Background: Mosquito-borne diseases are a growing concern for temperate regions including the northeastern US. There the two primary mosquito vectors, Cx. pipiens and Ae. albopictus are widespread, endemic circulation of West Nile virus causes sporadic outbreaks, and imported arboviruses such as dengue, chikungunya, and Zika are on the rise. With temperate mosquito-borne disease outbreaks likely to increase in frequency, it is critical to reduce mosquito populations in the northeastern US. Community-based source reduction is heralded as the most sustainable component of integrated mosquito management. Yet mosquitoes develop rapidly, requiring weekly maintenance of mosquito habitat. This is onerous and community commitment flags. The development of predictive models to inform focused vector-control efforts is therefore of great utility. Objectives and Methods: The overarching objective of this research is to make robust predictive modeling frameworks based on empirically derived relationships of the ecology and epidemiology of mosquito-borne disease systems in the northeastern US. We aim to quantify the relationships between local environmental and meteorological conditions and mosquito vectors. In Chapters 2 and 4 we use lengthy surveillance records to develop models and use model ensembles to generate predictions based on out-of-sample data. For chapter 3 we use more spatially refined data to investigate the influence of intra-urban heterogeneities and how climatic conditions influence mosquito populations across these defined differences. Results: In Chapter 2, we model and forecast WNV infection rates among mosquito vectors using meteorological and hydrological conditions. We show that real-time climate information can predict WNV Culex infection rates prior to when human risk is greatest. In Chapter 3, we link infrastructure degradation and vegetation patterns with Ae. albopictus infestation levels as well as the interactive effect of precipitation across these environmental conditions. In Chapter 4, we identify key land use characteristics and meteorological conditions associated with annual Ae. albopictus abundance. Further we use imported chikungunya cases to delineate areas of high arboviral importation and, in combination with areas of high Ae. albopictus abundance, areas at heightened risk for arboviral transmission. Conclusions: While temperate outbreaks are often self-limiting they may be increasing in frequency and severity. Due to the multitude of invasive vectors and arboviruses, vector control techniques that work for multiple mosquito species are likely more effective and sustainable. Here we build build empirical models that accurately predict mosquito dynamics before populations peak which is critical for vector control. We recommend integrating predictive modeling into mosquito management guidelines as this could focus valuable resources to when and where mosquito-borne transmission risk is greatest. Further we find social and ecological determinants of mosquito dynamics, supporting further study that combine socio-ecological processes into model frameworks.

This study investigated the effects of temperature and relative humidity (both controlled and natural) on the lifecyle and morphology of adults of members of the Anopheles gambiae complex in northern KwaZulu-Natal, South Africa. Laboratory investigations into the effects of simulated temperature and relative humidity regimes concentrated on seasonal differences in longevity, egg hatchability, reproductive potential and adult survivorship of An. arabiensis. Differences were found in the life table parameters when these mosquitoes were reared under conditions of seasonal temperature and relative humidity. During the cool season the lifespan and adult survivorship of mosquitoes were greater than those reared during the warm season. In summer, the egg hatchability and reproductive potential were greatest whereas in winter An. arabiensis underwent gonotrophic dissociation although these females were found to take blood meals readily. The influence of seasonal temperature and relative humidity on the body size of An. arabiensis was investigated, both in the laboratory and under field conditions. In both environments, these factors were found to significantly influence body size. In winter, there was a 13% increase in wing size compared to summer bred mosquitoes. A comparison of body size of An. arabiensis, An. merus and An. gambiae reared under laboratory conditions of seasonal temperature and relative humidity showed that the wing size of An. arabiensis was greater than that of An. merus and An. gambiae. The effect of temperature and relative humidity on morphological criteria used in species separation was also investigated. Seasonal differences in wing spot size were compared for An. arabiensis, An. merus and An. gambiae. From this investigation it was concluded that the pale and dark spots on the wing of Anopheles mosquitoes could not be used in species identification due to the large degree of inter-species overlap in the wing spot measurements. The measurement of the pale band at the junction of the 3rd and 4th tarsomere on the hind leg was also investigated for its use in species separation and were found to be useful within the An. gambiae complex. The implications of this study on the transmission and control of malaria are discussed with reference to the late season transmission during March to May that is characteristic of the region. / Thesis (Ph.D)-University of Natal, Pietermaritzburg, 1996.

Thesis (M.S.) -- Mississippi State University, 2006. / Includes bibliographical references (p. 91-96). Available online in PDF format.

Bacillus sphaericus 2362 is a mosquito pathogenic bacterium. Its greatest industrial potential may be in developing countries where mosquitos are often vectors for diseases. This strain is typical of the species in that it is unable to grow using carbohydrates as a sole source of carbon. The goal of this research was to determine the metabolic deficiency(s) responsible for the inability of this organism to grow on carbohydrates. Compounds that supported light growth of this organism on an agar-solidified, defined medium included acetate, glycerol, and gluconate. Growth in a defined liquid medium with acetate as the source of carbon was much slower than growth in a complex, protein-based broth. B. sphaericus grew poorly in a defined, liquid medium with glycerol or gluconate as the carbon source. Activity of enzymes responsible for the initiation of metabolism of some substrates was not detected in cell extracts. These enzymes were: glucokinase, hexokinase, beta-galactosidase, and amylase. Growth of this bacterium on glycerol as a sole source of carbon implies the presence of the enzymes from the lower half of the Embden-Meyerhof-Parnas (EMP) pathway. Two enzymes of the upper half of the EMF pathway, phosphofructokinase and fructose diphosphate aldolase, were undetected in cell extracts. In addition, glucose dehydrogenase activity was not detected. The inability to form glucose-6-phosphate from glucose prevents the catabolism of this and related substrates via the Entner-Doudoroff (ED), hexose monophosphate (HMP), and EMF pathways. Oxygen uptake studies indicated that B. sphaericus oxidized gluconate slightly but only when the cells were grown in a complex, protein-based medium supplemented with gluconate. Although gluconokinase activity was detected in cell extracts, no activity was detected for the key enzymes of the ED (phosphogluconate dehydratase/KDPG aldolase), or HMP (6-phosphogluconate dehydrogenase) pathway. It is unclear how B. sphaericus grows on a defined medium with gluconate as the sole source of carbon. In addition to enzymatic deficiencies, whole cells were unable to accumulate [¹⁴C]glucose or [¹⁴C]sucrose. / Master of Science

A population survey was conducted on the mosquito species recorded in Denton, Texas for the years of 2005 to 2015. Data used in this project were obtained from an ongoing, long-term surveillance program led by the City of Denton and conducted through the University of North Texas. Research focused on the population dynamics and community structure of mosquitoes collected within urban areas of Denton, Texas in relation to certain environmental variables. A total of 80,837 female mosquitoes were captured and represented 38 species found under the following genera: Aedes, Anopheles, Coquillettidia, Culex, Culiseta, Mansonia, Orthopodomyia, Psorophora, Toxorhynchites, and Uranotaenia. Culex quinquefasciatus was the most abundant species followed by Aedes vexans. Seasonal patterns of the most abundant species revealed high variability throughout the study. Container breeders were most abundant in August and those that breed in floodwaters were most abundant in the months of May and September. Samples were tested for arbovirus presence through the Texas Department of State Health Services in Austin, Texas and multiple pools tested positive for West Nile virus throughout the study. Stepwise multiple regression and Spearman's rank correlation analyses were performed to examine the relationship between the mosquito community and environmental variables. Data revealed that temperature, precipitation, and dew point were the most important variables influencing the mosquito population in the City of Denton.

The Bunyaviridae family is one of the largest among RNA viruses, comprising more than 350 serologically distinct viruses. The family is classified into five genera, Orthobunyavirus, Hantavirus, Nairovirus, Phlebovirus, and Tospovirus. Orthobunyaviruses, nairoviruses and phleboviruses are maintained in nature by a propagative cycle involving blood-feeding arthropods and susceptible vertebrate hosts. Like most arthropod-borne viruses, bunyavirus replication causes little damage to the vector, whereas infection of the mammalian host may lead to death. This situation is mimicked in the laboratory: in cultured mosquito cells no cytopathology is observed and a persistent infection is established, whereas in cultured mammalian cells orthobunyavirus infection is lytic and leads to cell death. Bunyaviruses encode four common structural proteins: an RNA-dependent RNA polymerase, two glycoproteins (Gc and Gn), and a nucleoprotein N. Some viruses also code for nonstructural proteins called NSm and NSs. The NSs protein of the prototype bunyavirus, Bunyamwera virus, seems to be one of the factors responsible for the different outcomes of infection in mammalian and mosquito cell lines. However, only limited information is available on the growth of bunyaviruses in cultured mosquito cell lines other than Aedes albopictus C6/36 cells. Here, I compared the replication of Bunyamwera virus in two additional Aedes albopictus cell clones, C7-10 and U4.4, and two Aedes aegypti cell clones, Ae and A20, and investigated the impact of virus replication on cell function. In addition, whereas the vertebrate innate immune response to arbovirus infection is well studied, relatively little is known about mosquitoes’ reaction to these infections. I investigated the immune responses of the different mosquito cells to Bunyamwera virus infection, in particular antimicrobial signaling pathways (Toll and IMD) and RNA interference (RNAi). The data obtained in U4.4 cells suggest that NSs plays an important role in the infection of mosquitoes. Moreover infection of U4.4 cells more closely resembles infection in Ae and A20 cells and live Aedes aegypti mosquitoes. My data showed that the investigated cell lines have various properties, and therefore they can be used to study different aspects of mosquito-virus interactions.

Evarcha culicivora is a salticid with an unusual preferred diet (vertebrate blood obtained indirectly by preying on female mosquitoes that have themselves had recent blood meals) and an unusual affinity for particular plant species (Lantana camara and Ricinus communis). This thesis is a study of how individuals of this species interact with each other, with a general objective being to clarify the role of visual attention and crossmodality priming in the mate-choice behaviour of this species. E. culicivora’s courtship and display behaviour was shown to be especially complex and highly variable. Experiments on vision-based mate-choice showed that mutual mate-choice behaviour is pronounced in E. culicivora and that both sexes prefer large mates over small mates. Olfactometer experiments showed that E. culicivora is attracted to the odours of bloodfed female mosquitoes, Lantana camara and Ricinus communis and opposite-sex conspecifics. A prior diet of blood-fed female mosquitoes enhances attractiveness to the opposite sex. Opposite-sex conspecifics paired with the odour of blood-fed female mosquitoes are also more attractive. Cross-modality priming effects were investigated in other experiments that showed individuals of E. culicivora responded more to visual cues of opposite-sex conspecifics when in the presence of certain odours (of opposite-sex conspecifics, blood-fed female mosquitoes and L. camara).

The Santa Cruz valley in Arizona is a rapidly urbanizing area. Complaints by residents of the area about pest mosquitoes prompted the investigation of mosquito breeding sources and a search for management techniques that would reduce mosquito populations. Many types of mosquito breeding sites were found in the area, and eight species of mosquitoes were identified. The greatest source of mosquitoes was a 2400 hectare irrigated pecan orchard. The most numerous and annoying mosquitoes were Aedes vexans (Meigen) and Psorophora columbiae (Dyar and Knab). The orchard is irrigated ca. every two weeks from April through October by flooding level areas, called borders, between rows of trees. Mosquitoes hatched with every irrigation studied, from April through September, but reached annoying numbers from late April through mid-September. A. vexans was the dominant species in early spring and P. columbiae was dominant in summer. Highest populations were reached coincident with the summer rainy season in July and August. Tests were performed to determine the efficacy of Bacillus thuringiensis israelensis (B.t.i.) as an additive to irrigation water for control of mosquito larvae. The larvicidal material was effective at all concentrations from .586 to 2.344 l/ha and with all techniques used. The most cost-effective application technique was to use fertilizer tanks to drip a mixture of B.t.i. into irrigation water in ditches before the water ran into fields. The general rate of three parts larvicide per million parts irrigation water was found to be effective, especially when supplemented with a spray of one part larvicide to 64 parts water applied to the ends of borders two to three days following irrigation. An increase in larvicide concentration was found to be necessary during the peak of mosquito season. A successful management program was developed and applied for 1 year, during which no mosquito complaints were made by citizens, the population of mosquitoes in the orchard was reduced to a point where farm laborers were no longer annoyed, and farm managers were satisfied that the program was cost effective.

Introduction: Vector-borne infectious diseases represent a major public health problem in both developing and developed nations. In particular, West Nile Virus (WNV), a mosquito-borne disease that can lead to severe disease and death in humans, caused over 2,100 reported cases in the United States last year (CDC, 2016). In Maricopa County, Arizona WNV has caused 474 reported cases during the last five years, with a case-fatality rate at 7.8%. Aim: To examine the association between weather patterns and incidence of WNV in Maricopa County, AZ from 2007 to 2013. Methods: We analyzed weekly data on climatological variables and WNV incidence from Maricopa County, AZ. The specific independent variables of interest were precipitation, minimum temperatures, mean temperatures, and maximum temperatures. A full model was generated using multiple linear regression, and a stepwise selection procedure yielded a minimal model. Results: The full multiple linear regression model explains 45.30% of the observed variance in WNV incidence. The variable showing a significant impact on WNV incidence in this model was rainfall (p <0.0001). Stepwise selection results explained 45.16% of the variance observed in the data. This model included two significant predictors: precipitation and maximum temperature. Conclusion: Climatic variables, particularly the amount of rainfall and maximum temperatures, significantly influence WNV dynamics in Maricopa County, Arizona. These findings are in line with prior studies and could be useful to guide mosquito control programs in the state of Arizona.

Se por um lado as usinas hidrelétricas suprem as necessidades de energia do país, essas também são responsáveis pela proliferação de doenças cujos agentes são transmitidos, em sua grande maioria, por mosquitos que utilizam as áreas inundadas dessas usinas como criadouros. Pode-se observar tal cenário na UHE de Ourinhos, que está localizada no rio Paranapanema entre as cidades de Ourinhos, SP, e Jacarezinho, PR, onde foram definidas três estações de coleta usadas para a avaliação da dinâmica de população nos períodos pré e pós inundação do reservatório, a partir dos dados coletados descreveu-se as alterações ocorridas na população de culicídeos da UHE Ourinhos, diante dos impactos da inundação e calculou-se riqueza, dominância, diversidade e , IAEP e similaridade. Sendo que para captura de adultos utilizou-se armadilha de Shannon e aspirador à bateria, e para os imaturos conchas entomológicas em coleções de água estagnada. Entre as espécies de importância epidemiológica coletadas e identificadas temos: Aedes albopictus, Aedes scapularis, Anopheles albitarsis, Anopheles darlingi, Culex quinquefasciatus, Culex nigripalpus, Haemagogus leucocelaenus e Psorophora ferox. Destaca-se a redução do número de espécies no período pós enchimento, juntamente com a recolonização do nicho por novas espécies ou espécies antes raras, como exemplificado pelo surgimento do An. darlingi, e ascensão do An. albitarsis, espécies consideradas vetores primário e secundário da malária, no Brasil, respectivamente. Como conclusão, depreende-se que o lago formado pela represa de Ourinhos alterou a dinâmica de culicídeos do local, fato que pode representar menor contato desses hematófagos com a população no entorno do lago recém formado / If the hydroelectric power plants supply the needs of the country, they are also responsible for the proliferation of diseases whose pathogens are transferred, in most of time, by mosquitoes that using the flooded areas such as breeding. It can be observed this scenario in the HPP of Ourinhos, which is located on the Paranapanema river between the cities of Ourinhos, SP, and Jacarezinho, PR, where three stations were established to collect used for assessing the diversity of populations in the pre and post flooding of the reservoir from the data collected described the changes occurring in the population of Culicidae of Ourinhos HPP, before the impacts of flooding and it was estimated richness, dominance, and diversity, standardized index of abundance of species and similarity. Where to catch the adult was used the Shannons trap and vacuum, and for the immature forms \"entomological ladle\" in collections of stagnant water. Among the species of epidemiological importance have collected and identified: Aedes albopictus, Aedes scapularis, Anopheles albitarsis s.l, Anopheles darlingi, Culex quinquefasciatus, Culex nigripalpus, Haemagogus leucocelaenus and Psorophora ferox. It is reducing the number of species in the period after filling, together with the recolonization of the niche for new species or rare species before, as exemplified by the emergence of Anopheles(Nys.) darlingi and Anopheles albitarsis s.l rise of species, as primary and secondary vectors malaria in Brazil, respectively. In conclusion, it appears that the lake formed by the dam of Ourinhos changed the diversity of the mosquitoes in site, which may represent less contact with the blood of people around the newly formed lake