogroup (Treponema pedis), although detected by PCR, was not isolated. This is the first report describing isolation of DD treponemes from a wildlife host, suggesting that the disease may be evolving to include a wider spectrum of cloven-hoofed animals.

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Canine parvovirus (CPV) and feline panleukopaenia virus (FPLV) are two closely related viruses, which are known to cause severe disease in younger unvaccinated animals. As well as causing disease in their respective hosts, CPV has recently acquired the feline host range, allowing it to infect both cats and dogs. As well as causing disease in dogs, there is evidence that under some circumstances CPV may also cause disease in cats. This study has investigated the prevalence of parvoviruses in the faeces of clinically healthy cats and dogs in two rescue shelters. Canine parvovirus was demonstrated in 32.5% (13/50) of faecal samples in a cross sectional study of 50 cats from a feline only shelter, and 33.9% (61/180) of faecal samples in a longitudinal study of 74 cats at a mixed canine and feline shelter. Virus was isolated in cell cultures of both canine and feline origin from all PCR-positive samples suggesting they contained viable, infectious virus. In contrast to the high CPV prevalence in cats, no FPLV was found, and none of 122 faecal samples from dogs, or 160 samples collected from the kennel environment, tested positive for parvovirus by PCR. Sequence analysis of major capsid VP2 gene from all positive samples, as well as the non-structural gene from 18 randomly selected positive samples, showed that all positive cats were shedding CPV2a or 2b, rather than FPLV. Longitudinally sampling in one shelter showed that all cats appeared to shed the same virus sequence type at each date they were positive (up to six weeks), despite a lack of clinical signs. Fifty percent of the sequences obtained here were shown to be similar to those recently obtained in a study of sick dogs in the UK (Clegg et al., 2011). These results suggest that in some circumstances, clinically normal cats may be able to shed CPV for prolonged periods of time, and raises the possibility that such cats may be important reservoirs for the maintenance of infection in both the cat and the dog population.

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Canine parvovirus type 2 (CPV-2) is a severe enteric pathogen of dogs, causing high mortality in unvaccinated dogs. After emerging, CPV-2 spread rapidly worldwide. However, there is now some evidence to suggest that international transmission appears to be more restricted. In order to investigate the transmission and evolution of CPV-2 both nationally and in relation to the global situation, we have used a long-range PCR to amplify and sequence the full VP2 gene of 150 canine parvoviruses obtained from a large cross-sectional sample of dogs presenting with severe diarrhea to veterinarians in the United Kingdom, over a 2-year period. Among these 150 strains, 50 different DNA sequence types (S) were identified, and apart from one case, all appeared unique to the United Kingdom. Phylogenetic analysis provided clear evidence for spatial clustering at the international level and for the first time also at the national level, with the geographical range of some sequence types appearing to be highly restricted within the United Kingdom. Evolution of the VP2 gene in this data set was associated with a lack of positive selection. In addition, the majority of predicted amino acid sequences were identical to those found elsewhere in the world, suggesting that CPV VP2 has evolved a highly fit conformation. Based on typing systems using key amino acid mutations, 43% of viruses were CPV-2a, and 57% CPV-2b, with no type 2 or 2c found. However, phylogenetic analysis suggested complex antigenic evolution of this virus, with both type 2a and 2b viruses appearing polyphyletic. As such, typing based on specific amino acid mutations may not reflect the true epidemiology of this virus. The geographical restriction that we observed both within the United Kingdom and between the United Kingdom and other countries, together with the lack of CPV-2c in this population, strongly suggests the spread of CPV within its population may be heterogeneously subject to limiting factors. This cross-sectional study of national and global CPV phylogeographic segregation reveals a substantially more complex epidemic structure than previously described.

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Canine parvovirus (CPV) and canine enteric coronavirus (CECoV) are often cited as causes of diarrhoea in dogs. This study aimed to determine the prevalence of CPV and CECoV in dogs presenting with severe diarrhoea to PDSA PetAid hospitals throughout the UK. A total of 355 samples were collected from the PDSA between 2006 and 2008. All samples were tested for CPV using a long range PCR and for CECoV using RT-PCR. The prevalence of CPV was 58 per cent (95 per cent confidence interval [CI] 52 to 63 per cent), with some evidence for regional variation. The prevalence of CECoV was 7.9 per cent (95 per cent CI 5.1 to 10.7 per cent). Analysis showed that animals with no history of vaccination were more likely to be CPV positive, with greatest effect in younger animals. CPV-positive animals were more likely to present with depression/lethargy than CPV-negative cases. The volume of diarrhoea and the presence of haemorrhage did not appear to be associated with the likelihood of detecting CPV. This study shows that CPV is a common finding in dogs presenting to PDSA hospitals with severe diarrhoea, and that CECoV is a less common but still potentially important pathogen. It also confirms that young and unvaccinated animals appear to be more at risk of presenting with CPV.

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