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

BACKGROUND: Bovine digital dermatitis (BDD) is an infectious foot disease found commonly in dairy herds. Foot-trimming is an important husbandry procedure for reducing the ensuing lameness; however, epidemiological, and microbiological studies have identified this as a risk activity for transmitting BDD. Three disinfectants have previously been identified in laboratory work as effective for removing viable BDD-associated Treponema spp., from hoof knife blades. The present study enrolled 133 dairy cattle with BDD lesions, and swabbed hoof knife blades before and after foot-trimming, and after knife disinfection with one of three disinfectants (1:100 FAM30®, 2% Virkon® and 2% sodium hypochlorite) to assess their efficacy under field conditions. RESULTS: Detection of BDD treponeme phylogroup DNA was undertaken by direct PCR of swabs, and viable treponemes were detected by PCR of swab cultures after 6 weeks' incubation. Where hoof knives did not contact the lesion, BDD-associated treponemes were detected after foot-trimming in 12/22 (54.5%) cases by direct PCR and 1/22 (4.5%) cases by PCR of cultured organisms. Where contact was made with the lesion, 111/111 (100%) samples taken after trimming were positive by direct PCR and 47/118 (39.8%) were positive by culture PCR. Viable organisms were identified in cultures from lesion stages M2, M3, M4 and M4.1. No viable organisms were detected after disinfection of hoof knives. CONCLUSIONS: Hoof knives post-trimming were frequently contaminated with BDD-associated treponeme DNA. Viable organisms were identified in cultures whether contact had been made between hoof knife and lesion or not, although contact clearly increased the frequency of detection of viable organisms. The three disinfectants tested were effective for removing viable organisms. The disinfection protocol used in this study should therefore be considered reliable for adoption as standard industry practice.

Missing pieces of the puzzle to effectively control digital dermatitis.

Since the first report of bovine digital dermatitis (DD) in 1974, there is a large body of the literature published; however, effective prevention and control of the disease remain elusive. Although many aspects of the pathogenesis of DD have been investigated, even some of the most basic questions such as the aetiology of this disease remain under debate. Treponema spp. have been strongly associated with DD lesions and occur in abundance in advanced lesions; however, efforts to induce disease with pure cultures of these organisms have been largely underwhelming and inconsistent. Furthermore, although the disease has been presented for several decades, there is limited scientific evidence regarding effective treatment of DD. Apparent discrepancies between effectiveness in vitro and in vivo have challenged the scientific community to identify new potential treatment options. With no treatment resulting in a 100% cure rate, the current expectation is manageable control, but prospects for the eradication of the disease are unlikely using current approaches. In order to develop more effective approaches to control DD on-farm, there is a critical need for a deeper understanding regarding the causation, ecology, transmission and treatment of this disease. In this article, we attempt to provide insights into specific research needs related to DD in order to assist the industry, researchers, pharmaceutical companies and research sponsors with decision-making and identified research gaps.

Between Colonial, National, and International Medicine: The Case of Bejel.

In the 1920s and 1930s, doctors stationed in the Middle East and North Africa debated whether bejel, a form of endemic syphilis, was an Arab version of syphilis, or a separate disease altogether. Using their clinical experience in the region, they tried to weave this unfamiliar phenomenon into a civilizational narrative, which placed European civilization at the top of a hierarchy. The assumption was that there was something inherent to Islamic societies and their hygienic habits that accounted for this difference. After World War II, the eradication of bejel was declared to be one of the objectives of both the Iraqi government and the newly founded World Health Organization. Examining the postwar life of bejel, I question how colonial legacies affected postcolonial and international medical theories and practices, on both national and international levels.

Bovine digital dermatitis: Current concepts from laboratory to farm.

Bovine digital dermatitis (DD) is a severe infectious disease causing lameness in dairy cattle worldwide and is an important ruminant welfare problem that has considerable economic issues. Bovine DD is endemic in many regions worldwide and it is important to understand this major disease so that effective control strategies can be identified. There is substantial evidence that specific treponeme phylotypes play an important causative role in bovine DD. This review considers current research, including DD Treponema spp. investigations, associated DD pathobiology, and current and potential treatment and control options. Epidemiological data, alongside new microbiological data, help delineate important transmission routes and reservoirs of infection that allow effective interventions to be identified. Better on-farm housing hygiene, pasture access, routine footbathing and claw trimming with disinfected equipment need to be implemented to significantly reduce the incidence of DD. There is a paucity of peer reviewed research into both commonly used and novel treatments. In vitro antimicrobial susceptibility studies of DD treponemes and effective treatment of human treponematoses clearly indicate that antibiotics frequently selected for DD treatments are not the most efficacious. Whilst there are understandable concerns over milk withdrawal times in dairy cattle, more needs to be done to identify, license and implement more appropriate antibiotic treatments, since continued overuse of less efficacious antibiotics, applied incorrectly, will lead to increased disease recurrence and transmission. More research is needed into methods of preventing DD that circumvent the use of antibiotics, including vaccination and transmission blocking studies, to reduce or hopefully eradicate DD in the future.

A randomized trial to evaluate the effect of a trace mineral premix on the incidence of active digital dermatitis lesions in cattle.

A balanced, parallel-group, single-blinded randomized efficacy study divided into 2 periods was conducted to evaluate the effect of a premix containing higher than typically recommended levels of organic trace minerals and iodine (HOTMI) in reducing the incidence of active digital dermatitis (DD) lesions acquired naturally and induced by an experimental infection challenge model. For the natural exposure phase of the study, 120 healthy Holstein steers 5 to 7 mo of age without signs of hoof disease were randomized into 2 groups of 60 animals. The control group was fed a standard trace mineral supplement and the treatment group was fed the HOTMI premix, both for a period of 60 d. On d 60, 15 steers free of macroscopic DD lesions were randomly selected from each group for the challenge phase and transported to an experimental facility, where they were acclimated and then challenged within a DD infection model. The same diet group allocation was maintained during the 60 d of the challenge phase. The primary outcome measured was the development of an active DD lesion greater than 20mm in diameter across its largest dimension. No lesions were identified during the natural exposure phase. During the challenge phase, 55% (11/20) and 30% (6/20) of feet were diagnosed with an active DD lesion in the control and treatment groups, respectively. Diagnosis of DD was confirmed by histopathologic demonstration of invasive Treponema spp. within eroded and hyperplastic epidermis and ulcerated papillary dermis. All DD confirmed lesions had dark-field microscopic features compatible with DD and were positive for Treponema spp. by PCR. As a secondary outcome, the average DD lesion size observed in all feet was also evaluated. Overall mean (standard deviation) lesion size was 17.1 (2.36) mm and 11.1 (3.33) mm for the control and treatment groups, respectively, with this difference being driven by acute DD lesions >20mm. A trend existed for the HOTMI premix to reduce the total DD infection rate and the average size of the experimentally induced lesions. Further research is needed to validate the effect of this intervention strategy in the field and to generate prevention and control measures aimed at optimizing claw health based on nutritional programs.

Presence of digital dermatitis treponemes on cattle and sheep hoof trimming equipment.

Digital dermatitis (DD) is an infectious foot disease causing severe lameness in dairy cattle (worldwide) and sheep (UK). This study investigated whether DD Treponema phylogroups can be present on equipment used to trim ruminant hooves and, therefore, consider this trimming equipment as a possible vector for the transmission of DD. Equipment was tested after being used to trim DD symptomatic and asymptomatic cattle and sheep hooves, and subsequently after disinfection of equipment. After trimming, 'Treponema medium/Treponema vincentii-like', 'Treponema phagedenis-like' and 'Treponema denticola/T putidum-like' DD spirochaetes, were shown to be present on 23/37 (62%), 21/37 (57%) and 20/37 (54%) of knives, respectively. After disinfection, detection rates for the DD treponemes were 9/37 (24%), 6/37 (16%) and 3/37 (8%), respectively. Following culture of a swab, an isolate belonging to the T phagedenis-like spirochaetes was identified from a knife sample after trimming a DD positive cow. No isolates were obtained from knife samples after disinfection. This new data has, for the first time, identified treponemes in the farm environment, and highlighted disinfection of hoof trimming equipment between animals and between farms, as a logical precaution to limit the spread of DD.

The endemic treponematoses.

The agents of human treponematoses include four closely related members of the genus Treponema: three subspecies of Treponema pallidum plus Treponema carateum. T. pallidum subsp. pallidum causes venereal syphilis, while T. pallidum subsp. pertenue, T. pallidum subsp. endemicum, and T. carateum are the agents of the endemic treponematoses yaws, bejel (or endemic syphilis), and pinta, respectively. All human treponematoses share remarkable similarities in pathogenesis and clinical manifestations, consistent with the high genetic and antigenic relatedness of their etiological agents. Distinctive features have been identified in terms of age of acquisition, most common mode of transmission, and capacity for invasion of the central nervous system and fetus, although the accuracy of these purported differences is debated among investigators and no biological basis for these differences has been identified to date. In 2012, the World Health Organization (WHO) officially set a goal for yaws eradication by 2020. This challenging but potentially feasible endeavor is favored by the adoption of oral azithromycin for mass treatment and the currently focused distribution of yaws and endemic treponematoses and has revived global interest in these fascinating diseases and their causative agents.

A novel Treponema pallidum antigen, TP0136, is an outer membrane protein that binds human fibronectin.

The antigenicity, structural location, and function of the predicted lipoprotein TP0136 of Treponema pallidum subsp. pallidum were investigated based on previous screening studies indicating that anti-TP0136 antibodies are present in the sera of syphilis patients and experimentally infected rabbits. Recombinant TP0136 (rTP0136) protein was purified and shown to be strongly antigenic during human and experimental rabbit infection. The TP0136 protein was exposed on the surface of the bacterial outer membrane and bound to the host extracellular matrix glycoproteins fibronectin and laminin. In addition, the TP0136 open reading frame was shown to be highly polymorphic among T. pallidum subspecies and strains at the nucleotide and amino acid levels. Finally, the ability of rTP0136 protein to act as a protective antigen to subsequent challenge with infectious T. pallidum in the rabbit model of infection was assessed. Immunization with rTP0136 delayed ulceration but did not prevent infection or the formation of lesions. These results demonstrate that TP0136 is expressed on the outer membrane of the treponeme during infection and may be involved in attachment to host extracellular matrix components.

Anti-HBc screening in Egyptian blood donors reduces the risk of hepatitis B virus transmission.

Occult hepatitis B virus (HBV) in blood donors is considered as a potential risk for transmission of HBV infection. The aim of this study was to determine the prevalence of anti-hepatitis B core antibody (anti-HBC) positivity in Egyptian blood donations as well as to estimate the frequency of HBV-DNA in anti-HBc-positive donations. The study included 760 Egyptian healthy blood donors, representing 26 different Egyptian governorates screened according to routine practice for the presence of hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibodies (Abs), HIV-1/2 Abs and Treponema Abs. The accepted blood units for donation were tested for the presence of total anti-HBc Abs by two tests. Positive units for anti-HBc were further tested for HBV-DNA by polymerase chain reaction. According to routine screening, a total of 48/760 units (6.3%) were rejected [38 (5%) HCV-Ab-positive units, 9 (1.18%) HbsAg-positive units and 1 (0.13%) Treponema-Ab-positive unit]. Among the accepted blood units for donation, prevalence of anti-HBc was 78/712 units (10.96%). HBV-DNA was detected in 9/78 (11.54%) of the anti-HBc-positive units, and thus, occult HBV infection was detected in 9/712 (1.26%) of the accepted blood donations. Implementing anti-HBc test to the routine assay for the forthcoming two decades would certainly eliminate possible HBV-infected units. Rejection of these units will be beneficial to decrease the risk of HBV transmission with its potential consequences particularly in immunocompromised recipients.

Prevalence of skin allograft discards as a result of serological and molecular microbiological screening in a regional skin bank in Italy.

BACKGROUND: Postmortem skin is widely used in the treatment of patients with severe burns. Skin specimens must be screened for transmissible agents including human immunodeficiency virus (HIV), hepatitis B (HBV) and C (HCV) virus, human T-cell lymphotropic virus (HTLV), cytomegalovirus (CMV) and Treponema pallidum. METHODS: Four hundred and sixty-one cadaveric donors underwent serological and molecular microbiological (polymerase chain reaction, PCR) screening at Siena Skin Bank between 2000 and 2004. RESULTS: 74/461 donors (16.1%) were found ineligible under current regulations. CONCLUSIONS: These results are interesting in a local context and underline the importance of screening involving both routine serological procedures and molecular microbiological investigation. The latter has not been uniformly introduced in many countries and very limited data is available to assess its cost-benefit ratio in the field of skin donor screening.

Porphyromonas gingivalis heat shock protein vaccine reduces the alveolar bone loss induced by multiple periodontopathogenic bacteria.

OBJECTIVES: Heat shock protein (HSP) can be utilized as a vaccine to cross-protect against multiple pathogenic species. The present study was performed to evaluate Porphyromonas gingivalis heat shock protein 60 (HSP60) as a vaccine candidate to inhibit multiple bacteria-induced alveolar bone loss. MATERIAL AND METHODS: Recombinant P. gingivalis HSP60 was produced and purified from P. gingivalis GroEL gene. Rats were immunized with P. gingivalis HSP60, and experimental alveolar bone loss was induced by infection with multiple periodontopathogenic bacteria. RESULTS: There was a very strong inverse relationship between postimmune anti-P. gingivalis HSP immunoglobulin G (IgG) levels and the amount of alveolar bone loss induced by either P. gingivalis or multiple bacterial infection (p=0.007). Polymerase chain reaction data indicated that the vaccine successfully eradicated the multiple pathogenic species. CONCLUSIONS: We concluded that P. gingivalis HSP60 could potentially be developed as a vaccine to inhibit periodontal disease induced by multiple pathogenic bacteria.

Intraoral dissemination of treponemes after periodontal therapy.

Oral treponemes are related to chronic periodontitis, but the effect of periodontal therapy on the majority of treponemal species is unknown. The aim of this prospective study was to evaluate the dynamics in prevalence profiles of treponemes in different habitats of the oral cavity. Thirty-five patients with chronic periodontitis were randomly assigned to mechanical debridement alone (control group) or systemic amoxicillin/metronidazole plus chlorhexidine (test group). Subgingival and mucous membrane plaque samples were taken at baseline, after 10 days, and during supportive periodontal therapy at 3, 6, 9, 12, 18, and 24 months. T. denticola, T. lecithinolyticum, T. maltophilum, T. socranskii, T. vincentii, and treponemal phylotypes I-VII were detected using polymerase chain reaction (PCR) and dot blot analysis. For the majority of the assessed treponemes, a significant intragroup increase in prevalence in the different habitats ( P<0.05) occurred over the study course but, compared to debridement alone, adjunctive antimicrobial therapy resulted in a nonsignificant trend toward lower prevalence in the subgingival habitat. In no case were treponemes eradicated from the oral cavity. After both therapies, possibly new infection with and/or dissemination of Treponema ssp. occurred, which led to treponemes recovering in different habitats and to increased intraoral prevalence. The prescribed adjunctive antimicrobial therapy may limit this increase in the subgingival region.

The endemic treponematoses.

Treponemal diseases comprise venereal syphilis (Treponema pallidum subsp. pallidum) and the endemic (non-venereal) treponematoses, i.e. yaws (T. pallidum subsp. pertenue), endemic syphilis (T. pallidum subsp. endemicum) and pinta (T. carateum). Treponemal diseases are distinguished on the basis of epidemiological characteristics and clinical manifestations. They are at present indistinguishable by morphological, immunological or serological methods. Several minor genetic differences have been identified among the subspecies. The endemic treponematoses have not yet been eliminated and are currently thought to affect at least 2.5 million persons. Renewed action towards the elimination of these diseases should be undertaken.

Antimicrobial prophylaxis in pregnancy: a randomized, placebo-controlled trial with cefetamet-pivoxil in pregnant women with a poor obstetric history.

OBJECTIVE: This study was undertaken to measure the impact of a single oral dose of cefetamet-pivoxil on pregnancy outcome in a population with substantial rates of low birth weight and high prevalence rates of maternal infections. STUDY DESIGN: A total of 320 pregnant women with a poor obstetric history, defined as a history of low birth weight or stillbirth, were randomized to receive a single oral dose of 2 gm of cefetamet-pivoxil or a placebo at a gestational age between 28 and 32 weeks. Patients were assessed at delivery and 1 week post partum for pregnancy outcome, postpartum endometritis, human immunodeficiency virus-1 and gonococcal infections. RESULTS: A total of 253 (79%) women gave birth at the maternity hospital, of whom 210 (83%) attended the follow-up clinic. Overall, 18.1% of these pregnant women were human immunodeficiency virus-1 seropositive, whereas 9.5% had antibodies against Treponema pallidum. There was a significant difference between cefetamet-pivoxil- and placebo-treated women in infant birth weight (2927 gm vs 2772 gm, p = 0.03) and low birth weight (< 2500 gm) rates (18.7% vs 32.8%, p = 0.01, odds ratio 2.1, 95% confidence interval 1.2 to 3.8). The stillbirth rate was 2.2% in the cefetamet-pivoxil group and 4.2% in the placebo group (not significant). Postpartum endometritis was found in 17.3% in the intervention arm versus 31.6% in the placebo group (p = 0.03, odds ratio 2.2, 95% confidence interval 1.1 to 7.6). Neisseria gonorrhoeae was isolated from the cervix in 5 of 103 (4.9%) women in the intervention and in 14 of 101 (13.9%) in the placebo group (p = 0.04, odds ratio 3.2, 95% confidence interval 1.1 to 10.5). CONCLUSION: A single oral dose of cefetamet-pivoxil administered to pregnant women with a poor obstetric history seemed to improve pregnancy outcome in this population with high rates of maternal infections. Larger studies should be carried out to examine the public health impact, the feasibility, and the overall cost/benefit ratio of this intervention.