scholarly journals Evidences of the Low Implication of Mosquitoes in the Transmission ofMycobacterium ulcerans, the Causative Agent of Buruli Ulcer

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Rousseau Djouaka ◽  
Francis Zeukeng ◽  
Jude Daiga Bigoga ◽  
David N’golo Coulibaly ◽  
Genevieve Tchigossou ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Adult Stage ◽  
Mosquito Species ◽  
Buruli Ulcer ◽  
Mycobacterium Ulcerans ◽  
Tropical Regions ◽  
Transmission Cycle ◽  
Risk Environments ◽  
Public Health Threat ◽  
Mode Of Transmission

Background.Buruli ulcer (BU) continues to be a serious public health threat in wet tropical regions and the mode of transmission of its etiological agent,Mycobacterium ulcerans(MU), remains poorly understood. In this study, mosquito species collected in endemic villages in Benin were screened for the presence ofMU. In addition, the ability of mosquitoes larvae to pick upMUfrom their environment and remain colonized through the larval developmental stages to the adult stage was investigated.Methods.7,218 adults and larvae mosquitoes were sampled from endemic and nonendemic villages and screened forMUDNA targets (IS2404,IS2606, and KR-B) using qPCR.Results. MUwas not detected in any of the field collected samples. Additional studies of artificially infected larvae ofAnopheles kisumuwithMUstrains revealed that mosquitoes larvae are able to ingest and hostMUduring L1, L2, L3, and L4 developmental stages. However, we noticed an absence of these bacteria at both pupae and adult stages, certainly revealing the low ability of infected or colonized mosquitoes to vertically transmitMUto their offspring.Conclusion.The overall findings highlight the low implication of mosquitoes as biological vectors in the transmission cycle ofMUfrom the risk environments to humans.

scholarly journals Community-based geographical distribution of Mycobacterium ulcerans VNTR-genotypes from the environment and humans in the Nyong valley, Cameroon

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Francis Zeukeng ◽  
Anthony Ablordey ◽  
Solange E. Kakou-Ngazoa ◽  
Stephen Mbigha Ghogomu ◽  
David N’golo Coulibaly ◽  
...  
Keyword(s):  
Environmental Samples ◽  
Tandem Repeats ◽  
Buruli Ulcer ◽  
Variable Number ◽  
Mycobacterium Ulcerans ◽  
Community Based ◽  
Human Samples ◽  
Route Of Transmission ◽  
Mode Of Transmission ◽  
Animal Reservoirs

Abstract Background Genotyping is a powerful tool for investigating outbreaks of infectious diseases and it can provide useful information such as identifying the source and route of transmission, and circulating strains involved in the outbreak. Genotyping techniques based on variable number of tandem repeats (VNTR) are instrumental in detecting heterogeneity in Mycobacterium ulcerans (MU) and also for discriminating MU from other mycobacteria species. Here, we describe and map the distribution of MU genotypes in Buruli ulcer (BU) endemic communities of the Nyong valley in Cameroon. We also tested the hypothesis of whether the suspected animal reservoirs of BU that share the human microhabitat are shedding contaminated fecal matters and saliva into their surrounding environments. Methods Environmental samples from suspected MU-risk factors and lesion swabs from human patients were sampled in BU-endemic communities and tested for the presence of MU by qPCR targeting three independent sequences (IS2404, IS2606, KR-B). Positive samples to MU were further genotyped by VNTR with confirmation by sequencing of four loci (MIRU1, Locus 6, ST1, Locus 19). Results MU was detected in environmental samples including water bodies (23%), biofilms (14%), detritus (10%), and in human patients (73%). MU genotypes D, W, and C were found both in environmental and human samples. The micro geo-distribution of MU genotypes from communities showed that genotype D is found both in environmental and human samples, while genotypes W and C are specific to environmental samples and human lesions, respectively. No obvious focal grouping of MU genotypes was observed at the community scale. An additional survey in the human microhabitat suggests that domestic and wild animals do not shed MU in their saliva and feces in sampled communities. Conclusions VNTR typing uncovered different MU genotypes circulating in the endemic communities of the Akonolinga district. A MU environmental genotype was found in patients, yet the mechanism of contamination remains to be investigated; and recovering MU in culture from the environment remains key priority to enable a better understanding of the mode of transmission of BU. We also conclude that excretions from suspected animals are unlikely to be major sources of MU in the Nyong Valley in Cameroon.

scholarly journals Snapshot fecal survey of domestic animals in rural Ghana forMycobacterium ulcerans

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2065 ◽  
Author(s):  
Nicholas J. Tobias ◽  
Nana Ama Ammisah ◽  
Evans K. Ahortor ◽  
John R. Wallace ◽  
Anthony Ablordey ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Buruli Ulcer ◽  
Domestic Animals ◽  
Mycobacterium Ulcerans ◽  
Animal Reservoir ◽  
Rural Ghana ◽  
Reservoir Species ◽  
Mode Of Transmission ◽  
High Concentrations ◽  
Negative Controls

Identifying the source reservoirs ofMycobacterium ulceransis key to understanding the mode of transmission of this pathogen and controlling the spread of Buruli ulcer (BU). In Australia, the native possum can harborM. ulceransin its gastrointestinal tract and shed high concentrations of the bacteria in its feces. To date, an analogous animal reservoir in Africa has not been identified. Here we tested the hypothesis that common domestic animals in BU endemic villages of Ghana are reservoir species analogous to the Australian possum. Using linear-transects at 10-meter intervals, we performed systematic fecal surveys across four BU endemic villages and one non-endemic village in the Asante Akim North District of Ghana. One hundred and eighty fecal specimens from a single survey event were collected and analyzed by qPCR for theM. ulceransdiagnostic DNA targets IS2404and KR-B. Positive and negative controls performed as expected but all 180 test samples were negative. This structured snapshot survey suggests that common domestic animals living in and around humans do not shedM. ulceransin their feces. We conclude that, unlike the Australian native possum, domestic animals in rural Ghana are unlikely to be major reservoirs ofM. ulcerans.

scholarly journals Mycobacterium ulcerans Population Genomics To Inform on the Spread of Buruli Ulcer across Central Africa

mSphere ◽  
2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Koen Vandelannoote ◽  
Delphin Mavinga Phanzu ◽  
Kapay Kibadi ◽  
Miriam Eddyani ◽  
Conor J. Meehan ◽  
...  
Keyword(s):  
Disease Control ◽  
Population Genomics ◽  
Demographic History ◽  
Buruli Ulcer ◽  
Central Africa ◽  
Mycobacterium Ulcerans ◽  
Evolutionary Trajectory ◽  
Content Type ◽  
Mode Of Transmission ◽  
The Impact

ABSTRACT Buruli ulcer is a neglected tropical disease of skin and subcutaneous tissue caused by infection with the pathogen Mycobacterium ulcerans. Many critical issues for disease control, such as understanding the mode of transmission and identifying source reservoirs of M. ulcerans, are still largely unknown. Here, we used genomics to reconstruct in detail the evolutionary trajectory and dynamics of M. ulcerans populations at a central African scale and at smaller geographical village scales. Whole-genome sequencing (WGS) data were analyzed from 179 M. ulcerans strains isolated from all Buruli ulcer foci in the Democratic Republic of the Congo, The Republic of Congo, and Angola that have ever yielded positive M. ulcerans cultures. We used both temporal associations and the study of the mycobacterial demographic history to estimate the contribution of humans as a reservoir in Buruli ulcer transmission. Our phylogeographic analysis revealed one almost exclusively predominant sublineage of M. ulcerans that arose in Central Africa and proliferated in its different regions of endemicity during the Age of Discovery. We observed how the best sampled endemic hot spot, the Songololo territory, became an area of endemicity while the region was being colonized by Belgium (1880s). We furthermore identified temporal parallels between the observed past population fluxes of M. ulcerans from the Songololo territory and the timing of health policy changes toward control of the Buruli ulcer epidemic in that region. These findings suggest that an intervention based on detecting and treating human cases in an area of endemicity might be sufficient to break disease transmission chains, irrespective of other reservoirs of the bacterium. IMPORTANCE Buruli ulcer is a destructive skin and soft tissue infection caused by Mycobacterium ulcerans. The disease is characterized by progressive skin ulceration, which can lead to permanent disfigurement and long-term disability. Currently, the major hurdles facing disease control are incomplete understandings of both the mode of transmission and environmental reservoirs of M. ulcerans. As decades of spasmodic environmental sampling surveys have not brought us much closer to overcoming these hurdles, the Buruli ulcer research community has recently switched to using comparative genomics. The significance of our research is in how we used both temporal associations and the study of the mycobacterial demographic history to estimate the contribution of humans as a reservoir in Buruli ulcer transmission. Our approach shows that it might be possible to use bacterial population genomics to assess the impact of health interventions, providing valuable feedback for managers of disease control programs in areas where health surveillance infrastructure is poor.

scholarly journals Mycobacterium ulceransin Mosquitoes and March flies captured from endemic areas of Northern Queensland, Australia

2018 ◽  
Author(s):  
Avishek Singh ◽  
William John Hannan McBride ◽  
Brenda Govan ◽  
Mark Pearson ◽  
Scott A. Ritchie
Keyword(s):  
Causative Agent ◽  
Buruli Ulcer ◽  
Mycobacterial Infection ◽  
Blood Feeding ◽  
Mycobacterium Ulcerans ◽  
Mechanical Transmission ◽  
Environmental Reservoir ◽  
Nontuberculous Mycobacterial Infection ◽  
Mode Of Transmission ◽  
Endemic Areas

AbstractMycobacterium ulceransis the causative agent of Buruli ulcer (BU). This nontuberculous mycobacterial infection has been reported in over 33 countries worldwide. In Australia, the majority of cases of BU have been recorded in coastal Victoria and the Mossman-Daintree areas of north Queensland. Mosquitoes have been postulated as a vector ofM. ulceransin Victoria, however the specific mode of transmission of this disease is still far from being well understood. In the current study, we trapped and analysed 16,900 (allocated to 845 pools) mosquitoes and 296 March flies from the endemic areas of north Queensland to examine for the presence ofM. ulceransDNA by polymerase chain reaction. Seven of 845 pools of mosquitoes were positive on screening using the IS2404 PCR target but only one pool was positive for presence ofM. ulceransafter confirmatory testing. None of the March fly samples were positive for the presence ofM. ulcerans.M. ulceranswas detected on proboscises of deliberately exposed mosquitoes.Author SummaryThe causative agent of Buruli ulcer is Mycobacterium ulcerans. This destructive skin disease is characterized by extensive and painless necrosis of skin and underlying tissues usually on extremities of body due to production of toxin named mycolactone. The disease is prevalent in Africa and coastal Australia. The exact mode of transmission and potential environmental reservoir for the pathogen still remain obscure. Aquatic and biting insects have been identified as important niche in transmission and maintenance of pathogen in the environment. In this study we screened mosquitoes and march flies captured from endemic areas of northern Queensland for the presence ofM. ulcerans.In addition, we conducted artificial blood feeding experiment to identify the role of mosquitoes in transmission of this pathogen. We found one pool of mosquito out of 845 pools positive forM. ulceransand none of the March fly samples were positive. This could indicate a low burden of the bacteria in the environment coinciding with a comparatively low number of human cases ofM. ulceransinfection seen during the trapping period of the study. Evidence to support mechanical transmission via mosquito proboscises was found.

scholarly journals Potential Animal Reservoir of Mycobacterium ulcerans: Systematic Review

2018 ◽  
Author(s):  
Avishek Singh ◽  
John McBride ◽  
Brenda Govan ◽  
Mark Pearson
Keyword(s):  
Systematic Review ◽  
Buruli Ulcer ◽  
Mycobacterium Ulcerans ◽  
Published Data ◽  
Animal Reservoir ◽  
Permanent Disability ◽  
Route Of Transmission ◽  
The World ◽  
Mode Of Transmission ◽  
Animal Reservoirs

Mycobacterium ulcerans is the causative agent of the Buruli ulcer, also known, in Australia, as Daintree ulcer or Bairnsdale ulcer. This destructive skin disease is characterized by extensive and painless necrosis of the skin and soft tissue with the formation of large ulcers, commonly on the leg or arm. To date, 33 countries with tropical, subtropical and temperate climates in Africa, the Americas, Asia and the Western Pacific have reported cases of Buruli Ulcer. The disease is rarely fatal, although it may lead to permanent disability and/ or disfigurement if not treated appropriately or in time. It is the third most common mycobacterial infection in the world after tuberculosis and leprosy. The precise mode of transmission of M. ulcerans is yet to be elucidated. Nevertheless, it is possible that the mode of transmission varies with different geographical areas and epidemiological settings. The knowledge about the possible route of transmission and potential animal reservoir of M. ulcerans is poorly understood and still remains patchy. We conducted a systematic review with selected key words on PubMed and INFORMIT databases to aggregate available published data on animal reservoirs of M. ulcerans. After certain inclusion and exclusion criteria, a total of 17 studies were included in the review. A variety of animals, e.g rodents, shrews, possums (ringtail and brush tail), horses, dogs, alpacas, koalas and Indian flap-shelled turtles have been recorded as being infected with M. ulcerans around the world. The majority of studies included in this review identified animal reservoirs, either aquatic or terrestrial, as predisposing for the emergence and reemergence of M. ulcerans infection. Taken together, the selected studies in this systematic review and discussed so far, it is clear that exotic wildlife, aquatic animals and native mammals play a significant role as reservoirs for M. ulcerans.

scholarly journals Interaction of Mycobacterium ulcerans with Mosquito Species: Implications for Transmission and Trophic Relationships

2010 ◽  
Vol 76 (18) ◽  
pp. 6215-6222 ◽  
Author(s):  
John R. Wallace ◽  
Matthew C. Gordon ◽  
Lindsey Hartsell ◽  
Lydia Mosi ◽  
M. Eric Benbow ◽  
...  
Keyword(s):  
Mosquito Species ◽  
Buruli Ulcer ◽  
Mycobacterium Ulcerans ◽  
Trophic Relationships ◽  
Stagnant Water ◽  
Plant Materials ◽  
Ochlerotatus Triseriatus ◽  
Slow Moving ◽  
Aquatic Food ◽  
Toxorhynchites Rutilus

ABSTRACT Mycobacterium ulcerans is the causative agent of Buruli ulcer, a severe necrotizing skin disease that causes significant morbidity in Africa and Australia. Person-to-person transmission of Buruli ulcer is rare. Throughout Africa and Australia infection is associated with residence near slow-moving or stagnant water bodies. Although M. ulcerans DNA has been detected in over 30 taxa of invertebrates, fish, water filtrate, and plant materials and one environmental isolate cultured from a water strider (Gerridae), the invertebrate taxa identified are not adapted to feed on humans, and the mode of transmission for Buruli ulcer remains an enigma. Recent epidemiological reports from Australia describing the presence of M. ulcerans DNA in adult mosquitoes have led to the hypothesis that mosquitoes play an important role in the transmission of M. ulcerans. In this study we have investigated the potential of mosquitoes to serve as biological or mechanical vectors or as environmental reservoirs for M. ulcerans. Here we show that Aedes aegypti, A. albopictus, Ochlerotatus triseriatus, and Culex restuans larvae readily ingest wild-type M. ulcerans, isogenic toxin-negative mutants, and Mycobacterium marinum isolates and remain infected throughout larval development. However, the infections are not carried over into the pupae or adult mosquitoes, suggesting an unlikely role for mosquitoes as biological vectors. By following M. ulcerans through a food chain consisting of primary (mosquito larvae), secondary (predatory mosquito larva from Toxorhynchites rutilus septentrionalis), and tertiary (Belostoma species) consumers, we have shown that M. ulcerans can be productively maintained in an aquatic food web.

scholarly journals Hosts and transmission of Mycobacterium ulcerans: a systematic review

2021 ◽  
Vol 22 (4) ◽  
pp. 439-447
Author(s):  
I.F. Aboagye
Keyword(s):  
Research Question ◽  
Buruli Ulcer ◽  
Aquatic Organisms ◽  
Mycobacterium Ulcerans ◽  
Future Research ◽  
Pubmed Database ◽  
Mode Of Transmission ◽  
Living Organisms ◽  
Aquatic Bugs

The control of Buruli ulcer (BU), a debilitating neglected tropical disease, is hampered by the inadequate understanding of the mode of transmission of its causative agent, Mycobacterium ulcerans (M. ulcerans). The DNA of M. ulcerans has been detected in some living organisms and non-living environmental samples of both aquatic and terrestrial sources. However, it is unclear whether the identified organisms support in vivo multiplication of the bacterium or play any role in its transmission. This paper identifies hosts of M. ulcerans, reviews progress made in unravelling the exact mode of transmission of M. ulcerans and identifies research gaps in this aspect of BU epidemiology. Using the search terms, ‘niche, Mycobacterium ulcerans’ and ‘mode of transmission, Mycobacterium ulcerans’ as well as defined inclusion criteria, information was obtained from the PubMed database and reviewed to assess their importance to the research question. Aquatic bugs of the genera Appasus and Diplonychus as well as Naucoris cimicoides and possums were identified to support in vivo multiplication of the bacterium. Bite of M. ulcerans contaminated Aedes notoscriptus, bite of aquatic bugs harboring or contaminated with M. ulcerans, and M. ulcerans contaminated skin-puncturing materials present in nature create opportunity for its transmission and infection. Appropriate protective measures may be useful to reduce the risk of exposure to M. ulcerans in BU endemic areas, and incorporation of trophic interactions of aquatic organisms known to support in vivo multiplication of M. ulcerans is needed in future research for better understanding of the spread of M. ulcerans in nature. French title: Hôtes et transmission de Mycobacterium ulcerans: une revue systématique   Le contrôle de l'ulcère de Buruli (UB), une maladie tropicale négligée débilitante, est entravé par la compréhension insuffisante du mode de transmission de son agent causal, Mycobacterium ulcerans (M. ulcerans). L'ADN de M. ulcerans a été détecté dans certains organismes vivants et des échantillons environnementaux non vivants de sources aquatiques et terrestres. Cependant, il n'est pas clair si les organismes identifiés favorisent la multiplication in vivo de la bactérie ou jouent un rôle dans sa transmission. Cet article identifie les hôtes de M. ulcerans, passe en revue les progrès réalisés pour démêler le mode exact de transmission de M. ulcerans et identifie les lacunes de la recherche dans cet aspect de l'épidémiologie de l'UB. À l'aide des termes de recherche « niche, Mycobacterium ulcerans » et « mode de transmission, Mycobacterium ulcerans » ainsi que des critères d'inclusion définis, des informations ont été obtenues à partir de la base de données PubMed et examinées pour évaluer leur importance pour la question de recherche. Des punaises aquatiques des genres Appasus et Diplonychus ainsi que Naucoris cimicoides et possums ont été identifiées pour soutenir la multiplication in vivo de la bactérie. La piqûre d'Aedes notoscriptus contaminé par M. ulcerans, la piqûre d'insectes aquatiques hébergeant ou contaminés par M. ulcerans et les matériaux de perforation de la peau contaminés par M. ulcerans présents dans la nature créent une opportunité de transmission et d'infection. Des mesures de protection appropriées peuvent être utiles pour réduire le risque d'exposition à M. ulcerans dans les zones d'endémie UB, et l'incorporation d'interactions trophiques d'organismes aquatiques connus pour favoriser la multiplication in vivo de M. ulcerans est nécessaire dans les recherches futures pour une meilleure compréhension de la propagation de M. ulcerans dans la nature.  

scholarly journals Buruli Ulcer (Acha-ere): Pathogenesis and Manifestation

2019 ◽  
pp. 1-5
Author(s):  
Elendu C. Onwuchekwa ◽  
Uzochukwu G. Ekeleme ◽  
Oliver Onu-Osi ◽  
Okonudo P. Osezele
Keyword(s):  
Subcutaneous Tissue ◽  
Buruli Ulcer ◽  
Central Africa ◽  
Mycobacterium Ulcerans ◽  
Actin Dynamics ◽  
Tropical Regions ◽  
West And Central Africa ◽  
Chronic Skin ◽  
Pass Through ◽  
Syndrome Protein

Infection of subcutaneous tissue with Mycobacterium ulcerans can lead to chronic skin ulceration known as Buruli ulcer. It has been reported in over 33 countries around the world, the greatest burden of disease is in the tropical regions of West and Central Africa, Australia, and Japan. It primarily affects children aged 5-15 years. Buruli ulcers generally begin as a painless dermal papule or subcutaneous edematous nodule, which over a period of weeks to months, breaks down to form an extensive necrotic ulcer with undermined edges. The pathogenesis of this neglected tropical disease is dependent on a lipidlike toxin, mycolactone, which diffuses through tissue away from the infecting organisms and elucidate its cytotoxic and immunosuppressive properties. The underlying molecular targets for mycolactone are: First, it can target scaffolding proteins (such as Wiskott Aldrich Syndrome Protein), which control actin dynamics in adherent cells and therefore lead to detachment and cell death. Second, it prevents the co-translational translocation (and therefore production) of many proteins that pass through the endoplasmic reticulum for secretion or placement in cell membranes.  Treatment includes a prolonged course of antibiotics and surgical debridement. Early identification and treatment are key, as lesions heal with scarring that can be a significant source of morbidity.

Interactions between ecological and socio-economic drivers of Buruli ulcer burden in Sub-Saharan Africa: opportunities for an improved control

2018 ◽  
Author(s):  
Andes Garchitorena ◽  
Matthew H. Bonds ◽  
Jean-Francois Guégan ◽  
Benjamin Roche
Keyword(s):  
Socioeconomic Factors ◽  
Disease Transmission ◽  
Access To Health Care ◽  
Buruli Ulcer ◽  
Mycobacterium Ulcerans ◽  
Sub Saharan Africa ◽  
Aquatic Environments ◽  
Human Populations ◽  
Complex Interactions ◽  
Sub Saharan

This chapter provides an overview of the complex interactions between ecological and socioeconomic factors for the development and control of Buruli ulcer in Sub-Saharan Africa. We review key ecological and evolutionary processes driving the environmental persistence and proliferation of Mycobacterium ulcerans, the causative agent, within aquatic environments, as well as transmission processes from these aquatic environments to human populations. We also outline key socioeconomic factors driving the economic and health burden of Buruli ulcer in endemic regions, revealed by reciprocal feedbacks between poverty, disease transmission from exposure aquatic environments and disease progression to severe stages owing to low access to health care. The implications of such insights for disease control, both in terms of limitations of current strategies and directions for the future, are discussed.

scholarly journals Cellular Immunity Confers Transient Protection in Experimental Buruli Ulcer following BCG or Mycolactone-Negative Mycobacterium ulcerans Vaccination

PLoS ONE ◽  
2012 ◽  
Vol 7 (3) ◽  
pp. e33406 ◽  
Author(s):  
Alexandra G. Fraga ◽  
Teresa G. Martins ◽  
Egídio Torrado ◽  
Kris Huygen ◽  
Françoise Portaels ◽  
...  
Keyword(s):  
Cellular Immunity ◽  
Buruli Ulcer ◽  
Mycobacterium Ulcerans
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