Novas alternativas são necessárias para controlar o mosquito transmissor da dengue, como a manipulação genética. Baseada na técnica do inseto estéril (SIT) que compreende a esterilização, a criação em massa e a liberação de grandes números de insetos machos estéreis em uma área alvo, a tecnologia RIDL, baseada em SIT, compreende criação em massa e liberação de mosquitos machos que carregam gene letal para sua prole, neste caso a linhagem OX513A de Aedes aegypti é testada nesse projeto, através da avaliação em testes laboratoriais e em testes de campo com marcação liberação e recaptura, comparando esta linhagem com linhagens selvagens. Foi mensurada a competitividade, longevidade e dispersão. Os testes foram realizados no bairro de Itaberaba (Juazeiro/BA) e na Universidade de São Paulo. Além da avaliação foi realizado o monitoramento com armadilhas ovitrampa, captura de mosquitos adultos com aspirações em residências. E o desenvolvimento de um plano de comunicação para a sociedade. Os resultados apontam que a compatibilidade entre as linhagens (transgênica e selvagem) foi positiva e a competitividade não apresentou tendência entre as fêmeas de escolherem uma linhagem ou outra. Estatisticamente não há diferença entre o número de ovos e larvas (logo a fertilidade) entre a linhagem selvagem e transgênica. O monitoramento da área de estudo confirmou a presença de A. aegypti, e não foi capturado nenhum indivíduo de Aedes albopictus. Para avaliar a dispersão, os mosquitos machos transgênicos foram liberados no ambiente e esses apresentaram uma sobrevivência no campo de 2,3 dias e um raio de vôo de 80 metros do ponto de liberação. O índice de esterilidade relativa foi determinado baseado na competitividade e proporção de ovos fluorescentes encontrados. Foi possível estabelecer uma produção em massa para realizar a fase de pré-supressão com a liberação de 540.000 machos ao longo de seis semanas e obtenção de 17% de larvas transgênicas oriundas do cruzamento desses machos com fêmeas do campo. Baseado nesses dados iniciou-se a fase de supressão com a liberação alvo de 400.000 por semana, aproximadamente 05 vezes mais esperando alcançar o estágio de supressão. / New alternatives are needed to control mosquitoes that transmit Dengue. Based on insect technique Sterile (SIT), which comprises sterilizing, mass rearing and release a large number of sterile males in an area target, RIDL technology based on SIT, but using transgenesis instead of radiation. Doing the same process for mass rearing and release of male mosquitoes carrying lethal gene to their offspring, in this case the strain OX513A of Aedes aegypti is under test in this project, through the evaluation of laboratory and field trials with mark-release-recapture (MRR), comparing transgenic with wild-type. We measured competitiveness, longevity and dispersal. The tests were performed in Itaberaba neighborhood (Juazeiro / BA) and at University of São Paulo. The evaluation was carried out with monitoring through ovitraps and adult mosquitoes collection with aspiration in houses. It was also developed a communication plan to society/community in general. The results indicate that the compatibility between the lines (transgenic and wild-type) was positive, and competitiveness showed no trend among females to choose one lineage or another. Statistically there were no difference between the number of eggs and larvae (resulting fertility) between the transgenic line and wild-type. The study area monitoring confirmed the presence of Ae. aegypti, and no Aedes albopictus was captured. To evaluate dispersion, transgenic males were released into the environment and they showed a field survival of 2.3 days and a flight range of 80 meters from the release point. The relative sterility index was determined based on the competitiveness and fluorescent proportion of eggs. Mass production was established to perform the pre-suppression phase releasing 540,000 males over six weeks and obtaining 17% of transgenic larvae in response of transgenic males mating field females. Based on these data suppression process have started with a release target of 400,000 per week, this is about 05 times more to reach the suppression stage briefly.

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.

Graduation date: 1996

I tested a theoretical model proposing that anemia favors transmission of blood-borne parasites to vectors by accelerating the blood-feeding rate. Using Aedes aegypti, the yellow fever mosquito, initially, I was not able to confirm this phenomenon either in an artificial or a live system; anemia did not correlate with blood-feeding rate, time or volume. I then analyzed the feeding rate over different time intervals to examine the possibility that inconsistent feeding rates masked the expected results; a comparison of the blood-feeding rate at one particular time period supports the theory. I then continued investigating the influence of anemia on egg production of mosquitoes and found that anemia has negative influence on vector's fecundity. I conclude that although anemia has opposite influences on mosquitoes in blood-feeding rate and egg production, they can get, at least under certain conditions, benefit from blood-feeding on anemic hosts. / Graduation date: 1992

Ball State University LibrariesLibrary services and resources for knowledge buildingMasters ThesesThere is no abstract available for this thesis.

The question of how to create communities where people altruistically care for, and look out for each other’s health and well-being is increasingly a central question in academic literature. However, altruism has long been belittled or ignored in the literature in terms of its ability to influence human behaviour. This tendency appears to have been carried over into the management of West Nile Virus (WNV), a sometimes serious disease that has spread throughout North America since first arriving in 1999. Specifically, government health educators have focused only on telling the public how what are referred to here as Community Protective Measures (CPMs) such as the elimination of standing water, can reduce personal risk or protect family members from the disease, rather than explaining how these measures can help protect others in their community as a whole. As a different approach to addressing this issue, this study sought to determine which communities and people (1) were undertaking CPMs out of an altruistic concern for others in their community, or (2) could be encouraged to engage in CPMs by making salient the benefits of these measures to the community. Study results came back positive, those that live in urban areas, and married or widowed people as opposed to singles or divorcees, those with children exhibiting significantly more concern for others about the disease. Additionally, women; married or widowed people; those who have younger children (0-18 years old); and those who had certain strong positive feelings about their community, namely knowing people better in the community, being involved in the community, and having a sense that people help each other in the community; were significantly more likely to already be willing to take action against the disease at least partly for the purposes of protecting the health of others. Additionally, albeit not significantly, a trend was noted in this regard with respect to those that rented and those who had children.. With regard to those who could be encouraged for altruistic reasons to undertake CPMs, such was found to be significantly the case for those not living in an Adult Lifestyle Communities (ALCs); those living in a city, town, or hamlet for a long (11-25 years) period of time; younger individuals (18 -35 years old), and singles or divorcees as opposed to married or widowed individuals. Although not found to be significant, a trend in this regard was found with respect to those that perceived themselves to live in a small- or medium-sized neighbourhoods, urban as opposed to suburban areas, females, renters, and those without children. A pilot study in a community with the characteristics where respondents were found to respond to learning about the community benefits of CPMs, as well as efforts to instill the characteristics of places where people already tend to be altruistically inclined, is recommended. The thesis concludes by discussing how relying upon, and encouraging altruistic tendencies could be applied to a variety of issues ranging from the control of other infectious diseases, to encouraging other health promoting behaviour such as the donation of organs, to addressing wider national as well as global matters like poverty or global climate change. By doing so, health and other planners could potentially take a more holistic, less rational, and advocacy approach to planning that seeks to build community capacity to deal with problems rather than reacting on a problem-by-problem basis.

The question of how to create communities where people altruistically care for, and look out for each other’s health and well-being is increasingly a central question in academic literature. However, altruism has long been belittled or ignored in the literature in terms of its ability to influence human behaviour. This tendency appears to have been carried over into the management of West Nile Virus (WNV), a sometimes serious disease that has spread throughout North America since first arriving in 1999. Specifically, government health educators have focused only on telling the public how what are referred to here as Community Protective Measures (CPMs) such as the elimination of standing water, can reduce personal risk or protect family members from the disease, rather than explaining how these measures can help protect others in their community as a whole. As a different approach to addressing this issue, this study sought to determine which communities and people (1) were undertaking CPMs out of an altruistic concern for others in their community, or (2) could be encouraged to engage in CPMs by making salient the benefits of these measures to the community. Study results came back positive, those that live in urban areas, and married or widowed people as opposed to singles or divorcees, those with children exhibiting significantly more concern for others about the disease. Additionally, women; married or widowed people; those who have younger children (0-18 years old); and those who had certain strong positive feelings about their community, namely knowing people better in the community, being involved in the community, and having a sense that people help each other in the community; were significantly more likely to already be willing to take action against the disease at least partly for the purposes of protecting the health of others. Additionally, albeit not significantly, a trend was noted in this regard with respect to those that rented and those who had children.. With regard to those who could be encouraged for altruistic reasons to undertake CPMs, such was found to be significantly the case for those not living in an Adult Lifestyle Communities (ALCs); those living in a city, town, or hamlet for a long (11-25 years) period of time; younger individuals (18 -35 years old), and singles or divorcees as opposed to married or widowed individuals. Although not found to be significant, a trend in this regard was found with respect to those that perceived themselves to live in a small- or medium-sized neighbourhoods, urban as opposed to suburban areas, females, renters, and those without children. A pilot study in a community with the characteristics where respondents were found to respond to learning about the community benefits of CPMs, as well as efforts to instill the characteristics of places where people already tend to be altruistically inclined, is recommended. The thesis concludes by discussing how relying upon, and encouraging altruistic tendencies could be applied to a variety of issues ranging from the control of other infectious diseases, to encouraging other health promoting behaviour such as the donation of organs, to addressing wider national as well as global matters like poverty or global climate change. By doing so, health and other planners could potentially take a more holistic, less rational, and advocacy approach to planning that seeks to build community capacity to deal with problems rather than reacting on a problem-by-problem basis.

Thesis (Ph. D.)--University of Tennessee, Knoxville, 2009. / Title from title page screen (viewed on Nov. 13, 2009). Thesis advisor: Reid R. Gerhardt. Vita. Includes bibliographical references.

Anopheles species composition and relative seasonal abundance were measured in an irrigated division (low historical malaria incidence) and in a rain-fed division (high historical malaria incidence) of southern Sri Lanka. Twelve species of anophelines were represented in adult and larval collections with Anopheles vagus Donitz being the most abundant. In cattle-baited net trap collections, Anopheles adults were significantly more abundant in the irrigated division than in the rain-fed division. In pyrethrum-spray sheet collections, cattle-baited but trap collections and larval collections, Anopheles abundance was significantly greater in the rain-fed division. Houses were of poorer construction in the rain-fed division, where pyrethrum-spray sheet collections consisted mainly of Anopheles subpictus Grassi (98%) and Anopheles culicifacies Giles (2%). Hut trap collections also consisted mainly of An. subpictus (88%) and An. culicifacies (7%). Net trap collections consisted mainly of An. vagus (43%) and Anopheles peditaeniatus Leicester (31%). Larval collections also consisted of An. peditaeniatus (24%) and An. vagus (21%). Weak associations were found between species abundance and environmental factors explored in this study (e.g., vegetation, water quality, sunlight exposure). The greater malaria risk in the rain-fed division is due in part to the occurrence of potential vectors in relatively higher numbers.

The irrigation farming methods on the Makhathini Flats are thought to be responsible for recent increase in malaria cases in the Mamfene area of northern KwaZulu-Natal despite ongoing malaria control activities. Their coincidence with the period of intensive fanning is an interesting one. This study was therefore carried out to determine the relationship between larval habitats and adult mosquito population in malaria transmission using Geographic Information System (GIS). Four types of breeding sites were utilised by malaria vectors in Mamfene, viz; types 1, II, III and IV. Habitat type I was tap pools, type II was irrigation spillage in agricultural land, type III was spillage outside but adjacent to the agricultural land and type IV was depression pools located both in the Balamhlanga swamp and inland. The cumulative larval density in all habitats peaked in March 1995 (20/man-hr), with irrigation spillage (type III) recording the highest density index (33/man-hr) as compared to tap pools (type I) which recorded 32.8/man-hr while other waterbodies recorded I3 .4/man-hr (type II) and O.5/man-hr (type IV) respectively. Subsamples of both larvae and adults of An. gambiae group were identified by the Polymerase Chain Reaction (PCR) technique. Of the larvae identified, 94.1 % and 5.9% (n=289) were An. arabiensis and An. quadriannulatus respectively while in the adult component, the composition was 98.7% and 1.3% (n=303) for An. arabiensis and An. quadriannulatus respectively. This confirmed An. arabiensis as the dominant malaria vector in Mamfene area while the exophilic behaviour of An. quadriannulatus was portrayed. Of the An. gambiae group dissected for parity, 51 .5%) were found parous. This is an indication that the population was old and was able to maintain transmission locally despite ongoing vector control measures. The Global Positioning System (GPS) was used to position larval and adult mosquito sampling sites. The spatial distribution of adult mosquitoes from the breeding sites were plotted using GIS soft ware (Map Info ) and the distance between the breeding sites and study houses were measured using a utility distance tool. With the aid of GIS, the adult mosquito density in houses could be used as an indicator to locate the breeding sites in the vicinity. The importance of these findings in terms of application in cost-effective malaria control cannot be over-emphasized. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1995.