Ovine footrot: new insights into bacterial colonisation

Abstract

A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. Ovine footrot is characterised by interdigital dermatitis (ID) and by the separation of the skin and hoof horn (underrunning 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 spp. in biopsies from the ovine interdigital skin of healthy, ID and footrot affected feet and (ii) to characterize the virulence of D. nodosus strains in those biopsies. Post-slaughter biopsy samples (n=241) were collected and analysed by real-time PCR to determine prevalence and load of the different bacterial species. The highest prevalence and load of D. nodosus were found on feet with ID. The vast majority of samples contained virulent D. nodosus and some samples contained both virulent and benign D. nodosus. Notably, the more pathogenic subspecies of F. necrophorum was found in samples from UK sheep. Our findings provide further insights into the role bacterial colonisation may play in the early stage of ID and in the progression towards footrot.https://mc.manuscriptcentral.com/vetrec Veterinary Record

A distinct bacterial dysbiosis associated skin inflammation in ovine footrot

“…Increased proportions of Corynebacteria were also observed in canine atopic dermatitis34. Of the bacterial genera identified, Dichelobacter, Fusobacteria and Treponema all linked to ovine or bovine foot disease467810. Prevotella and Porphyromonas were isolated from footrot cases in goats35 and were recently reclassified from Bacteriodes melaninogenicus 36, a species regularly isolated from bovine interdigital necrobacillosis (bovine footrot)37.…”

“…3 = severely damaged/misshapen sole and/or heel area of the digit (>75%). Then, ovine feet disease status was scored as described previously16, allowing classification into healthy, ID or footrot feet according to established scoring criteria: absence of interdigital skin lesion = healthy; slight interdigital skin lesion (≤5% affected) = mild ID; moderate to severe ID lesion (>5% affected); presence of underrunning lesion = footrot8. The sample set (n = 191) included 53 healthy, 55 interdigital dermatitis (ID) and 83 footrot biopsy samples.…”

“…Tissue homogenisation and DNA extractions were performed as described previously using QIAamp cador ® kit (QIAGEN, Hilden, Germany)8. Virulent D. nodosus was quantified based on the presence of aprV2 gene by quantitative PCR in an Applied Biosystems ® 7500 Fast Real-Time PCR System (Thermo Fisher Scientific Inc., Waltham, USA) as previously described7.…”

“…Fusobacterium necrophorum, also a Gram negative bacterium, is attributed to play a role in the initiation of ID prior to D. nodosus infection1, and/or in the exacerbation of footrot lesions once it is established5. Other bacteria such as Treponema have also been detected in footrot cases, but its role in the disease process remains unclear678. A microbiota study, using a pyrosequencing approach, found 27 different bacterial genera in the ovine interdigital skin where Peptostreptococcus was the most abundant genus in healthy interdigital skin, Corynebacterium was mainly associated with ID and Staphylococcus was the most abundant read genus in footrot samples6.…”

Development and assessment of management practices in a flock-specific lameness control plan: A stepped-wedge trial on 44 English sheep flocks

“…Culling ewes with two or more episodes of lameness within a year reduced the prevalence of lameness by removing ewes with chronic disease that are likely to spread disease within the flock (Witcomb et al, 2014;Maboni et al, 2016), or ewes with non-infectious causes of lameness that did not respond to treatment, such as a toe granuloma. These repeatedly lame ewes accounted for approximately 44% of all recorded treatments, representing a significant cost in time and money.…”