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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Sistema de detecção de focos de tuberculose bovina no Estado de São Paulo utilizando métodos moleculares e epidemiológicos / A molecular and epidemiological based-work system for detection of bovine tuberculosis focus in the state of São Paulo

Cesar Alejandro Rosales Rodriguez 05 May 2005 (has links)
Foi estabelecida uma parceria entre o Departamento de Medicina Veterinária Preventiva e Saúde Animal (VPS) da FMVZ-USP, a Coordenadoria de Defesa Agropecuária do Estado de São Paulo e o Serviço de Inspeção Federal (SIF) para organizar um sistema capaz de detectar focos de tuberculose bovina no Estado, com base nas rotinas de inspeção de carcaças em abatedouros, cujos objetivos foram: 1) conhecer a diversidade genética de isolados de Mycobacterium bovis em bovinos no Estado de São Paulo; 2) estudar a distribuição espacial desses focos; 3) estudar a tipologia das unidades de criação de bovinos caracterizadas como focos de tuberculose; 4) verificar se é possível, com a atual infra-estrutura existente em São Paulo, operar um sistema de vigilância para detecção de focos de tuberculose bovina. Assim, foi estruturado um sistema de coleta, envolvendo as redes SISP (Sistema de Inspeção do Estado de São Paulo) e SIF, que realizou as coletas de materiais e informações de maio de 2002 a janeiro de 2004. Todo o material seguiu para o VPS, onde foram processados. As propriedades caracterizadas como focos foram rastreadas e delas foi coletada outro conjunto de informações. Seguem os resultados alcançados: 1) foram identificados 33 diferentes espoligotipos dentre os 248 isolados de M. bovis de bovinos no Estado de São Paulo. Os isolados do espoligotipo SB0295 foram re-discriminados em 13 novos perfis genéticos de M. bovis pela técnica MIRU-VNTR; 2) dentre os dois espoligotipos mais prevalentes estudados (SB0295 e SB0121), apenas o SB0295 apresentou-se de forma agrupada nas análises espaciais; 3) foram geradas várias informações sobre a tipologia e o manejo das unidades de criação de bovinos caracterizadas como focos de tuberculose; 4) a atual infra-estrutura existente no Estado de São Paulo foi capaz de operar um sistema de detecção de focos de tuberculose bovina / A partnership between the Department of Preventive Veterinary Medicine and Animal Health (VPS) of the FMVZ-USP, the Coordination of Agriculture and Animal Defense of the State of São Paulo, and the Federal Inspection Service (SIF) was established to organize a work system for detection of bovine tuberculosis focus in the state, based on routine methods of carcass inspection in the abattoir, with the following objectives: 1) to determine the genetic diversity of the isolates of Mycobacterium bovis from bovines in the state of São Paulo; 2) to study the spatial distribution of the focuses; 3) to study the typology of the bovine breading units (farms), which were characterized as tuberculosis focus; 4) to verify the possibility of operating a surveillance system for detection of bovine tuberculosis focus based on the current network in the state of São Paulo. Thus, it was performed a system for data collection involving the current systems SISP (System of Inspection of the State of São Paulo) and SIF, who performed the collection of biological samples and information from May 2002 to January 2004. All samples were addressed to the VPS, where they were processed. Farms characterized as focus were traced to obtain new information. The results obtained in this study follow: 1) A total of 33 different spoligotypes were determined out of 248 bovine isolates of M. bovis in the state of São Paulo. The spoligotype SB0295 isolates were re-discriminated into 13 new M. bovis genetic profiles by the MIRU-VNTR technique; 2) From the two most prevalent spoligotypes analyzed in this study (SB0295 e SB0121), only SB0295 showed a cluster presentation by the spatial analyses; 3) Several information about typology and bovine breeding unit management were generated regarding the status of tuberculosis focus; 4) the current network in the state of São Paulo was capable of operating a system for detection of bovine tuberculosis focus
22

Mycobacterium tuberculosis complex-specific antigens for use in serodiagnosis of bovine tuberculosis

Modise, Boitumelo Magret 31 May 2013 (has links)
Bovine tuberculosis (BTB) is a zoonotic disease that affects domestic and wild animals, and humans. It is caused by Mycobacterium bovis (M. bovis) and has a wide host range. The effective control of BTB is of paramount importance and this can be achieved through the use of accurate and comprehensive diagnostic tests. The most widely used methods to detect BTB are the skin test and in vitro gamma interferon assay which do not detect anergic animals, but serological tests such as ELISA and fluorescence polarization assay (FPA) have been found promising in ancilliary tuberculosis diagnosis. The overall aim was to study M. tuberculosis complex (MTBC) protein, mycobacterial protein bovis 70 (MPB70) as a target for serological assays in the detection of antibodies to bovine tuberculosis. The MPB70 protein was expressed, purified and labeled with fluorescein (FITC). The mpb70 gene was fragmented into three regions without disrupting predicted epitopes. The resulting protein Fragments were expressed as fusion proteins with the monster green fluorescent protein (MGFP). The recombinant MPB70 (rMPB70) and the expressed gene fragments 2&3 were tested in immunoblots and ELISAs. The rMPB70 and fragment 2-MGFP reacted with chicken antibodies raised against rMPB70 and immune sera from BTB infected buffaloes. MPB70 peptides were synthesized as an approach to identify even smaller antigenic regions. The peptides BT1G (residues 31-45) and BT51L (residues 81-95) were recognised by anti-MPB70 chicken antibodies in the ELISA and fall within fragment 1 and 2, respectively. The tracers (rMPB70-FITC, fragment 2-MGFP fusion and peptides BT1G&BT51L) were tested in the FPA, but the results failed to distinguish between immune sera from chickens immunized with rMPB70 and negative control sera. Even though the FPA was not successful, the MPB70 fragment 2-MGFP fusion protein, which was recognized by sera from BTB infected buffaloes, was tested in an ELISA using panels of sera from uninfected and naturally M. bovis infected buffaloes and cattle. The diagnostic performance of the ELISA was, however, overall unsatisfactory and hence of very limited use as a serological test to detect antibody responses to BTB as a stand-alone assay. Sera from some of the animals gave false positive reactions indicating that MPB70 was not sufficiently specific for serodiagnosis of M. tuberculosis complex infections. / Dissertation (MSc)--University of Pretoria, 2012. / Veterinary Tropical Diseases / unrestricted
23

Epidemiology and public health significance of bovine tuberculosis in cattle in the highlands of Cameroon

Awah Ndukum, Julius January 2012 (has links)
Bovine tuberculosis (TB) is a contagious neglected zoonosis of cattle that is prevalent but under-investigated in Cameroon, hence this study was designed to assess the epidemiology of bovine TB in cattle, risks for M. bovis infection in cattle and humans; and public health implications of zoonotic bovine TB in the highlands of Cameroon. A retrospective study of meat inspection records (1994 – 2010) was done to estimate the prevalence of TB lesions in slaughtered cattle in the North West region. The prevalence of bovine TB and anti-bovine TB antibodies in live cattle based on tuberculin skin tests (2 surveys) and immune-chromatographic assays respectively were carried out in the Western and Adamawa highlands of Cameroon. The performance of the tuberculin tests for bovine TB diagnosis in cattle using various tuberculin skin test cut-off points against the detection of anti-bovine TB antibodies (hypothesised risks of exposure) was compared. Suspected TB lesions from slaughtered cattle and infected human sputa were cultured on Lowentein – Jesen and Middlebrook 7H9 media to isolate mycobacteria agents for molecular genotyping using genomic deletion analysis and spoligotyping. Risk factors for exposure and transmission of zoonotic bovine TB infection of cattle and cattle professionals, and its public health significance were determined using structured questionnaires. Seventeen years of meat inspection record revealed that suspect TB lesions were identified in 599 of 129,165 slaughtered cattle at the Bamenda abattoir. The lungs and associated lymph nodes (over 60%) were the most affected tissues. Other results showed that the prevalence of anti-bovine TB antibodies in cattle in the study regions was 37.17%. Chi square statistics revealed that irrespective of the tuberculin test cut-off value (P<0.05; χ2>48), strong associations existed between the detection of anti-bovine TB antibodies and disease status. A 95% confidence interval analysis of the comparative cervical tuberculin tests revealed that the prevalence rates were 4.67% – 7.15%, 12.02% – 15.67% and 20.56% – 24.98% at the ≥ 4mm, ≥ 3mm and ≥ 2mm cut-off points, respectively. Overall, the best test performance was realised at ≥ 3-mm, though the ≥ 2-mm cut-off point predicted more positive reactors. Age, sex, breed and husbandry practices served as significant (P<0.05) risks to the prevalence and exposure of bovine TB in cattle. The feedbacks from cattle professionals suggested that there was high possibility of cattle to cattle and cattle to human transmission of bovine TB such as intimate and repeated animal / animal and animal / human interactions, consuming unpasteurised milk and eating raw meat. Genomic deletion analysis of cultured isolates showed evidence of M. tuberculosis from cattle and M. bovis from human while spoligotyping identified five cattle M. bovis strains; and four spoligotype patterns that had not been previously described anywhere. The study has important epidemiological and public health implications requiring prompt and decisive actions from the Cameroonian authority towards controlling zoonotic bovine TB in both humans and animals. A multidisciplinary approach is needed for further collaborative research and effective control strategies such as enhancing the awareness of people to this deadly disease through continuous education, proper food handling and personal hygiene, healthy husbandry practices and maintenance of the environment.
24

Quantifying contact rates and space use in the Eurasian badger (Meles meles) : implications for the transmission of bovine tuberculosis

Reed, Nicola Louise January 2011 (has links)
This thesis examines the space use, movement and contact rate patterns of a high- density, group-living, Eurasian badger (Meles meles) population in the UK naturally infected with bovine tuberculosis (bTB). Recently developed proximity logging devices were deployed on a representative sample of 51 badgers from eight different social groups to track their movements using radio-telemetry and to quantify their within- and between-group contact rates. Whilst interactions within social groups accounted for more than 90% of contacts, the entire study population was ultimately connected through interactions among individuals from neighbouring groups. Both within and between-group contacts, and also the use of denning sites, were heavily influenced by seasonal and demographic factors, which appear to be motivated to a large extent by reproductive behaviours. Nevertheless, by using social network analysis I found that badgers that tested positive for bTB were found to interact with fewer of their group members and for a shorter amount of time. Specifically these test-positive individuals were found to associate with test-negative group members significantly less than would be expected by chance. Those animals testing positive for bTB were also found to use outlying setts significantly more frequently than those that tested negative. The within and between-group contact rates of individuals were found to correlate with their sett use patterns. Those animals that spent less time interacting with group members and those that spent more time interacting with members of foreign social groups, were found to spend a greater proportion of their time at outlier setts. The findings in this thesis suggest a link between wider roaming behaviour and the disease status of an individual. This adds support to the argument that the social disruption of badger populations, for example through culling, may promote rather than alleviate the spread of bTB as a result of increased movement and contacts between groups. State-of-the-art technology has enabled me to demonstrate the strong influence that badger social organisation may have on the transmission of an economically significant infectious disease. My findings suggest that disease control measures might be enhanced by taking into account seasonal and individual-level variation in ranging behaviour and use of outlier setts, for example, by identifying and targeting functional groups of individuals, specific areas, or times of the year that contribute disproportionately to disease spread.
25

Disease and demography in the Woodchester Park badger population

McDonald, Jennifer Leslie January 2014 (has links)
The topic of badgers in the UK is often a contentious one, dividing opinions and sparking political debate. On one hand, badgers represent an important part of the British ecosystem but on the other a wildlife reservoir of disease implicated in the transmission of bovine tuberculosis (TB) to livestock in the UK. This has prompted strong interest in their population dynamics and epidemiology. Using data from a long-term study of a naturally infected badger population in Woodchester Park, Gloucestershire, this thesis explores a range of capture-mark-recapture (CMR) models to further understand disease and demographic processes. The first section examines long term population dynamics, simultaneously estimating demographic rates alongside their drivers using integrated population models (IPMs). The findings provide new insight into badger demography, highlighting density-dependent mechanisms, vulnerabilities to changing climate and disease prevalence and subsequently how multi-factorial analyses are required to explain fluctuating badger populations. The following sections use multistate models to answer pertinent questions regarding individual disease dynamics, revealing rates of TB infection, progression and disease-induced mortality. A key finding was sex-differences in disease response, with males more susceptible to TB infection. After applying a survival trajectory analysis we suggest sex differences are due to male immune defence deficiencies. A comparative analysis demonstrated similarities between epidemiological processes at Woodchester Park to an unconnected population of badgers from a vaccine study, supporting its continued use as a model population. The final study in this thesis constructs an IPM to estimate disease and population dynamics and in doing so uncovers disease-state recruitment allocation rates, demographic and population estimates of badgers in varying health-states and predicts future dynamics. This model aims to encapsulate the more commonly held notion of populations as dynamic entities with numerous co-occurring processes, opening up avenues for future analyses within both the badger-TB system and possible extensions to other wildlife reservoir populations.
26

Comparação entre meios de cultura e condições de incubação para o primo isolamento de Mycobacterium bovis de bovinos brasileiros / Comparison between media and incubation conditions for primary isolation of Mycobacterium bovis from Brazilian cattle

Ikuta, Cássia Yumi 21 June 2011 (has links)
Considerando que os meios de cultura e as condições de incubação são os principais fatores para o sucesso do primo isolamento, além do método de descontaminação, quatro meios de cultura e três condições de incubação foram investigados. Noventa e sete amostras de lesões granulomatosas foram submetidas ao método de descontaminação com cloreto de 1-hexadecilpiridinio (HPC) a 1,5%, e semeadas em dois meios a base de ovo, Stonebrink e Löwenstein-Jensen com piruvato de sódio, e em dois meios a base de ágar, B83 e Middlebrook 7H11. Cada meio foi incubado a 37ºC por 90 dias em três condições de incubação, atmosfera com 10% de CO2, atmosfera normal e atmosfera com suposta tensão de CO2 obtida pela queima do algodão hidrófobo e fechamento do tubo com rolha de cortiça. O tipo de condição de incubação utilizado teve influência nos meios a base de ovo apenas no inicio da incubação (30 dias), mas nenhuma nos meios a base de ágar. A incubação em atmosfera com 10% de CO2 diminuiu o tempo de aparecimento da primeira colônia e aumentou o número de UFC. O meio B83 foi mais rápido no aparecimento das colônias e teve o maior sucesso de isolamento aos 30 dias, mas não houve diferença com os meios Stonebrink e Löwenstein-Jensen com piruvato, no sucesso de isolamento e número de UFC aos 60 e 90 dias. De acordo com os dados, em sete oportunidades houve isolamento de M. bovis apenas no meio de Stonebrink e em quatro apenas no B83, assim, sugere-se a utilização desses dois meios de cultura em paralelo, incubados em atmosfera com acréscimo de CO2 / Considering that the culture media and the incubation conditions are the main factors for the success of primary isolation, besides the decontamination procedure, four culture media and three incubation conditions were investigated. Ninety-seven samples of granulommatous lesions were submitted to the decontamination procedure by 1-hexadecylpyridinium chloride at 1,5% w/v, and inoculated on two egg-based media, Stonebrink and Löwenstein-Jensen with sodium pyruvate, and two agar-based media, B83 and Middlebrook 7H11. Each medium was incubated at 37ºC for 90 days in three incubation conditions, in air containing 10% CO2, in air, and in air with a supposed higher CO2 tension created by burning the hydrophobic cotton used to close the tubes and subsequently closing with a cork. The type of incubation condition used had influence on the egg-based media only at the beginning of incubation (30 days), but none on the agar-based media. The incubation in air containing 10% CO2 decreased the time to first appearance of colonies and increased the number of colonies. B83 medium showed a faster growth and detected more isolates at 30 days of incubation. However, there was no difference between B83, Stonebrink and Löwenstein-Jensen with pyruvate at 60 and 90 days of incubation. According to the data, seven M. bovis isolates grew only on Stonebrink and four only on B83, therefore, the use of both media, in parallel, incubated in air containing CO2 is suggested.
27

Impact de l’évolution du schéma de prophylaxie et des structures et pratiques d’élevage sur l’évolution de la tuberculose bovine en France entre les années 1965 et 2000 : modélisation de l’incidence cheptel et de la dynamique de transmission intra-élevage de l’infection / Impact of the Evolution of Pontrol programs and Herd Structures on the Evolution of Bovine Tuberculosis in France Between 1965 and 2000 : Modeling Herd Incidence and of the Within-herd Infection Dynamic

Bekara, Mohammed El Amine 25 November 2014 (has links)
En France, la lutte collective contre la tuberculose bovine à partir de 1965 a permis d’obtenir en 2000 le statut officiellement indemne. En parallèle de cette évolution, plusieurs schémas de prophylaxie ont été appliqués et le cheptel bovin français a connu une évolution dans sa structure démographique et dans les pratiques de sa gestion. L’objectif principal de cette thèse était d’étudier la relation entre ces trois évolutions parallèles. Deux approches ont été utilisées : l’analyse d’une série de données longue et la modélisation mécaniste de la tuberculose bovine. L’analyse d’une série de données longue, grâce à un modèle spatio-Temporel hiérarchique Bayésien, nous a permis de mettre en évidence, en plus de l’effet de schéma de prophylaxie, l’impact des structures et pratiques d’élevage sur le taux d’incidence de la maladie au niveau départemental. Quatre facteurs de risque ont ainsi pu être identifiés : l’augmentation de la taille et de la densité des élevages, la proportion plus importante de vaches laitières, et la part de la surface agricole utile occupée par les pâtures. Ces variables sont liées à la professionnalisation et à la spécialisation des élevages bovins en France.La modélisation mécaniste, fondée sur un modèle stochastique compartimental, nous a montré que les pratiques d’élevage ont un effet sur la dynamique de transmission intra-Élevage de la tuberculose bovine : la médiane estimée de paramètre de transmission de l’infection durant la période de stabulation était 5 fois plus élevée que durant la période de pâturage. De plus, ce modèle a permis de montrer que les changements des structures et pratiques d’élevage avaient un poids important sur le risque de transmission entre élevages, au pâturage, par rapport aux changements de schémas de prophylaxie. Une expérimentation ex-Ante fondée sur le modèle a montré qu’environ un quart des variations du risque de transmission inter-Élevages au pâturage étaient expliquées par les changements des pratiques d’élevage contre un dixième par les changements de schémas de prophylaxie. Ce résultat suggère que l’éradication de la maladie en France est sans doute plus complexe qu’il n’y paraît. / In France, the collective control of bovine tuberculosis (bTB) from 1965 allowed France to obtain in 2000 the bTB-Free status. In parallel to this evolution, several control programs have been applied and cattle population has changed in its demographic structure and herd management practices. The main objective of this thesis was to study the relationship between these three parallel evolutions. Two different approaches were used: data analysis of bTB incidence between 1965 and 2000 in French departments, and modeling of within-Herd bTB transmission.Data analysis using a spatio-Temporal hierarchical Bayesian model has allowed us demonstrating, in addition to the effect of control program, the impact of the evolution of herd structures and management practices on the incidence rate of the disease at the departmental level. Four factors were associated with an increased risk of bTB: the average herd density and size, the percentage of dairy cows in the cattle population, and the percentage of permanent grassland in cultivated surfaces area. These four factors are linked to the progressive professionalization and specialization of cattle farming in France.The mechanistic modeling work, based on a stochastic compartmental model, showed that herd husbandry practices management have an effect on the dynamics of within-Herd transmission of bTB: when animals are inside buildings, the estimated median of the infection transmission parameter was 5 times higher than during the grazing period. In addition, this model has shown that, compared to the impact of changes in control program, changes in herd structures and management practices had a significant weight on the risk of transmission between farms, on pastures. An ex-Ante experimentation based on the model showed that about a quarter of the variations in the risk of transmission between herds on pasture was explained by changes in husbandry practices management against 10% explained by changes in control programs. This result suggests that eradication of the disease in France is probably more complex than it seems.
28

Epidemiology of bovine tuberculosis and influence of liver fluke co-infection in Cameroon, Central Africa

Kelly, Robert Francis January 2017 (has links)
Despite Africa accounting for ~20% of the global cattle population, prevalence estimates and related risk factors of bovine tuberculosis (bTB), caused by Mycobacterium bovis, are still poorly quantified in many countries across the continent. Control of bTB in Africa is difficult due to poor monitoring of cattle movements and limited abattoir surveillance. Also M. bovis is zoonotic and risk factors for transmission include living in close contact with cattle and consumption of unpasteurised milk. Cattle keeping is integral to some rural populations in Cameroon and understanding the epidemiology of bTB in cattle populations is important both to bovine and public health. Detection of bTB in cattle is difficult due to variability of immune responses to M. bovis infection. The interferon-γ (IFN-γ) assay maybe useful to estimate bTB prevalence and identify bTB risk factors in Cameroon. However its performance can vary at different stages of bTB pathogenesis and in different cattle populations. Recently Fasciola hepatica co-infections have been reported to suppress IFN-γ responses in M. bovis infected cattle but the potential effect with F. gigantica co-infections on bTB prevalence estimates in Cameroon is unknown. An abattoir study was conducted in Cameroon to assess the performance of the IFN-γ assay. In 2012-13; 2064 slaughtered cattle were sampled from Bamenda abattoir (North West Region; NWR) and Ngaoundere abattoir (Vina Division; VD). Individual animal data was collected from routine meat inspection including identification of bTB and Fasciola pathology. Cattle were also tested for bTB using the IFN-γ assay and an M. bovis antibody ELISA. In the absence of a gold-standard diagnostic, the IFN-γ assay was compared to other diagnostic tests to assess agreement and identify factors that affected performance of the assay. Agreement between IFN-γ assay, TB lesion identification and an M. bovis antibody ELISA was poor-moderate, probably partly related to differences in immune response detected. A presence of Fasciola gigantica also increased the odds of false negative IFN-γ assay results. On further investigation co-infected cattle had increased odds of TB lesions and reduced IFN-γ responses that potentially could lead to ~20% reduction in test sensitivity. In an attempt to take into account the potential impact of F. gigantica, when estimating bTB prevalence, an antibody ELISA was developed to detect the exposure in live cattle. To highlight the awareness of disease in cattle-rearing communities, estimate prevalence and identify risk factors of bTB in cattle populations; two cross-sectional studies were conducted in 2013. A stratified clustered cross-sectional study of pastoral cattle herds, in the NWR and the VD, sampled 1448 pastoral cattle reared by 100 pastoralists. A smaller cross-sectional study sampled 60 dairy cattle from 46 small-holder co-operative dairy farmers. Individual animal data and herd-level data were collected and animals were screened by both the single comparative intradermal skin test (SCITT) and IFN-γ assay. Awareness of zoonotic TB was low yet consumption of raw milk was high in cattle-keeping communities highlighting the need for accurate bTB prevalence estimates. Despite the high awareness of the clinical presentation of bTB, clinical signs identified by pastoral herdsmen were not associated with cattle being bTB positive. The SCITT was used to compare two manufacturers cut offs for the IFN-γ assay, ≥0.05 and ≥0.1, and highlighted that these two diagnostics may detect different populations of bTB positive cattle. Using the IFN-γ assay at ≥0.1, bTB prevalence was highest in dairy cattle (21.67%) and was also present in pastoral cattle in the NWR and VD (11.33% and 6.55% respectively). Importantly, as F. gigantica is endemic in Cameroon and its influence could mean the true prevalence of bTB could be higher. Female pastoral cattle were at lower odds of being IFN-γ assay positive potentially due to immunosuppressive factors had lower odds of disease. Husbandry practices also decreased the odds of being IFN-γ assay positive such as drinking from streams, antelope and contact with herds at grazing. Age increased the odds of pastoral cattle being IFN- assay positive potentially being a confounder to chronicity of bTB and other co-infections may influence IFN-γ responses. Dairy cattle herds had different risk factors for being IFN- positive likely due to differences in husbandry practices. Considering the potential risk to public health of M. bovis this thesis highlights the extent of bTB across two major cattle keeping regions in Cameroon and the public health risk in cattle-rearing communities. Furthermore the relationship between Fasciola co-infection and IFN- responses to M. bovis described has potential implications for bTB diagnosis in cattle populations where the parasite is present across the globe.
29

Etude des souches de Mycobacterium bovis à l'origine de foyers de tuberculose bovine en France de 1978 à aujourd'hui : une approche moléculaire et génomique / Study of Mycobacterium bovis strains responsible of French outbreaks between 1978 and today : molecular and genomic approach

Hauer, Amandine 18 March 2015 (has links)
Mycobacterium bovis, agent étiologique de la tuberculose bovine (bTB), affecte principalement les bovins mais évolue également dans des systèmes multi-hôtes. La France possède le statut UE indemne de bTB depuis 2000, mais la prévalence de la maladie a augmenté régulièrement ces cinq dernières années. Son contrôle passe par la connaissance des nouveaux facteurs de risque. Pour les déceler, nous avons étudié l’évolution spatio-temporelle de la bTB via la caractérisation des souches isolées de foyers français depuis 1978. A partir de plus de 2.000 souches, environ 600 profils génétiques ont été définis par spoligotypage et typage MLVA. Les groupes majoritairement identifiés, SB0120, SB0134, SB0121 et la «famille F4», sont différenciés plus finement par le MLVA qui augmente la puissance des études d’épidémiologie moléculaire. La diminution de la variabilité génétique et des changements de la distribution géographique des souches s’explique par des modifications dans les pratiques d’élevages et par la prolifération de certains génotypes évoluant dans des systèmes multi-hôtes. L’identification des groupes clonaux existants en France est confirmée par l’étude de mutations SNP effectuée suite au séquençage total de 82 génomes sélectionnés. De nouveaux outils de typage visant à affiner l’identification des souches, définir des profils de transmission méconnus et établir des liens épidémiologiques entre animaux sauvages et de rente sont envisagés. / Myobacterium bovis is the causative agent of bovine tuberculosis (bTB), principally affecting cattle but also evolving in multi-host livestock-wildlife systems. Prevalence is regularly increasing in France, an EU bTB-free state since 2000’s, after a 50 year collective fighting-campaign. To control the disease, it is necessary to acknowledge new risk factors. For identifying them, we have studied the spatial-temporary evolution of the disease by characterizing M. bovis strains causative of French outbreaks since 1978. Within more than 2,000 strains, around 600 profiles could be defined by spoligotyping and MLVA. SB0120, SB0134, SB0121 and the « F4 family » are the major spoligotypes isolated. In these groups, the refinement of differentiation can be increased by MLVA typing for powerful molecular epidemiological studies. Decreases in genetically and geographical variability could be explained by changes in husbandry practices and by the proliferation of unique genotypes in multi-host systems. Identification of clonal groups coexisting in France is confirmed by the study of SNPs mutations deduced from the whole genome sequencing of 82 representative strains. New typing tools for refining strains identification and disclosing unknown transmission patterns between livestock and wildlife are foreseeable
30

Enfoque epidemiológico em dados de tuberculose e brucelose visando a implantação de um sistema informatizado de monitoramento e vigilância

Todeschini, Bernardo January 2010 (has links)
A vigilância epidemiológica é descrita como o conjunto de procedimentos de coleta, processamento e análise de dados utilizado para dar suporte aos processos de tomadas de decisão por parte dos agentes de saúde animal e humana. A crescente atuação de profissionais do setor privado em sanidade animal tem ampliado a vigilância epidemiológica passiva, com geração de montantes significativos de dados. Neste contexto, surge o Programa Nacional de Controle e Erradicação da Brucelose e Tuberculose Animal - PNCEBT que promove, entre suas estratégias, a habilitação de médicos veterinários privados - MVH - para realização de testes diagnóstico dessas enfermidades em bovídeos. Nesta pesquisa, foi realizada uma compilação de todos os dados gerados pelos MVH relacionados ao PNCEBT no ano de 2008 no Rio Grande do Sul, os quais foram posteriormente analisados com distintas técnicas estatísticas, com objetivo de caracterizar o perfil de ocorrência demográfica e espacial destes testes, bem como buscar indicativos de frequência de enfermidades. Foram analisados resultados de 63.226 testes de bovinos e bubalinos realizados em 5.012 estabelecimentos e 332 municípios do estado, devidamente tratados por procedimentos de imputação múltipla e de detecção de valores extremos. Foi possível verificar que os animais de aptidão leiteira representam a maioria dos animais testados, e que motivação econômica, como bonificações, é o principal estímulo para realização dos testes. Os animais de aptidão leiteira apresentaram, ainda, maior frequência em casos positivos para ambas as enfermidades, quando comparados com as demais aptidões. Os animais do sexo feminino apresentaram maior frequência em ambas as enfermidades, com relação aos machos. Foi verificada maior frequência de animais positivos para tuberculose com o avanço da idade, ao passo que a brucelose se revelou mais freqüente em animais entre 48 e 60 meses. A análise espacial demonstra variações entre regiões nos percentuais de animais testados e de positivos em ambas as enfermidades. As maiores frequências de estabelecimentos positivos para tuberculose ocorreram nas mesorregiões metropolitana e centro-oriental do estado, as quais apresentam altas densidades de estabelecimentos por km². Foi constatado ainda que a distância percorrida pelo MVH para realização de testes pode ser fator limitante na ocorrência dos mesmos, sendo que 49,5% dos testes foram realizados em uma distância máxima de 50 km, considerando-se a ida e o retorno. Foi verificado que municípios onde foram realizados testes têm 67,5 vezes mais chance de ter um MVH residente. Foi possível concluir, assim, que o adequado enfoque aos dados de vigilância permite a realização de inferências relevantes, sendo factível a estruturação de sistemas de monitoramento e vigilância - MOSS. Tais sistemas podem incrementar a qualidade e acessibilidade dos dados, permitindo aos gestores públicos e privados a realização de análises customizadas que tragam maior eficiência e eficácia às ações em saúde animal. / Epidemiological surveillance is described as a set of procedures of collecting, processing and data analysis used for supporting the decision making process of animal and human health managers. The growing participation of private sector professionals on animal health issues has been widening the passive epidemiological surveillance, generating significant amounts of data. In this context, the National Program of Animal Brucellosis and Tuberculosis Control and Eradication – PNCEBT, promotes, amongst other strategies, the accreditation of private veterinarians to make diagnosis tests on bovine, increased significantly the amount of data on bovine tuberculosis and brucellosis. In the present research, a compilation of all data from diagnosis tests performed by accredited private veterinarians on behalf of PNCEBT in the state of Rio Grande do Sul in 2008 was made, which was analyzed through distinct statistics techniques, aiming at characterizing the demography and spatial patterns of occurrence, as well as to assess the frequencies of those diseases. Data from 63.226 individual tests performed in 5.012 farms on 332 municipalities were analyzed, after treatment by multiple imputation and outlier values diagnosis. It was possible to conclude that the majority of tests were from dairy related animals; economical reasons, such as bonus programs, were the main motivation for the farmers to perform tests on their properties. Higher frequencies for both diseases were found in dairy cattle, when compared to other purposes animals. Female presented higher frequencies for both diseases when compared to males. It was also observed that the frequency of tuberculosis increased with age, while for brucellosis the frequency was higher between 48 to 60 months-old animals. Spatial analysis evidenced higher frequencies of positive tuberculosis farms in the metropolitana and centro-oriental mesorregions, which had higher farm density per km². It was also verified that the distance by MVH to perform tests might be a limiting factor for them to occur, being 49.5% of the tests performed at maximum round-way distance of 50 km. The municipalities which had tests performed showed 67.5 times more chances of having a resident MVH. It was possible to conclude that an appropriate approach of surveillance data allows the making of relevant inferences, being feasible the establishment of monitoring and surveillance systems - MOSS. These systems could improve data quality and accessibility, allowing public and private managers to perform custom analysis to bring more efficiency and efficacy to animal health programs.

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