Comprehensive Case-Control Study of Protective and Risk Factors for Buruli Ulcer, Southeastern Australia.

To examine protective and risk factors for Buruli ulcer (BU), we conducted a case-control study of 245 adult BU cases and 481 postcode-matched controls across BU-endemic areas of Victoria, Australia. We calculated age- and sex-adjusted odds ratios for socio-environmental, host, and behavioral factors associated with BU by using conditional logistic regression. Odds of BU were >2-fold for persons with diabetes mellitus and persons working outdoors who had soil contact in BU-endemic areas (compared with indoor work) but were lower among persons who had bacillus Calmette-Guérin vaccinations. BU was associated with increasing numbers of possums and with ponds and bore water use at residences. Using insect repellent, covering arms and legs outdoors, and immediately washing wounds were protective; undertaking multiple protective behaviors was associated with the lowest odds of BU. Skin hygiene/protection behaviors and previous bacillus Calmette-Guérin vaccination might provide protection against BU in BU-endemic areas.

Ketogenic Diet Impairment of Mycobacterium ulcerans Growth and Toxin Production and Enhancement of Host Response to Infection in an Experimental Mouse Model.

Ketogenic diets have been used to treat diverse conditions, and there is growing evidence of their benefits for tissue repair and in inflammatory disease treatment. However, their role in infectious diseases has been little studied. Buruli ulcer (Mycobacterium ulcerans infection) is a chronic infectious disease characterized by large skin ulcerations caused by mycolactone, the major virulence factor of the bacillus. In the current study, we investigated the impact of ketogenic diet on this cutaneous disease in an experimental mouse model. This diet prevented ulceration, by modulating bacterial growth and host inflammatory response. ß-hydroxybutyrate, the major ketone body produced during ketogenic diet and diffusing in tissues, impeded M. ulcerans growth and mycolactone production in vitro underlying its potential key role in infection. These results pave the way for the development of new patient management strategies involving shorter courses of treatment and improving wound healing, in line with the major objectives of the World Health Organization.

Vaccine-Specific Immune Responses against Mycobacterium ulcerans Infection in a Low-Dose Murine Challenge Model.

The neglected tropical disease Buruli ulcer (BU) is an infection of subcutaneous tissue with Mycobacterium ulcerans There is no effective vaccine. Here, we assessed an experimental prime-boost vaccine in a low-dose murine tail infection model. We used the enoyl reductase (ER) domain of the M. ulcerans mycolactone polyketide synthases electrostatically coupled with a previously described Toll-like receptor 2 (TLR-2) agonist-based lipopeptide adjuvant, R4Pam2Cys. Mice were vaccinated and then challenged via tail inoculation with 14 to 20 CFU of a bioluminescent strain of M. ulcerans Mice receiving either the experimental ER vaccine or Mycobacterium bovis bacillus Calmette-Guérin (BCG) were equally protected, with both groups faring significantly better than nonvaccinated animals (P < 0.05). To explore potential correlates of protection, a suite of 29 immune parameters were assessed in the mice at the end of the experimental period. Multivariate statistical approaches were used to interrogate the immune response data to develop disease-prognostic models. High levels of interleukin 2 (IL-2) and low gamma interferon (IFN-γ) produced in the spleen best predicted control of infection across all vaccine groups. Univariate logistic regression revealed vaccine-specific profiles of protection. High titers of ER-specific IgG serum antibodies together with IL-2 and IL-4 in the draining lymph node (DLN) were associated with protection induced by the ER vaccine. In contrast, high titers of IL-6, tumor necrosis factor alpha (TNF-α), IFN-γ, and IL-10 in the DLN and low IFN-γ titers in the spleen were associated with protection following BCG vaccination. This study suggests that an effective BU vaccine must induce localized, tissue-specific immune profiles with controlled inflammatory responses at the site of infection.

Bacille Calmette Guérin (BCG) and new TB vaccines: Specific, cross-mycobacterial and off-target effects.

The Bacille Calmette Guérin (BCG) vaccine was developed over a century ago and has become one of the most used vaccines without undergoing a modern vaccine development life cycle. Despite this, the vaccine has protected many millions from severe and disseminated forms of tuberculosis (TB). In addition, BCG has cross-mycobacterial effects against non-tuberculous mycobacteria and off-target (also called non-specific or heterologous) effects against other infections and diseases. More recently, BCG's effects on innate immunity suggest it might improve the immune response against viral respiratory infections including SARS-CoV-2. New TB vaccines, developed over the last 30 years, show promise, particularly in prevention of progression to disease from TB infection in young adults. The role of BCG in the context of new TB vaccines remains uncertain as most participants included in trials have been previously BCG immunised. BCG replacement vaccines are in efficacy trials and these may also have off-target effects.

Buruli ulcer in southern Côte D'ivoire: dynamic schemes of perception and interpretation of modes of transmission.

Buruli ulcer (BU) belongs to the group of neglected tropical diseases and constitutes a public health problem in many rural communities in Côte d'Ivoire. The transmission patterns of this skin infection are poorly defined, hence the current study aimed to contribute to the understanding, perceptions and interpretations of its mode of transmission using a socio-environmental approach. Social and environmental risk factors that may expose people to infection, and the dynamics of local transfer of knowledge and practices related to BU, were assessed in two endemic locations in southern Côte d'Ivoire, i.e. Taabo and Daloa. Data were generated by the administration of a household questionnaire (N=500) between February and June 2012 to assess how the population perceived transmission of BU, focus group discussions with local communities (N=8) to analyse ideologies regarding transmission patterns and semi-structured interviews with patients or their parents, former BU patients and traditional healers (N=30). The interviewees' empirical knowledge of the disease was found to be close to its biomedical description. Their aetiological perception of the disease was linked to natural (e.g. dirty water, insects) and supernatural (e.g. witchcraft, fate) causes. Some informants attributed the spread of the disease to recently immigrated neighbouring communities whose arrival coincided with an increase in reported BU cases. However, the general consensus seemed to be that the main mode of transmission was contact with infested soil or ulcerated wounds. The participants were aware that BU was a socio-environmental problem in these endemic areas, offering a good starting point for educational campaigns for at-risk communities. Buruli ulcer control programmes should therefore include educational campaigns and Water, Sanitation and Hygiene (WASH) interventions for those at risk in affected communities.

Treatment and prevention of Mycobacterium ulcerans infection (Buruli ulcer) in Australia: guideline update.

• Guidelines reflecting contemporary clinical practice in the management of Buruli ulcer (Mycobacterium ulcerans infection) in Australia were published in 2007. • Management has continued to evolve, as new evidence has become available from randomised trials, case series and increasing clinical experience with oral antibiotic therapy. • Therefore, guidelines on the diagnosis, treatment and prevention of Buruli ulcer in Australia have been updated. They include guidance on the new role of antibiotics as first-line therapy; the shortened duration of antibiotic treatment and the use of all-oral antibiotic regimens; the continued importance, timing and role of surgery; the recognition and management of paradoxical reactions during antibiotic treatment; and updates on the prevention of disease.

Application of geographical information system (GIS) technology in the control of Buruli ulcer in Ghana.

BACKGROUND: Buruli ulcer (BU) disease is a chronic debilitating skin disease caused by Mycobacteriumulcerans. It is associated with areas where the water is slow-flowing or stagnant. Policy makers take the necessary strategic and policy decisions especially where to target interventions based on available evidence including spatial distribution of the disease. Unfortunately, there is limited information on the spatial distribution of BU in Ghana. The aim of the study was to use Geographical Information System (GIS) technology to show the spatial distribution and hot spots of BU in Greater Accra and Eastern Regions in Ghana. The information could then be used by decision makers to make the necessary strategic and policy decisions, especially where to target intervention. METHODS: We conducted a community case search and spatial mapping in two districts in Eastern region (Akuapem South and Suhum- Kraboa-Coaltar) and two districts in Greater Accra region (Ga West and Ga South Municipalities) of Ghana to identify the spatial distribution of BU cases in the communities along the Densu River. These municipalities are already known to the Ministry of Health as having high case load of BU. Structured questionnaires on demographic characteristics, environmental factors and general practices were administered to the cases.Using the E-trex Garmin Geographical Positioning System (GPS), the location of the case patient was marked along with any important attributes of the community. ArcGIS was used to generate maps showing BU distribution and hot spots. RESULTS: Two hundred and fifty-seven (257) probable BU patients were enrolled in the study after the case search. These cases and their houses (or homes) were located with the GPS. The GIS maps generated showed a varying distribution of BU in the various communities. We observed clustering of BU patients downstream of the Densu River which had hitherto not been observed. CONCLUSIONS: There is clustering of BU in areas where the river was most contaminated. The identified hot spots for BU should be targeted for interventions by policy makers to ensure effective control of BU in Ghana.

[Health promotion and community-based approach to Buruli ulcer: results of a psychosocial- and behavioural survey in two villages in Benin]. / Promotion de la santé et approche communautaire de l'ulcère de Buruli: résultats d'une enquête psychosociocomportementale dans deux villages du Bénin.

INTRODUCTION: Buruli ulcer (BU) is an infectious disease caused by Mycobacterium ulcerans. Benin, one of the most severely affected countries, notified 365 cases in 2012. This article presents the results of a psychosocial and behavioural survey conducted in the context of a health promotion (HP) project with community participation. This paper describes the diagnosis, prevention, behaviours, as well as perceptions and experiences related to BU. METHODS: A cross-sectional study was conducted in two villages (Azonme, Houedota) of Benin Atlantic department. From 15 May to 19 June 2011, a volunteer survey was conducted with 15 former patients and 15 new patients, selected by purposive sampling and 30 randomly selected healthy individuals. Encoding and data analysis were performed with SPSS and Excel. RESULTS: Respondents were aged 11 to 100 years with a mean age of 36.63 years and 55% were men. More than 96% of respondents were aware of BU (symptoms, mode of transmission, prevention and treatment). % were familiar with the mode of transmission, but were not aware of preventive measures. Twenty-none of the 30 patients or former patients were treated in hospital. The attributed and perceived (including non-medical) causes of the disease were water (52), bacteria (17), bad luck (5). 92% of respondents were satisfied with the services of health professionals but proposed changes (46) concerning hospital accessibility and cost of care. DISCUSSION: These results show similarities and differences compared to those reported in the literature on the subject. These surveys were the basis for health promotion interventions with the participation of two communities.

Enhancing Buruli ulcer control in Ghana through social interventions: a case study from the Obom sub-district.

BACKGROUND: Buruli ulcer is considered a re-emerging disease in West Africa where it has suffered neglect over the years, though children below the age of 16 years are the worst affected in most endemic regions. Due to delayed health seeking, the disease leads to disabilities resulting from amputation and loss of vital organs like the eye leading to school dropout and other social and economic consequences for the affected family. Early treatment with antibiotics is effective; however, this involves daily oral and intramuscular injection at distant health facilities for 56 days making it a challenge among poor rural folks living on daily subsistence work. The mode of transmission of Buruli ulcer is not known and there is no effective preventive vaccine for Buruli ulcer. Thus the only effective control tool is early case detection and treatment to reduce morbidity and associated disabilities that occurs as a result of late treatment. It is therefore essential to implement interventions that remove impediments that limit early case detection; access to early effective treatment and this paper reports one such effort where the feasibility of social interventions to enhance Buruli ulcer control was assessed. METHODS: This was a qualitative study using in-depth interviews to generate information to ascertain the benefit or otherwise of the intervention implemented. Clinical records of patients to generate data to determine the feasibility and effectiveness of social interventions in the fight against Buruli ulcer was examined. In all, 56 in-depth interviews (28 at baseline and 28 at evaluation) were conducted for this report. RESULTS: At full implementation, treatment default and dropout reduced significantly from 58.8% and 52.9% at baseline to 1.5% and 1.5% respectively. The number of early case detection went up significantly. Affected families were happy with social interventions such as provision of transportation and breakfast to patients on daily basis. Families were happy with the outpatient services provided under the intervention where no patient was admitted into the hospital. CONCLUSION: The study showed that with a little more investment in early case detection, diagnosis and treatment, coupled with free transportation and breakfast for patients, most of the cases could be treated effectively with the available antibiotics to avoid disability and complications from the disease.

[International cooperation with the neglected tropical disease Buruli ulcer in Togo].

The objectives of this paper are to grasp the current status of an endemic disease, known as Buruli ulcer (BU), in the Republic of Togo and the expansion of international assistance in the field. By adopting the explicit support model, this paper also compares the obtained research results with those of the Republic of Ghana and Benin, to clarify the primary functions played among respective governments, WHO, and NGO. Under the auspices of the WHO Global Buruli Ulcer Initiative (GBUI, 1998-), National Buruli Ulcer Control Programme (NBUCP) in the Togo was initiated in 1999. However, due to the shortage of national budget and politico-economic instabilities of the nation, the actual implementation of NBUCP proved to be problematic. It was after 2007 that the programme began to move forward with the interventions of NGOs like DAHW and Handicap International. Currently, major players involved in the implementation of the policies provided by the GBUI are WHO, NGOs and the targeted governments. In other words, the organizations involved in BU treatment work together by fulfilling their functions. Unlike the neighboring countries, the Togolese government encountered much difficulty in materializing its national programme. Largely due to the political instability and the severe shortage of national budget, stronger assistances from NGOs were required at various levels of the national health measures from formulating to implementing the programme. As the programmes in Togo and Ghana/Benin expanded over the years, the respective support model revealed to be unique and different. In Ghana and Benin, intimate cooperation among WHO, government and NGOs has been established. In Togo, strengthening of collaboration among the three players is expected.

A human model of Buruli ulcer: The case for controlled human infection and considerations for selecting a Mycobacterium ulcerans challenge strain.

Critical knowledge gaps regarding infection with Mycobacterium ulcerans, the cause of Buruli ulcer (BU), have impeded development of new therapeutic approaches and vaccines for prevention of this neglected tropical disease. Here, we review the current understanding of host-pathogen interactions and correlates of immune protection to explore the case for establishing a controlled human infection model of M. ulcerans infection. We also summarise the overarching safety considerations and present a rationale for selecting a suitable challenge strain.

Multi-epitope vaccine candidates based on mycobacterial membrane protein large (MmpL) proteins against Mycobacterium ulcerans.

Buruli ulcer (BU) is a neglected tropical disease. It is caused by the bacterium Mycobacterium ulcerans and is characterized by skin lesions. Several studies were performed testing the Bacillus Calmette-Guérin (BCG) vaccine in human and animal models and M. ulcerans-specific vaccines in animal models. However, there are currently no clinically accepted vaccines to prevent M. ulcerans infection. The aim of this study was to identify T-cell and B-cell epitopes from the mycobacterial membrane protein large (MmpL) proteins of M. ulcerans. These epitopes were analysed for properties including antigenicity, immunogenicity, non-allergenicity, non-toxicity, population coverage and the potential to induce cytokines. The final 8 CD8+, 12 CD4+ T-cell and 5 B-cell epitopes were antigenic, non-allergenic and non-toxic. The estimated global population coverage of the CD8+ and CD4+ epitopes was 97.71%. These epitopes were used to construct five multi-epitope vaccine constructs with different adjuvants and linker combinations. The constructs underwent further structural analyses and refinement. The constructs were then docked with Toll-like receptors. Three of the successfully docked complexes were structurally analysed. Two of the docked complexes successfully underwent molecular dynamics simulations (MDS) and post-MDS analysis. The complexes generated were found to be stable. However, experimental validation of the complexes is required.

The search for a Buruli Ulcer vaccine and the effectiveness of the Bacillus Calmette-Guérin vaccine.

Buruli Ulcer is a neglected tropical disease that is caused by Mycobacterium ulcerans. It is not fatal; however, it manifests a range of devastating symptoms on the hosts' bodies. Various drugs and treatments are available for the disease; however, they are often costly and have adverse effects. There is still much uncertainty regarding the mode of transmission, vectors, and reservoir. At present, there are no official vector control methods, prevention methods, or a vaccine licensed to prevent infection. The Bacillus Calmette-Guérin vaccine developed against tuberculosis has some effectiveness against M. ulcerans. However, it is unable to induce long-lasting protection. Various types of vaccines have been developed based specifically against M. ulcerans; however, to date, none has entered clinical trials or has been released for public use. Additional awareness and funding are needed for research in this field and the development of more treatments, diagnostic tools, and vaccines.

Identification of potential candidate vaccines against Mycobacterium ulcerans based on the major facilitator superfamily transporter protein.

Buruli ulcer is a neglected tropical disease that is characterized by non-fatal lesion development. The causative agent is Mycobacterium ulcerans (M. ulcerans). There are no known vectors or transmission methods, preventing the development of control methods. There are effective diagnostic techniques and treatment routines; however, several socioeconomic factors may limit patients' abilities to receive these treatments. The Bacillus Calmette-Guérin vaccine developed against tuberculosis has shown limited efficacy, and no conventionally designed vaccines have passed clinical trials. This study aimed to generate a multi-epitope vaccine against M. ulcerans from the major facilitator superfamily transporter protein using an immunoinformatics approach. Twelve M. ulcerans genome assemblies were analyzed, resulting in the identification of 11 CD8+ and 7 CD4+ T-cell epitopes and 2 B-cell epitopes. These conserved epitopes were computationally predicted to be antigenic, immunogenic, non-allergenic, and non-toxic. The CD4+ T-cell epitopes were capable of inducing interferon-gamma and interleukin-4. They successfully bound to their respective human leukocyte antigens alleles in in silico docking studies. The expected global population coverage of the T-cell epitopes and their restricted human leukocyte antigens alleles was 99.90%. The population coverage of endemic regions ranged from 99.99% (Papua New Guinea) to 21.81% (Liberia). Two vaccine constructs were generated using the Toll-like receptors 2 and 4 agonists, LprG and RpfE, respectively. Both constructs were antigenic, non-allergenic, non-toxic, thermostable, basic, and hydrophilic. The DNA sequences of the vaccine constructs underwent optimization and were successfully in-silico cloned with the pET-28a(+) plasmid. The vaccine constructs were successfully docked to their respective toll-like receptors. Molecular dynamics simulations were carried out to analyze the binding interactions within the complex. The generated binding energies indicate the stability of both complexes. The constructs generated in this study display severable favorable properties, with construct one displaying a greater range of favorable properties. However, further analysis and laboratory validation are required.

Vaccination efforts for Buruli ulcer.

BACKGROUND: Buruli ulcer is one of the most common mycobacterial diseases usually affecting poorer populations in tropical and subtropical environments. This disease, caused by M. ulcerans infection, has devastating effects for patients, with significant health and economic burden. Antibiotics are often used to treat affected individuals, but in most cases, surgery is necessary. AREA COVERED: We present progress on Buruli ulcer vaccines and identify knowledge gaps in this neglected tropical disease. EXPERT OPINION: The lack of appropriate infrastructure in endemic areas, as well as the severity of symptoms and lack of noninvasive treatment options, highlights the need for an effective vaccine to combat this disease. In terms of humoral immunity, it is vital to consider its significance and the magnitude to which it inhibits or slows down the progression of the disease. Only by answering these key questions will it be possible to tailor more appropriate vaccination and preventative provisions.

Buruli ulcer.

Buruli Ulcer (BU) is a neglected, necrotizing skin disease, caused by M. ulcerans, that can leave patients with prominent scars and lifelong disability. M. ulcerans produces a diffusible lipid toxin, mycolactone, essential for bacterial virulence. Prevention is difficult as little is known about disease transmission and there is no vaccine. There have been several recent advances in the field. These include sequencing of the bacterial genome and of the giant plasmid responsible for mycolactone synthesis, better understanding of the bacterial lifecycle and of the mechanism of action of the toxin. This work has revealed a number of possible vaccine candidates, some of which are shared with other mycobacteria, e.g. M. tuberculosis, while other targets are unique to M. ulcerans. In this review, we discuss several M. ulcerans vaccine targets and vaccination methods, and outline some of the gaps in our understanding of the bacterium and the immune response against it.

Systematic review of M. Bovis BCG and other candidate vaccines for Buruli ulcer prophylaxis.

Buruli ulcer, caused by Mycobacterium ulcerans, is a neglected tropical disease endemic to over 30 countries, with increasing incidence in temperate, coastal Victoria, Australia. Strategies to control transmission are urgently required. This study systematically reviews the literature to identify and describe candidate prophylactic Buruli ulcer vaccines. This review highlights that Mycobacterium bovis Bacillus Calmette-Guérin (BCG) vaccine is the only vaccine studied in randomised controlled trials and confirms its importance as a benchmark for comparison against putative vaccines in pre-clinical studies. Nevertheless, BCG alone is unable to offer long-term protection in humans. A number of experimental vaccines that exceed the protection provided by BCG in mice have emerged, particularly those utilising recombinant BCG expressing immunogenic M. ulcerans proteins. Although progress is promising, there remain key questions about the optimal approach to characterising the immunological correlates of protection in humans and strategies to investigate the safety and efficacy of such vaccines in humans.

Understanding the transmission of Mycobacterium ulcerans: A step towards controlling Buruli ulcer.

Mycobacterium ulcerans is the causative agent of Buruli ulcer, a rare but chronic debilitating skin and soft tissue disease found predominantly in West Africa and Southeast Australia. While a moderate body of research has examined the distribution of M. ulcerans, the specific route(s) of transmission of this bacterium remain unknown, hindering control efforts. M. ulcerans is considered an environmental pathogen given it is associated with lentic ecosystems and human-to-human spread is negligible. However, the pathogen is also carried by various mammals and invertebrates, which may serve as key reservoirs and mechanical vectors, respectively. Here, we examine and review recent evidence from these endemic regions on potential transmission pathways, noting differences in findings between Africa and Australia, and summarising the risk and protective factors associated with Buruli ulcer transmission. We also discuss evidence suggesting that environmental disturbance and human population changes precede outbreaks. We note five key research priorities, including adoption of One Health frameworks, to resolve transmission pathways and inform control strategies to reduce the spread of Buruli ulcer.