A Dissertation submitted to the Faculty of Medicine, University of the witvmtersrand, Johannesburg, in fulfilment of the requirements for the Degree of Master of Science in Medicine. / The potential of Aedes aegypti to act as a vector of dengue (DEN) viruses was assessed in the tropical and subtropical regions of South Africa. The prevalence in bamboo pot ovitraps, utilization of artificial larval habitats and antihropophflism of Ae. aegypti was measured in fifteen populations from coastal Natal and five from the Transvaal. Pot indices generally ranged from 40-100 per cent (x±s;c= 60,3±9,8), with a mean abundance index of 0,43±0,15 (sx) mosquitoes/pot/day. Artificial container indices ranged from 11-83 per cent (X±si = 56,8±5,6). Biting rates ranged from 0,2-29,0 per manhour, in direct relationship to the level of urbanization. The feral Nduntupopulation was least anthropophilic, although pot and abundance indices were high. To investigate the presence of subspp. aegypti and formosus, the pale scales on tergite-1 were counted in ten or more siblings from each of 196 families, representing eighteen populations. At least 118 of these families were heterogeneous, each containing some siblings with no pale scales and others with pale scales on tergite-1, thus invalidating this character for distinguishing between the subspp. Isozyme electrophoresis 'did not provide diagnostic electromorphs for distingllishing between different populations. Allelomorph frequencies and the numberof pale scales on tergite-l and tergite-2 differed significantly in individual populations but not between anthropophilic and non-anthropophilic populations. As there was no correlation between tergal morphology, isozymes and anthropophilism, the populations could not be resolved into the two subspp. Based on the only morphological character that appears to be reliable, viz. the blackness of the background scales, all of the populations are probably Ae. aegypti formosus. The vector competence of five populations for DEN-1 and DEN-2 viruses was tested in the laboratory after allowing mosquitoes to feed on an infective blood-virus mixture. Viral antigen was detected by indirect fluorescent antibody test. Head-squash infection rates (HSIRs)ranged from 11-54 per cent for DEN-land from 19- 46 per cent for DEN...2. Transmission rates (TRs) were determined by in vitro capillary method and ranged from 67-100 per cent for DEN-1 and from 11-86 pier cent for DEN-2.Meanvector competence indices (calculated from HSIRsand TRS) ware 0,13-0,41 for DEN-l and 0,,18-0,34 for DEN-2.It is concluded that, should DEN be reintroduced to South Africa via the shipping or tourist industries, Ae. aegypti would be an efficient urban vector. The Durban population is of particular epidemiological importance because it was highly anthropophilic and was the most vectorially competent of the South African populations. / Andrew Chakane 2018

O estudo de mosquitos é extremamente importante, pois muitos são considerados vetores de diversos patógenos transmissíveis ao homem. Aedes aegypti e Aedes albopictus são responsáveis por transmitir arbovírus, como os da dengue, chikungunya, zika e febre amarela urbana, no mundo. Neste trabalho foram empregados Ae. aegypti e Ae. albopictus para: analisar a atividade locomotora de machos, fêmeas virgens e fêmeas inseminadas naturalmente; comparar a atividade locomotora de fêmeas injetadas intratoracicamente com extrato de glândulas acessórias (AG) de machos co e heteroespecíficos; e verificar a taxa de inseminação de fêmeas injetadas com glândulas acessórias de machos co e heteroespecíficos, quando são posteriormente expostas a seus machos coespecíficos. Os mosquitos foram coletados em ovitrampas instaladas no Parque Municipal do Piqueri, Zona Leste da cidade de São Paulo, durante o outono e a primavera de 2015 e outono de 2016. Após a emergência dos adultos, estes foram transferidos para quatro gaiolas matrizes separadas por espécie e sexo, dos quais obtivemos machos e fêmeas virgens de cada espécie. Em outras duas gaiolas foram agrupadas por espécie, 40 fêmeas e 40 machos para cópula por 24 horas para obtermos fêmeas inseminadas naturalmente. Posteriormente, todos os mosquitos foram transferidos para uma incubadora por quatro dias para análise da atividade locomotora. Na comparação de fêmeas injetadas com glândulas acessórias, foram extraídas as glândulas de machos de Ae. aegypti e Ae. albopictus e estas injetadas intratoracicamente em fêmeas co e heteroespecíficas. Todas as fêmeas injetadas foram transferidas para uma incubadora por três dias. Para a análise dos dados foram utilizados os testes estatísticos F e T e ANOVA. Após a atividade locomotora, as fêmeas injetadas foram expostas a seus machos coespecíficos e posteriormente tiveram suas espermatecas dissecadas para verificar a presença de espermatozoides a fim de analisar a taxa de inseminação. Nos machos, fêmeas virgens e fêmeas inseminadas naturalmente de Ae. aegypti e Ae. albopictus, o padrão da atividade locomotora foi diurno e bimodal no outono e na primavera. Em Ae. aegypti machos a atividade foi mais evidente no outono e em Ae. albopictus na primavera. Nas fêmeas de Ae. aegypti virgens a atividade foi mais evidente que nas inseminadas naturalmente em ambas as estações. Nas fêmeas de Ae. albopictus não houve diferença na atividade das virgens e inseminadas. Nas fêmeas de Ae. aegypti injetadas com AG a atividade locomotora foi diurna, com padrão unimodal e menos marcada. Nas fêmeas de Ae. albopictus injetadas com AG não houve diferença. Na taxa de inseminação, somente Ae. albopictus fêmeas injetadas com AG heteroespecíficas apresentaram espermatozoides após cópula coespecífica. Este estudo contribui para compreensão do comportamento de mosquitos vetores como Ae. aegypti e Ae. albopictus / The study of mosquitoes is extremely important, since many are considered vectors of several pathogens transmissible to man. Aedes aegypti and Aedes albopictus are responsible for transmitting arboviruses, such as dengue, chikungunya, zika and urban yellow fever, in the world. This study employed Ae. aegypti and Ae. albopictus to: analyze the locomotor activity of males, virgin females and females naturally inseminated; compare the locomotor activity of females injected intratoracically with extract of accessory glands (AG) of co and heterospecific males; and verify the rate of insemination of females injected with accessory glands of co and heterospecific males when later exposed to their co-specific males. The mosquitoes were collected in ovitraps installed in Piqueri Municipal Park, East of São Paulo city, during the autumn and spring of 2015 and autumn of 2016. After the emergence of adults, they were transferred to four cages, separated by species and sex from which we obtained virgin males and females of each species. In the other two cages, they were grouped by species, 40 females and 40 males for mating during 24 hours to obtain naturally inseminated females. Thereafter, all the mosquitoes were transferred to an incubator for four days to the locomotor activity analysis. In the comparison of females injected with accessory glands, the male glands of Ae. aegypti and Ae. albopictus were extracted and injected intratoracically into co and heterospecific females. All injected females were transferred to an incubator for three days. For the analysis, the statistical tests F and T and ANOVA were used. After the locomotor activity, the injected females were exposed to their co-specific males and later had their spermathecas dissected to verify the presence of spermatozoa in order to analyze the insemination rate. In males, virgin and naturally inseminated females of Ae. aegypti and Ae. albopictus, the pattern of locomotor activity was diurnal and bimodal in autumn and spring. Aedes aegypti males activity was more evident in autumn and in Ae. albopictus in spring. In virgin females of Ae. aegypti the activity was more evident than in the naturally inseminated in both seasons. In females of Ae. albopictus, there was no difference in the activity of virgin and inseminated. In females of Ae. aegypti injected with AG the locomotor activity was diurnal, with a unimodal and less marked pattern. In the females of Ae. albopictus injected with AG there was no difference. In the insemination rate, only Ae. albopictus females injected with heterospecific AGs presented spermatozoa after coespecific mating. This study contributes to the understanding of mosquito vectors behavior such as Ae. aegypti and Ae. albopictus

O estudo de mosquitos é extremamente importante, pois muitos são considerados vetores de diversos patógenos transmissíveis ao homem. Aedes aegypti e Aedes albopictus são responsáveis por transmitir arbovírus, como os da dengue, chikungunya, zika e febre amarela urbana, no mundo. Neste trabalho foram empregados Ae. aegypti e Ae. albopictus para: analisar a atividade locomotora de machos, fêmeas virgens e fêmeas inseminadas naturalmente; comparar a atividade locomotora de fêmeas injetadas intratoracicamente com extrato de glândulas acessórias (AG) de machos co e heteroespecíficos; e verificar a taxa de inseminação de fêmeas injetadas com glândulas acessórias de machos co e heteroespecíficos, quando são posteriormente expostas a seus machos coespecíficos. Os mosquitos foram coletados em ovitrampas instaladas no Parque Municipal do Piqueri, Zona Leste da cidade de São Paulo, durante o outono e a primavera de 2015 e outono de 2016. Após a emergência dos adultos, estes foram transferidos para quatro gaiolas matrizes separadas por espécie e sexo, dos quais obtivemos machos e fêmeas virgens de cada espécie. Em outras duas gaiolas foram agrupadas por espécie, 40 fêmeas e 40 machos para cópula por 24 horas para obtermos fêmeas inseminadas naturalmente. Posteriormente, todos os mosquitos foram transferidos para uma incubadora por quatro dias para análise da atividade locomotora. Na comparação de fêmeas injetadas com glândulas acessórias, foram extraídas as glândulas de machos de Ae. aegypti e Ae. albopictus e estas injetadas intratoracicamente em fêmeas co e heteroespecíficas. Todas as fêmeas injetadas foram transferidas para uma incubadora por três dias. Para a análise dos dados foram utilizados os testes estatísticos F e T e ANOVA. Após a atividade locomotora, as fêmeas injetadas foram expostas a seus machos coespecíficos e posteriormente tiveram suas espermatecas dissecadas para verificar a presença de espermatozoides a fim de analisar a taxa de inseminação. Nos machos, fêmeas virgens e fêmeas inseminadas naturalmente de Ae. aegypti e Ae. albopictus, o padrão da atividade locomotora foi diurno e bimodal no outono e na primavera. Em Ae. aegypti machos a atividade foi mais evidente no outono e em Ae. albopictus na primavera. Nas fêmeas de Ae. aegypti virgens a atividade foi mais evidente que nas inseminadas naturalmente em ambas as estações. Nas fêmeas de Ae. albopictus não houve diferença na atividade das virgens e inseminadas. Nas fêmeas de Ae. aegypti injetadas com AG a atividade locomotora foi diurna, com padrão unimodal e menos marcada. Nas fêmeas de Ae. albopictus injetadas com AG não houve diferença. Na taxa de inseminação, somente Ae. albopictus fêmeas injetadas com AG heteroespecíficas apresentaram espermatozoides após cópula coespecífica. Este estudo contribui para compreensão do comportamento de mosquitos vetores como Ae. aegypti e Ae. albopictus / The study of mosquitoes is extremely important, since many are considered vectors of several pathogens transmissible to man. Aedes aegypti and Aedes albopictus are responsible for transmitting arboviruses, such as dengue, chikungunya, zika and urban yellow fever, in the world. This study employed Ae. aegypti and Ae. albopictus to: analyze the locomotor activity of males, virgin females and females naturally inseminated; compare the locomotor activity of females injected intratoracically with extract of accessory glands (AG) of co and heterospecific males; and verify the rate of insemination of females injected with accessory glands of co and heterospecific males when later exposed to their co-specific males. The mosquitoes were collected in ovitraps installed in Piqueri Municipal Park, East of São Paulo city, during the autumn and spring of 2015 and autumn of 2016. After the emergence of adults, they were transferred to four cages, separated by species and sex from which we obtained virgin males and females of each species. In the other two cages, they were grouped by species, 40 females and 40 males for mating during 24 hours to obtain naturally inseminated females. Thereafter, all the mosquitoes were transferred to an incubator for four days to the locomotor activity analysis. In the comparison of females injected with accessory glands, the male glands of Ae. aegypti and Ae. albopictus were extracted and injected intratoracically into co and heterospecific females. All injected females were transferred to an incubator for three days. For the analysis, the statistical tests F and T and ANOVA were used. After the locomotor activity, the injected females were exposed to their co-specific males and later had their spermathecas dissected to verify the presence of spermatozoa in order to analyze the insemination rate. In males, virgin and naturally inseminated females of Ae. aegypti and Ae. albopictus, the pattern of locomotor activity was diurnal and bimodal in autumn and spring. Aedes aegypti males activity was more evident in autumn and in Ae. albopictus in spring. In virgin females of Ae. aegypti the activity was more evident than in the naturally inseminated in both seasons. In females of Ae. albopictus, there was no difference in the activity of virgin and inseminated. In females of Ae. aegypti injected with AG the locomotor activity was diurnal, with a unimodal and less marked pattern. In the females of Ae. albopictus injected with AG there was no difference. In the insemination rate, only Ae. albopictus females injected with heterospecific AGs presented spermatozoa after coespecific mating. This study contributes to the understanding of mosquito vectors behavior such as Ae. aegypti and Ae. albopictus

No description available.

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.

No description available.

Thesis (M.S.)--Rutgers University, 2009. / "Graduate Program in Geography." Includes bibliographical references (p. 76-79).

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No description available.