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  1. Comparison of Mycobacterium ulcerans (Buruli ulcer) and Leptospira sp. (Leptospirosis) dynamics in urban and rural settings

    International audience ; Background: Zoonotic pathogens respond to changes in host range and/or pathogen, vector and host ecology. Environmental changes (biodiversity, habitat changes, variability in climate), even at a local level, lead to... mehr

     

    International audience ; Background: Zoonotic pathogens respond to changes in host range and/or pathogen, vector and host ecology. Environmental changes (biodiversity, habitat changes, variability in climate), even at a local level, lead to variability in environmental pathogen dynamics and can facilitate their transmission from natural reservoirs to new susceptible hosts. Whilst the environmental dynamics of aquatic bacteria are directly linked to seasonal changes of their habitat they also rely on the ecological processes underpining their transmission. However data allowing the comparison of these ecological processes are lacking. Here we compared the environmental dynamics of generalist and vector-borne aquatic bacterial pathogens in the same unit of time and space, and across rural and urban habitats in French Guiana (South America).Principal findings: Using Leptospira sp. and Mycobacterium ulcerans we performed an environmental survey that allowed the detection of both pathogens in urban vs. rural areas, and during rainy vs. dry weather conditions. All samples were subjected to qPCR amplifications of LipL32 (Leptospira sp.) and IS2404 and KR (M. ulcerans) genetic markers. We found (i) a greater presence of M. ulcerans in rural areas compared with Leptospira sp., (ii) that modified urban environments were more favourable to the establishment of both pathogens, (iii) that Leptospira sp. presence was enhanced during the rainy season and M. ulcerans during the dry period, and (iv) differences in the spatial distribution of both bacteria across urban sites, probably due to the mode of dissemination of each pathogen in the environment.Conclusions: We propose that in French Guiana simplified and modified urban ecosystems might favour leptospirosis and Buruli ulcer emergence and transmission. Moreover, disease risk was also constrained by seasonality. We suggest that the prevention of aquatic bacterial disease emergence in impoverished urban areas of developing countries would benefit from seasonal diseases ...

     

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    Quelle: BASE Fachausschnitt AVL
    Sprache: Englisch
    Medientyp: Aufsatz aus einer Zeitschrift
    Format: Online
    Übergeordneter Titel: ISSN: 1935-2727 ; EISSN: 1935-2735 ; PLoS Neglected Tropical Diseases ; https://hal.umontpellier.fr/hal-02063496 ; PLoS Neglected Tropical Diseases, 2019, 13 (1), pp.e0007074. ⟨10.1371/journal.pntd.0007074⟩
    Schlagworte: [SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie; [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology; [SDV.EE.SANT]Life Sciences [q-bio]/Ecology; environment/Health; [SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases
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    info:eu-repo/semantics/OpenAccess

  2. Epithelial stratification shapes infection dynamics
    Erschienen: 2019
    Verlag:  HAL CCSD ; Public Library of Science

    International audience ; Infections of stratified epithelia contribute to a large group of common diseases, such as dermatological conditions and sexually transmitted diseases. To investigate how epithelial structure affects infection dynamics, we... mehr

     

    International audience ; Infections of stratified epithelia contribute to a large group of common diseases, such as dermatological conditions and sexually transmitted diseases. To investigate how epithelial structure affects infection dynamics, we develop a general ecology-inspired model for stratified epithelia. Our model allows us to simulate infections, explore new hypotheses and estimate parameters that are difficult to measure with tissue cell cultures. We focus on two contrasting pathogens: Chlamydia trachomatis and Human papillomaviruses (HPV). Using cervicovaginal parameter estimates, we find that key infection symptoms can be explained by differential interactions with the layers, while clearance and pathogen burden appear to be bottom-up processes. Cell protective responses to infections (e.g. mucus trapping) generally lowered pathogen load but there were specific effects based on infection strategies. Our modeling approach opens new perspectives for 3D tissue culture experimental systems of infections and, more generally, for developing and testing hypotheses related to infections of stratified epithelia. Author summary Many epithelia are stratified in layers of cells and their infection can result in many pathologies, from rashes to cancer. It is important to understand to what extent the epi-thelial structure determines infection dynamics and outcomes. To aid experimental and clinical studies, we develop a mathematical model that recreates epithelial and infection dynamics. By applying it to a virus, human papillomavirus (HPV), and a bacteria, chla-mydia, we show that considering stratification improves our general understanding of disease patterns. For instance, the duration of infection can be driven by the rate at which the stem cells of the epithelium divide. Having a general model also allows us to investigate and compare hypotheses. This ecological framework can be modified to study specific pathogens or to estimate parameters from data generated in 3D skin cell culture experiments. PLOS ...

     

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  3. First Detection of an Enterovirus C99 in a Captive Chimpanzee with Acute Flaccid Paralysis, from the Tchimpounga Chimpanzee Rehabilitation Center, Republic of Congo

    International audience ; Enteroviruses, members of the Picornaviridae family, are ubiquitous viruses responsible for mild to severe infections in human populations around the world. In 2010 Pointe-Noire, Republic of Congo recorded an outbreak of... mehr

     

    International audience ; Enteroviruses, members of the Picornaviridae family, are ubiquitous viruses responsible for mild to severe infections in human populations around the world. In 2010 Pointe-Noire, Republic of Congo recorded an outbreak of acute flaccid paralysis (AFP) in the humans, caused by wild poliovirus type 1 (WPV1). One month later, in the Tchimpounga sanctuary near Pointe-Noire, a chimpanzee developed signs similar to AFP, with paralysis of the lower limbs. In the present work, we sought to identify the pathogen, including viral and bacterial agents, responsible for this illness. In order to identify the causative agent, we evaluated a fecal specimen by PCR and sequencing. A Human enterovirus C, specifically of the EV-C99 type was potentially responsible for the illness in this chimpanzee. To rule out other possible causative agents, we also investigated the bacteriome and the virome using next generation sequencing. The majority of bacterial reads obtained belonged to commensal bacteria (95%), and the mammalian virus reads matched mainly with viruses of the Picorna-viridae family (99%), in which enteroviruses were the most abundant (99.6%). This study thus reports the first identification of a chimpanzee presenting AFP most likely caused by an enterovirus and demonstrates once again the cross-species transmission of a human pathogen to an ape.

     

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