Dengue fever poses a constant serious risk and continues to be a major public health threat in Saudi Arabia, particularly in the city of Jeddah where, since 2006, despite formally introduced Control Strategies, there has been a significant increase in the number of cases. International literature suggests that a range of variables can influence the persistence of dengue, including climatic conditions, the quality of the urban environment, socioeconomic status and control strategies. The overall aims of this research are to understand neighbourhood influences on the pattern of dengue fever across Jeddah City and to make a preliminary determination of the enabling factors for, and barriers to, the effective implementation of the Control Strategies for dengue fever in Jeddah City. A mixed methods research design using quantitative and qualitative data was used. Quantitative data were obtained from administrative sources for dengue fever cases and some of the spatial and temporal variables associated with them, but new variables were created for neighbourhood status and the presence of surface water. Qualitative data are drawn from key informant interviews with 15 people who were, or who had been, working on dengue fever Control Strategies. A qualitative descriptive analysis was based on pre- determined and emergent themes. The spatial and temporal analysis of the variables related to dengue fever in Jeddah City neighbourhoods revealed that neighbourhood status has a direct relationship with dengue fever cases, which is mediated through population density and the presence of non- Saudi immigrants. While there was no relationship with the presence of swamps, seasonal variations in the incidence of dengue were most pronounced in neighbourhoods of low socioeconomic status. The qualitative review of dengue Control Strategies indicated five themes: (1) workforce characteristics and capability, (2) knowledge about dengue fever in Saudi Arabia and Jeddah City, (3) operational strategies for dengue fever control in Jeddah City, (4) the progress of implementation, and (5) overall view of the Government strategies in Jeddah City. This analysis found that the Strategies were well regarded but that aspects of implementation were not always effective. Nevertheless, both quantitative and qualitative results showed the persistence dengue fever problems in Jeddah City neighbourhoods and suggested how cases might be controlled. The number of dengue fever cases in Jeddah City neighbourhoods could continue to rise if the direct and indirect variables affecting dengue fever at the neighbourhood level are not well controlled. Careful attention to the further monitoring of patterns of dengue and specific neighbourhood Control Strategies are recommended, and established Control Strategies need to be implemented as designed. Nonetheless, there is still a need to develop new approaches that can examine and address neighbourhood level issues of dengue fever control.

No description available.

Objective: Globally, about 50 to 100 million patients are infected with dengue fever per year and the average mortality rate is about 3.5 to 5% in Asia. Because of appropriate geographic location and cultural factors, dengue fever has been the important subject of infectious disease that Taiwan faces. In order to control and prevent the spread of dengue fever effectively, how to diagnose the suspected case correctly by the clinical symptoms and to improve the early reporting rates become critical research questions. The purpose of this study is to explore the correlation between clinical symptoms and diagnosis of dengue fever, and the factors associated with being reported at the first outpatient visit among confirmed case by using Dengue Fever Survey Form, which including demographics, clinical symptoms, level of the first outpatient visit and whether the patient is reported at the first outpatient visit. Design: 593 virologically confirmed cases during 2006 Dengue endemics in Kaohsiung city were studied. The data were from Dengue Fever Survey Form, which were collected from January 1 to December 31,2006. Result: The mean age of cases was 46.45¡Ó19.06 years (range 2 years to 89 years). The most common symptoms were fever (97.3%), pain (75.2%), GI symptoms (74.7%), skin rash (49.2%), and thirsty/dry mouth (49.1%). Chi-square tests showed gender, age in group, viral type, whether dengue hemorrhagic fever or not, level of the first outpatient visit, pain and gastrointestinal symptoms were significantly associated with being reported at the first outpatient visit. The result of the analysis of logistic regression indicated that the significant predictors of being reported at the first outpatient visit were gender, age in group, viral type, level of the first outpatient visit, gastrointestinal symptoms and fatigue. Conclusion: Reporting of infectious disease is essential to detection of outbreaks, planning of control program and provision of appropriate treatment. Clinical symptoms of dengue fever and the level of the first outpatient visit will influence rates of being reported at the first outpatient visit. All medical providers involved in diagnosis and treatment of dengue fever should strengthen their knowledge by continuing learning in order to improve early identification rates. In addition, health department could try to improve the detection and reporting systems to make the reporting steps more convenient and advance early reporting rates.

In recent years, dengue viral infection has become one of the most widely-spread mosquito-borne diseases in the world, with an estimated 50-100 million cases annually, resulting in 500,000 hospitalizations. Due to the nature of the immune response to each of the four serotypes of dengue virus, secondary infections of dengue put patients at higher risk for more severe infection as opposed to primary infections. The current hypothesis for this phenomenon is antibody-dependent enhancement, where strain-specific antibodies from the primary infection enhance infection by a heterologous serotype. To determine the mechanisms responsible for the increase in disease severity, we develop mathematical models of within-host virus-cell interaction, epidemiological models of virus transmission, and a combination of the within-host and between-host models. The main results of this thesis focus on the within-host model. We model the effects of antibody responses against primary and secondary virus strains. We find that secondary infections lead to a reduction of virus removal. This is slightly different than the current antibody-dependent enhancement hypothesis, which suggests that the rate of virus infectivity is higher during secondary infections due to antibody failure to neutralize the virus. We use the results from the within-host model in an epidemiological multi-scale model. We start by constructing a two-strain SIR model and vary the parameters to account for the effect of antibody-dependent enhancement. / Master of Science

As early as in 1915, 1931 and 1942, there were serious outbreaks of dengue fever occurred to the entire island of Taiwan. In 1942, there were five million people in the whole Taiwan infected with dengue fever. After the significant outbreaks of dengue fever in the entire Kaohsiung District of Taiwan Island in 1987 and 1988, except that the regional epidemics occurred in three places of Northern and Central Taiwan, namely Jhonghe City of Taipei County, Taichung City and Taipei City, all other regional outbreaks of dengue fever mostly occurred in Kaohsiung County or City, Tainan City and Pingtung County. Apparently, the epidemic situation of dengue fever has become an epidemic disease of Southern Taiwan, and gradually developed as a ¡§community disease¡¨ or ¡§environmental disease.¡¨ Coincidently, the year of 2006 was a peak period for the propagation of dengue fever. Under the circumstances that the number of dengue fever patients was getting higher and higher, both the government and the competent authorities took compulsory measures or epidemic prevention acts (such administrative acts as insecticide spraying against mosquitoes in residences after forceful unlocking of doors, emergency public spraying of chemicals against mosquitoes, taking blood tests, and so on). It seemed so obvious that the liberty of living, liberty of property and personal liberty, which are the basic rights of civilians under the protection of the Constitution, were involved. Besides, whenever dengue fever is epidemic, it is common to see conflicts (arguments) over the door unlocking and insecticide spraying problems frequently happened between the citizens and the government departments concerned. In the legal aspect, it is necessary to review whether these acts comply with the provisions of the Constitution. Apart from collecting the related local and foreign literatures to investigate the change of the administrative system of epidemic control, the study introduces the details of the three major directions in taking epidemic prevention measures against dengue fever in Taiwan, including such administrative and management acts as the preventive measures to be taken during the ordinary days, the epidemic control measures after receiving the report of dengue fever cases, and the epidemic prevention measures after the confirmation of dengue fever cases. In addition, regarding the various compulsory epidemic control measures taken by the health administrative authorities, such as the problems of forceful unlocking of doors for intrusion of residences, forceful (emergency) spraying of insecticide, and the compensation for the loss of property rights after the death of real estate owners¡¦ animals or plants caused by the chemical spraying, etc., the study reviews the reference of laws and the proper legal procedures to be complied with. It includes the theories and principles of the Constitution that Taiwan government should comply with. Although the paper encounters limitations in the studying process, it is still hoped that from the limited literatures with limited information, major directions can be found out as a reference for the competent authorities or scholars to improve or solve the abovementioned problems in the later days. It is also expected that the later researchers can have further understanding of the implementation or practical aspects of the epidemic prevention measures of dengue fever, and finally achieve in-depth development and breakthrough in the studies of the solutions. Keywords: dengue fever, basic human rights, epidemic prevention measures

The impact of Community - on health is one of the core issues of sociology and social epidemiology. Dengue fever, whose occurrence and eradication highly depend in the environment of the community, provides an opportunity to explore the relationship between the community and the health. This study focuses on the outbreak of Dengue fever in 2006 in Kaohsiung City and analyzes how community factors affect the cluster infections of. This study uses the theories of social capital and social vulnerability to explore the effect population, socioeconomic status, and public participation in the community on cluster infection. Social capital is formed by community members through participating in public affairs and voluntary organizations; social vulnerability refers to the overall socio-economic conditions that shape the ability of community to respond to the undesirable events. The social capital index was constructed composed of the Community Development Association, the voting rate of warden elections. Social vulnerability index is based on the compositions of the population, including the proportion of elderly males, population change rate, ratio of low-income households the proportion of dependents than average household income. In addition to consideration the spatial characteristics of dengue fever, this thesis uses Moran's I and LISA test dengue fever outbreaks, and correct the result by Geographically Weighted Regression. The results shows the impact of community factors on the health of residents, provide health sociology and control of dengue fever different reflections direction.

Incidence of dengue fever (DF) has been estimated a 30 fold increase in the past 50 years. Clinical manifestations of DF range from a simple febrile illness with physical soreness to life-threatening dengue hemorrhagic fever (DHF). The need for a better classification of the severity in DEN infections has been proposed to clarify the immunopathogenesis for the prevention and management of serious DEN infections. We attempted to investigate whether different mechanisms involved in the varied manifestations of bleeding tendency and vascular leakage in DF. In a hospital-based study, we first compared clinical features as well as laboratory data including virus load, T helper (Th1/Th2) cytokines, and vascular leakage-related mediators between patients with DHF and DF. Moreover, we defined another class of patients associated with bleeding tendency but not fulfilled with DHF criteria, called DF w/B, for a further comparison. The virus load in blood was not significantly different among DF, DHF and DF w/B. DF patients had a higher Th1 cytokine, IFNr, expression (70.0 ¡Ó 10.7 vs. 33.1 ¡Ó 8.0 vs. 33.0 ¡Ó 7.1 pg/ml; DF vs. DF w/B, p = 0.009; DF vs. DHF, p = 0.002), and both DHF and DF w/B patients had a significantly higher IL-10 levels (14.3 ¡Ó 4.1 vs. 26.2 ¡Ó 3.3 vs. 26.0 ¡Ó 3.5 pg/ml; DF vs. DF w/B, p = 0.023; DF vs. DHF, p = 0.016) than DF patients. Both DHF and DF w/B patients also had a higher rate of secondary dengue infection (DF w/B vs. DHF vs. DF: 50.0%, 74.4% and 14.3%¡A p < 0.001). By contrast, DHF but not DF w/B patients had significantly higher vascular leakage-related mediators: sVCAM-1, PGE2 and TNF£\ levels than DF patients. Patients with DF w/B had a higher platelet counts (DF w/B vs. DHF: 66.0 ¡Ó 8.3 vs. 20.7 ¡Ó 2.1 x109/L, p < 0.001) but lower ALT levels than those with DHF (DF w/B vs. DHF: 56.3 ¡Ó 7.7 and 144.7 ¡Ó 20.5 IU/L). This study provides new insight to different immune mechanisms involved in patients with DF, DF w/B, and DHF. DF involves augmented Th1 reaction, and DF w/B involves altered Th2 reaction, but DHF involves both altered Th2 reaction and augmented vascular insult. Clarification of the immune mechanisms among DF, DFw/B and DHF will facilitate certain specific treatment and prevention of DF patients from varied bleeding tendency and vascular leakage manifestations.

Dengue fever has increased to the point where it has become a major international public health and economical problem, mainly in urban and semi-urban areas in tropical and subtropical regions. Worldwide 2,5 billion people live in regions where dengue can be transmitted and approximately 100 million people get infected yearly. In 2002 there was a great outbreak in Latin America, and Costa Rica was in the top three regarding reported cases. At the time of writing, reports show that cases of dengue are currently low in Costa Rica. Although the figures vary, dengue remains a public health problem. This study aimed to describe Costa Rican registered nurses’ views and experiences of caring for patients with dengue fever. Data were collected with semi-structured interviews and conducted with eight registered nurses from Costa Rica, and analysed with qualitative content analysis method with search for similarities and differences which later were categorized. The result was divided into five categories; the conception about dengue fever, caring, patient education, prevention and the future. The result showed a similar perception of the disease and was described as terrible, causing a lot of suffering for the patient, as well as a burden on the health care, that requires large financial resources. To control dengue and suppress the proliferation it is important to have different preventive means and to educate people to achieve a change of the mindset.

Throughout the early twentieth century, dengue fever was considered to be a nonthreatening illness, only infecting visitors of the tropics. However, in the last fifty years, there has been a resurgence of dengue fever; it is now considered to be the most consequential arbovirus, infecting more than 50 million people each year and leaving about half of the world's current population at risk of infection. The purpose of this thesis is to explore the various environmental factors that have contributed to the resurgence of dengue fever that has been seen in the last half century. Most notable of these factors are climate change and the increasing urbanization associated with population growth. Specifically, increasing temperatures and precipitation increases the available habitat for the dengue fever vector, the Aedes mosquito, while concurrently increasing both the longevity of the virus and the mosquito. Furthermore, changing sociodemographic factors associated with urbanization have helped spread the mosquito around the world, as the vector largely relies on human transportation. Finally, substandard housing often associated with insufficient water management systems creates the ideal breeding spots for the dengue vector. The Aedes mosquito is known to be one of the most versatile and one of the toughest mosquitoes in the world, which has allowed it to quickly adapt and succeed in these changing environments. Understanding these factors and their influence on the spread of dengue fever is vital in order to effectively manage current and future outbreaks. This is specifically important in regards to dengue fever and severe dengue as no vaccine or medications currently exists to treat this virus.

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.