O objetivo do estudo foi confirmar se a redução da fecundidade dos mosquitos Aedes aegypti infectados por Plasmodium gallinaceum ocorre por morte das células foliculares dos ovários. Mosquitos infectados produzem menos ovos quando comparado aos mosquitos sadios. Uma explicação é a redução da viabilidade celular que ocorre nos ovários de fêmeas 18, 22 e 24 horas após o repasto sanguíneo infectado (RSI) como foi observado pela técnica MTT. Utilizando o acridine orange, não foi possível observar a morte das células foliculares no intervalo de 18 horas, mas 22 e 24 horas após o RSI essas células estão em morte em relação ao mesmo intervalo do repasto sanguíneo controle (RSC). A análise do DNA fragmentado foi realizada através do TUNEL. Ovários de 22 e 24 horas após RSC e RSI foram negativos nas regiões dos cortes histológicos examinados. Sendo assim, podemos concluir que, utilizando esses ensaios foi possível identificar a morte das células foliculares como uma resposta a redução da fecundidade, porém não foi possível determinar que o tipo de morte é apoptose. / The objective of this study was to confirm the hypothesis that the fertility reduction in Plasmodium gallinaceum-infected Aedes aegypti occurs by follicular cells death. A significant reduction in the number of eggs laid by infected mosquitoes was confirmed. It was observed a reduction of viable cells in 18, 22 and 24 hours PBM infected by MTT assay. It was not possible to observe cell death in ovary tissue 18 hours PBM infected, but the follicular cells showed orange color 22 and 24 hours indicating they are in death in relation to the same interval of PBM control. To determine if these cells exhibit apoptosis, we use the TUNEL which mark the fragmented DNA, a characteristic of the apoptosis process. Ovaries 22 and 24 hours PBM infected and control were negative for TUNEL marker from ovary histological preparations. Thus, we conclude that fecundity reduction occurs as a response to follicular cells death caused by P. gallinaceum infection but it was not possible to affirm if the type of follicular cells death is apoptosis.

Les maladies transmises par les moustiques représentent une menace permanente en santé publique. La principale mesure pour protéger les populations contre les piqûres infectieuses repose actuellement sur l’utilisation d’insecticides, mais celle-ci est menacée par la propagation des mécanismes de résistance au sein des populations de moustiques. Dans ce contexte, les répulsifs représentent un outil de choix pour réduire à la fois les nuisances provoquées par les moustiques et le risque d’infection. Parmi eux, le DEET (N, N-diéthyl-3-méthylbenzamide) a prouvé une efficacité remarquable aussi bien lors d’expérimentations en laboratoire que sur le terrain. Malgré cela, les répulsifs ont toujours été utilisés de manière empirique, et leur mode d’action reste très mal connu. Le but de ce projet de thèse a été : i) de participer à l’évaluation du potentiel d’intégration du répulsif DEET dans la lutte antivectorielle, ii) de mesurer l’impact de paramètres physiologiques du moustique d’intérêt épidémiologique tels que l’expérience, l’âge et l’infection sur l’efficacité des méthodes de lutte, répulsifs et insecticides pyréthrinoïdes et iii) de quantifier l’impact des répulsifs et insecticides sur les traits d’histoire de vie des moustiques. Les expériences ont été réalisées sur Anopheles gambiae et Aedes albopictus, respectivement vecteurs de l’agent du paludisme et d’arbovirus tels que le virus de la dengue. Nos résultats ont permis de démontrer que l’état physiologique du moustique influe sur l’efficacité des méthodes de lutte ; premièrement, les moustiques porteurs de la mutation kdr ayant obtenu un repas de sang en contact avec de la perméthrine ne sont plus irrités par ce composé lors d’une seconde exposition, dans les conditions testées et à une dose recommandée pour l’imprégnation de moustiquaires. Au contraire, un repas de sang obtenu en présence DEET n’a pas affecté l’efficacité de ce composé à inhiber un repas de sang à l’exposition suivante. Ensuite, le DEET s’est montré plus efficace chez les moustiques âgés que chez les moustiques jeunes, et les résultats sont similaires chez les deux espèces et indépendants du statut de résistance aux insecticides. D’autre part, l’efficacité de la deltaméthrine et du DEET ne sont pas modifiés lorsque les moustiques sont infectés par le parasite Plasmodium falciparum. Cependant, une augmentation de la mortalité a été observée chez les femelles anophèles infectées au stade sporozoites lors de certaines expérimentations, indépendamment du traitement chimique de la moustiquaire, et suggère un coût de l’infection « réplicat-dépendant ». Enfin, le DEET génère un impact au long terme sur la fécondité et la fertilité des moustiques, effets qui ne sont pas observés dans notre protocole pour la perméthrine. Ces résultats donnent donc des pistes pour redéfinir les priorités dans les programmes de lutte, afin de cibler en premier lieu les moustiques les plus à même de transmettre des pathogènes. Ils soulignent également la nécessité de considérer à la fois l’état physiologique du moustique et l’impact sur le long terme des insecticides et répulsifs lors de l’évaluation des outils de lutte. / Mosquito-borne diseases are a permanent public health threat. The main way to protect populations against infectious bites relies on the use of insecticides, but their efficacy is threatened by the spread of resistance mechanisms among vector populations. In this context, repellents are a promising tool for reducing both mosquito nuisance and infection risk. Among them, DEET (N, N-diéthyl-3-méthylbenzamide) has proven great efficacy both in laboratory and field experiments. Despite this, repellents, are still used from an empirical way and their mode of action remains poorly understood. The aim of the present project was to: i) participate to the evaluation of the potential of integration of the DEET repellent in mosquito control, ii) measure the impact of mosquito physiological parameters of epidemiological relevance such as experience, age and infection, on the efficacy of repellents and insecticides, and iii) quantify the impact of repellents and insecticides on mosquito life-history traits. Experiments were performed on Anopheles gambiae and Aedes albopictus, vectors of the malaria parasite and of arboviruses such as dengue, respectively. Our results allowed to demonstrate that mosquito physiological state influences the efficacy of control tools; first, after successfully obtaining a blood meal in contact with permethrin, mosquitoes carrying kdr mutation are no longer inhibited by this compound at the subsequent exposure, at the recommended dose for net impregnation and under our experimental design. On the contrary, a first blood meal obtained in presence of DEET does not affect its efficacy at the following exposure. Then, DEET appeared to be more efficient against old mosquitoes that against younger ones, and results are consistent in the two species, independently of the insecticide resistance status. Besides, efficacy of DEET and deltamethrin is not modified when mosquitoes are infected with Plasmodium falciparum. However, an increased mortality was observed in anopheles when infected with transmissible stages (i.e. sporozoites), independently of chemical exposure, which suggest a cost of infection and seems to be “replicate-dependent”. Finally, DEET produces a long-term impact on mosquito fecundity and fertility, which is not observed with permethrin under our protocol. These results give insights to redefine the priorities in mosquito control programs, in order to specifically targeting mosquitoes that are the most susceptible to transmit pathogens. These observations also underline the need for considering both mosquito physiological state and the long-term impact of repellents and insecticides during the evaluation of control tools.

Thoreau said that, "in wildness is the preservation of the world." The characters in the following collection of stories might be tempted to rephrase that statement to read, "in wildness is the preservation of the criminal world." These stories feature wild places where the natural world often is not as dangerous as the people who seek refuge in the borderlands between wilderness and civilization. Many crime stories take place in cities-for good reason. More people usually equates with more crime. However, anywhere that people choose to live, crime is sure to follow-crime against each other, crime against themselves, and even crime against the world they inhabit. In "Blood and Dirt," two brothers find themselves dependent on their native landscape for different reasons. One will have to let go, but the other will find him harder to shake loose than a cottonmouth wrapped around a cypress knee. "Wet Season" finds a man hiding in plain sight at the southern fringe of civilization, and doing a fine job of it until his past comes looking for him. Instead of watching the last reflection of his inner wildness disappear, the protagonist of "Great Apes" decides to internalize his problems. And in "Itch: A Vampire Story," a group of teenagers who enjoy the dark mythology of the undead learn firsthand of a dark reality in the Everglades. These characters are often seeking to escape the hectic contemporary world of computers and cell phones, mortgages and nine-to-five jobs. What they discover is that, while unspoiled nature may be hard to find, human nature is even more difficult to escape.

Mosquitos são insetos dípteros, pertencentes à Família Culicidae. São encontrados em quase todas as regiões do mundo, com exceção daquelas permanentemente congeladas. A família Culicidae apresenta duas subfamílias, Anophelinae e Culicinae as quais existem principalmente na região Neotropical (América do Sul e Central). Muitas espécies de Culicidae são vetores de diversos patógenos: vírus (arbovírus), filárias (nematoides) e protozoários. Neste projeto foram estudados espécimes adultos de vários gêneros de mosquitos oriundos dos parques da cidade de São Paulo, escolhidos por região (parques Anhanguera, Ibirapuera, Santo Dias e Shangrilá). Foi selecionado o gene mitocondrial citocromo C oxidase subunidade I (COI) que tem sido extensivamente usado para estudos populacionais e para resolver relacionamentos entre grupos fechados de espécies de insetos. O marcador mostrou-se adequado para as análises. As sequências foram comparadas através de métodos de análises evolutivas (UPGMA e Neighbor-joining). A utilização de outros marcadores como por exemplo microssatélites, para a continuidade dos estudos e futuras confirmações das espécies Cq. venezuelensis, Ma. titillans, Cx. declarator, Wy. sp., Cx. (Mel) ribeirensis e (Mel) Ma. wilsoni é uma necessidade, assim como os registros das respectivas sequências no banco de genes produzidas nesta pesquisa. O parque Anhanguera, mais distante dos aglomerados humanos, proporciona a circulação de parasitas de infecções silvestres; o parque Ibirapuera, no centro da malha urbana, favorece as espécies mais antropofílicas e sinantrópicas. / Mosquitoes are dipterous insects, belonging to the Culicidae family. Are found in almost all regions of the world, with the exception of those permanently frozen. The Culicidae family features two subfamily Anofelinea and Culicinae to which there are mainly in the Neotropical region (South and Central America). These agents cause illnesses and injuries in men and animals, receiving special attention for hematophagic habit. On this project we studied adult specimens of several mosquito genera from the city of São Paulo, chosen by region (parks Anhanguera, Ibirapuera, Santo Dias and Shangrilá). We selected the mitochondrial cytochrome C oxidase I (COI) gene that has been extensively used for population studies and to resolve relationships between closed groups of insect species. The marker proved to be adequate for the analyzes. The sequences were compared by methods of evolutionary analysis (UPGMA and Neighbor-joining). The use of other markers such as microsatellites for the continuity of studies and future confirmations of the species Cq. venezuelensis, Ma. titillans, Cx. declarator, Wy. sp., Cx. (Mel) ribeirensis and Ma. wilsoni and a need, as well as the records of the respective sequences in the gene bank produced in this research. The Anhanguera park furthest from human settlements, provides the circulation of wild-type parasites; the Ibirapuera park at the centre of the urban network, favors the more anthropogenic and synanthropic species.

Thesis (M.S.)--University of Delaware, 2007. / Principal faculty advisors: Jack B. Gingrich and Charles E. Mason, Dept. of Entomology & Wildlife Ecology. Includes bibliographical references.

An acid rain simulation was created under laboratory conditions to study the effects of mortality rates and developmental time of Aedes triseriatus (Say) mosquito larvae. Two hundred-forty instar 1 mosquitoes were placed into separate 120 ml glass jars containing rain water adjusted to pH 2, 3, 4, 5, 6, and 7 with a nitric acid solution. A second part of the experiment was set up like the first except a 70 percent to 30 percent sulfuric-nitric acid solution was used to adjust pH levels. Mortality and developmental time was observed until the insects reached maturity or died.No significant differences at the .05 level in mortality rates were observed between larvae raised in nitric acid solution as compared to sulfuric acid solution. However, exposures to 70 to 30% sulfuric-nitric solution resulted in a significantly (0.05) higher mortality at pH levels 4, 5, and 6 than the sulfuric acid or nitric acid exposures.Developmental time did not vary more the 0.5 days between the sulfuric acid exposure group and the nitric acid group except at pH 4.Ball State UniversityMuncie, IN 47306

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references. Also available on the World Wide Web.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Opportunistic feeding behaviour and partial exophily make An. arabiensis much more difficult to control by indoor residual spraying than any other vector in the Afro-tropical region. The persistent malaria outbreaks in Zimbabwe despite decades of indoor house spraying prompted this investigation into the role of An. arabiensis in malaria transmission and assessment of the possible impact of this control measure. The study was conducted in the malaria endemic districts of Binga and Gokwe. An. gambiae complex mosquitoes were collected from artificial outdoor resting sites, and from human dwellings by i) daytime hut searches, ii) pyrethrum spray catches and iii) exit window traps. Mosquito components were processed to enable: i) the distinction of An. arabiensis from An. quadriannulatus and An. merus on the basis of the pale band at the junction of the hind leg 3/4 tarsomeres; ii) species identification and scoring of inversion polymorphism on the basis of the X chromosome and autosomes respectively; iii) the determination of blood meal sources using the Ouchterlony precipitin test; and iv) identification of An. gambiae s.l. using polymerase chain reaction (PCR) and enzyme electrophoresis techniques. Entomological assessment of residual spraying included determining: the vector resting densities indoors and outdoors, bioassay and insecticides susceptibility tests. Data were also collected on hut profiles, knowledge-attitudes-practices surveys, and household malaria prevalence . surveys. An. arabiensis and An. quadriannulatus were found in sympatry in Binga and Gokwe, and in addition, An. merus was found in Gokwe. Most species identifications were made using PCR; which was found to have 7.5% and 41.6% levels of error for An. arabiensis and An. quadriannulatus respectively, using the cytogenetic technique as benchmark. The pale band technique yielded > 80% correct identification for An. arabiensis but the extent of overlap in the pale band lengths between An. arabiensis and An. quadriannulatus renders the method unsuitable for distinguishing these two species. Inversions 2Rb and 3Ra were found floating in An. arabiensis, with 60% frequency in the former. The Wright's F statistic value of -0.0416 indicated an excess of heterozygotes, and a state of panmixis in the vector population. No significant differences were observed between 2Rb karyotypes in host choice. Human blood indices among indoor (0.82), exit trap (0.98) and outdoor resting (0.30) specimens suggested exophilic behaviour. This was corroborated by the high fed:gravid ratios of 6.8: 1 and 11.6: 1 in sprayed and non-sprayed dwellings respectively. This was worsened by a high feeder-survivor index (FSI) of 93 % among exit trap specimens. The susceptibility to deltamethrin coupled with residual efficacy nine weeks post-spray indicated the suitability of the insecticide. Rural dwellings were suitably built for spraying but had no mosquito proofing. Personal protective measures are hardly known; sleeping outdoors occurs in Siabuwa. While An. arabiensis bites humans indoors the partial exophily it exhibits is a threat to indoor residual insecticide spraying. An integrated malaria control approach is recommended. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1996.

Larvae of Ae. triseriatus mosquitoes were collected from treeholes on the Ball State University campus. These insects were raised to adulthood under laboratory conditions. Newly hatched larvae were raised in deionized water. One hundred twenty-five of instar 1 mosquitoes (group A) were placed into separate baby food jars containing deionized water. These jars were separated into five groups. The pH of the water in each group was adjusted to 3, 4, 5, 6 and 7 with a 70% to 30% sulfuric-nitric acid solution. Subsequent groups consisting of instar 2, 3 and 4 larvae and pupae (groups B, C, D and E respectively) were exposed to the same experimental treatment as that of group A. The effects of each of these pH levels on mortality and development was observed until the insects reached maturity or died.Larvae in water of pH 3 experienced a higher percentage of mortality than mosquitoes exposed to less acidic solutions. A decrease in mortality with age was observed. Mortality of insects in group A was greater than that of any other group. Mosquitoes in group D experienced the lowest mortality.Variations of developmental time for mosquitoes in pH 3 were probably due to high mortality. Developmental time was similar for all groups. Slight variations between these groups may have been due to natural fluctuations in development. The total average developmental time for Ae. triseriatus mosquitoes of this study was 11.12 days.