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1
Evans, Peter J. "Community knowledge, attitudes and practices - urban mosquitoes and sustainable mosquito control". Thesis, University of Exeter, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241460.
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2
Greenfield, Bethany Patricia Jane. "Metarhizium pathogenesis of mosquito larvae". Thesis, Swansea University, 2014. https://cronfa.swan.ac.uk/Record/cronfa42819.
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3
ROSSI, PAOLO. "Bacterial symbiosis in mosquitoes: from basic research to mosquito borne diseases control". Doctoral thesis, Università degli Studi di Camerino, 2011. http://hdl.handle.net/11581/401854.
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4
Luxananil, Plearnpis. "Studies on mosquito bio-control bacteria". 京都大学 (Kyoto University), 2004. http://hdl.handle.net/2433/147673.
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5
Bandzuh, John Thomas IV. "Perceptions of measures to control Aedes mosquitoes and mosquito-borne diseases in Costa Rica". Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/81449.
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Aedes mosquitoes are responsible for the transmission of several arboviruses throughout tropical and subtropical regions of the world. In the Americas, Aedes aegypti is the most competent vector of dengue, chikungunya, Zika, and yellow fever. With up to 400 million cases globally each year, dengue fever is the fastest growing vector-borne disease in the world, and it has become an increasingly significant risk to global health. In the Western Hemisphere, dengue, and more recently chikungunya and Zika, exists throughout much of Latin America and the Caribbean. Both diseases are spread via Aedes mosquitoes and both constitute major health risks in Costa Rica. A dengue outbreak in Costa Rica in 2013 was the largest epidemic in the country since the return of the disease in 1993. Moreover, between 2014 and 2015 there was a 54.9% increase in dengue cases in Costa Rica, further demonstrating the relevancy of research on mosquito-borne diseases. Given this context, this study employs qualitative methods to critically investigate measures to combat Aedes mosquito-borne diseases in Costa Rica. Data were collected using household interviews (n = 80); semi-structured key informant interviews with public health officials, researchers, nonprofit organizations, and community leaders (n = 22); and a focus group discussion in each of two study areas. The results provide broad and place-specific information about mosquito control efforts and other actions deployed in Costa Rica to mitigate mosquito-borne diseases. The data reveal differences in perceptions and disease incidence among household interviewees as well as where households source information about mosquitoes and mosquito-borne diseases. Varying degrees of knowledge on mosquitoes and mosquito-borne diseases were uncovered across the study sites, as were differing attitudes among the general population regarding mosquito control techniques (e.g., fumigation, education campaigns, and household visits by public health officials). Additionally, data indicated a gap in knowledge regarding the ability of the public to report mosquito-related problems to health authorities. Households also exhibited discrepancies in knowledge pertaining to chikungunya transmission and details about the vector.Master of Science
6
Conway, Michael. "Improving transgenic approaches to mosquito population control". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:44ba0b39-cded-4e96-a796-570affd53de0.
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The disease vectors Aedes aegypti and Aedes albopictus are serious and growing threats to global health. As vectors of the arboviruses dengue fever and chikungunya, these mosquitoes are responsible for hundreds of millions of cases and thousands of deaths each year. Absent specific treatments or vaccines, effective control of mosquito populations remains the only option for tackling a growing public health challenge. More effective control tools are urgently needed. Recently, a novel approach to pest population control has been developed based on the release of insects carrying a repressible, dominant lethal allele. This approach has achieved dramatic reductions in Ae. aegypti populations in regulated open field experiments. Despite this success, there remains scope to improve upon the current technology. It is proposed that an 'ideal' strain would combine the following features: (i) repressible lethality in late juvenile phases; (ii) a mechanism for removing females at an early developmental stage in the release generation; and (iii) orthogonal expression control mechanisms allowing both these systems to be combined in a single strain. This thesis describes research undertaken in pursuit of a 'next generation' strain. Two novel promoters from putative Osiris genes have been identified which confer a 102-103 – fold up-regulation in transgene expression specific to late pupal stages. One of these 'Osiris' promoters has been used to develop transgenic Aedes aegypti strains. 5 lines showed pupal-specific lethality of 98-100% penetrance, which was repressed in the presence of tetracycline. An Ae. albopictus orthologue of the sex-determining gene doublesex (dsx) has been isolated and characterised and a female-specific expression system developed. Transgenic lines show female-specific expression of a transgene; however, there remains some 'leaky' expression in male insects. Finally, a potential expression control tool based on an auxin-inducible expression system has been investigated. 11 different transgenic lines were developed based on three different construct designs. None showed auxin-inducible expression of a transgene.
7
Griffin, Lachlan Francis. "Fish as Mosquito Control Agents in Mangroves". Thesis, Griffith University, 2013. http://hdl.handle.net/10072/367242.
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The saltwater mosquito, Aedes vigilax (Skuse), is a major vector of Ross River virus and Barmah Forest virus across sub-tropical and tropical Australia, and poses a significant human health risk, particularly in densely populated areas such as South East Queensland and Northern New South Wales regions of eastern Australia. The insect uses saltmarsh and mangrove basin forests as oviposition and larval habitats, and various mosquito control methods exist that target larval stages. Fish, acting as predators of larvae, have routinely been used as a component of mosquito control strategies worldwide. If managed appropriately biological control using fish can be effective, but if mismanaged, biological control can have serious environmental consequences. For example, the release of the Mosquitofish (Gambusia holbrooki (Girard)) for mosquito control in Australian waterways has caused significant ecological damage; G. holbrooki is now a major invasive pest. Nonetheless, mosquito control strategies that include the use of native fish populations in the strategy may be more effective for controlling mosquitoes in mangrove basins than those that do not include native fish. However, little is known of fish populations (both exotic and native) within mangrove basins, and the impact these fish do, and could have on mosquito populations. This research examines the relationship between resident fish and saltwater mosquitoes in eastern Australian mangrove basin forests. It focussed specifically on two mangrove basin sites in the South East Queensland/Northern New South Wales region, and evaluates the potential of resident mangrove basin fish as biological control agents in mangrove ecosystems.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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8
Persson, Vinnersten Thomas. "Long Term Studies of Insect Abundances in Temporary Wetlands in Relation to Hydrology, Predation and Bti". Doctoral thesis, Uppsala universitet, Zooekologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-207841.
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Long-term insect abundances have been studied to investigate factors structuring the insect communities of the temporary wetlands around the River Dalälven floodplain. In the wet meadows and swamps in the River Dalälven floodplains recurrent floods are the ultimate prerequisite for high production of floodwater mosquitoes. In the larval stages these make up a superabundant potential prey for aquatic predatory insects while as adults they become nuisance for people and animals. Mosquito control with Bacillus thuringiensis israelensis (Bti) has been carried out in parts of the floodplain wetlands since 2002. This study investigate potential long-term effects of Bti on non-target insects in general, and non-biting midges (Diptera: Chironomidae) and aquatic predator insects in special in 10 temporary wetlands. Diving-beetles (Coleoptera: Dytiscidae) were the most common aquatic predatory insects in temporary flooded wetlands, and we found no indications that diving-beetles were negatively affected by mosquito larvae reduction with Bti-treatments. Non-target Bti-effects on the insect community in general, measured as increase or decrease of insect abundances, in general showed no effects of Bti except for Coleoptera. The non-biting midges were studied on species level, since this taxon previously has been associated with negative Bti non-target effects in the short-term. We found no reduced production of chironomids at neither family, nor subfamily level in Bti-treated as compared to untreated wetlands. We conclude that other factors than the occasional Bti-treatments dominate in structuring the chironomids fauna. For example, hydrology measured as floods and hydroperiod had substantial impact on insect emergence Increased hydroperiod was associated with lower insect emergence for the majority of the studied taxa, indicating an insect fauna adapted more to terrestrial conditions. In the final study, we developed and applied a molecular method to study interspecific predator – prey relationships between medium-sized diving beetles and floodwater mosquito larvae. Gut content analyses showed that floodwater mosquito larvae are a regular, but limited, part of the diet of medium-sized diving beetles. This thesis is one of the first long-term studies of insects of temporary wetlands in relation to mosquito control actions. The results indicate that hydrology is one of the major factors influencing and structuring the insect communities of the temporary flooded wetlands in the River Dalälven floodplains, and that mosquito control actions with Bti only have marginal effect on insect abundances.
9
Lambert, Ben. "Understanding mosquito vectors and methods for their control". Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:2ae215f9-b03a-4ef1-b892-252634f89cef.
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Mosquitoes spread diseases that shorten and worsen the lives of many people, chiefly children in poor countries, around the world. Since Ronald Ross' discovery at the end of the nineteenth century that mosquitoes transmit malaria, field entomologists have collected a great deal of information about mosquito ecology. Despite this tremendous effort, there still remain significant gaps in our knowledge of mosquito ecology, in part, reflecting the significant variation in mosquito ecology across species and geographies. The main aim of this thesis is an attempt to synthesise the substantial information that field entomologists have collected on mosquito lifespan. In Chapters 2 and 3, I conduct meta-analyses of the two predominant approaches used to estimate mosquito lifespan: mark-release-recapture experiments and female mosquito dissection-based studies, respectively. These analyses produce estimates of mosquito lifespan by species and genus, and more broadly, allow for an appraisal of these two experimental approaches. In Chapter 4, I describe a recently developed approach, known as near-infrared spectroscopy, which enables estimation of the age of individual mosquitoes, and then perform an in silico analysis to explore the use of this technology for estimating the average lifespan of wild populations of mosquitoes. The emergence of mosquito resistance to the main insecticides used in vector control, along with the concerning recent discovery that the malaria parasites in Asia are becoming resistant to arteminisin - an important drug used to treat malaria - highlight the need for novel approaches to control disease transmission. Some recently-proposed approaches involve genetic modification of the mosquito vectors, for example, to render them incapable of acting as hosts for disease or to reduce their fecundity. In Chapter 5, I model the impact of a release of mosquitoes carrying a genetic construct known as a homing endonuclease, which has been constructed to bias the sex of mosquito offspring towards males, in computational environments that capture some facets of the real life landscapes where mosquito borne disease is rife. About a century ago, the famous Italian Malariologist Giovanni Grassi declared that malaria was a "giant with clay feet"; reflecting the optimism, in some academic circles at the time, that eradication of this terrible disease would soon occur. Unfortunately, a century of often unsuccessful attempts to control and eradicate malaria, and other mosquito borne diseases, would follow Grassi's statement, meaning that this fight is likely to continue throughout the twenty-first century. We now know much more about mosquitoes and mosquito borne disease than we did a generation ago, but there is still crucial information that we do not. In this thesis, I argue that in order to make significant inroads to disease eradication, further research on mosquito ecology is crucial. Only when we better understand our unwitting mosquito foe, can we design and implement effective disease control measures that are so desperately needed in those most desperate parts of the world.
10
Eckert, Lesley. "Permethrin for Mosquito Control: Drinking Water Impacts and Treatment". Digital WPI, 2013. https://digitalcommons.wpi.edu/etd-theses/1118.
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"The goals of this study were (1) to evaluate the impacts of pesticides used for mosquito control on drinking water and (2) to investigate the removal of permethrin from water using activated carbon. A review of current literature on pesticide usage, toxicity, occurrence in the environment, and treatment techniques to remove pesticides from drinking water was conducted. The focus of the literature review was on pesticides used for mosquito control. Permethrin is a synthetic pyrethroid insecticide used extensively in the United States (US) for mosquito control and in agriculture, with approximately 2 million pounds applied each year. Permethrin was selected for investigation based on its widespread use in the US, its inclusion on the Contaminant Candidate List 3 (CCL3), its health hazards, and the lack of previous research on the removal of permethrin from drinking water. The removal of permethrin from water using powdered activated carbon (PAC) was investigated. Equilibrium adsorption experiments to assess removal of cis-, trans-, and total permethrin were conducted using two types of PAC (WPH 650 and WPH 1000). Initial total permethrin concentrations ranged from 2.0 to 4.6 ug/L. PAC doses ranged from 0.0 to 10 mg/L. Results showed that PAC addition is an effective method for removing permethrin from water. Total permethrin concentrations were reduced by 38% with 0.05 mg/L of PAC WPH 650, and reduced to below the detection limit with 3 mg/L of PAC WPH 650. Total permethrin concentrations were reduced by 35% with 0.05 mg/L of PAC WPH 1000 and by 83% with 5 mg/L of PAC WPH 1000. Results for cis- and trans- permethrin were similar. The Freundlich isotherm model provided appropriate fits to the data with an R-squared value of 0.91 for both WPH 650 and WPH 1000."
11
Kaahui, Soncy. "The Future of Mosquito Control: Wolbachia and Genome Editing". Scholarship @ Claremont, 2019. https://scholarship.claremont.edu/scripps_theses/1234.
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The impact that mosquitoes and vector-borne diseases have on humans is vast and continues to grow with our expanding global interactions, such as international travel and shipping, so the need for effective vector controls is imperative. Aedes aegypti is a species of mosquito that spreads some of the most common vector-borne diseases, including zika virus, dengue fever, chikungunya, and yellow fever. A. aegypti have yet to be successfully contained, so they are favorable targets for implementing these new vector-control techniques. A review of scientific literature was performed from 1965 to present, timeline was constructed of studies on A. aegypti and their diseases, with inclusion criteria of techniques like bacterial controls and genome editing. Bacterial controls, such as using an endosymbiont like Wolbachia, can result in sterilization of mosquitoes as well as inhibiting the ability for mosquitoes to be infected by pathogens. Genome editing techniques involve CRISPR and gene drives, allowing the manipulation of certain genes to decrease fitness or susceptibility of pathogens. Combining newly discovered genes that play a role in sterilization with the introduction of sterilizing Wolbachia bacteria could result in a more effective method for controlling A. aegypti. Neither technique is known to be entirely effective on its own, but research indicates that highly effective vector-controls could be developed by combining aspects from both fields.
12
Tomerini, Deanna Majella. "The Impact of Local Government Mosquito Control Programs on Ross River Virus Disease in Queensland, Australia". Thesis, Griffith University, 2008. http://hdl.handle.net/10072/366893.
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In this study, I have investigated the relationship between mosquito control and
mosquito-borne disease rates within Queensland, Australia. The thesis considers the
most prevalent arbovirus causing human disease in Australia (Ross River virus) and
estimates, how much Ross River virus disease is avoided through local government
mosquito control in Queensland, and then compares the monetary value of avoided
Ross River virus disease with the financial costs of local government mosquito
control.
A survey to collect information about mosquito control costs and practices was
designed and implemented in each of the 125 local governments in Queensland. This
survey collated previously dispersed information; because, although local
governments in Queensland are legally obliged to perform mosquito control for
disease prevention and nuisance reduction, there is no formal or regular reporting of
mosquito control costs and practices to the State.
A substantive conclusion from this research is that mosquito control has resulted in
lower Ross River virus disease notifications in some local government areas. Ross
River virus disease notifications are consistently lower in local government areas that
implement mosquito control programs that pre-empt mosquito outbreaks using
routine surveillance and then reduce mosquito abundance using mosquito control.
Furthermore, there is evidence that local governments using extensive freshwater
mosquito control, in addition to saltwater mosquito control, have relatively lower
annual Ross River virus disease rates and lower standard deviations of the annual
Ross River virus disease rates (indicating the freshwater mosquito control is
important in suppressing outbreaks of Ross River virus disease). In contrast, mosquito control practices in the inland local government areas tend to be reactive to
community complaints of mosquito abundance causing nuisance, and generally
include ad-hoc mosquito control treatments. There is no evidence that reactive, adhoc
mosquito control programs result in reduced Ross River virus disease
notifications.
The numbers of avoided Ross River virus notifications were estimated for the local
governments that are located in the south eastern coastal region of Queensland. It
has been estimated that an annual average of 2206 Ross River virus disease
notifications have been avoided through effective mosquito control; and, for each
actual notification of Ross River virus disease in the southern coastal local
governments, two notifications have been avoided.
The survey revealed that in excess of $10 million was spend by local governments
implementing mosquito control in Queensland in 2004. The majority of this
expenditure occurs in the more densely populated local governments located in the
southern coastal strip of the state.
A comparison of the financial costs of mosquito control and the financial value of
avoided disease produced a cost-benefit ratio of 0.37, meaning that on average, 37%
of the costs of mosquito control are directly recouped through the value of avoided
Ross River virus disease. In years when the risk of Ross River virus outbreaks is
relatively low, due to below average rainfall, the costs of mosquito control exceed
the value of avoided Ross River virus notifications—but in years where the risk of an
epidemic of Ross River virus is high, effective mosquito control practices can avoid
an epidemic of Ross River virus disease, and in this situation the financial value of
avoided disease exceeds the costs of the mosquito control program.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
Full Text
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Bhatia, Mrigesh Roopchandra. "Economic evaluation of malaria control interventions in Surat, India". Thesis, London School of Hygiene and Tropical Medicine (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249409.
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Tokarz, Ryan E. "Spatial-temporal Distribution of Mosquito Larval Hot Spots in Papoli, Uganda: A Community-Based Approach to Mosquito Control". Scholar Commons, 2017. https://scholarcommons.usf.edu/etd/7448.
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Mosquito species of the Anopheles gambaie complex are the predominant vectors of malaria transmission throughout sub-Saharan Africa. These mosquitoes tend to be endophilic, as well as anthropophilic, making them prime candidates for disease transmission. Within the same region, related mosquito vectors play a significant role in the transmission of additional human and zoonotic diseases. Furthermore, mosquito nuisance biting is an immense issue that cannot be ignored in terms of its impact on African communities. Depending on the respective factors involved, mosquito control programs throughout the continent have attempted to tackle these issues in a multitude of ways. This research approached the issue by developing and integrating an American-style mosquito control district within the eastern Ugandan community of Papoli. The basic structure of such a district was blended with a community-based approach, employing local community members and leaders, thus ensuring an effective and sustainable program. A guide detailing all aspects and steps needed to properly develop and implement such a program is outlined.
15
Meyabeme, Elono Alvine Larissa [Verfasser], Hans-Jörg [Akademischer Betreuer] Ferenz, Leon [Akademischer Betreuer] Blaustein i Matthias [Akademischer Betreuer] Liess. "Mosquito control : improving aquatic risk assessment and effieciency of mosquito control practices / Alvine Larissa Meyabeme Elono. Betreuer: Hans-Jörg Ferenz ; Leon Blaustein ; Matthias Liess". Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2011. http://d-nb.info/1025201817/34.
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Roberts, Gillian Mary. "The combination of Bacillus thuringiensis var. israelensis and surface active monolayers for mosquito control". Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328501.
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Asquith, Ilse Bernadette. "A statistical evaluation and analysis of mosquito repellent combination". Thesis, Nelson Mandela Metropolitan University, 2004. http://hdl.handle.net/10948/d1015732.
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The present product development project was aimed at studying the synergism and/or antagonism amongst various known insect repellent actives with the view to formulating a multi-active repellent product with improved properties when compared to current single-active commercial products. Advanced statistical methods were used to identify synergism between individual active substances and to define a formulation as close as possible to the “ideal” formulation. Several mosquito repellent samples were prepared and sent to the South African Bureau of Standards (SABS) in Pretoria to test for their efficiency in repelling mosquitoes. From the results of the repellency tests of the various active combinations, three actives were identified that showed promising signs of synergism. These actives were then studied in further detail to determine their optimum combination. In addition, it was shown that when using a natural flavourant as promoter and incorporating a slow-release agent into formulations for aerosols and lotions, a product is obtained that gives comparable levels of efficiency to current commercial products, but at much reduced levels of active loading. Accelerated stability tests performed on the final combination of the three actives used in the final formulation showed no adverse reactions over a three-week study. These tests shall be repeated once the final application form (lotion, aerosol, etc) and product packing have been decided.
18
Breitfuss, Mark, i n/a. "The Effects of Physical Habitat Modification for Mosquito Control, Runnelling, on Selected Non-Target Saltmarsh Resources". Griffith University. Australian School of Environmental Studies, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20031126.074304.
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Runnelling is a popular method of physical habitat modification employed on saltmarshes to control pest mosquito populations. The runnelling method involves linking the tidal source to isolated mosquito breeding pools via shallow channels that enable slow water movement of low amplitude tides. Increased tidal flushing inhibits mosquito development. The range of organisms which inhabit saltmarsh are likely to be influenced by altered tidal conditions as they exhibit specific physicochemical requirements for feeding, burrowing or growth. The dynamic nature of saltmarsh may mean that changes to the tidal frequency of a particular region of the saltmarsh promotes extension of marine-like conditions. Because runnels increase the frequency of flooding tidal events in specific regions of the saltmarsh this study predicted that resulting changes would be evident in the physical conditions of saltmarsh substrate, in the transport of buoyant vegetative propagules, in the population characteristics of surface grazing snails and in the density and aperture of crab burrows after flooding and non-flooding tidal events. The physical impacts of runnelling were determined at three marshes which appeared similar in terms of topography, substrate and tidal conditions. Soil water content and consolidation were measured using two sampling protocols: a) comparisons between modified and unmodified shores; and, b) comparisons with increasing lateral distance across the shore from the runnel edge. At one marsh, moisture levels were significantly higher at runnelled than at unrunnelled sites when tides filled the runnels, but this pattern was not found at the other marshes. Soil consolidation was greater at higher shore heights, but was not different between runnelled and unrunnelled shores. Measurements at different lateral distances from runnels demonstrated higher moisture levels and lower consolidation up to 5 m from the edge but not further away. Groups of marked Avicennia marina propagules were released at the three runnelled saltmarshes during flooding and non-flooding tidal events. Groups of propagules released within 10 m of a runnel were always transported significantly further from the starting position and further up the saltmarsh shore after both flooding and non-flooding tides than any other groups. In addition, the pattern of stranding on saltmarsh for significantly different groups was closely associated with the path of runnel construction so that propagules were located either in the runnel or in depressions linked to the runnel that had been isolated mosquito-breeding pools prior to runnelling. It is likely that altered physical soil conditions significantly affected the distribution and size structures of Salinator solida and Ophicardelus spp. snails recorded at the three saltmarshes. The interaction of tidal period and the presence of a runnel contributed to patterns with significant differences between runnelled and unrunnelled regions of the marsh. Generally, the runnel population of snails exhibited flood-like features even during non-flood periods. The distribution and size classes of snails did not differ with lateral distance from runnels. The burrow characteristics of the crab Helograpsus haswellianus were compared to increase the accuracy of estimating abundance from burrow counts. Including only those burrows which were obviously maintained by resident crabs significantly increased the confidence limits of estimating crab abundance using only burrow density counts. This method was applied to runnelled and unrunnelled sites to assess any changes in the density of burrows associated with the presence of runnels. Again, it is likely that physical soil conditions resulting from increased tidal frequency at the runnel did influence crab burrowing with fewer small burrows being found at the runnelled site, low on the shore. In addition, mid- and large-sized burrows tended to dominate close to the runnel edge. Site-specific soil characteristics may help to explain the lack of continuity in patterns associated with runnel effects on non-target saltmarsh resources. While the runnel may increase the soil water content of clayey substrates at some sites it could also result in de-watering of porous sandy soils at other shores. This was evident in the structure of the snail population and distribution of crab burrows which appeared to reflect altered soil physical characteristics associated with the runnel. Runnelling does affect non-target organisms in saltmarsh. However, the scale of impact was usually locally restricted (< 10 m from the runnel edge). The fact that patterns were not recorded at all sites suggests that the influence of runnels is variable and limited by substrate and some biological conditions. Given the efficiency and popularity of runnelling as a physical control method for reducing pest vector mosquito habitat, this study found no evidence to suggest that its use should be discontinued on any ecological basis measured.
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Breitfuss, Mark. "The Effects of Physical Habitat Modification for Mosquito Control, Runnelling, on Selected Non-Target Saltmarsh Resources". Thesis, Griffith University, 2003. http://hdl.handle.net/10072/367526.
Pełny tekst źródłaStreszczenie:
Runnelling is a popular method of physical habitat modification employed on saltmarshes to control pest mosquito populations. The runnelling method involves linking the tidal source to isolated mosquito breeding pools via shallow channels that enable slow water movement of low amplitude tides. Increased tidal flushing inhibits mosquito development. The range of organisms which inhabit saltmarsh are likely to be influenced by altered tidal conditions as they exhibit specific physicochemical requirements for feeding, burrowing or growth. The dynamic nature of saltmarsh may mean that changes to the tidal frequency of a particular region of the saltmarsh promotes extension of marine-like conditions. Because runnels increase the frequency of flooding tidal events in specific regions of the saltmarsh this study predicted that resulting changes would be evident in the physical conditions of saltmarsh substrate, in the transport of buoyant vegetative propagules, in the population characteristics of surface grazing snails and in the density and aperture of crab burrows after flooding and non-flooding tidal events. The physical impacts of runnelling were determined at three marshes which appeared similar in terms of topography, substrate and tidal conditions. Soil water content and consolidation were measured using two sampling protocols: a) comparisons between modified and unmodified shores; and, b) comparisons with increasing lateral distance across the shore from the runnel edge. At one marsh, moisture levels were significantly higher at runnelled than at unrunnelled sites when tides filled the runnels, but this pattern was not found at the other marshes. Soil consolidation was greater at higher shore heights, but was not different between runnelled and unrunnelled shores. Measurements at different lateral distances from runnels demonstrated higher moisture levels and lower consolidation up to 5 m from the edge but not further away. Groups of marked Avicennia marina propagules were released at the three runnelled saltmarshes during flooding and non-flooding tidal events. Groups of propagules released within 10 m of a runnel were always transported significantly further from the starting position and further up the saltmarsh shore after both flooding and non-flooding tides than any other groups. In addition, the pattern of stranding on saltmarsh for significantly different groups was closely associated with the path of runnel construction so that propagules were located either in the runnel or in depressions linked to the runnel that had been isolated mosquito-breeding pools prior to runnelling. It is likely that altered physical soil conditions significantly affected the distribution and size structures of Salinator solida and Ophicardelus spp. snails recorded at the three saltmarshes. The interaction of tidal period and the presence of a runnel contributed to patterns with significant differences between runnelled and unrunnelled regions of the marsh. Generally, the runnel population of snails exhibited flood-like features even during non-flood periods. The distribution and size classes of snails did not differ with lateral distance from runnels. The burrow characteristics of the crab Helograpsus haswellianus were compared to increase the accuracy of estimating abundance from burrow counts. Including only those burrows which were obviously maintained by resident crabs significantly increased the confidence limits of estimating crab abundance using only burrow density counts. This method was applied to runnelled and unrunnelled sites to assess any changes in the density of burrows associated with the presence of runnels. Again, it is likely that physical soil conditions resulting from increased tidal frequency at the runnel did influence crab burrowing with fewer small burrows being found at the runnelled site, low on the shore. In addition, mid- and large-sized burrows tended to dominate close to the runnel edge. Site-specific soil characteristics may help to explain the lack of continuity in patterns associated with runnel effects on non-target saltmarsh resources. While the runnel may increase the soil water content of clayey substrates at some sites it could also result in de-watering of porous sandy soils at other shores. This was evident in the structure of the snail population and distribution of crab burrows which appeared to reflect altered soil physical characteristics associated with the runnel. Runnelling does affect non-target organisms in saltmarsh. However, the scale of impact was usually locally restricted (< 10 m from the runnel edge). The fact that patterns were not recorded at all sites suggests that the influence of runnels is variable and limited by substrate and some biological conditions. Given the efficiency and popularity of runnelling as a physical control method for reducing pest vector mosquito habitat, this study found no evidence to suggest that its use should be discontinued on any ecological basis measured.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
Full Text
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Jacups, Susan Patricia. "Using statistical methods to evaluate and improve mosquito control for mosquito-borne disease reduction in the Northern Territory of Australia". Thesis, Charles Darwin University, 2011. http://espace.cdu.edu.au/view/cdu:23914.
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Mosquito borne-diseases are responsible for high rates of morbidity and mortality worldwide. Ross River, Barmah Forest, Murray Valley encephalitis and Kunjin viruses are presently endemic in the Northern Territory, while dengue virus and malaria are at risk of re-establishment. In this thesis, I describe the epidemiology of the major endemic mosquito-borne diseases of the Northern Territory, past and present, and evaluate control strategies adopted to reduce mosquito abundance and disease transmission. Some findings include; Aedes vigilax larval densities were almost 10 times greater in artificially incised drains compared with lower mangroves, despite the creation of drains for mosquito control purposes. I further analyse the effects of drainage channels, habitat modification, over time in three Darwin salt-marshes and one freshwater swamp near Alice Springs. In addition to significantly reducing vector-borne disease transmission and pest biting; habitat modification has restored all swamps to closer to their original ecosystems. To optimise the efficiency of environmentally-sensitive mosquito control programs, I examine current surveillance and control regimes. Findings indicate that most regimes are required to maintain tight mosquito control, although coastal surveillance could be reduced without a loss of information. I develop accurate predictive models for RRV infections in the Northern Territory, using weather and vector numbers. Such models assist public health campaigns, but rarely provide timely notification for vector control. I therefore created methodologies to produce rainfall thresholds —as early warning systems, which guide mosquito control before vector numbers peak, thereby reducing transmission potential. These findings can assist mosquito control programs in northern Australia and tropical regions worldwide.
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Staples, Kerry. "Evaluation of a mosquito control intervention and recommendations for development of best practice protocols by the Shire of Kalamunda". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2016. https://ro.ecu.edu.au/theses/1800.
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Abstract
The mosquito control program implemented by the Shire of Kalamunda Environmental Health Service has been assessed. Mosquito species and abundance has been evaluated along with an assessment on the current level of pesticide resistance and downstream S‐methoprene levels post‐treatment. The rate of Ross River virus transmission within the Shire has also been considered, along with the relationship between local species and virus transmission.
Methodology
Floating Emergence Traps were used in 15 storm‐water gullies to determine the effectiveness of S‐methoprene briquets in prevention of adult mosquito emergence over 124 days. Samples were taken monthly from October 2014 to March 2015. Two treatment methods were assessed, application of briquet using a float, and application without a float. These were compared to untreated control gullies. The productivity of gullies was also assessed. Twenty‐five carbon dioxide light traps were deployed in a treatment area and repeated in a control area. The treatment and control areas were reversed and sampled again the following season to allow for inter‐area baseline and seasonal differences. Nine water samples were taken and analysed for the presence of S‐methoprene. Samples were taken from the outlet of chains of storm‐water gullies during the first rainfall following application of S‐methoprene briquets in the area.
Results
Storm‐water gullies have been confirmed as a significant source of mosquito breeding and are likely to be increasing the spread of Ross River virus in the area in which they are located. Mosquito breeding peaks in early November, and decreases by February as the hot dry conditions prevent large scale breeding for all species. Gullies produced a mean of 108 mosquitoes per day over the season. Culex quinquefasciatus and Aedes notoscriptus are the most abundant species within the Shire at all times in the season. Numbers of C. quinquefasciatus emerging can exceed 1600 per day per gully. A. notoscriptus breeds to a lesser extent but can still exceed 70 adults per day. Both species are container breeders known to breed profusely in close contact with human habitation.
Treatment with S‐methoprene is highly effective against both species for at least 70 days and partially effective for up to 120 days, treatment provided no control by day 124. A total of 90% control was given over the 124 days. Treatment has a significant impact on the abundance of A. notoscriptus, reducing the population by two thirds at the tail end of the season. This is likely to actively reduce the transmission of Ross River virus (RRV) within the treatment area. Overall effectiveness of the briquet is not impacted significantly by the presence or absence of a float.
Treatment of storm‐water gullies correlates with reduced abundance of Aedes notoscriptus, which is a competent vector of RRV, and was found to be an important transmitter of this disease, especially when numbers of Culex annulirostris are higher than usual. Some improvements and supplements to the program are recommended, including timing of application and gully cleaning programs, and ongoing monitoring for priority vectors and evidence of pesticide resistance.
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Miller, Jane Elizabeth. "Laboratory and field studies of insecticide impregnated fibres for mosquito control". Thesis, London School of Hygiene and Tropical Medicine (University of London), 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322486.
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Latchford, Jane Ann. "The effectiveness and environmental impacts of runnelling, a mosquito control technique". Thesis, Latchford, Jane Ann (1997) The effectiveness and environmental impacts of runnelling, a mosquito control technique. PhD thesis, Murdoch University, 1997. https://researchrepository.murdoch.edu.au/id/eprint/51351/.
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This study is concerned with the effectiveness and ecological impacts of a mosquito control technique called 'runnelling'. The objective of runnelling is to provide a low cost, low maintenance physical modification of the environment to provide effective control of saltmarsh mosquitoes with few other environmental impacts. The major objective of this thesis was to find out if runnelling is an effective means of controlling mosquito populations, and if so, to determine if the technique produces unacceptable changes in the ecology of saltmarshes.
Four saltmarshes were chosen for study, all known mosquito breeding sites in the Peel-Harvey Estuary. The general approach was to monitor populations of flora and fauna in control and funnelled pans before and after runnelling.
There was a significant reduction in larval mosquito populations at all runnelled sites, most consistently in spring and summer. Mosquito populations were reduced to below problem levels in most instances. The runnels operated effectively shortly after construction through a combination of flushing, increased predation and reduced oviposition. Runnel maintenance was high at one site, where they had been incorrectly positioned, but all other runnels only required cutting back of vegetation after summer.
The environmental changes resulting from runnelling were either minimal in comparison to the natural variations encountered on the marsh, or they increased productivity.
Runnelling is recommended as a appropriate method of mosquito control where the productivity of the saltmarsh is important ecologically. It is a safer mosquito control technique than the favoured alternative, the chemical temephos, which can kill non target fauna.
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Byrne, Katharine. "Gene flow and insecticide resistance in the mosquito Culex pipiens". Thesis, Queen Mary, University of London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244074.
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Merryweather, A. T. "Molecular characterisation of esterases implicated in £organophosphate resistance in Culex quinquefasciatus mosquitoes". Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384444.
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Silva, Juliano Juscelino. "Atividade dos fungos entomopatogênicos Tolypocladium cylindrosporum, Lecanicillium psalliotae e Conidiobolus macrosporus isolados de mosquitos no Centro-Oeste do Brasil em Aedes aegypti". Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/7593.
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Microorganisms are agents of biological control, among them, the entomopathogenic fungi stand out. Tolypocladium cylindrosporum IP419 and IP425, Lecanicillium psalliotae IP456, IP491 and IP492 were isolated from sentinel larvae. Conidiobolus macrosporus IP396 and L. psalliotae IP455 isolated from adult culicíneos. At 5 and 15 days, depending on the fungus, conidia were scraped from sporulated culture plates and adjusted in suspensions. In 30 eggs/ replicate, 50 μL of suspension of the isolates IP419, IP425, IP455, IP456, IP491 and IP492 were applied in five concentrations (3.3 × 103 to 3.3 × 105 conidia/cm2). For IP 396, 2.5 × 104 conidia/cm2 was applied. In experiments with larvae (10 L3/repeat), five concentrations were applied (3.3 × 105 to 3.3 × 107 conidia/ml) for IP419, IP425, IP455, IP456, IP491 and IP492, and (103 to 105 conidia/ ml) for IP396. The controls were treated with distilled water. Adults were exposed to five concentrations (3.3 × 104 to 3.3 × 106 conidia/cm2) of conidia of IP419 and IP425. For IP396 and IP455, IP456, IP491 and IP492, adults were exposed to the sporulated culture. Adult controls were not exposed to fungi. Ten adults were exposed in 4 replicates. There was no significant activity of the isolates tested against eggs. Mortality of larvae treated with T. cylindrosporum was ≤ 90% at the lowest concentration (3.3 × 105 conidia/ml) and 100% at the highest concentration (3.3 × 107 conidia/ml). The LC50 and LC90 were 3.5 × 104 conidia/ml and 6.8 × 106 conidia/ml for IP419 and 5.9 × 105 and 1.3 × 107 conidia/ml for IP425. The TL50 and TL90 for IP419 at the highest concentration (3 × 107 conidia/ml) was ≤ 7 hours. The concentrations applied had a significant effect (P <0.001). In larvae treated with IP396, mortality of L3 increased with conidia concentration, in the highest concentration (105 conidia /ml), was ≤ 57% in 48 h. There was no growth of the fungus on L3 exposed in agar medium for IP396, for T. cylindrosporum the fungal development was ≤ 70%. Mortality of larvae in controls was ≤ 15%. L. psalliotae had no larvicidal activity. Mortality of adults treated with T. cylindrosporum was ≤ 75%. There was fungal development on corpses ≤ 65%, the concentrations applied had a significant effect (P <0.001). The cumulative mortality of IP396 treated adults reached 100% after 5 days, and ≥ 80% over 10 days for L. psalliotae. The results show that T. cylindrosporum and C. macrosporus have potential for integrated control of larvae and adults of A. aegypti.
Microrganismos são agentes de controle biológico, dentre eles, destacam-se os fungos entomopatogênicos. Tolypocladium cylindrosporum IP419 e IP425, Lecanicillium psalliotae IP456, IP491 e IP492 foram isolados de larvas sentinela. Conidiobolus macrosporus IP396 e L. psalliotae IP455 isolados de culicíneos adultos. Em 5 e 15 dias, dependendo do fungo, conídios foram raspados de placas com cultura esporulada e ajustados em suspensões. Em ovos (30 ovos/repetição), foram aplicados 50 μL de suspensão dos isolados IP419, IP425, IP455, IP456, IP491 e IP492 em cinco concentrações (3,3 × 103 a 3,3 × 105 conídios/cm2). Para IP396, aplicou-se 2,5 × 104 conídios/cm2. Em testes com larvas (10 L3/repetição), cinco concentrações foram aplicadas (3,3 × 105 a 3,3 × 107 conídios/ml) para IP419, IP425, IP455, IP456, IP491 e IP492, e (103 a 105 conídios/ml) para IP396. Os controles foram tratados com água destilada. Adultos foram expostos a cinco concentrações (3,3 × 104 a 3,3 × 106 conídios/cm2) de conídios de IP419 e IP425. Para IP396 e IP455, IP456, IP491 e IP492, adultos foram expostos à cultura esporulada. Adultos controle não foram expostos aos fungos. Foram expostos 10 adultos, em 4 repetições. Não houve atividade significante dos isolados testados contra ovos. A mortalidade de larvas tratadas com T. cylindrosporum, foi ≤ 90% na menor concentração (3,3 × 105 conídios/ml) e 100% na maior concentração (3,3 × 107 conídios/ml). A CL50 e CL90 foi de 3.5 × 104 conídios/ml e 6.8 × 106 conídios/ml para IP419 e de 5.9 × 105 e 1.3 × 107 conídios/ml para IP425. O TL50 e TL90 para IP419, na maior concentração (3 × 107 conídios/ml) foi ≤ 7 horas. As concentrações aplicadas tiveram efeito significativo (P < 0,001). Em larvas tratadas com IP396, a mortalidade de L3 aumentou com a concentração de conídios, na maior concentração (105 conídios/ml), foi ≤ 57% em 48 h. Não houve crescimento do fungo sobre L3 expostas em meio ágar para IP396, para T. cylindrosporum o desenvolvimento fúngico foi ≤ 70%. A mortalidade de larvas nos controles foi ≤ 15%. L. psalliotae não teve atividade larvicida. A mortalidade de adultos tratados com T. cylindrosporum foi ≤ 75%. Houve desenvolvimento fúngico sobre cadáveres ≤ 65%, as concentrações aplicadas tiveram efeito significativo (P < 0,001). A mortalidade acumulada de adultos tratados com IP396 chegou a 100% após 5 dias, e ≥ 80% em dez dias para L. psalliotae. Os resultados mostram que T. cylindrosporum e C. macrosporus têm potencial para controle integrado de larvas e adultos de A. aegypti.
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Marbiah, Nuahn Tomanh. "Control of disease due to perennially transmitted malaria in children of rural Sierra Leone". Thesis, London School of Hygiene and Tropical Medicine (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244618.
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Hammond, Andrew Marc. "The development of gene drives for genetic control of the malaria mosquito". Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/53131.
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Genetic drive systems have the potential to modify entire insect populations in a few years through the super-Mendelian inheritance of a genetic trait. We describe a novel gene drive system called CRISPRh, which acts as a selfish genetic element in the malaria mosquito Anopheles gambiae. CRISPRh is a synthetic allele containing CRISPR/Cas9 endonuclease designed to specifically target and insert a copy of itself into its homologous chromosome in the germline of heterozygous individuals. Using a gene targeting approach, we identified three genes that confer recessive female sterility upon disruption. By inserting CRISPRh at each of these genes, we achieved super-Mendelian inheritance of CRISPRh alleles, ranging from 91 to 99.6% of the progeny of heterozygotes. Population modelling predicts that these high rates of transmission and a recessive knockout phenotype would enable CRISPRh alleles to spread rapidly through a wild mosquito population, causing population suppression through the generation of sterile females. We tested the potential of one CRISPRh allele to invade a caged population of naïve mosquitoes and observed an average increase from 50-76.4% over six generations, demonstrating the first gene drive designed to spread through a natural vector population. The CRISPRh constructs described here generate strong unintended fertility effects and are highly susceptible to target site resistance, making them unsuitable for malaria control. We expect that simple modifications can solve these issues and allow the development of gene drives for the suppression of mosquito populations to levels that do not support malaria transmission.
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Abdoarrahem, Mostafa Mohamed Omar. "Factors influencing the activity of mosquito control agent (Bacillus thuringiensis subsp. israelensis)". Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/54112/.
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For toxicity, B. thuringiensis must be taken into the larval midgut, where a community of other bacteria is already present. The culturable flora from the Aedes aegypti mosquito midgut was analysed and its role in larval growth and insect mortality was determined. In contrast to published reports concerning B. thuringiensis subsp. kurstaki, subsp. israelensis caused toxicity and larval death even in the absence of other bacteria. The pBtoxis plasmid of B. thuringiensis subsp. israelensis encodes all the mosquitocidal toxins and a number of other coding sequences. The potential effects of selected genes on host phenotype was assessed. No evidence was found for antibiotic production from putative antibiotic synthesis genes. The plasmid also carries potential germination genes organised in a single ger operon. Comparison of the germination responses of spores from strains with and without pBtoxis revealed that this plasmid could promote activation of the spores under alkaline conditions but not following heat treatment. Introduction of the ger operon on a recombinant plasmid to the plasmidless strain established this operon as the first with an identified role in alkaline activation. Mosquito midgets provide an alkaline environment and in which enhanced germination may occur. Co-feeding experiments showed that in competition to colonise intoxicated A. aegypti larvae, B. thuringiensis carrying pBtoxis, are able to outgrow the plasmid-cured strain. This indicates a selective advantage for the presence of pBtoxis. The strain carrying the recombinant ger genes also outgrew its plasmidless parent, indicating that the ger genes may be responsible for this effect, perhaps by allowing strains a head-start by germinating more rapidly in the insect gut.
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Molloy, Jennifer C. "Wolbachia-mosquito interactions and engineered female-specific lethality for Aedes-arbovirus control". Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:d7556f27-9f04-4355-9191-9d3477ce5b94.
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Aedes aegypti and Aedes albopictus are the primary vectors of dengue (DENV) and chikungunya (CHIKV) viruses, causing millions of infections annually. Novel genetic mosquito control methods are being trialled, including population replacement using disease refractory mosquitoes transinfected with the intracellular bacterial endosymbiont Wolbachia, and population suppression by release of male mosquitoes carrying self-limiting genes. The underlying cause of Wolbachia-induced DENV refractoriness is unconfirmed. In Chapter 2, I examine in Ae. albopictus the hypothesis that reactive oxygen species (ROS) induced immune activation plays a role, but neither ROS nor innate immune pathways were upregulated. In Chapter 3, an untargeted analysis of the Ae. albopictus lipidome showed it is significantly altered by Wolbachia infection, highlighting sphingolipids as candidates for future investigations into DENV-refractoriness. Genetic constructs for population suppression are better characterised than Wolbachia-host interactions but incompletely described modes of action and reliance on random genome integration to control expression fails to take full advantage of engineering approaches to design optimal genetic control phenotypes. In Chapter 4, I engineer female-specific, late-acting lethality in Ae. aegypti using specific effectors crossed with candidate pupal-stage promoters and a doublesex cassette causing sexspecific splicing. In Chapter 5, I transform and characterise Ae. aegypti lines producing sex-specific Drosophila melanogaster alcohol dehydrogenase (Adh) to evaluate potential for early-stage inducible genetic sexing. No effective lines were produced but I suggest future design alterations. Overall, this thesis contributes to understanding the molecular mechanisms underlying two distinct genetic control strategies in Aedes mosquitoes. It promotes the use of that mechanistic knowledge to engineer optimal traits for control and for improving mass-rearing methods to meet the clear need for effective and economical area-wide control of arbovirus vectors.
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Morris, Alison Claire. "Genetic transformation of the mosquito Aedes aegypti using a transposable genetic element". Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279703.
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Theron, Dirk Leopold. "The biological control of malaria mosquito larvae using smaller indigenous freshwater fish species". Thesis, University of Limpopo, 1987. http://hdl.handle.net/10386/2611.
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Rightor, John Albert. "An integrated mosquito management program for James City County, Virginia". Thesis, This resource online, 1987. http://scholar.lib.vt.edu/theses/available/etd-11072008-063536/.
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Jenkins, Adam. "Analysis of anopheline mosquito behavior and identification of vector control targets in the post-genomic era". Thesis, Boston College, 2015. http://hdl.handle.net/2345/bc-ir:104489.
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Thesis advisor: Marc A.T. MuskavitchThe protozoan Plasmodium falciparum, the mosquito-borne pathogen that causes human malaria, remains one of the most difficult infectious parasites to combat and control. Campaigns against malaria eradication have succeeded, in most instances, at the level of vector control, rather than from initiatives that have attempted to decrease malaria burden by targeting parasites. The rapid evolution and spread of insecticide-resistant mosquitoes is threatening our ability to combat vectors and control malaria. Therefore, the development, procurement and distribution of new methods of vector control are paramount. Two aspects of vector biology that can be exploited toward these ends are vector behaviors and vector-specific insecticide targets. In this thesis, I describe three aspects of vector biology with potential for the development of improved means of vector control: photopreference behavior, long non-coding RNA (lncRNA) targets and epigenetic gene ensemble targets. My studies of photopreference have revealed that specific mosquito species within the genus Anopheles, An. gambiae and An. stephensi, exhibit different photopreference behaviors, and that each gender of mosquito in these species exhibits distinct light-dependent resting behaviors. These inter-specific behavioral differences may be affected by differing numbers of long-wavelength sensing Opsin genes in each species, and my findings regarding species-specific photopreferences suggest that some behavioral interventions may need to be tailored for specific vector mosquito species. Based on the advancement of next-generation sequencing technologies and the generation by others of assembled genomes of many anopheline mosquito species, I have identified a comprehensive set of approximately 3,000 lncRNAs and find that RNA secondary structures are notably conserved within the gambiae species complex. As lncRNAs and epigenetic modifiers cooperate to modulate epigenetic regulation, I have also analyzed the conservation of epigenetic gene ensembles across a number of anopheline species, based on identification of homologous epigenetic ensemble genes in An. gambiae compared to Drosophila melanogaster. Further analyses of these ensembles illustrate that these epigenetic genes are highly stable among many anopheline species, in that I detect only eight gene family expansion or contraction events among 169 epigenetic ensemble genes within a set of 12 anopheline species. My hope is that my findings will enable deeper investigations of many behavioral and epigenetic processes in Anopheles gambiae and other anopheline vector mosquitoes and thereby enable the development of new, more effective means of vector and malaria control
Thesis (PhD) — Boston College, 2015
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Biology
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Yusof, Muhammad Zubir. "Mosquito control workers in Malaysia : is lifetime pesticide exposure associated with health impacts?" Thesis, University of Aberdeen, 2016. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=230766.
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Use of pesticides has been linked to health effects among exposed workers. Organophosphate and pyrethroid pesticides are commonly used to control mosquito-borne diseases in Malaysia. This project aimed to estimate workers' lifetime exposure to pesticides and to examine the relationship between that exposure and health-related quality of life and neurobehavioural performances. A total of 158 workers who had regular contact with pesticides and 176 officebased workers were recruited to the study. Information on past exposure was collected through questionnaire and occupational history interview to help reconstruct workers' historical exposures. Personal inhalation and dermal exposure measurement were carried out to evaluate current pesticide exposure. Subjective inhalation and dermal models were used to allow the estimation of combined pesticide intake for each worker. Neurobehavioural performance was assessed using CANTAB® computerized tests. Total lifetime pesticides intake for exposed workers ranged from 0.006 g to 12,800 g (median (IQR) = 379 g (131, 794)). Estimated dermal exposure accounted for the majority of total lifetime intake of pesticides (median (IQR) = 369 g (128, 772)). After adjusting for age, education, smoking and BMI, exposure to pesticides was associated with lower physical health scores. All of the neurobehavioural performance test scores, with the exception of Reaction Time (RT) and Pattern Recognition Memory (PRM) tests, showed significant differences in relation to total lifetime pesticides intake after adjusting for age, education and smoking. The majority of pesticide-exposed workers indicated a positive awareness about pesticide risk. However, this awareness was not reflected to their selfprotective behaviours such as wearing PPE. Findings from this study suggest that lifetime pesticide intake is associated with physical health and cognitive impairment. It is not clear if this association is causal. Occupational hygiene control measures should focus on reducing the amount of pesticides workers get on their skin due to the high percentage of total intake arising from dermal exposure.
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Kröger, Iris Angela [Verfasser]. "The role of crustaceans within an integrated mosquito control management / Iris Angela Kröger". Landau : Universitätsbibliothek Landau, 2014. http://d-nb.info/1048022218/34.
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Francis, Stephen Starko. "West Nile virus in Nevada : mosquito infection rates and weather /". abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1440921.
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Thesis (M.S.)--University of Nevada, Reno, 2006."December, 2006." Includes bibliographical references (leaves 29-33). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2006]. 1 microfilm reel ; 35 mm.
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Nsengimana, Ferdinand. "Comparison of Malaria Control Interventions in Southern Africa". ScholarWorks, 2018. https://scholarworks.waldenu.edu/dissertations/5918.
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There is lack of evidence on which of the two highly recommended malaria prevention methods, insecticide treated bednets and indoor residual spraying, is more effective than the other. There is also limited peer reviewed literature that compares the characteristics of people who use the two malaria prevention methods. Based on the Health Belief Model, the research questions tested whether there is any relationship between the use of mosquito bednet or the use of indoor residual spraying and contracting malaria, and whether there is any relationship between sociodemographic and socioeconomic factors and the use of malaria prevention methods. Using a quantitative research design, secondary data from the 2011 Angola malaria indicator survey were analyzed. Chi-square for association, logistic regression, and multinomial logistic regression tests were used. There was no statistically significant association between the use of mosquito bednet and having malaria. However, the use of indoor residual spraying significantly reduced the likelihood of getting malaria. There was also a statistically significant association between place of residence, wealth index, level of education, and number of household members and using mosquito bednet and between wealth index and using indoor residual spraying. In conclusion, the malaria prevention programs should focus on indoor residual spraying. It is recommended that all households in southern Africa malaria prone areas should be regularly sprayed. The findings of this study contribute to positive social change in the sense that by using more effective malaria prevention method, individuals will be able to function normally on daily basis, save on expenses related to employment loses or treatment and care of the sick, as well as loss of life and improve own economic status.
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Araujo, Anderson Luis Albuquerque de. "Analise matematica de um modelo de controle de populações de mosquitos". [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/307407.
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Orientador: Jose Luiz BoldriniDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica
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Resumo: Neste trabalho, consideramos um problema de controle ótimo governado por uma equação diferencial parcial parabólica, que modela o crescimento e a difusão de uma população de mosquitos em uma certa região do plano. Para este modelo relativamente simples, mostramos a existência de uma trajetória ótima a ser seguida por uma unidade volante de pulverização de inseticida, no sentido de minimizar um certo funcional que leva em conta a população total de mosquitos bem como os custos da operação. Caracterizamos também tais trajetórias (controles) ótimas pela derivação de suas respectivas condições de otimalidade de primeira ordem. Para isso, usamos o formalismo de Dubovitskii e Milyutin, o qual está baseado na separação de certos cones associados ao funcional a ser minimizado e ás restrições do problema, incluindo a equação. Também analisamos o problema do ponto de vista do método de penalização
Abstract: In this work, we consider an optimal control problem governed by a parabolic partial differential equation, which models the growth and diffusion of a mosquito population in a certain region of the Euclidean plane. For this relatively simple model, we show the existence of an optimal trajectory to be followed by a insecticide spraying device, in the sense of minimizing a certain functional that takes in consideration both the the total mosquito population and the operational costs. We also characterize such optimal trajectories (controls) by deriving their respective first order optimal conditions. For this, we use the Dubovitskii and Milyutin formalism, which is based on the separation of certain cones associated to the functional to be minimized, and to the restrictions of the problem, including the equation. We also analyze the problem from the point of view of the penalization method
Mestrado
Analise Matematica
Mestre em Matemática
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Silva, Filho Cícero Alfredo da 1977. "Problemas de controle ótimo com restrições envolvendo a equação de transporte com renovação". [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/307412.
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Orientador: José Luiz BoldriniTese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação Científica
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Resumo: O objetivo do trabalho é o de analisar de forma matematicamente rigorosa dois problemas de controle ótimo com restrições dadas por sistemas de equações diferenciais que incluem a equação de transporte com renovação, bem como um conjunto de restrições para a classe dos controles. Tais sistemas modelam as dinâmicas de populações de mosquitos (considerados em dois grupos: indivíduos jovens, em fase aquática, e adultos) e suas interações com os recursos do meio ambiente (alimentos, por exemplo); além disso, leva-se em conta o processo de maturação da população jovem, a qual fica, portanto estruturada por idade e cuja dinâmica é governada por uma equação de transporte com renovação. Nestes problemas, as populações estão submetidas à atuação de um controle externo, um agente químico, por exemplo, que afeta as respectivas taxas de mortalidade, modificando-as; no caso dos indivíduos jovens, tal atuação pode depender do nível de maturação (idade) do indivíduo. O primeiro problema considera apenas a variação no tempo da população de adultos, enquanto que o segundo problema leva em conta também a sua distribuição espacial. Em cada um desses problemas, mostra-se, sob certas condições, a existência de controle ótimo, isto é, um controle que minimiza um dado funcional objetivo; obtêm-se também as correspondentes condições de otimalidade que caracterizam tal controle ótimo
Abstract: The objective of this work is to analyze in a mathematically rigorous way two optimal control problems with restrictions given by systems of differential equations including the transport equation with renewal, as well as, a restriction set for the controls. Such systems model the dynamics of mosquito populations (considered in two groups: young individual, in aquatic phase, and adults) and their interaction with the environmental resources (food material, for instance); moreover, the maturation process of the population of young individuals is taken in consideration, and thus it becomes age structured and its dynamics is governed by a transport equation with renewal. In these problems, the populations are submitted to the action of an external control, a chemical agent, for instance, which affects the respective mortality rates, changing them; in the case of the young individuals, such action may depend on the individual maturation level. The firs problem considers only the time variation of the adult population; the second problem takes in consideration also its spatial distribution. In each of those problems, it is shown that, under certain conditions, there exists optimal contra, that is, a control minimizing a given objective functional; the associated optimality conditions characterizing such optimal controls are also obtained
Doutorado
Matematica Aplicada
Doutor em Matemática Aplicada
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Vyas-Patel, N. "Romanomermis species (Nematoda: Mermithidae), as biocontrol agents for larval mosquito control in East Africa". Thesis, University of Reading, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.255206.
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White, Stephanie Lyn. "A comparison study of gravid and under house CO2 mosquito traps in Harris County, Texas". Texas A&M University, 2008. http://hdl.handle.net/1969.1/85981.
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Harris County Mosquito Control Division (HCMCD) is responsible for
surveillance of mosquito species that are vectors of St. Louis Encephalitis (SLE) virus
and West Nile Virus (WNV) within Harris County, Texas, including the Houston
metroplex. The metroplex area has some unique attributes and a vast variety of
environmental habitats that are attractive to vectors of arboviruses and for the
transmission of arboviruses to the human population. Data describing the efficacy of
Gravid (GV) and Underhouse (UH) CO2 traps were analyzed to determine if there is a
significant difference between these two trap types with respect to the number of
mosquitoes and the variety of mosquito species caught. This study was conducted during
the off-peak HCMCD trapping season, to gain information in preparation for a yearround
trapping program utilizing Underhouse CO2 traps for WNV and SLE virus
surveillance.
Adjusting for the week of collection, results suggest that Gravid traps caught
significantly (P = 0.009) more mosquitoes (mean = 23.134 per trap) in the study area
than Underhouse traps (mean = 3.616 per trap), and that Underhouse Traps caught a larger variety of mosquito species (n = 13) than Gravid Traps (n = 11), out of 15 total
different species caught. Gravid and Underhouse traps caught 9 out of 15 of the same
mosquito species during the study period. Culex quinquefasciatus mosquito catches in
Gravid traps and temperature were strongly correlated (Spearman's Correlation
Coefficient = 0.707, P = 0.005).
Geographic Information System spatial analysis indicated clustering of Culex
quinquefasciatus mosquito catches in both Gravid traps, week 9 and 21 (Moran's I =
0.69, P = 0.040 and 0.74, P = 0.021, respectfully ) and Underhouse traps, week 13 and
19 (Moran's I = 0.92, P = 0.002, and 0.89, P = 0.011, respectfully).
It is recommended that Harris County Mosquito Control Division continue to
utilize gravid traps as a primary method of surveillance. Gravid traps (16,194) caught
85% more mosquitoes than Underhouse traps (2,531) over the fourteen week study
period. Their overall success far outweighs the additional materials or labor required for
their use in a successful surveillance program.
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Araujo, Anderson Luis Albuquerque de. "Análise matemática de um modelo de controle de populações de mosquitos". [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/307380.
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Orientador: Jose Luiz BoldriniTese (doutorado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica
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Resumo: A proliferação de mosquitos em regiões habitadas é uma importante questão de saúde pública, uma vez que tais insetos são vetores de várias doenças infecciosas. Assim, o estudo de técnicas de controle de populações de mosquitos tem um papel relevante na busca da eficiência no seu combate; em particular, a compreensão adequada de modelos matemáticos que descrevem tais situações pode auxiliar na tomada de decisão sobre quais seriam os procedimentos mais adequados para atingir este fim. Com este objetivo, neste trabalho fizemos a análise matemática rigorosa de um certo problema de controle ótimo associado a uma equação diferencial parcial que modela o crescimento e a difusão de uma população de mosquitos em uma região dada. Analisamos o problema de controlar tal população através da aplicação de inseticida por uma unidade volante de pulverização, buscando trajetórias ótimas a serem seguidas por esta unidade a fim de minimizar um certo funcional que envolve tanto a população total quanto os custos da operação
Abstract: The proliferation of mosquitoes in inhabited regions is an important public health issue since these insects are vectors of several infectious diseases. Thus, the study of techniques for controlling of mosquito populations has an important role in the quest for efficient combat techniques; in particular, the adequate understanding of mathematical models that describe such situations may help in the decision process of finding appropriate procedures to attain that. With this goal, in this work we performed a rigorous mathematical analysis of a certain optimal control problem associated to a partial differential equation modeling the growth and spreading of the mosquito population in a given region. We analyze the problem of controlling such population through the application of insecticide by a spraying unit; our objective is to search for optimal paths to be followed by this unit in order to minimize a certain functional that involves both the whole mosquito population and the operational costs
Doutorado
Analise Matematica
Doutor em Matemática
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Acheson, Emily. "Predicting Disease Vector Distributions Through Space and Time Using Environmental and Vector Control Data". Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32797.
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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.
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Dongus, Stefan. "Urban agriculture and operational mosquito larvae control : mitigating malaria risk in Dar es Salaam, Tanzania /". [S.l.] : [s.n.], 2009. http://edoc.unibas.ch/diss/DissB_8749.
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Hurst, Timothy Parker. "Evaluation of Australian native fish and lavicides for the integrated control of freshwater mosquito vectors /". [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18164.pdf.
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Mutunga, James Mutuku. "Molecular, Biochemical, and Toxicological Evaluation of Anticholinesterases for control of the Malaria Mosquito, Anopheles gambiae". Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/51210.
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Pyrethroids are the only class of insecticides approved by the World Health Organization (WHO) for use in insecticide treated nets (ITNs), the first line of malaria vector control. Widespread resistance development to pyrethroids undermines current control efforts, and hence an urgent need for alternative chemistries. I report the evaluation of pharmacological differences between insect and vertebrate acetylcholinesterase (AChE) as well as selectivity and toxicity testing of new carbamate insecticides on Anopheles gambiae, the African malaria mosquito. AChE gorge pharmacology data revealed differences between insect and vertebrate AChE that can be exploited in the design of a bivalent insecticide. Toxicokinetic analysis showed that metabolic detoxication and cuticular penetration affect toxicity of carbamates in a manner dependent on the chemical structure.
Structure activity relationships of side-chain branched N-methylcarbamates emphasized the importance of structural complementarity of ligands to the AChE catalytic active site and the substrate, acetylcholine. Monovalent pyrazoles and acetophenone oxime carbamates were toxic to both susceptible and carbamate-resistant mosquitoes carrying a G119S mutation within the catalytic site. A bivalent phthalimide-pyrazole carbamate and sulfenylated phenyl N-methyl carbamates were highly toxic when topically applied onto insect but less toxic by treated filter paper assays. In vitro evaluation of a molecular mosquito-selectivity model using AChE peripheral site ligands confirmed that selectivity of PRC 472 was due to presence of I70 in mosquito, which is Y70 in human AChE. The findings presented here are important steps in the on-going search of a mosquito-selective and resistance mitigating carbamate insecticide for control of malaria mosquitoes.Ph. D.
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Sikaala, Chadwick. "Community-based monitoring of vector control interventions impact upon mosquito population dynamics in rural Zambia". Thesis, University of Liverpool, 2014. http://livrepository.liverpool.ac.uk/2006479/.
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Over the last decade, the malaria burden has reduced drastically across many parts of sub-Saharan Africa. This is mainly due to effective implementation of integrated malaria control programmes that include large scale application of vector control in the form of long-lasting insecticidal nest (LLINs) and indoor residual spraying (IRS), both of which target the most efficient human-seeking malaria vector species. However, in spite of these efforts, malaria has yet to be eliminated from most of Africa. However, recent increases in the physiological resistance of vector populations, especially to the pyrethroids that remain the only active ingredients currently used on nets threaten these achievements. Furthermore, various forms of behavioural resilience and resistance exhibited by some vector species to LLIN and IRS delivery formats for insecticides respectively limit and undermine these valuable impacts upon malaria transmission. To monitor the impact that LLINs and IRS have on vector population dynamics and malaria transmission, more effective, practical and affordable entomological surveillance systems are required. Currently, surveillance of mosquito populations are conducted by the centralized specialist teams with limited personnel, resources and geographic outreach. None of these existing systems can adequately monitor vector population dynamics longitudinally across the vastness of entire countries. The overall goal of the study was to demonstrate how a community-based surveillance system can be applied to longitudinally monitor vector population dynamics and assess the impact that LLINs and IRS have on malaria transmission in rural Zambia. To achieve this overall goal, the following specific objectives were addressed: (1) To evaluate the efficacy of exposure-free mosquito trapping methods for measuring malaria vector density, as alternatives to human landing catch; (2) To assess the cost-effectiveness using a community-based (CB) mosquito trapping scheme for monitoring vector population dynamics; (3) To determine the extent to which a community-based mosquito trapping scheme captures trends in epidemiological indicators of malaria infection risk; (4) To determine the impact of indoor residual spraying with different classes of insecticides on malaria infection burden and vector abundances in an area of high coverage with insecticide treated nets using a community-based platform. To address objective 1, a 3 x 3 Latin square method was used to evaluate the sensitivity of the Center for Disease and Control and Prevention miniature light traps (LT), the Ifakara tent trap (ITT), window exit traps (WET) and the resting boxes (RB) using the golden standard human land catch (HLC) as the reference method. The mean catches of HLC indoor, HLC outdoor, CDC-LT, ITT, WET, RB indoor and RB outdoor, were 1.687, 1.004, 3.267, 0.088, 0.004, 0.000 and 0.008 for Anopheles quadriannulatus Theobald respectively, and 7.287, 6.784, 10.958, 5.875, 0.296, 0.158 and 0.458, for An. funestus Giles, respectively. The LT (Relative rate (RR) [95% Confidence Interval] = 1.532 [1.441, 1.628] P < 0.001) and ITT (RR = 0.821 [0.765, 0.881], P < 0.001), were the only exposure-free alternatives which had comparable sensitivities relative to HLC indoor for sampling An. funestus. To address objectives 2 and 3, the two most sensitive of these exposure-free trapping methods, the LT and ITT, were applied through a CB longitudinal entomological surveillance system implemented by local community health workers (CHW) trained in basic entomology. This surveillance platform was conducted using a monthly sampling cycle for over 2 years in 14 population clusters distributed across two rural districts covering over 4,000km2 of south-east Zambia. Parallel active surveillance of malaria parasite infection rates amongst humans was also conducted by CHWs in the same population clusters to determine the epidemiological relevance of these CB entomological surveys. Prior to the end of the study, a controlled quality assurance (QA) survey was conducted by a centrally supervised expert team using HLC, LT and ITT to evaluate accuracy of the CB trapping data. While the relative sampling efficiencies of both CB surveys were less than their QA counterparts, the costs of implementing per sampling night were far less expensive than any QA survey. The cost per specimen of Anopheles funestus captured was lowest for CB-LT ($5.3), followed by potentially hazardous QA-HLC ($10.5) and then CB-ITT ($28.0). Time-trends of malaria diagnostic positivity (DP) followed those of An. funestus density with a one-month lag and the wide range of mean DP across clusters was closely associated with mean densities of An. funestus caught by CB-LT (P<0.001). To address objective 4, the same 14 cluster populations, with pre-existing high coverage of pyrethroid-impregnated long-lasting insecticidal nets (LLINs), were quasi-randomly assigned to receive IRS with either of two pyrethroid formulations, namely Deltamethrin (Wettable granules (WG)) (DM-WG) and Lambdacyhalothrin (Capsule suspension (CS)) (LC-CS), or with an emulsifiable concentrate (EC) or CS formulation of the organophosphate pirimiphosmethyl (PM), or with no supplementary vector control measure. DP conducted is described in objective 2. Over the first 3 months, the PM-CS IRS supplement offered the greatest level of protection against malaria followed by LC-SC and then by DM-WG. Neither pyrethroid formulation provided protection beyond 3 months after spraying, but both PM CS and EC formulations persisted for 6 months and 12 months respectively. The CS formulation of PM provided greater protection than the combined pyrethroid IRS formulations throughout its effective life (Incremental protective efficacy (IPE) [95%CI] = 0.79 [0.75, 0.83]) over 6 months. The EC formulation of PM provided incremental protection for the first three months (IPE [95%CI] = 0.23 [0.15, 0.31]) that was approximately equivalent to the two pyrethroid formulations (LC-CS, IPE [95%CI] = 0.31 [0.10, 0.47] and DM-WG, IPE [95%CI] = 0.19 [-0.01, 0.35]) but the additional protection provided by the former, apparently lasted an entire year. There were no obvious differences in the densities of An. funestus during the first three months post-spraying for both pyrethroid formulations (DM-WG (IPE[95%CI]=0.01[-0.56,0.37],P=0.103) and LC-CS (IPE[95%CI]=-0.03[-0.88,0.44],P=0.195) and PM-EC (IPE[95%CI]=-0.04[-0.30,0.17], P=0.103). However, where PM-CS was applied, mosquito densities were dramatically reduced during the same period (IPE [95%CI] =0.93[0.87, 0.97], P<0.001). Between the fourth and the sixth month after spraying with DM-WG, there was an apparent, but presumably spurious, three-fold increase in An. funestus densities while LC-CS, PM-EC and PM-CS achieved 5, 3 and 71-fold reductions, respectively. However, from the seventh to twelfth months after spraying, DM-WG and PM-EC had no obvious effect on the An. funestus densities while insufficient data was available to examine the incremental impact of LC-CS or PM-CS. When applied at this pilot scale, this CB mosquito-trapping scheme provided entomological evidence that complements epidemiological monitoring data to demonstrate how supplementing LLINs with IRS can reduce malaria transmission beyond levels achieved with LLINs alone in this setting where physiological resistance to pyrethroids occurs, especially when a non-pyrethroid organophosphate insecticide is used. Overall, it appears that CB trapping schemes are affordable, cost-effective, and epidemiologically relevant. It also appears, based on the evidence from this pilot scale evaluation, that they may be applicable to routine programmatic monitoring of vector population dynamics on unprecedented national scales.
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Obermayr, Ulla Verfasser], i Joachim [Akademischer Betreuer] [Ruther. "Development and Evaluation of Push-Pull Strategies in Mosquito Control / Ulla Obermayr. Betreuer: Joachim Ruther". Regensburg : Universitätsbibliothek Regensburg, 2016. http://d-nb.info/1107761913/34.
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Chebabi, Abramides Gisela. "Effectiveness of an Integrated Vector Management control strategy for the tiger mosquito (Aedes albopictus): a case study in Sant Cugat del Vallès (Barcelona)". Doctoral thesis, Universitat Autònoma de Barcelona, 2012. http://hdl.handle.net/10803/117521.
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El mosquito tigre, Aedes albopictus (Skuse, 1894), es una especie invasora que actualmente se encuentra en los cinco continentes, extendiéndose desde su área nativa en el sudeste de Asia a través del comercio internacional de neumáticos usados y del bambú de la suerte. En Cataluña fue detectado por primera vez en el año 2004, en el municipio Sant Cugat del Vallès, y se expandió rápidamente en los últimos cinco años a más de 200 municipios de Cataluña y Alicante. Esta especie es un vector de diferentes arbovirosis, y ha sido asociada con la transmisión del virus del dengue y la chikungunya en varias zonas del mundo, causando una gran preocupación a las personas y las autoridades de salud pública. En Europa, el brote de fiebre chikungunya que ocurrió en Italia en 2007, y los posteriores casos autóctonos de dengue en Francia y Croacia en 2010, acentuaron la necesidad de establecer programas efectivos de vigilancia y control del vector.
Los objetivos de este estudio fueron: (1) Evaluar la efectividad de una estrategia de gestión integrada de vectores para el control de la población de Aedes albopictus en Sant Cugat del Vallès (2), determinar algunos factores que afectan las poblaciones de mosquitos en los domicilios inspeccionados durante las campañas "puerta-a-puerta", (3) describir los recipientes preferidos por las larvas de la especie, (4) analizar la percepción y la participación de la población de Sant Cugat en el control de esta especie invasora y (5 ) proponer como estrategia de control un protocolo específico para la localidad.
En total se visitaron 3.720 viviendas y se entrevistó a 720 personas. Además durante 2008-2010 se aplicó en seis barrios del área un programa de gestión integrada para controlar al mosquito tigre. La estrategia incluyó la reducción de los focos de cría (con visitas puerta-a-puerta), los tratamientos larvicidas (Bacillus thuringiensis israelensis y diflubenzuron), tratamientos adulticidas (alfa-cipermetrin) y la limpieza de los vertederos incontrolados. En 2010 también se realizó un estudio de las densidades de larvas en los recipientes donde fueron detectadas. La efectividad de la introducción se evaluó con un modelo lineal generalizado donde la variable dependiente fue la abundacia de huevos de mosquitos monitorizados a través de trampas de oviposición.
Los resultados mostraron un número significativamente inferior de huevos en las áreas intervenidas en 2008-2009 comparadas con las áreas control. En 2008, las medianas acumuladas de huevos fueron respectivamente de 175 y 272 en las zonas de intervención y control; en 2009, estas medianas fueron de 884 y 1668 huevos. En los tres años estudiados se observó relación entre algunos factores ambientales y una mayor detección de recipientes con crecimiento de larvas destacando: las instalaciones con huertas (15%; IC 95%: 9-20%), materiales apilados (15%; IC 95%: 9-20%), locales comerciales (11%; IC del 95%: 7-15%), gallineros (5%; IC 95%: 2-8%) y obras (3%; IC 95%: 1-6%).
En el estudio de la densidad larvaria, destacaron los pequeños contenedores (≤0,5 l) como preferidos para el desarrollo de la especie. Imbornales, bidones, residuos sólidos y cubos fueron frecuentemente detectados con crecimiento de larvas de Aedes albopictus.
La cooperación ciudadana, un factor esencial para el éxito, fue elevada gracias a la colaboración de los propietarios de las casas que facilitaron el acceso al interior de sus viviendas privadas. Estos hallazgos sugieren que la estrategia fue efectiva para disminuir el número de huevos. Finalmente, presentamos un protocolo basado en en la estrategia utilizada para controlar esta especie durante estos años. Este trabajo podría utilizarse como modelo para controlar las poblaciones de Ae. albopictus en otros municipios de la región del Mediterráneo.The Asian tiger mosquito, Aedes albopictus (Skuse, 1894), is an invasive species that is currently found in the five continents, spreading from its native area in Southeast Asia through the international trade of used tires and lucky bamboo. In Catalonia it was first reported in 2004 in the municipality of Sant Cugat del Vallès, and has quickly expanded over the last five years to more than 200 municipalities in Catalonia and Alicante. This species is a vector of several arboviruses, and it has been associated with the transmission of dengue and chikungunya virus in several areas of the world causing serious concerns to people and public health authorities. In Europe, the outbreak of chikungunya fever in Italy during 2007, and subsequent autochthonous cases of dengue fever in France and Croatia in 2010, raised the urgency of establishing effective surveillance and control programs for the vector. The objectives of this study were: (1) To evaluate the effectiveness of an Integrated Vector Management (IVM) control strategy of the Aedes albopictus population in Sant Cugat del Vallès; (2) to determine the several key factors affecting mosquito populations in the premises inspected during the “door-to-door” campaigns; (3) to describe the larval containers preferred by the species; (4) to explore the perception and the involvement of the population of Sant Cugat in the control of this invasive species and (5) to propose a standard protocol towards an IVM control strategy at local level. During 2008-2010 an IVM campaign was performed in six neighbourhoods of Sant Cugat del Vallès. The IVM strategy included source reduction campaign (with door-to-door visits), larvicide treatments (Bacillus thuringiensis israelensis and diflubenzuron), adulticide treatments (alpha-cipermetrin) and cleaning up uncontrolled landfills. The effectiveness of the introduction was evaluated through Generalised Linear Models based on the differences in the abundance of mosquitoes monitored through oviposition traps. In addition in 2010 a larval survey was carried out. In total 3720 dwellings were visited and 820 householders were interviewed. The results showed the number of eggs significantly reduced in the intervened areas in 2008-2009 when compared to the control ones. In 2008, the accumulate median of eggs was 175 and 272 in the intervention and control areas, respectively. In 2009, these medians were 884 and 1668 eggs. In the three study years an association was observed between some environmental factors, such as premises with vegetable garden (15%; CI 95%: 9-20%), stacked materials (15%; CI 95%: 9-20%), coops (5%; CI 95%: 2-8%) as well as commercial premises (11%; CI 95%: 7-15%), and sites with works (3%; CI 95%: 1-6%), with the detection of larval breeding containers. The larval density surveys highlight small containers (≤0.5 l) as preferred breeding sites for this species. In the peridomestic areas of the inspected premises, containers as scuppers, drums, solid waste and buckets were frequently found with Aedes albopictus larval breeding. Citizen cooperation proved to be an essential factor for success. A high level of collaboration by the home onwers, who allowed entry into their private dwellings was attained. These findings suggest that the strategy was effective in reducing the number of eggs. Finally, we propose a protocol building on our practical experience and research on the control of this species over the years of this study. This work might be a model for controlling the populations of Ae. albopictus in other municipalities of the Mediterranean region.