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The family Culicidae has great public health importance for being composed by haematophagous insects in majority, which can be vector of diseases for the human being and other vertebrates. The knowledge about culicideos fauna, besides of data about various species that compose the Caatinga biome, can also bring information about species that are vector of pathogens, providing important tools in case of eventual epidemic outbreak at the region. The Caatinga biome occupies around 55% of all northeast region, representing 11% of Brazil s surface, and holds the position of the less preserved biome of the country, relative to its total area. This work aimed to realize a mosquitoes fauna survey, as well as ecologic aspects analysis for adult species in two areas of Caatinga and immature in three semi permanent breeding grounds. The study was realized in the city of Poço Redondo, semi-arid of Sergipe, where the Unidade de Conservação Monumento Natural Grota do Angico is located under exclusive domain of Caatinga. Collects were made monthly in two areas of Caatinga, between 5 p.m. and 8 p.m. using the Shannon trap for adults, and in three breeding grounds with plastic dipper method for mosquito larvae collects. On ecologic aspects analysis were used the Shannon diversity index, Pielou s equitability, Berger-Parker dominance, Nonmetric multidimensional scaling (NMDS) for species composition. A number of 1788 specimens were collected on total among adults and immature, distributed on ten genus, Aedes, Aedomyia, Anopheles, Coquilettidia, Culex, Haemagogus, Mansonia, Ochlerotatus, Psorophora and Uranotaenia and 21 species. The adults resulted in 583 specimens, 268 from shrubby Caatinga and 315 from arboreal Caatinga, dominant species were Mansonia (Man) indubitans and Ochlerotatus (Och) scapularis,there was no difference between these areas on species composition or abundance, however, the arboreal Caatinga was richer in species. In relation to the immature, breeding sede captured the larger number of specimens (N=590), followed by breeding cancela (N=436) and the smaller value on breeding trilha (N=179). Species composition did not show difference between breedings, dominant species were Anopheles (Nys) albitarsis and Culex (Cx) chidesteri. The presence of mosquitoes species with vector importance, some of that capable to adapt on anthropic ambient, associated with lack of knowledge about Caatinga s mosquitoes suggests future studies to avoid epidemiologic outbreaks in the Unidade de conservação Monumento Natural Grota do Angico . / A família Culicidae apresenta grande importância em saúde pública por ser composta de insetos em sua maioria hematófagos, os quais podem veicular diversas doenças para o homem e demais vertebrados. O conhecimento sobre a fauna de culicídeos, além de gerar informações sobre as espécies que compõem o bioma Caatinga, permite conhecer espécies vetoras de patógenos fornecendo importantes ferramentas em caso de eventuais surtos epidêmicos na região. O bioma Caatinga ocupa cerca 55% de toda a região Nordeste, representando 11% da superfície do Brasil, e detém a posição de bioma menos conservado em relação à área total. O presente trabalho objetivou realizar levantamento da fauna de mosquitos, bem como análise de aspectos ecológicos para as espécies de adultos em duas áreas de Caatinga e espécies de imaturos em três criadouros semipermanentes de solo. O estudo foi realizado no município de Poço Redondo, situado no alto sertão sergipano, na unidade de conservação Monumento Natural Grota do Angico, sob o domínio exclusivo de Caatinga. As coletas foram realizadas mensalmente em dois ambientes de Caatinga das 17 às 20 horas através de armadilha de Shannon para adultos, e em três criadouros de solo utilizando metodologia de concha para coleta de larvas. Para análise de aspectos ecológicos foram utilizados os índices de diversidade de Shannon, equitabilidade de Pielou, dominância de Berger-Parker e escalonamento multidimensional não métrico (NMDS) para composição de espécies. No total foram coletados 1788 espécimes entre adultos e imaturos, distribuídos em dez gêneros, Aedes, Aedomyia, Anopheles, Coquilettidia, Culex, Haemagogus, Mansonia, Ochlerotatus, Psorophora e Uranotaenia e 21 espécies. Os adultos somaram 583 exemplares, sendo 268 na Caatinga arbustiva e 315 na Caatinga arbórea, as espécies dominantes foram Mansonia (Man) indubitans e Ochlerotatus (Och) scapularis, a composição de espécies e a abundância não diferiram entre as áreas, no entanto a Caatinga arbórea apresentou maior riqueza de espécies. Em relação aos imaturos, no criadouro sede foi capturado maior número de espécimes (N=590), seguido do criadouro cancela (N= 436) e os menores valores no criadouro trilha (N= 179). A composição das espécies não variou entre as áreas, as espécies dominantes para imaturos foram Anopheles (Nys) albitarsis e Culex (Cx) chidesteri. A presença de espécies com importância vetorial, dentre elas algumas com capacidade de adaptação ao ambiente antropizado, aliada ao déficit de conhecimento sobre os mosquitos da Caatinga sugerem continuidade de estudos para evitar que quadros epidemiológicos possam se instalar na unidade de conservação Monumento Natural Grota do Angico.

Introdução: Este trabalho tem por objetivo identificar focos de filariose linfática na amazônia ocidental brasileira e constatar a infecção natural pela W. bancrofti do mosquito vetor, o C. quinquefasciatus. O estudo abrangeu as cidades de Porto Velho (RO), Guajará Mirim (RO) e Humaitá (AM). Método: foi utilizada a técnica da gota espessa de sangue, colhida após 22h00, corada com Giemsa para avaliação humana, e a Reação em Cadeia da Polimerase (PCR) para pesquisa de DNA de W. bancrofti em mosquitos vetores. Foram analisadas e avaliadas amostras do sangue de moradores dos bairros mais antigos dessas cidades e escolares noturnas e captura de mosquitos. Resultados: O inquérito hemoscópico em moradores resultou em 935 indivíduos (54,4%) examinados de um total de 1.720 cadastrados. As pesquisas entre escolares noturnos envolveram 2.709 indivíduos (75,2%) de um total de 3.601. Todos negativos para a presença de microfilaremia. Foram coletadas 7.849 fêmeas de C. quinquefasciatus, todas apresentaram resultados negativos para DNA de W. bancrofti. / Introduction: This work is aimed to identify possible lymphatic filariasis foci in the Western Brazilian Amazonian. Porto Velho and Guajara-Mirim (Rondonia State) and Humaita (Amazonas State) were the study target area. Methods: Blood thick film method with samples collected from 10 PM to 1 AM were stained using Giemsa to evaluate human infection and PCR for W. bancrofti DNA in mosquitoes vectors. Samples from the neighborhoods of these areas and from students attending public nighttime classes in the cities referred to above were analyzed and evaluated, as well as mosquitoes captured in the houses. Results: 935 individuals (54.4%) out of a total of 1,720 individuals engaged. Sample with night students involving 2,709 individuals (75.2%) out of the total of 3,601 previously selected. No individual examined was positive for the presence of microfilariae in the blood stream. 7,849 female C.quinquefasciatus specimens were captured and after evaluated by using PCRmethod, all of them were found negative for W. bancrofti DNA.

No description available.

Molecular dating (or molecular clock) is a powerful technique that uses the mutation rate of biomolecules to estimate divergence times among organisms. In the last two decades, the theory behind the molecular clock has been intensively developed, and it is now possible to employ sophisticated evolutionary models on genome-scaled datasets in a Bayesian framework. The molecular clock has been successfully applied to virtually all types of organisms and molecules to estimate timing of speciation, timing of gene duplications, and generation times: this knowledge allows contextualizing past and present events in the light of (paleo)ecological scenarios. Molecular clock studies are routinely used in evolutionary and ecological studies, but their use in applied fields such as agricultural and medical entomology is still scarce in particular because of a paucity of genome data. Genome-scaled clocks have been successfully applied, for example, to various model organisms such as Anopheles and Drosophila, as well as to invasive mosquitoes Aedes aegypti and Aedes albopictus. Many other invasive pests are emerging worldwide aided by global trade, increased connectivity among countries, lack of prevention, and flawed invasive species management. Among them, there is Aedes koreicus and Aedes japonicus, two invasive mosquito species which are monitored for public health concerns because of their harboured human pathogenic viruses. For these, as well as for other insects of societal relevance, such as the parasitoid Trissolcus japonicus, there is a paucity of gene markers and no genome data for large scale molecular clock studies. Invasive pests are typically studied using microevolutionary approaches that tackle events at an intraspecific level: these approaches provide important information for the pest management, for example, by revealing invasion routes and insecticide resistances. Approaches that tackle the deep-time evolution of the pest, such as the molecular clock, are instead less used in pest science. Many important traits associated with invasiveness have evolved by speciation over a long time frame: the molecular clock can reveal the paleo-ecological conditions that favoured these traits helping a better understanding of pest biology. Molecular clock, when coupled with phylogenomics, can further identify genes and patterns that characterize the pest: this knowledge can be used to enhance management practices. Although this is a data-driven thesis, its major aim is to provide new results to demonstrate the utility of the molecular clock in pest science. This has been done by systematically apply the molecular clock to various neglected organisms of medical and agricultural relevance. To this aim, I generated new genome data and/or assembled the largest genome-scaled data to date. I studied the molecular clock in mosquitoes, focusing on the Aedini radiation (Chapter 2) and identified a strong incongruence between the mitochondrial and nuclear phylogeny for what concerns their molecular clock. This result highlighted the importance of employing genome scaled data for these species to exclude stochastic effects due to poor/inaccurate sampling in clock studies. To tackle the absence of data, I further assembled the whole mitogenome of emerging invasive species Aedes koreicus and Aedes japonicus with the aim of producing useful data for molecular typing and of inferring divergence estimates using whole mitogenomes (Chapter 3). Dated phylogenies point toward more recent diversification of Aedini and Culicini compared to estimates from previous works, addressing the issue of taxon sampling sensitivity in dated phylogeny. Although it is possible to perform molecular clock studies on single/few gene markers, the current trend is to couple this methodology with genome-scaled datasets to reduce the stochastic effect of using few genes. For this reason, I sequenced the draft genome of A. koreicus and A. japonicus (Chapter 4). The assemblies were extremely fragmented, highlighting the problem of sequencing large genomes using short reads. The assemblies provided, however enough information for genome skimming allowing extraction of BUSCO genes for downstream analyses, whole mitogenome assemblies (used in Chapter 3), and characterisation of the associated metagenome. These data need to be integrated by long reads; it provides, however a first framework to investigate the genome evolution of these species. I further sequenced and assembled the genome of Trissolcus japonicus, the parasitoid wasp of the invasive pest Halyomorpha halys. To elucidate its divergence, estimate and define an intraspecific typing system to differentiate strains for biocontrol strategies, I reconstructed the mitochondrial genomes of two populations: the mitogenomes were surprisingly identical, suggesting that they belong to the same de facto population. I further provide a detailed clock investigation of Zika, a virus harboured and transmitted by some Aedes species (Chapter 5). Using the largest set of genomes to date, I could set the origin of ZIKV in the middle age and its first diversification in the mid-19th century. From a methodological point of view, the clocking of this virus highlighted the importance of checking for recombination and for cell-passages to obtain correct divergence estimates. I finally show my contributions to molecular clock studies of three other invasive species (Chapter 6): I helped disentangle the divergence times of Bactrocera, a genus of invasive fruit files pest of agriculture; I contributed in performing a phylogenomics study of opsin genes in Diptera; I used chloroplast and nuclear genome data to reconstruct the divergences of the invasive reed Arundo. In the various Chapters of my thesis, I highlighted the limits and the problems of current molecular clock methodologies and identified the best practices for different types of organisms in order to develop a cross-discipline understanding of the molecular clock techniques. The various results presented in this thesis further demonstrate the utility of the molecular clock approach in pest studies.

No description available.

O Estado de São Paulo apresenta uma das mais altas taxas de infecções por vírus dengue no Mundo, mas apesar dessa situação, poucos são os estudos dirigidos às populações do mosquito Aedes aegypti. O objetivo deste trabalho foi caracterizar geneticamente e morfologicamente populações de Ae. aegypti localizadas em seis municípios (Santos, S.P., Campinas, São Carlos, Catanduva, S.J.R.P.) do Estado de São Paulo durante 2011 e 2012. Todos os marcadores biológicos indicaram estruturação populacional. Os oito loci microssatélites apontaram diferenciação genética moderada entre as populações (Fst= 0.04; p < 0,05) e os níveis de diversidade nucleotídica do gene COI (&pi; =0,0062) e do gene ND4 (&pi;=0,017) foram moderadamente altos. Duas linhagens geneticamente distintas foram encontradas no Estado. Ao longo dos meses que compreenderam o estudo, foram encontradas diferenças morfo-genéticas temporais entre as seis populações analisadas, possivelmente indicativas de microevolução. Os resultados obtidos podem ser úteis para compreendermos a dispersão deste mosquito vetor. / The State of São Paulo displays one of the highest rates of dengue infection in the world, but despite this fact, a few populational studies of Ae. aegypti have been undertaken. The aim of this study was to genetically and morphologically characterize Ae. aegypti populations from six locations in the São Paulo State (Santos, S.P., Campinas, São Carlos, Catanduva, S.J.R.P.) during 2011 and 2012. The phenetic and genetic analyses revealed that populations of Ae. aegypti are structured. Eight microsatellites loci were polymorphic and genetic differentiation among samples was moderate (Fst= 0.04; p < 0.05). Nucleotide diversities of COI (&pi; = 0.0062) and ND4 gene (&pi; = 0.017) were moderately high. Two lineages distinct genetically were found in the State. Over the months comprised by the study, we found the temporal genetics and morphologics differences among the six populations, a possibly indicative of microevolution of mosquitoes. The results of this study may be useful for understand the spread of this vector mosquitoes in the State of São Paulo.

[Truncated abstract] A functional ecosystem is increasingly being recognised as a requirement for health and well being of resident human populations. Clearing of native vegetation for agriculture has left 1.047 million hectares of south-west Western Australia affected by a severe form of environmental degradation, dryland salinity, characterised by secondary soil salinisation and waterlogging. This area may expand by a further 1.7-3.4 million hectares if current trends continue. Ecosystems in saline affected regions display many of the classic characteristics of Ecosystem Distress Syndrome (EDS). One outcome of EDS that has not yet been investigated in relation to dryland salinity is adverse human health implications. This thesis focuses on one such potential adverse health outcome: increased incidence of Ross River virus (RRV), the most common mosquito-borne disease in Australia. Spatial analysis of RRV notifications did not reveal a significant association with dryland salinity. To overcome inherent limitations with notification data, serological RRV antibody prevalence was also investigated, and again no significant association with dryland salinity was detected. However, the spatial scale imposed limited the sensitivity of both studies. ... This thesis represents the first attempt to prospectively investigate the influence of secondary soil salinity on mosquito-borne disease by combining entomological, environmental and epidemiological data. The evidence collected indicates that RRV disease incidence is not currently a significant population health priority in areas affected by dryland salinity despite the dominant presence of Ae. camptorhynchus. Potential limiting factors include; local climatic impact on the seasonal mosquito population dynamics; vertebrate host distribution and feeding behaviour of Ae. camptorhynchus; and the scarce and uneven human population distribution across the region. However, the potential for increased disease risk in dryland salinity affected areas to become apparent in the future cannot be discounted, particularly in light of the increasing extent predicted to develop over coming decades before any benefits of amelioration strategies are observed. Finally, it is important to note that both dryland salinity and salinity induced by irrigation are important forms of environmental degradation in arid and semi-arid worldwide, with a total population of over 400 million people. Potential health risks will of course vary widely across different regions depending on a range of factors specific to the local region and the complex interactions between them. It is therefore not possible to make broad generalisations. The need is highlighted for similar research in other regions and it is contended that an ecosystem health framework provides the necessary basis for such investigations.

La Fièvre de la Vallée du Rift (FVR) est une zoonose observée pour la première fois au Kenya en 1930 qui s'est peu à peu propagée à la plupart des pays d'Afrique. La FVR est une maladie à transmission vectorielle dont le virus appartient au genre Phlebovirus de la famille des Bunyaviridæ. En Afrique de l'Est, l'émergence de foyers est prédite par des modèles statistiques, ce qui n'est pas le cas en Afrique de l'Ouest où les facteurs et les mécanismes en jeu sont encore mal définis. L'objectif de cette thèse est d'identifier les facteurs et les processus épidémiologiques expliquant l'émergence de foyers de FVR au Sénégal, en mettant en œuvre une approche éco-épidémiologique centrée sur les principaux moustiques vecteurs du virus. Par l'étude de variables environnementales et climatiques et par leur exploitation dans des modèles mathématiques, nous avons tenté de répondre à deux questions épidémiologiques majeures : (1) quelles sont les zones potentiellement à risque, et (2) quelles sont les périodes favorables à l'apparition de foyers. L'étude a été menée à l'échelle locale, dans une zone d'environ 10 km2 autour du village de Barkedji situé dans la région sylvo-pastorale du Ferlo.Pour localiser les zones à risque de transmission du virus, nous utilisons la télédétection et l'analyse paysagère afin de caractériser l'environnement favorable aux deux principaux candidats vecteurs du virus, Aedes vexans et Culex poicilipes. Pour identifier les périodes à risque, nous avons développé un modèle d'abondance de populations de moustique des deux espèces vectrices prenant en compte la dynamique des gîtes larvaires (les mares), et dont les simulations ont été validées avec des données de terrain de capture de moustiques. Pour se faire, nous avons dû préalablement développé un modèle dynamique de hauteur d'eau des mares temporaires, modèle calibré et validé à partir de données de terrain et de données d'observation de la Terre.Les résultats de l'analyse paysagère ont confirmé que les milieux favorables aux vecteurs de la maladie pouvaient être caractérisés par télédétection. Ils ont aussi mis en évidence l'importance des mares et de la densité de végétation environnante, et ont abouti à une cartographie de l'hétérogénéité spatiale du risque de circulation de la FVR. Les résultats de l'analyse temporelle ont montré que les années de circulation active du virus coïncidaient avec les années pour lesquelles les deux espèces de moustiques étaient présentes en forte quantité. On observe ainsi deux années à très forte densité des deux moustiques vecteurs, en 1987 et en 2003, correspondant aux années d'épidémie/épizootie les plus importantes dans la région. / The Rift Valley fever (RVF) is an arboviral zoonosis, first identified in Kenya in 1930, which has spread over many African countries. The RVF virus (RVFV) is a mosquito-borne virus member of the family Bunyaviridae, genus Phlebovirus. Statistical models that are used for predicting RVF outbreaks in East Africa do not work in West Africa where the factors and processes involved are still not well described. The aim of this thesis is to identify the factors and epidemiological processes that explain the emergence of RFV outbreaks in Senegal. To achieve that, we have chosen an eco-epidemiological approach targeted on the main candidate mosquito vectors of the RFV virus. By using the environmental and climatic variables and by their exploitation in mathematical models, we tried to answer two major epidemiological questions: (1) where are the potential zones at risk? And, (2) when are the periods favourable to RFV outbreaks?The study has been carried out at a local scale, in an area of about 10 km2 centred on the village of Barkedji in the pastoral Ferlo region in northern Senegal.When identifying risk areas for virus transmission, we used remote sensing and landscape analysis to characterize favourable environments fot the two main candidate vectors, Aedes vexans and Culex poicilipes (Diptera: Culicidae). For predicting risk of RVF outbreaks, we developed a mosquito population model for the two vector species taking into account the dynamics of the ponds as breeding sites. The results of the simulation have been validated with captured mosquito field data. This required the prior development of a temporary pond dynamics model that was calibrated and validated with field and remote sensing data.The results of the landscape analysis confirmed that favourable environments for the mosquito vectors of the RVF could be characterised by remote sensing. The importance of the ponds and the surrounding vegetation density was also highlighted, allowing to map the spatial heterogeneity of RVF circulation risk. The results of the mosquito model simulations showed that years of active virus circulation matched the years when both vector species were densely present. Indeed, the simulations showed high mosquito densities in 1987 and 2003, which correspond to the most important epidemic and epizootic events in that region.

PhD (Mathematics) / Department of Mathematics and Applied Mathematics / In this study, we developed multiscale models of vector-borne diseases. In general, the transmission of vector-borne diseases can be considered as falling into two categories, i.e. direct transmission and environmental transmission. Two representative vector-borne diseases, namely; malaria which represents all directly transmitted vector-borne diseases and schistosomiasis which represents all environmentally transmitted vector-borne diseases were studied. Based on existing mathematical modelling science base, we established a new multiscale modelling framework that can be used to evaluate the effectiveness of vector-borne diseases treatment and preventive interventions. The multiscale models consisted of systems of nonlinear ordinary differential equations which were studied for the provision of solutions to the underlying problem of the disease transmission dynamics. Relying on the fact that there is still serious lack of knowledge pertaining to mathematical techniques for the representation and construction of multiscale models of vector-bone diseases, we have developed some grand ideas to placate this gap. The central idea in multiscale modelling is to divide a modelling problem such as a vector-bone disease system into a family of sub-models that exist at different scales and then attempt to study the problem at these scales while simultaneously linking the sub-models across these scales. For malaria, we formulated the multiscale models by integrating four submodels which are: (i) a sub-model for the mosquito-to-human transmission of malaria parasite, (ii) a sub-model for the human-to-mosquito transmission of malaria parasite, (iii) a within-mosquito malaria parasite population dynamics sub-model and (iv) a within-human malaria parasite population dynamics sub-model. For schistosomiasis, we integrated the two subsystems (within-host and between-host sub-models) by identifying the within-host and between-host variables and parameters associated with the environmental dynamics of the pathogen and then designed a feedback of the variables and parameters across the within-host and between-host sub-models. Using a combination of analytical and computational tools we adequately accounted for the influence of the sub-models in the different multiscale models. The multiscale models were then used to evaluate the effectiveness of the control and prevention interventions that operate at different scales of a vector-bone disease system. Although the results obtained in this study are specific to malaria and schistosomiasis, the multiscale modelling frameworks developed are robust enough to be applicable to other vector-borne diseases. / NRF