Leptospirosis : Current challenges of an old disease

Leptospirosis is an infectious disease which affects man and animals, and is considered as the most common zoonosis worldwide. Every year, it is responsible for serious epidemics in tropical and developing countries. The pathogen is Leptospira interrogans, an extremely mobile and helicoidal spirochete. The clinical presentation of leptospirosis varies due to the diversity within the genus Leptospira and its complex epidemiology. Several mammal species may develop leptospirosis, mainly in its chronic form, and thus act as reservoirs for the disease. Human leptospirosis, or Weil’s disease, has a high mortality rate and is caused by Leptospira interrogans serogroup Icterohaemorrhagiae. The vaccination of man and animals has limited effects because vaccines are specific to the serovar and induce only a short-term immunity. The microagglutination test (MAT) used for the diagnosis of leptospirosis also has limitations, such as the inability to identify the early stage of the disease. However, progress is expected in diagnostic procedures, as the recently sequenced genome of Leptospira and the development of specific genetic tools mark the beginning of the post-genomic era in research on spirochetes. Our efforts are currently turned towards the understanding of leptospiral virulence mechanisms, as well as the development of more effective vaccines and diagnostic tests. The Spirochetes’ Biology Unit at Institut Pasteur, Paris, has just identified the first leptospiral virulence factor, Loa22, a protein of the OmpA family exposed on the cell surface of the bacteria. Loa22 is a candidate for the development of a vaccine.La leptospirose, maladie infectieuse atteignant l'homme et les animaux, est considérée comme la zoonose la plus répandue dans le monde; chaque année, elle est responsable de graves épidémies dans les pays tropicaux et en voie de développement. Son agent causal, Leptospira interrogans, est un spirochète de forme hélicoïdale, extrêmement mobile. Le tableau clinique varie du fait de la diversité du genre Leptospira et d'une épidémiologie complexe. Les leptospiroses animales touchent plusieurs espèces de mammifères qui développent majoritairement des formes chroniques de la maladie et deviennent ainsi des réservoirs de l'agent infectieux. La forme humaine ou maladie de Weil, dont le taux de mortalité est élevé, est provoquée par les leptospires du sérogroupe Icterohaemorrhagiae. La vaccination de l'homme et des animaux a des effets limités car les vaccins utilisés sont spécifiques du sérovar et n'offrent qu'une protection de courte durée. Le test de microagglutination (MAT) présente des inconvénients comme l'impossibilité d'identifier la phase précoce de la maladie mais des progrès diagnostiques sont encore envisageables. En effet, le récent séquençage du génome des leptospires et le développement d'outils génétiques spécifiques marquent le début de l'ère post-génomique dans la recherche sur les spirochètes. Nos efforts portent actuellement sur la compréhension des mécanismes de virulence des leptospires, ainsi que sur la mise au point de tests diagnostiques et de vaccins plus performants. L'Unité de Biologie des Spirochètes, de l'Institut Pasteur de Paris, vient d'identifier un facteur de virulence des leptospires, une protéine de la famille OmpA, Loa22, exposée à la surface de la bactérie. La protéine Loa22 est un candidat pour le développement d'un vaccin

Serological trail of Brucella infection in an urban slum population in Brazil

Introduction: Brucellosis is a re-emerging zoonosis with new cases reported each year in many Latin American countries, but it is mostly under-recognized. This study presents a serological investigation of infection with Brucella abortus and Brucella canis in a poor urban community in the city of Salvador, Brazil. Methodology: Human sera (n = 180) were randomly selected from 3,171 samples taken from healthy individuals during 2003-2004 and tested with C-ELISA for B. abortus and I-ELISA for B. canis. Results: Thirteen percent (24/180) of the individuals were positive for B. abortus and 4.6 % (8/174) were positive for B. canis. Among the variables studied only age (older than 45 years) appeared to be a risk factor for the detection of Brucella antibodies. Conclusion: These results indicate the presence of Brucella infection in this settlement and highlight the need to understand the epidemiology of infection under these circumstances to establish the necessary measures for surveillance and control.Facultad de Ciencias Veterinaria

Transcriptome Sequencing Reveals Wide Expression Reprogramming of Basal and Unknown Genes in Leptospira biflexa Biofilms

The genus Leptospira is composed of pathogenic and saprophytic spirochetes. Pathogenic Leptospira is the etiological agent of leptospirosis, a globally spread neglected disease. A key ecological feature of some pathogenic species is their ability to survive both within and outside the host. For most leptospires, the ability to persist outside the host is associated with biofilm formation, a most important bacterial strategy to face and overcome hostile environmental conditions. The architecture and biochemistry of leptospiral biofilms are rather well understood; however, the genetic program underpinning biofilm formation remains mostly unknown. In this work, we used the saprophyte Leptospira biflexa as a model organism to assess over- and underrepresented transcripts during the biofilm state, using transcriptome sequencing (RNA-seq) technology. Our results showed that some basal biological processes like DNA replication and cell division are downregulated in the mature biofilm. Additionally, we identified significant expression reprogramming for genes involved in motility, sugar/lipid metabolism, and iron scavenging, as well as for outer membrane-encoding genes. A careful manual annotation process allowed us to assign molecular functions to many previously uncharacterized genes that are probably involved in biofilm metabolism. We also provided evidence for the presence of small regulatory RNAs in this species. Finally, coexpression networks were reconstructed to pinpoint functionally related gene clusters that may explain how biofilm maintenance is regulated. Beyond elucidating some genetic aspects of biofilm formation, this work reveals a number of pathways whose functional dissection may impact our understanding of leptospiral biology, in particular how these organisms adapt to environmental changes.Agencia Nacional de Investigación e Innovació

The OmpA-Like Protein Loa22 Is Essential for Leptospiral Virulence

Pathogenic mechanisms of Leptospira interrogans, the causal agent of leptospirosis, remain largely unknown. This is mainly due to the lack of tools for genetic manipulations of pathogenic species. In this study, we characterized a mutant obtained by insertion of the transposon Himar1 into a gene encoding a putative lipoprotein, Loa22, which has a predicted OmpA domain based on sequence identity. The resulting mutant did not express Loa22 and was attenuated in virulence in the guinea pig and hamster models of leptospirosis, whereas the genetically complemented strain was restored in Loa22 expression and virulence. Our results show that Loa22 was expressed during host infection and exposed on the cell surface. Loa22 is therefore necessary for virulence of L. interrogans in the animal model and represents, to our knowledge, the first genetically defined virulence factor in Leptospira species

ANATOMOPATOLOGIA DA PARATUBERCULOSE EM BOVINOS LEITEIRO DE RESENDE- R.J

A Paratuberculose, uma doença causada pelo Mycobacterium avium subsp. paratuberculosis (Map), é caracterizada por uma enterite crônica granulomatosa. Visamos registrar a anatomopatologia de três casos de paratuberculose em bovinos leiteiros autóctones oriundos de Resende-RJ. Esses animais apresentavam sinais clínicos de paratuberculose e, após teste de ELISA positivo, foram eutanasiados e necropsiados. Amostras de intestino, linfonodos mesentéricos e válvula ileocecal foram colhidas, fixadas em formol neutro tamponado a 10%,  processadas  e coradas pelo HE (hematoxilina-eosina) e ZN (Ziehl-Neelsen). Alterações macroscópicas, como espessamento da parede do intestino delgado, mucosas congestas e corrugadas, foram observadas. A linfadenomegalia e linfangectasia também foram evidentes, assim como a congestão e edemaciação das válvulas ileocecais. Os principais achados histopatológicos foram enterite, linfangite e linfadenite granulomatosas. As lesões intestinais se resumiam à mucosa e submucosa, principalmente do jejuno e do íleo e caracterizavam-se por infiltrado inflamatório de linfócitos, eosinófilos e macrófagos epitelióides. A coloração de ZN demonstrou bacilos álcool ácido resistentes (BAAR) nos macrófagos, no ápice das vilosidades e lâmina própria e, ainda, no parênquima dos linfonodos mesentéricos. A anatomopatologia foi característica e considerada uma valiosa ferramenta no diagnóstico da paratuberculose. PALAVRAS-CHAVE: anatomopatológico; bovino; Map; paratuberculos

Reactive oxygen species, ageing and the hormesis police

For more than 50 years, the free radical theory served as the paradigm guiding most investigations of ageing. However, recent studies in a variety of organisms have identified conceptual and practical limitations to this theory. Some of these limitations are related to the recent discovery that caloric restriction and other experimental manipulations promote longevity by inducing hormesis effects in association with increased reactive oxygen species (ROS). The beneficial role of ROS in lifespan extension is consistent with the essential role of these molecules in cell signalling. However, the identity of specific forms of ROS that promote longevity remains unclear. In this article, we argue that in several model systems, hydrogen peroxide plays a crucial role in the induction of hormesis.The authors wish to thank Molly Burhans for preparing the figures. This work was supported by Fundacao para a Ciencia e Tecnologia (FCT) and COMPETE/QREN/EU (PTDC/BIA-MIC/114116/2009), a grant from the Roswell Park Alliance Foundation and by a National Cancer Institute Support Grant (P30CA016056) to Roswell Park Cancer Institute. Authors have no conflict of interest to declare

Simplified sewerage to prevent urban leptospirosis transmission: a cluster non-randomised controlled trial protocol in disadvantaged urban communities of Salvador, Brazil.

INTRODUCTION: Leptospirosis is a globally distributed zoonotic and environmentally mediated disease that has emerged as a major health problem in urban slums in developing countries. Its aetiological agent is bacteria of the genus Leptospira, which are mainly spread in the urine of infected rodents, especially in an environment where adequate sanitation facilities are lacking, and it is known that open sewers are key transmission sources of the disease. Therefore, we aim to evaluate the effectiveness of a simplified sewerage intervention in reducing the risk of exposure to contaminated environments and Leptospira infection and to characterise the transmission mechanisms involved. METHODS AND ANALYSIS: This matched quasi-experimental study design using non-randomised intervention and control clusters was designed to assess the effectiveness of an urban simplified sewerage intervention in the low-income communities of Salvador, Brazil. The intervention consists of household-level piped sewerage connections and community engagement and public involvement activities. A cohort of 1400 adult participants will be recruited and grouped into eight clusters consisting of four matched intervention-control pairs with approximately 175 individuals in each cluster in baseline. The primary outcome is the seroincidence of Leptospira infection assessed through five serological measurements: one preintervention (baseline) and four postintervention. As a secondary outcome, we will assess Leptospira load in soil, before and after the intervention. We will also assess Leptospira exposures before and after the intervention, through transmission modelling, accounting for residents' movement, contact with flooding, contaminated soil and water, and rat infestation, to examine whether and how routes of exposure for Leptospira change following the introduction of sanitation. ETHICS AND DISSEMINATION: This study protocol has been reviewed and approved by the ethics boards at the Federal University of Bahia and the Brazilian National Research Ethics Committee. Results will be disseminated through peer-reviewed publications and presentations to implementers, researchers and participating communities. TRIAL REGISTRATION NUMBER: Brazilian Clinical Trials Registry (RBR-8cjjpgm)

Evaluation of Mycobacterium avium subsp. paratuberculosis faecal culture protocols and media Avaliação de protocolos de cultivo fecal e meios para a cultura de Mycobacterium avium subsp. paratuberculosis

Paratuberculosis is an important enteritis of ruminants caused by Mycobacterium avium subsp. paratuberculosis (Map). The disease is officially considered exotic in Brazil, but recent serological surveys and the isolation of the agent suggest it may occur in our herds. The aim of this study was to evaluate three different formulations of Herrold's egg yolk agar with mycobactin J (HEYM) and four faecal culture protocols considering their ability for Map growth as well as cost and ease of application. Three formulations of HEYM were inoculated with two suspensions of Map. Spiked faeces and naturally contaminated faecal samples were treated by the four faecal culture protocols. Centrifugation protocol and HEYM recommended by OIE showed the best results on the recovery of Map.<br>A paratuberculose é uma importante enterite de ruminantes causada por Mycobacterium avium subsp. paratuberculosis (Map). A enfermidade é oficialmente considerada exótica no Brasil, mas inquéritos sorológicos recentes e o isolamento do agente etiológico sugerem que ela pode estar presente em nossos rebanhos. O objetivo do estudo foi avaliar três diferentes fórmulas do Ágar gema de ovo de Herrold suplementado com micobactina J (HEYM) e quatro protocolos de cultura fecal quanto ao crescimento de Map, bem como custo e facilidade de implementação. Três fórmulas de HEYM foram inoculadas com duas suspensões de Map. Fezes contaminadas artificialmente e naturalmente com Map foram tratadas pelos quatro protocolos de cultura fecal. O protocolo da centrifugação e a fórmula de HEYM recomendada pela OIE demonstraram os melhores resultados quanto à recuperação de Map

Serological trail of Brucella infection in an urban slum population in Brazil.

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2014-11-06T13:07:31Z No. of bitstreams: 1 Angel OM Serological....pdf: 42010 bytes, checksum: f93d2e662a5639b99ea36ffb4ef2412c (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2014-11-06T13:07:41Z (GMT) No. of bitstreams: 1 Angel OM Serological....pdf: 42010 bytes, checksum: f93d2e662a5639b99ea36ffb4ef2412c (MD5)Made available in DSpace on 2014-11-06T13:24:58Z (GMT). No. of bitstreams: 1 Angel OM Serological....pdf: 42010 bytes, checksum: f93d2e662a5639b99ea36ffb4ef2412c (MD5) Previous issue date: 2012Universidad de Antioquia. Facultad de Ciencias Agrarias. Grupo de investigación Vericel. Medellín, ColombiaFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Instituto de Biologia. Salvador, BA, BrasilYale School of Public Health. Department of Epidemiology of Microbial Diseases. New Haven, USAUniversidad de la Plata. Facultad de Ciencias Veterinarias. Laboratorio de Inmunología Veterinaria. Buenos Aires, ArgentinaINTRODUCTION: Brucellosis is a re-emerging zoonosis with new cases reported each year in many Latin American countries, but it is mostly under-recognized. This study presents a serological investigation of infection with Brucella abortus and Brucella canis in a poor urban community in the city of Salvador, Brazil. METHODOLOGY: Human sera (n = 180) were randomly selected from 3,171 samples taken from healthy individuals during 2003-2004 and tested with C-ELISA for B. abortus and I-ELISA for B. canis. RESULTS: Thirteen percent (24/180) of the individuals were positive for B. abortus and 4.6 % (8/174) were positive for B. canis. Among the variables studied only age (older than 45 years) appeared to be a risk factor for the detection of Brucella antibodies. CONCLUSION: These results indicate the presence of Brucella infection in this settlement and highlight the need to understand the epidemiology of infection under these circumstances to establish the necessary measures for surveillance and control