Made available in DSpace on 2014-06-11T19:26:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-24Bitstream added on 2014-06-13T19:12:53Z : No. of bitstreams: 1 patarro_tf_me_sjrp.pdf: 771112 bytes, checksum: a164331065235e873e875755e608132b (MD5) / A alta incidência da dengue no Brasil, causada pela elevada freqüência de seu vetor, o Aedes aegypti, torna importante conhecer a organização de suas populações em termos de diferenciação genética. Esse conhecimento poderá levar a métodos de monitoramento e controle mais eficientes. No presente trabalho, a técnica RAPD-PCR foi utilizada na análise de quatro populações brasileiras de A. aegypti, sendo três classificadas pela SUCEN (Superintendência do Controle de Endemias) como resistentes aos inseticidas utilizados para seu controle (São Luís- SL; São José do Rio Preto- RP; Araçatuba- AR) e uma classificada como portadora de resistência em desenvolvimento (Bauru- BA). Uma quinta população, procedente dos Estados Unidos, suscetível aos mesmos inseticidas (Rockefeller- RO) foi utilizada para comparação. A aplicação dos métodos estatísticos de Nei, (1973, 1978) produziu índices que permitem considerar o conjunto de populações analisadas, no total de primers, como portador de diferenciação genética muito alta conforme a classificação de Wright (1978). Assim indicaram os valores de Gst (0,277), que mede a diferenciação gênica; de Hs (0,129), que mede a heterozigose média e de Ht (0,181), que mede a heterozigose total. Porém, considerando-se as comparações das populações duas a duas, verifica-se que essa diferenciação foi variável, sendo que a comparação entre as populações RP e AR mostrou que estas são as populações menos diferenciadas geneticamente, enquanto as mais diferenciadas foram SL x RO e SL x BA. Os cálculos de similaridade de Nei e Li (1979) confirmaram os dados obtidos com os índices mencionados, reforçando a idéia de maior similaridade entre RP e AR, seguida de RO e BA. De modo geral, pode-se dizer que não é fácil interpretar a estrutura das populações de A. aegypti quanto às causas de sua diferenciação... / The high incidence of dengue in Brazil, caused by the high frequency of its vector, Aedes aegypti, makes the organization of their populations in terms of genetic differentiation something important to know. This knowledge could lead to more efficient methods of monitoring and control of the vector. In this study, the RAPD-PCR was used in the analysis of four Brazilian populations of A. aegypti, three of which were classified by SUCEN (Superintencia do Controle de Endemias) as resistant to the insecticides used for its control (San Luis-SL; São Jose do Rio Preto, RP; Araçatuba-AR) and one considered in resistance development (Bauru-BA). A fifth population, from the United States, susceptible to these insecticides (Rockefeller-RO) was used for comparison. The application of the statistical methods of Nei (1973, 1978) produced indices that allowed us to consider the set of populations studied, in the total of primers, as having a very high genetic differentiation, according to the classification of Wright (1978). This is indicated by the values of Gst (0.277), which measure the genetic differentiation, the values of Hs (0.129), which measures the average heterozygosity and of Ht (0.181), that measure the total heterozygosity. However, considering the pair-wise comparisons of populations, this differentiation was variable, being the populations RP and AR the less differentiated genetically, while the more differentiated were SL x RO and BA x SL. The estimation of the similarity of Nei and Li (1979) confirmed the data obtained with the indices mentioned, reinforcing the idea of greater similarity between RP and AR, followed by RO and BA. In general, it is not easy to interpret the structure of A. aegypti populations as to on the causes of their genetic differentiation, since they are under strong interference of the human activity, which includes not only the passive transport... (Complete abstract click electronic access below)

abstract: This dissertation is focused on environmental releases from U.S. wastewater infrastructure of recently introduced, mass-produced insecticides, namely neonicotinoids as well as fipronil and its major degradates (sulfone, sulfide, amide, and desulfinyl derivatives), jointly known as fiproles. Both groups of compounds recently have caught the attention of regulatory agencies worldwide due to their toxic effects on pollinators and on aquatic invertebrates at very low, part-per-trillion levels (Chapter 1). Mass balance studies conducted for 13 U.S. wastewater treatment plants (WWTPs) showed ubiquitous occurrence (3-666 ng/L) and persistence of neonicotinoids (Chapter 2). For the years 2001 through 2016, a longitudinal nationwide study was conducted on the occurrence of fiproles, via analysis of sludge as well as raw and treated wastewater samples. Sludge analysis revealed ubiquitous fiprole occurrence since 2001 (0.2-385 µg/kg dry weight) and a significant increase (2.4±0.3-fold; p<0.005) to elevated levels found both in 2006/7 and 2015/6. This study established a marked persistence of fiproles during both wastewater and sludge treatment, while also identifying non-agricultural uses as a major source of fiprole loading to wastewater (Chapter 3). Eight WWTPs were monitored in Northern California to assess pesticide inputs into San Francisco Bay from wastewater discharge. Per-capita-contaminant-loading calculations identified flea and tick control agents for use on pets as a previously underappreciated source term dominating the mass loading of insecticides to WWTPs in sewage and to the Bay in treated wastewater (Chapter 4). A nationwide assessment of fipronil emissions revealed that pet products, while representing only 22±7% of total fipronil usage (2011-2015), accounted for 86±5% of the mass loading to U.S. surface waters (Chapter 5). In summary, the root cause for considerable annual discharges into U.S. surface waters of the neonicotinoid imidacloprid (3,700-5,500 kg/y) and of fipronil related compounds (1,600-2,400 kg/y) is domestic rather than agricultural insecticide use. Reclaimed effluent from U.S. WWTPs contained insecticide levels that exceed toxicity benchmarks for sensitive aquatic invertebrates in 83% of cases for imidacloprid and in 67% of cases for fipronil. Recommendations are provided on how to limit toxic inputs in the future. / Dissertation/Thesis / Doctoral Dissertation Civil, Environmental and Sustainable Engineering 2017

Orientador: Antonio Luiz Caldas Júnior / Resumo: A estratégia de prevenção de dengue tem se baseado no controle do vetor, com ênfase ao uso de inseticidas. Este tipo de controle, quando utilizado por longos períodos, pode ter sua eficácia comprometida devido ao surgimento de resistência dos vetores aos inseticidas utilizados. A Organização Mundial de Saúde, reconhecendo o impacto deste problema no sucesso dos programas de controle, sugeriu uma padronização de bioensaios para o monitoramento periódico das populações expostas a inseticidas. Quando se propõe avaliar o nível de suscetibilidade de uma linhagem é importante que se considere a quais inseticidas ela foi exposta, uma vez que o tipo de tratamento a que estão submetidas caracteriza a pressão de seleção de linhagens resistentes. Como no Programa de Controle de Dengue do Estado de São Paulo a opção por inseticidas diferiu do programa nacional, neste estudo procurou-se avaliar o nível de suscetibilidade de algumas linhagens de Aedes aegypti do Estado de São Paulo de forma comparativa com linhagens do Nordeste, e avaliar a relação entre a exposição aos diferentes produtos e a presença de resistência. Os resultados dos bioensaios indicaram haver um nível maior de resistência ao grupo dos organofosforados nas linhagens do Nordeste onde apenas este grupo de inseticida foi utilizado tanto para o controle de larvas como de adultos. Nas linhagens de São Paulo, o nível de resistência aos organofosforados é menor, porém, foi observada resistência aos piretróides em quase todas amostras estudadas enquanto que a suscetibilidade a este grupo de inseticidas ainda não está alterada na maioria das linhagens do Nordeste. / Abstract: dengue control has been generally based on vector control through the use of insecticides. This strategy might loose efficacy if resistance to insecticide arises and this is especially frequent when insecticides are used for a long time. The World Health Organization proposed standard methods for evaluation resistance to pesticides in insects recognizing the impact of resistance on the failure of vector control activities. While assessing resistance status on a vector population, one should consider the history of insecticide that this strain has been exposed to, as this represents the press to resistance selection. In Brazil, there was a difference on the choice of insecticides that were used against the adult stage of Aedes aegypti. While in the State of São Paulo the pyretroid cypermethrin has been used since 1989, in the other states this insecticide has been introduced only in 1999. Before that, adult control was done with insecticides of organophosphorus group (malathion and fenitrothion). For immature stage of the vector there was no difference on insecticide choice and the another organophosphorus product (temephos) have been used since the 80's. The objective of this study was to evaluate the influence of insecticide use on the status of susceptibility of different strains of Aedes aegypti. Bioassays indicated that resistance levels to organophosphorus in larvae were higher in strains from the Northeast Region where this class of pesticide was the choice for both immature and adult stages of the vector. The bioassays with the adult stage indicated important resistance to pyretroids in the strains from the State of Sao Paulo probably due to the continuous use of the same product during 10 years. By the other hand the level of susceptibility to pyretroids in the strains from Northeast region was higher... (Complete abstract click electronic access below) / Mestre

Submitted by FABIANA DA SILVA FRANÇA (fabiana21franca@gmail.com) on 2017-11-09T15:38:24Z No. of bitstreams: 2 arquivototal.pdf: 3033279 bytes, checksum: f2b56b36fa23f100495d8d218c7e3669 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-11-09T15:38:24Z (GMT). No. of bitstreams: 2 arquivototal.pdf: 3033279 bytes, checksum: f2b56b36fa23f100495d8d218c7e3669 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2013-08-30 / Dengue is a viral systemic disease caused by an arboviral of Flaviviridae family, affecting about a 100 million cases per year in Brazil. It is endemic in tropical regions such as Southeast Asia, South Pacific, East Africa, Caribbean and Latin America. The disease is transmitted by Aedes aegypti (Linnaeus, 1762), a mosquito that is the main target for the disease control through strategies ranging from the larval to the adult combat. The larvicides commonly used to combat the vector, besides being toxic, present drop in larvicide efficacy since the A. aegypti larvae has developed resistance to these products. Thus, the search for new active principles that are effective in combating the mosquito is required. In this sense, Agave sisalana is a plant that is produced in several states in the Brazilian northeast region, which is used in the sisal industry. Only 5% of the plant is recovered, and its residual liquid completely wasted. In this way, the aim of this research project was to investigate the larvicidal action of the juice of Agave sisalana against larvae of A. aegypti. In larvicidal activity assays, fourth stage A. aegypti larvae were used, exposed to different concentrations of A. sisalana liquid waste during 24 hours. After the larvicidal activity assays, it was possible to determine the LC50 that was 5.9 mg / mL. Next we explored the cytotoxic activity of A. sisalana in hemocytes of A. aegypti larvae through the flow cytometry. The experiments showed an increase of cellular necrosis after 12 hours of exposure of the larvae to submaximal concentrations of sisal liquid waste (7.4% in control group vs. 28.5% in the experimental group after 12 hours; 6.2% in the control group vs. 22.7% in the experimental group after 24 hours). The histological alterations were confirmed by histopathological analysis, which showed lyses of the mesentery epithelial cells of larvae as well as peritrophic membrane destruction. Furthermore, nitric oxide (NO) production by hemocytes, an important defense strategy of mosquitoes, was checked after 3, 6 and 24 hours of larvae exposure to the A. sisalana liquid waste. There was a reduction in NO levels of approximately 76.6% after 3 hours, 83% after 6 hours and 83.8% after 24 hours of exposure. In this way, the A. sisalana liquid waste constitutes an effective alternative and economically feasible for the dengue vector combat. The outcomes of our research resulted in the patent application for an insecticide against A. aegypti larvae. / A dengue é uma doença viral sistêmica, causada por um arbovírus da família Flaviviridae, acometendo cerca de 700 mil casos por ano no Brasil. É endêmica de regiões tropicais como o sudeste asiático, sul do Pacífico, África Oriental, Caribe e América Latina. A dengue é transmitida pelo mosquito Aedes aegypti (Linnaeus, 1762), que é o principal alvo de combate para controle da doença, por meio de estratégias que vão desde o combate às formas larvares até o mosquito adulto. Os larvicidas comumente utilizados no combate do vetor, além de serem tóxicos, vêm apresentando queda na capacidade larvicida já que as larvas do A. aegypti tem desenvolvido resistência a esses produtos. Sendo assim, a busca por novos princípios ativos que sejam eficientes no combate do mosquito se faz necessária. Nesse sentido, a Agave sisalana é uma planta que é produzida em vários estados do nordeste brasileiro, a qual é utilizada na indústria sisaleira. Apenas 5% da planta é aproveitada, sendo o seu resíduo líquido completamente desperdiçado. Dessa forma, este projeto de pesquisa teve como objetivo investigar a ação larvicida do suco de Agave sisalana contra larvas de A. aegypti. Nos ensaios de atividade larvicida, utilizou-se larvas de quarto estágio de A. aegypti, testando-se diferentes concentrações de suco de A. sisalana durante 24 horas. Após os ensaios de atividade larvicida foi possível determinar a CL50, que foi de 5,9 mg/mL. A pesquisa também explorou a atividade citotóxica da A. sisalana em hemócitos de larvas de A. aegypti, através da citometria de fluxo. Verificou-se um aumento no percentual de necrose celular a partir de 12 horas de exposição das larvas a concentrações submáximas de suco de sisal (7,4% no grupo controle vs. 28,5% no grupo experimental após 12 horas; 6,2% no grupo controle vs.22,7% no grupo experimental após 24 horas). As alterações histológicas foram confirmadas em exames histopatológicos, que mostraram lise celular de células epiteliais do mesentério das larvas e destruição da membrana peritrófica. A produção de óxido nítrico (NO) pelos hemócitos, uma importante estratégia de defesa dos mosquitos, foi verificada após 3,6 e 24 horas de exposição das larvas ao suco de A. sisalana. Observou-se uma diminuição dos níveis de NO da ordem de 76,6% após 3 horas de exposição, 83 % após 6 horas de exposição, e 83,8 % após 24 horas de exposição. Sendo assim, o suco de A. sisalana pode se constituir numa alternativa efetiva e economicamente viável para o combate ao vetor da Dengue. Essa pesquisa resultou no pedido de patente de um inseticida formulação a base de A. sisalana para combate às larvas de A. aegypti.

Submitted by PAULO FRANCISCO VEIGA BIZERRA null (paulo_veiga22@hotmail.com) on 2018-03-10T16:15:00Z No. of bitstreams: 1 003-2018-Paulo Francisco Veiga Bizerra2.pdf: 2018178 bytes, checksum: a64e6835d0947709c560109bd815c3e7 (MD5) / Approved for entry into archive by Fabio Sampaio Rosas null (fabio@dracena.unesp.br) on 2018-03-14T11:58:06Z (GMT) No. of bitstreams: 1 bizerra_pfv_me_dra.pdf: 2018178 bytes, checksum: a64e6835d0947709c560109bd815c3e7 (MD5) / Made available in DSpace on 2018-03-14T11:58:06Z (GMT). No. of bitstreams: 1 bizerra_pfv_me_dra.pdf: 2018178 bytes, checksum: a64e6835d0947709c560109bd815c3e7 (MD5) Previous issue date: 2018-02-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O imidacloprido (IMD) é um inseticida neonicotinóide largamente utilizado em diversas culturas agrícolas e em animais para o controle de pragas. O IMD é rapidamente absorvido pelo trato gastrointestinal e por contato, sendo rápida e uniformemente distribuído nos órgãos e tecidos. Dados da literatura mostram que as concentrações mais elevadas foram observadas nos órgãos de eliminação: fígado e rins. O fígado é o principal órgão envolvido na biotransformação de substâncias exógenas (xenobióticos), convertendo compostos hidrofóbicos em hidrossolúveis, mais facilmente eliminados pelo organismo. Vários estudos vêm sendo conduzidos sobre os efeitos tóxicos do IMD em animais, causando danos ao fígado. Nesse sentido, o objetivo desse estudo foi avaliar os mecanismos envolvidos na toxicidade do IMD sobre a bioenergética de mitocôndrias e hepatócitos isolados de rato e ações do IMD sobre o metabolismo de carboidratos e proteínas em fígado de rato em perfusão. Em mitocôndrias isoladas, o IMD promoveu uma diminuição dose-dependente no estado 3 da respiração e na produção de ATP, sem afetar o potencial de membrana mitocondrial. Experimentos subsequentes medindo o consumo de oxigênio mostraram que o IMD não afeta a cadeia respiratória e que seu efeito é semelhante ao da oligomicina (inibidora da FoF1-ATP sintase) e/ou ao do atractilosídeo (inibidor do translocador de nucleotídeos de adenina, ANT). IMD inibiu a atividade da FoF1-ATP sintase em mitocôndrias rompidas e inibiu parcialmente a despolarização do potencial de membrana induzida pelo ADP. Esses resultados indicam que o IMD afeta a bioenergética mitocondrial por meio da inibição da FoF1-ATP sintase. Em Experimentos com hepatócitos isolados de rato os resultados da respiração foram semelhantes aos encontrados nas mitocôndrias isoladas, porém o IMD afetou a produção intracelular de ATP e induziu a morte celular somente nos hepatócitos isolados de ratos previamente tratados com dexametasona, um ativador do citocromo P450. No fígado de rato em perfusão o IMD também inibiu a produção de glicose por meio da gliconeogênese. Esses resultados sugerem que a toxicidade do IMD pode estar associada a alterações no metabolismo energético celular sendo a enzima FoF1-ATP sintase o principal alvo da ação tóxica deste inseticida, e que os metabólitos formados na biotransformação do IMD podem ser mais tóxicos do que o próprio IMD. / Imidacloprid (IMD) is a neonicotinoid insecticide widely used in various crops and animals for pest control. IMD is rapidly absorbed by the gastrointestinal tract, being rapidly and evenly distributed in the organs and tissues. The highest concentrations were observed in the elimination organs: liver and kidneys. The liver is the main organ involved in the biotransformation of exogenous substances (xenobiotics), with the capacity to convert hydrophobic compounds into water soluble metabolites, which are more easily eliminated by the organism. Studies have been conducted on the toxic effects of IMD on animals, causing damage to the liver. In this sense, the objective of this study was to evaluate the mechanisms involved in the toxicity of IMD on the bioenergetics of mitochondria and isolated hepatocytes of rats and its actions on the metabolism of carbohydrates and proteins in liver of rats in perfusion. In isolated mitochondria, IMD promoted a dose-dependent decrease in the state 3 of mitochondrial respiration and ATP levels, without affecting mitochondrial membrane potential. Subsequent experiments measuring oxygen consumption have shown that IMD does not affect the electron transport chain and that its effect is similar to that of oligomycin (FoF1-ATP synthase inhibitor) and/or atracytoside (ANT adenine nucleotide translocator inhibitor). In the perfusion rat liver IMD inhibited the activity of FoF1-ATP synthase in freeze/thaw-disrupted mitochondria and partially inhibited the depolarization of the membrane potential induced by ADP. These results indicate that IMD affects in mitochondrial bioenergetics by inhibiting FoF1-ATP synthase. In experiments with isolated hepatocytes respiration results were similar to those found in isolated mitochondria, but IMD affected the intracellular production of ATP and induced cell death only in hepatocytes isolated from rats previously treated with dexamethasone, a cytochrome P450 activator. IMD also inhibited the production of glucose by gluconeogenesis. These results suggest that IMD toxicity may be associated with changes in cellular energy metabolism with the enzyme FoF1-ATP synthase being the main target of the toxic action of this insecticide, and that the metabolites formed in the biotransformation of the IMD may be more toxic than the IMD itself. / FAPESP: 2015/19549-8

Made available in DSpace on 2014-06-11T19:29:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2002Bitstream added on 2014-06-13T20:38:57Z : No. of bitstreams: 1 macoris_mlg_me_botfm.pdf: 251783 bytes, checksum: a5223df144086a30007cf7ea32979838 (MD5) / A estratégia de prevenção de dengue tem se baseado no controle do vetor, com ênfase ao uso de inseticidas. Este tipo de controle, quando utilizado por longos períodos, pode ter sua eficácia comprometida devido ao surgimento de resistência dos vetores aos inseticidas utilizados. A Organização Mundial de Saúde, reconhecendo o impacto deste problema no sucesso dos programas de controle, sugeriu uma padronização de bioensaios para o monitoramento periódico das populações expostas a inseticidas. Quando se propõe avaliar o nível de suscetibilidade de uma linhagem é importante que se considere a quais inseticidas ela foi exposta, uma vez que o tipo de tratamento a que estão submetidas caracteriza a pressão de seleção de linhagens resistentes. Como no Programa de Controle de Dengue do Estado de São Paulo a opção por inseticidas diferiu do programa nacional, neste estudo procurou-se avaliar o nível de suscetibilidade de algumas linhagens de Aedes aegypti do Estado de São Paulo de forma comparativa com linhagens do Nordeste, e avaliar a relação entre a exposição aos diferentes produtos e a presença de resistência. Os resultados dos bioensaios indicaram haver um nível maior de resistência ao grupo dos organofosforados nas linhagens do Nordeste onde apenas este grupo de inseticida foi utilizado tanto para o controle de larvas como de adultos. Nas linhagens de São Paulo, o nível de resistência aos organofosforados é menor, porém, foi observada resistência aos piretróides em quase todas amostras estudadas enquanto que a suscetibilidade a este grupo de inseticidas ainda não está alterada na maioria das linhagens do Nordeste. / dengue control has been generally based on vector control through the use of insecticides. This strategy might loose efficacy if resistance to insecticide arises and this is especially frequent when insecticides are used for a long time. The World Health Organization proposed standard methods for evaluation resistance to pesticides in insects recognizing the impact of resistance on the failure of vector control activities. While assessing resistance status on a vector population, one should consider the history of insecticide that this strain has been exposed to, as this represents the press to resistance selection. In Brazil, there was a difference on the choice of insecticides that were used against the adult stage of Aedes aegypti. While in the State of São Paulo the pyretroid cypermethrin has been used since 1989, in the other states this insecticide has been introduced only in 1999. Before that, adult control was done with insecticides of organophosphorus group (malathion and fenitrothion). For immature stage of the vector there was no difference on insecticide choice and the another organophosphorus product (temephos) have been used since the 80’s. The objective of this study was to evaluate the influence of insecticide use on the status of susceptibility of different strains of Aedes aegypti. Bioassays indicated that resistance levels to organophosphorus in larvae were higher in strains from the Northeast Region where this class of pesticide was the choice for both immature and adult stages of the vector. The bioassays with the adult stage indicated important resistance to pyretroids in the strains from the State of Sao Paulo probably due to the continuous use of the same product during 10 years. By the other hand the level of susceptibility to pyretroids in the strains from Northeast region was higher... (Complete abstract click electronic access below)

This PhD. thesis summarizes the effect of adipokinetic hormones (AKHs) on a spectrum of mobilized lipids in model insect species the locust Locusta migratoria and the firebug Pyrrhocoris apterus. The results revealed that mobilization of diacylglycerols and fatty acids from the fat body into the haemolymph is not uniform and suggested there is partial specificity of individual AKHs. This could contribute to the answer of the question why some insect species have more than one AKH. The results of the thesis are supplemented by studies of AKH effect on lipid metabolism in stress conditions elicited by insecticide treatments. Co-application of AKH and insecticide enhanced the effect of insecticide

Ph.D. / This study consisted of a two-tiered approach to assessment of the effects of EDCs on aquatic organisms, and heavy metal accumulation in the aquatic environment, by integrating field work and laboratory-based experiments. In the last three decades a considerable portion of research in aquatic health and aquatic toxicology has been largely focused on endocrine disruptors, aiming to establish how certain chemicals discharged into the environment, especially organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), surfactants and plasticisers, can mimic endogenous hormones and thereby induce reproductive abnormalities. The rationale behind the present study was the growing interest in the study of endocrine disrupting chemicals (EDCs) internationally and the aspects of this field of research that are relevant to South Africa’s aquatic environment and its endemic aquatic organisms. The field work was carried out in the Rietvlei Wetland System and consisted of a combination of plant root analysis and application of the South African Scoring System 5 (SASS5) macroinvertebrate index. Three characteristic wetland macrophytes used in the study were Typha capensis, Phragmites australis and Persicaria lapathifolia. Samples of plants, sediment and water were taken from predetermined locations along the wetland system in the Rietvlei Nature Reserve and analyzed for heavy metals by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The heavy metals analyzed in this study; lead, arsenic and cadmium, have also been implicated as endocrine disruptors. The results of heavy metal accumulation in the plant roots reflected a pollution trend along the wetland, suggesting that plant roots are useful bioindicators of contamination in freshwater systems.

No description available.

Within this thesis, I performed a systematic review of approaches to broad-scale modelling of disease vector distributions and determined the most widely used methods predict current species niches and project the models forward under future climate scenarios without temporal validation. I then provided a forward-looking summary of emerging techniques to improve the reliability and transferability of those models, including historical calibration. I then predicted Anopheles mosquito distributions across Tanzania in 2001 (before large-scale ITN distributions) and compared this model with countrywide ITN use by 2012 to assess where the most suitable mosquito habitats were located and whether ITN rollouts in Tanzania ensured coverage of such areas. I concluded that ITNs in Tanzania did not optimally target areas most at risk of malaria. In doing so, I provided a new approach to monitoring and evaluating vector control interventions across large spatial scales.