Associations between digital dermatitis lesion grades in dairy cattle and the quantities of four Treponema species

Abstract

Digital dermatitis (DD) presents as painful, ulcerative or proliferative lesions that lead to bovine lameness affecting economic efficiency and animal welfare. Although DD etiological agent(s) have not been established, it is widely accepted that DD is a polymicrobial disease significantly associated with species of Treponema and the non-linear disease progression may be attributed to interactions among infecting bacteria. We postulated the morphological changes associated with DD lesion grades are related to interactions among infecting species of Treponema. We developed a novel species-specific qPCR that can identify the absolute abundance of the four of the most common species of Treponema in DD, T. phagedenis, T. medium, T. pedis and T. denticola, in a single reaction. We found species abundance and the number of distinct Treponema species present is higher in active, ulcerative lesions than in healing lesions, chronic lesions, and DD-free skin. Treponema spp. were present in both DD-free skin and M3 lesions following treatment with oxytetracycline. We have also found positive correlations among T. phagedenis, T. medium and T. pedis indicating they are significantly more likely to be found together than apart and their absolute quantities tend to increase together, a relationship which is not present with T. denticola. Further, we found Treponema, particularly viable T. denticola, in lesions 5 days post treatment with oxytetracycline (M3). Our findings suggest that pathogenicity may be closely associated with Treponema abundance, particularly T. phagedenis, T. medium and T. pedis, and interactions among them, independent of T. denticola. Our results provide a novel, consistent method to identify species of Treponema within DD lesions and associate Treponema spp. and abundance with morphological changes related to host pathogenicity.Electronic supplementary materialThe online version of this article (10.1186/s13567-018-0605-z) contains supplementary material, which is available to authorized users.

Removal of bovine digital dermatitis-associated treponemes from hoof knives after foot-trimming: a disinfection field study

“…Positive cultures came from cases with M2, M3, M4 and M4.1 lesions. It has been shown that treponeme numbers are higher in active ulcerative lesions (as previously determined using qPCR to quantify bacterial DNA, rather than using culture) [16]. Our results indicate that higher percentages of M2, M3 and M4.1 lesions lead to positive cultures post-trimming when compared to the chronic M4 stage; however, this effect could be due to smaller sample sizes in the other lesion categories and overall insufficient sample size.…”

Treponema spp. Isolated from Bovine Digital Dermatitis Display Different Pathogenicity in a Murine Abscess Model

“…A species-specific qPCR assay [ 14 ] was used for in-tissue Treponema quantification. Clones targeting unique genes of Treponema pedis (CP004120), T. phagedenis (WP_002698807.1) and T. medium (WP_016523385.1) were generated and used for quantification.…”

“…are consistently identified in active bovine DD lesions [ 8 , 10 , 11 , 12 ], the exact role of these spirochetes in the aetiopathogenesis of DD remains unclear [ 13 ]. Treponema phagedenis , T. medium , T. pedis are among the most commonly detected species in DD lesions [ 8 , 10 , 11 , 14 , 15 ]. Interestingly, DD-associated treponemes have also been associated with other hoof-related animal diseases, including contagious ovine digital dermatitis [ 16 ] and elk hoof disease [ 17 ].…”

“…Active DD lesions have a higher Treponema spp. diversity than either chronic or initial stages of the disease [ 8 , 11 , 14 ]. In addition, different species of Treponema are associated with different DD stages [ 14 ], suggesting their interactions could be related to disease progression.…”

“…diversity than either chronic or initial stages of the disease [ 8 , 11 , 14 ]. In addition, different species of Treponema are associated with different DD stages [ 14 ], suggesting their interactions could be related to disease progression. In other Treponema -associated diseases, such as periodontal disease in humans, the association of treponemes and other organisms extends beyond simple cohabitation and is associated with nutritional and pathogenic synergies [ 20 ].…”