The classical SIR and SIS epidemiological models are extended by considering the number of adequate contacts per infective in unit time as a function of the total population in such a way that this number grows less rapidly as the total population increases. A diffusion term is added to the SIS model and this leads to a reaction–diffusion equation, which governs the spatial spread of the disease. With the parameter R0 representing the basic reproduction number, it is shown that R0 = 1 is a forward bifurcation for the SIR and SIS models, with the disease–free equilibrium being globally asymptotic stable when R0 is less than 1. In the case when R0 is greater than 1, for both models, the endemic equilibrium is locally asymptotically stable and traveling wave solutions are found for the SIS diffusion model. Nonstandard finite difference (NSFD) schemes that replicate the dynamics of the continuous SIR and SIS models are presented. In particular, for the SIS model, a nonstandard version of the Runge-Kutta method having high order of convergence is investigated. Numerical experiments that support the theory are provided. On the other hand the SIS model is extended to a Volterra integral equation, for which the existence of multiple endemic equilibria is proved. This fact is confirmed by numerical simulations. / Dissertation (MSc)--University of Pretoria, 2012. / Mathematics and Applied Mathematics / unrestricted

Part I of this thesis deals with general methodology and the experimental work can be clearly divided into two sections. Part II deals with studies carried out chiefly to determine further the epidemiological factors influencing serum lipid (and in particular, serum triglyceride) levels in the population groups of Southern Africa. The original objectives are described on page 70 and the main conclusions summarised on page 114. Part III describes three studies which were conducted in an attempt to fill some of the gaps in the considerable literature on the relationship between dietary carbohydrate and serum lipids in man. Both in the review of the literature at the beginning of this section and in the interpretation of the results of each of the studies, discussion has been chiefly limited to experiments conducted in man. There is a great deal of information available on studies carried out in experimental animals which show marked species differences from man with regards kinetic behaviour of serum and liver triglycerides(l). Where relevant, of course, reference has been made to these studies. The significance of each of the three studies has been discussed separately, but the principal objectives are mentioned on page 138 and the general conclusions are summarised on page 205.

A study was conducted in Rich County, Utah to determine the extent of avian tuberculosis in livestock, poultry and wild birds. Sensitivity was elicited in cattle, swine and chickens by tuberculin testing. The Mycobacterium avium organism was obtained from tissues and specimens of cattle, swine, goats, chickens, magpies and sparrows. Methods of eradication of avian tuberculosis and the relationship of avian tuberculosis to mammalian tuberculosis are discussed.

This dissertation investigates the emergence and development of cause-of-death registration in nineteenth-century Massachusetts. I examine the historical, demographic, sociopolitical, and theoretical conditions that gave rise to the first state-implemented cause-of-death registration system in the United States, Massachusetts's vital registration system. Developments in almost every arena of social life during the nineteenth century were shaped in some fashion through disease. The disease ecology changed dramatically during this period shifting from acute infectious to chronic degenerative diseases, which marked the beginning of the epidemiological transition. Registration systems were key components in this transitional period, providing the raw data on which nineteenth-century public health policy emerged. The greatest challenge that public-health reformers faced in implementing and regulating cause-of-death registration was standardizing the language and practice of disease and cause-of-death reporting. I look closely at issues of implementation and regulation and examine the relative impact that standardized nomenclature and reporting practices had on cause-of-death registration in Massachusetts from 1850 through 1912. Efforts to standardize disease and cause-of-death terminology in the United States and internationally did not, however, successfully emerge until the late nineteenth century. While many disease terms were in common, their diagnostic applications were not. I argue that certain constitutive and regulative features of death registration did not match up with the institutional mandate of Massachusetts's vital registration system until forty years after its implementation. The institution-building process required the alignment of these features as normative practices, culminating in the organized efforts of European and American medical professionals to instruct physicians in proper nomenclature through explicit references and sanctions in the 1900 International Classification of Diseases. The pragmatic conditions out of which both Massachusetts' cause-of-death registration system and the International Classification of Diseases emerged did not consist of special circumstances or unique cultural practices. The social meanings of mortality in nineteenth-century Massachusetts reflected the public commitments of a diverse set of communities and practices that shared similar resources in working out the struggles and triumphs of communicating the language of death and disease.

Made available in DSpace on 2014-12-17T14:46:47Z (GMT). No. of bitstreams: 1 LucianaMR_DISSERT.pdf: 3077063 bytes, checksum: 33dba30f3f983ca2c3893ca88edc953a (MD5) Previous issue date: 2010-10-07 / This is an exploratory descriptive study with quantitative approach, aiming to verify the nurses' knowledge concerning the epidemiological surveillance activities at the Onofre Lopes hospital (HUOL), in Natal, Rio Grande do Norte. The study was performed with 63 nurses from the hospital and the data were collected through a questionnaire. All data were analyzed using descriptive statistics. The results were discussed and organized into four sections: nurses' knowledge on hospital epidemiological surveillance; procedures of the professional nurse through compulsory notification diseases; difficulties found by nurses to register the compulsory notification diseases and suggestions of strategies to joint epidemiological surveillance service with the care practices of nurses. The results showed that 55.55% of nurses know the main action of epidemiological surveillance, compulsory notification of diseases, and that 42.86% reported to the Hospital Epidemiology Center , while 57.14% did not allocate the information for this service. Most nurses found it difficult to perform notification for not knowing its flow; for the surveillance service does not operate 24 hours and for vagueness on diagnostic of disorders. Suggestions of strategies to improve the quality of epidemiological information are focused on training of nurses in hospital epidemiological surveillance; working in partnership with the surveillance center; diffusion of information on surveillance and conducting a daily active search. It comes to conclusion that most nurses don't notify the Surveillance Center about Compulsory Notification Diseases and it wasn't observed the incorporation of integrality values between the hospital surveillance and all nurses, since this principle guides the actions of health services based on dialogue, listening, ethical commitment, sharing of knowledge among professionals of various services and respect towards other professionals. Therefore, the integrality gap in the actions of the nurses studied, as well as in the surveillance service does not mobilize the potential of such services to changes in the sense of achievement of practices aimed at a special attention model that combines preventive and corrective actions, proposed and desired by SUS. Through the difficulties presented, it becomes important to recommend educational processes with strategy to transform the conducts, besides proposing actions under the principle of integrality provide responses agile and effective, as the purpose of VE hospital emergency care by the current epidemic / Trata-se de um estudo descritivo explorat?rio com abordagem quantitativa, com objetivo de verificar o conhecimento dos enfermeiros sobre as a??es de vigil?ncia epidemiol?gica no Hospital Universit?rio Onofre Lopes (HUOL), no Munic?pio de Natal, Estado do Rio Grande do Norte. O estudo foi desenvolvido com 63 enfermeiros do referido hospital e os dados foram coletados atrav?s de um question?rio. Todos os dados foram analisados atrav?s de estat?stica descritiva. Os resultados foram organizados e discutidos em quatro se??es: conhecimento dos enfermeiros sobre vigil?ncia epidemiol?gica hospitalar; procedimentos do profissional enfermeiro mediante as doen?as de notifica??o compuls?ria; dificuldades dos enfermeiros para registrar as doen?as de notifica??o compuls?ria e as sugest?es de estrat?gias para articular o servi?o de vigil?ncia epidemiol?gica com as pr?ticas assistenciais dos enfermeiros. Os resultados mostraram que 55,55% dos enfermeiros conhecem a principal a??o de vigil?ncia epidemiol?gica, a notifica??o compuls?ria de doen?a, e que 42,86% notificaram ao N?cleo Hospitalar de Epidemiologia, enquanto 57,14% n?o destinaram as informa??es para esse servi?o. A maior parte dos enfermeiros revelou dificuldades para realizar notifica??o por desconhecerem o fluxo de notifica??o; pelo servi?o de vigil?ncia n?o funcionar 24 horas e por indefini??o diagn?stica das doen?as. As sugest?es de estrat?gias para melhorar a qualidade da informa??o epidemiol?gica est?o voltadas para capacita??o do enfermeiro em vigil?ncia epidemiol?gica hospitalar; trabalho em parceria com o n?cleo de vigil?ncia; divulga??o das informa??es sobre vigil?ncia e realiza??o de busca ativa di?ria. Conclu?-se que a maioria dos enfermeiros n?o notifica ao N?cleo de Vigil?ncia as Doen?as de Notifica??o Compuls?ria e n?o se percebe a incorpora??o dos valores da integralidade entre a VE hospitalar com todos os enfermeiros, posto que este princ?pio norteia a??es dos servi?os de sa?de fundamentadas no di?logo, na escuta, no comprometimento ?tico, compartilhamento de saberes entre os profissionais dos diversos servi?os e respeito quanto ao trabalho dos outros profissionais. Assim, a lacuna da integralidade nas a??es dos enfermeiros estudados, bem como no servi?o de VE n?o mobiliza o potencial desses servi?os para mudan?as, no sentido de realiza??o de pr?ticas voltadas para um modelo de aten??o integral que articula a??es preventivas e curativas, proposto e desejado pelo SUS. Mediante as dificuldades apresentadas torna-se importante recomendar processos educativos com estrat?gia de transforma??o das pr?ticas, al?m de proposta de a??es ? luz do princ?pio da integralidade possibilitando respostas ?geis e efetivas, conforme prop?sito da VE hospitalar mediante as urg?ncias e emerg?ncias epidemiol?gicas atuais

Master of Science / Department of Biology / Samantha Wisely / As human populations increase world-wide, land use and land cover are altered to support the rapid anthropogenic expansion. These landscape alterations influence patterns of zoonotic infectious disease emergence and propagation. It is therefore becoming increasingly important to study emerging and re-emerging diseases to predict and manage for future epidemics. Studies of directly-transmitted infectious diseases should consider three components of disease epidemiology: characteristics of the pathogen, ecology of the host, and habitat configuration of the underlying landscape. I studied the influence of both the host ecology of the striped skunk (Mephitis mephitis) and the alteration of the underlying landscape on the epidemiology of rabies virus in the Flint Hills of Kansas. This tall-grass prairie is experiencing woody expansion due to anthropogenic disturbance, altering the landscape on which the rabies virus emerges and spreads. We first studied the behavioral and social ecology of the striped skunk using field and genetic methods. We concluded that 1) striped skunks reached high population densities in anthropogenically disturbed habitats, 2) these individuals were not closely related, and 3) contact rates could be influenced by temperature. Using habitat-specific skunk densities from this initial study, we created spatially-explicit contact networks of skunk populations across the Upper Kansas River Watershed and simulated the emergence and spread of rabies through the system. This modeling approach revealed a threshold of forest habitat beyond which striped skunks became increasingly connected and the rabies virus reached greater extents across the landscape. Based on these findings we recommend fire regimes and land cover alterations to reduce woody encroachment across the Flint Hills and to avoid future disease epidemics in the region.

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La surveillance syndromique est un concept récent en épidémiologie. Fondée sur le suivi automatisé d’indicateurs de santé non spécifiques, cette nouvelle approche offre des perspectives intéressantes pour la détection de phénomènes pathologiques émergents. Nous nous sommes basés sur les données actuellement collectées en France sur la mortalité bovine pour évaluer la faisabilité et la pertinence d’un système de surveillance syndromique basé sur cet indicateur. Nous avons d’abord modélisé le niveau de référence de la mortalité bovine en France puis proposé des méthodes pour identifier et quantifier d’éventuels excès de mortalité. Nous avons d’abord analysé des données réelles pour estimer rétrospectivement les conséquences sur la mortalité de l’épizootie de fièvre catarrhale ovine qui a touché le cheptel bovin français en 2007 et 2008. Nous avons ensuite proposé une méthode visant à identifier des regroupements d’unités spatiales présentant des augmentations inhabituelles de mortalité, et évalué ses performances pour détecter des foyers d’une maladie infectieuse dont nous avons simulé la propagation dans le cheptel bovin. Sur la base de ces travaux, nous discutons finalement de l’intérêt pour la protection de la santé animale d’un système de surveillance non spécifique basé sur la mortalité, et émettons des propositions pour la mise en place opérationnelle d’un tel système. / Syndromic surveillance is a recent concept in epidemiology. Based on automated monitoringof non-specific health indicators, this new approach offers interesting prospects for the detection of various health events. We analyzed data on cattle mortality routinely collected inFrance to assess the feasibility and relevance of a syndromic surveillance system based on this indicator. We modeled the baseline of cattle mortality in France and proposed methods to identify and quantify excess mortality. First we analyzed real data to retrospectively estimate the effects on mortality of the bluetongue outbreak which affected the French cattle in 2007 and 2008. We then proposed a method to detect unusual increases mortality, and evaluated its performance for the detection of outbreaks of an infectious disease of which we simulated the spread in the cattle population. We finally discuss the interest of a surveillance system based on non-specific mortality for the protection of animal health, and make proposals for the operational implementation of such a system.

Introdução: as infecções de sítio cirúrgico (ISC) estão entre as infecções relacionadas à assistência à saúde (IRAS) de maior frequência. Autoridades governamentais devem estabelecer prioridades para a vigilância epidemiológica, reconhecida como um importante instrumento para a redução das taxas de ISC. Vários países em desenvolvimento não possuem condições de conduzir um Sistema de Vigilância das Infecções de Sítio Cirúrgico (SVISC) que inclua todos os tipos de cirurgia; portanto, critérios devem ser utilizados para selecionar os indicadores mais adequados a serem monitorados. Desde 2004, o SVISC do estado de São Paulo tem focado somente as taxas de ISC dos procedimentos classificados como limpos; entretanto, em 2011 reconheceu a necessidade de implementar alterações no sistema vigente até então. Objetivos: o principal objetivo deste estudo foi selecionar e implementar indicadores para o novo SVISC do estado de São Paulo. Métodos: o estudo foi conduzido de agosto de 2011 a julho de 2013; uma combinação de três métodos foi utilizada sequencialmente: 1) Estudo metodológico de revisão da literatura e consulta a especialistas objetivando identificar os critérios mais adequados para a seleção dos indicadores a serem monitorados em âmbito governamental; 2) Elaboração de ferramenta documental para apoiar a implementação do novo sistema de VE das ISC; 3) Estudo epidemiológico descritivo dos resultados dos indicadores de ISC após a implementação do sistema. As instituições de saúde notificantes do novo sistema (n=555) representaram 82,7% de todas as instituições consideradas com potencial para notificação. Resultados: os principais critérios identificados para a seleção dos indicadores de ISC foram a) magnitude da realização do procedimento cirúrgico pelo Sistema Único de Saúde brasileiro; b) severidade do dano em caso de ISC; c) potencial impacto de estratégias de prevenção; d) recomendação por norma federal; e) potencial para futuro benchmarking com pelo menos três outros SVISC. A seguir são apresentados os procedimentos cirúrgicos selecionados para a vigilância no novo sistema e suas respectivas taxas de ISC para o percentil 75 e número de procedimentos cirúrgicos notificados referentes ao ano de 2012: parto cesariano: 0,79% (n=304.198), revascularização do miocárdio: 9,0% (n=12.000); artroplastia do joelho: 2,2% (n=10.225), artroplastia do quadril: 3,9% (n=9.984), craniotomia: 6,8% (n=8.514), mastectomia: 0,0% (n=9.515) e os seguintes procedimentos realizados por laparoscopia: colecistectomia: 0,0% (n=54.960), herniorrafia: 0,0% (n=21.627), histerectomia: 0,0% (n=9.071), apendicectomia: 0,0% (n=8.122) e colectomia 0,0% (n=1.963). Conclusões: o desenvolvimento de critérios suporta a seleção racional de indicadores de ISC para o monitoramento no âmbito governamental. Apesar da adesão satisfatória das instituições, os dados obtidos sugerem que algumas taxas podem ser subnotificadas. Esforços devem focar a melhoria da qualidade dos dados / Introduction: the surgical site infections (SSI) are among the most frequently healthcare associated infection (HAI). Governmental authorities should establish priorities for the epidemiologic surveillance which is recognized as an important strategy to reduce the SSI rates. Many developing countries cannot afford to manage Surgical Site Infection Surveillance System (SSISS) that includes all types of surgeries; therefore a criterion should be used to select the most appropriate indicators to be monitored. Since 2004, the SSISS in São Paulo have been focused on only crude rates of SSI in clean surgeries; however, in 2011 it was recognized that was necessary to implement changes in the ongoing system. Objective: the present study aimed to select and to implement indicators for the new SSISS in the São Paulo State. Methods: this study was carried out from August 2011 to July 2013; three methods were used sequentially 1) Methodological study carried out by means of literature review and consulting to HAI experts aiming to identify the best criteria for selection of SSI indicators to be monitored at the governmental level; 2) Development of a written tool to support the implementation of the new SSISS; 3) Epidemiological descriptive study on SSI indicators results after implementation. The participating healthcare institutions (n=555) represented 82.7% of total acute care hospitals in the State which were considered to be potential participants. Results: the main criteria identified to select the SSI indicators were: a) magnitude of the surgery in the Brazilian Universal Health System; b) severity of harm in case of SSI; c) potential impact of prevention strategies; d) recommendation by federal normative; d) potential for benchmarking against at least other three SSISS worldwide. The surgical procedures selected, the SSI rates identified (3rd quartiles) and the number of surgeries monitored in 2012 were respectively: cesarean section: 0.79% (n=304,198); coronary artery bypass graft: 9.0% (n=12,000); knee arthroplasty: 2.2% (n=10,225), hip arthroplasty: 3.9% (n=9,984), craniotomy: 6.8% (n=8,514), mastectomy: 0.0% (n=9,515) and the following laparoscopic procedures: cholecystectomy: 0.0% (n=54,960), herniorrhaphy: 0.0% (n=21,627), histerectomy: 0.0% (n=9,071), apendicectomy: 0.0% (n=8,122) and colectomia 0.0% (n=1,963). Conclusion: The development of criteria supported the rational selection of indicators for governmental monitoring of SSI. Despite good adherence to the project, data suggest that SSI may be underestimated. Efforts should be focused on the improvement of data quality for SSISS

O impacto que a epidemia da aids vem produzindo sobre a população infantil é particularmente importante, pois, do total de casos notificados no mundo todo, entre adultos e crianças, aproximadamente 10% têm menos de 15 anos de idade, sendo a maioria proveniente dos países em desenvolvimento. A aids confirma a associação, historicamente determinada, entre as condições concretas de vida e a produção da doença. Tomando a expressão da epidemia como objeto do estudo, teve por finalidade oferecer subsídios para a intervenção em saúde coletiva no fenômeno da aids infantil, de transmissão vertical, especialmente, para o aprimoramento do Sistema de Informação em Vigilância Epidemiológica da aids. Adotou-se a como refererencial teórico-filosófico a determinação social do processo saúde-doença e as categorias analíticas exclusão/inclusão social e processo de adoecimento e morte por aids. A fonte empírica de dados foi obtida do Sistema de Informação de Vigilância Epidemiológica da Secretaria de Estado da Saúde do Estado de São Paulo e do Programa de Aprimoramento das Informações de Mortalidade da Prefeitura Municipal de São Paulo. A análise dos dados demonstra a gravidade da situação: as crianças já nascem duplamente em desvantagem, têm suas mães e/ou pais acometidos pela doença e encontram pela frente um penoso processo de aprendizagem com a própria soropositividade. Evidenciaram-se situações que denotam exclusão social, na constatação do número de crianças órfãs de mães, na ocorrência de crianças institucionalizadas, na vulnerabilidade programática e no uso de drogas injetáveis pelas mães. No entanto, não ficou explícita a exclusão social como produto das formas diferenciadas de reprodução social dos grupos sociais. Apontou-se a necessidade de transformar a forma de captação da realidade pela vigilância epidemiológica, para superar os modelos multicausais que tornam invisíveis as dimensões sociais da doença. A ausência de visibilidade pública da exclusão social, especialmente no caso das crianças vulneráveis ao HIV/aids, está diretamente vinculada à sua ausência de autonomia, ou seja, à incapacidade do Sistema de Informação em Vigilância Epidemiológica em considerar a criança como sujeito com pleno direito de cidadania. Reconhece-se a necessária e urgente revisão da ficha de notificação, importante instrumento que informa sobre a epidemia, de modo a ser possível a caracterização da exclusão social das pessoas afetadas pelo HIV/aids no caso de crianças. Ao final apontam-se recomendações para a intervenção em saúde coletiva na Cidade de São Paulo frente à epidemia de aids infantil. / The impact that aids epidemic has been producing on the infantile population is particularly important, out of the total number of notified cases in the whole world, among adults and children, approximately 10% is composed of individuals who are younger than 15 years old and the majority comes from countries in development. Aids cases confirm the association, historically determined, between the concrete conditions of living and the disease production. Taking the expression of epidemic as the object of study, our study had as its objective to offer subsidy for the intervention of collective health at infantile aids phenomena, of vertical transmission, especially, to the improvement of Information System in Aids Epidemiological Surveillance. The social determination and the analytical categories social inclusion/exclusion and the process of becoming sick and dying due to aids were adopted as a theoretical-philosophic reference. Data is from the Sistema de Informação of the Vigilância Epidemiológica da Secretaria de Estado da Saúde do Estado de São Paulo (Health State Department of Epidemiological Surveillance Information System from the State of São Paulo) and from the Programa de Aprimoramento das Informações de Mortalidade da Prefeitura Municipal de São Paulo (Mortality Information Improvement Program from the Municipality of the City of São Paulo). The data analysis shows the seriousness of the situation: many children are born with double disadvantage, their fathers or mothers already have the disease and they will face a painful learning process with their own HIV positive status. We found some evident situations in which we could notice social exclusion, verifying the number of children without mothers, in institucionalized children, at programmatic vulnerability and the usage of injectable drugs by mothers. However, social exclusion was not explicit as a product of the different ways of social reproduction from the social groups. A need to transform the methodology of data recording by the epidemiological vigilance, to surpass the multicause models that make the social dimensions of the disease invisible. The lack of public ability to be aware and record data about social exclusion, especially in the case of children vulnerable to HIV/aids, is directly linked to the lack of autonomy, or due to the incompetence of the Epidemiological Surveillance Information System in considering the child as a person with rights to citizenship. We consider it urgent to review the notification record, important instrument that informs about the epidemic, in a way that enables health professionals to distinguish social exclusion of the affected people, mainly in case of HIV/aids positive children. At the end, proposals are made for intervention in collective health in the City of São Paulo, in order to better enable health professionals to have other resources to face infantile aids epidemic.