Treponemes Detected in Digital Dermatitis Lesions in Brazilian Dairy Cattle and Possible Host Reservoirs of Infection

Abstract

The main pathogenic treponemes causing bovine digital dermatitis were identified from 17 infected herds in southern Brazil for the first time in this study using PCR. We did not find a relationship between treponeme phylogroup composition and clinical classification. Treponema phagedenis was present in all lesions. Rumen fluid was implicated as a reservoir location for these pathogens.A lthough bovine digital dermatitis (BDD) has been known to occur in Brazil since the early 1990s (1), there have been no attempts to describe the possible pathogens involved, apart from reports of histopathological (2) and electron microscopic (3) findings. Treponema species are difficult to culture, so molecular approaches are useful for detecting and identifying these spirochetes (4, 5). The present study describes, for the first time, the frequencies of the major treponeme species in BDD lesions in Brazil. Similar results in Europe, North America, and Asia (6-11) confirm the polytreponemal aspect of this clinical condition.Farms in southern Brazil where BDD infections are endemic (n ϭ 28) were identified by consulting veterinary records. Previously identified dairy cows (n ϭ 200) were individually reexamined and, if positive for BDD (n ϭ 22), were photographed and their lesions classified according to clinical stage, from M1 to M4 (12-14). Samples (n ϭ 22) were surgically excised, placed in phosphatebuffered saline (PBS) solution, and refrigerated (4°C to 8°C) until processing. The infected digit was then topically treated with antibiotics (oxytetracycline) and bandaged. Using a stomach tube, ruminal fluid (Ն50 ml of fresh fluid) was collected from 15 cows from seven different BDD-positive herds, which were chosen by convenience. From one BDD-free herd with a history of lameness but without any clinical BDD lesions detected on previous examinations of the whole herd, ruminal fluid from 10 cows was sampled for use as a negative control. All samples underwent extraction of bacterial DNA, as previously described (12,15). A nested-PCR method was used, as previously described (10). The treponeme-specific primers were called Treponema sp., Treponema medium/T. vincentii-like, Treponema phagedenis-like, and Treponema denticola/T. putidum-like (10). The research was approved by the Committee for the Ethical Use of Animals of Pontifícia Universidade Católica do Paraná (PUCPR) (registration no. 646) in 2011.Of the herds, 17 (60.71%) had BDD lesions on the day of examination and were positive for subsequent molecular BDD detection. The lesions were in different clinical stages (14) and were classified as follows: 13.64% were M1, 45.45% were M2, 22.73% were M3, and 18.18% were M4. However, certain lesions classified as M2 or M3 contained areas that were M4 or M1. In comparison, the cows in the present study exhibited considerably more M2 lesions (45.45% versus 21.03% in the previous study) and fewer M4 lesions (18.18% versus 50.03% in the previous study) ( Table 1). The reason for this observation or why the different forms can transition f...

The Gastrointestinal Tract as a Potential Infection Reservoir of Digital Dermatitis-Associated Treponemes in Beef Cattle and Sheep

“…Various other studies now have detected one or more of the commonly associated DD treponeme phylogroups in dairy cow GI tract-associated areas. One study detected at least one of the three cultivatable DD treponeme phylogroups in 60% of rumen fluid samples tested (24), and using a metagenomic approach, another identified DD treponemes in rumen fluid and fecal samples (25). Additionally, DD-associated treponemes have been identified in environmental samples such as manure slurry from dairy farms using high-throughput sequencing (23).…”

“…There has been much debate about the gastrointestinal (GI) tract's role as a reservoir of infection of DD treponemes, with the bovine gingival and rectal tissues, rumen fluid, and feces identified as potential infection reservoirs. A previous study detected DD treponemes in the oral cavity and the rectum of dairy cattle (22), and more recent work detected DD treponeme phylogroups in rumen fluid, fecal samples, and slurry (23)(24)(25).To date, isolations of DD treponemes from the bovine GI tract have failed. The sheep GI tract has yet to be investigated as a reservoir of infection, and the tendency of beef cattle to be different breeds, fed different diets, and subjected to different housing regimes than dairy cattle gives reason for further investigations into both of these animals' GI tracts.…”

“…There has been much debate about the gastrointestinal (GI) tract's role as a reservoir of infection of DD treponemes, with the bovine gingival and rectal tissues, rumen fluid, and feces identified as potential infection reservoirs. A previous study detected DD treponemes in the oral cavity and the rectum of dairy cattle (22), and more recent work detected DD treponeme phylogroups in rumen fluid, fecal samples, and slurry (23)(24)(25).…”

Culture and molecular identification of microorganisms from Digital Dermatitis lesions in dairy cattle: Leptospira, an unexpected finding

“…For instance, L. broomii was isolated from the blood, cerebrospinal fluid and urine of human patients with leptospirosis in Denmark and France (Levett et al, 2006). L. fainei was previously isolated from cultures of uteri and kidneys of sows from two geographically distant pig herds in Australia (Perolat et al, 1998). L. fainei was successively cultured from two human patients with Weil's disease and antibody titers have been found in sera from cattle in Australia, France and Indonesia ( Chappel et al, 1996;Petersen et al, 2001).…”

“…The disease can result in economic losses having a negative impact on reproductive efficiency, productive life span, welfare, and milk production (Walker et al, 1995, Fidler et al, 2012. BDD has been reported in several European countries, Canada, United States, Mexico, Japan, and in some South American countries like Chile and Brazil (Molina et al, 1999, Nascimento et al, 2015.…”