Impacts of Urbanization on Vector Biology and Transmission of Dengue in China

描述（申请人提供）：城市化对中国登革热媒介生物学和传播的影响。登革热是中国南方的一个主要公共卫生问题。近年来，登革热在华南地区的流行间隔越来越短，流行范围也在不断扩大。由于登革热流行与中国经济发展带来的快速城市化同时发生，城市化为登革热病媒的生存和繁殖以及登革热病毒的传播创造了有利条件。该应用验证了城市化导致的环境变化影响白纹伊蚊（中国南方主要登革热媒介）的生物学和媒介能力的中心假设。我们将对广州市近20年的登革热疫情进行进一步的分子流行病学研究。这项研究的长期目标是确定登革热在城市环境中的流行机制，并制定有效的预防和控制方法。我们设计了以下两个具体目标。首先，我们将确定城市化对白纹伊蚊幼虫和成蚊生态的影响，白纹伊蚊是广州地区唯一的登革热媒介。这一目标将检验城市化为白纹伊蚊幼虫的生存和发育创造有利条件的假设，并随后增加登革热媒介的丰度。其次，我们将确定登革热病毒在城市环境中的传播模式。这一目的将检验登革热疫情与新血清型或基因型登革热病毒的传入和传播有关的假设，以及伊蚊的媒介能力。白纹伊蚊在登革热病毒血清型和基因型上存在差异，因此最有利的登革热病毒血清型/基因型可能成为流行型。本研究利用广州市登革热流行病学和媒介种群的独特情况，频繁发生登革热疫情。白纹伊蚊在城市环境中繁殖活跃。本研究将大大提高我们对登革热在城市地区传播的认识，并有助于制定有效的登革热监测和控制计划。

DESCRIPTION (provided by applicant): Impacts of Urbanization on Vector Biology and Transmission of Dengue in China. Dengue is a major public health problem in southern China. In recent years, the epidemic interval of Dengue outbreaks in southern China has become shorter and the epidemic area is expanding. Because Dengue epidemics coincide with rapid urbanization in China as a result of economic development, it has been suggested that urbanization creates favorable conditions for the survival and reproduction of Dengue vectors and for the transmission of Dengue virus. This application tests the central hypothesis that environmental changes resulting from urbanization affect the biology and vectorial capacity of Aedes albopictus, the major Dengue vector in southern China. We will further examine the molecular epidemiology of the Dengue virus in urban areas for major outbreaks in Guangzhou city in the past two decades. The long-term goal of this research is to determine the mechanisms of Dengue epidemics in urban environments and to develop effective prevention and control methods. We have designed the following two specific aims. First, we will determine the impact of urbanization on the larval and adult ecology of Aedes albopictus mosquitoes, the sole Dengue vector in the Guangzhou area where the present study will be conducted. This aim will test the hypothesis that urbanization creates favorable conditions for the survivorship and development of Aedes albopictus larvae and subsequently, increases the abundance of the Dengue vector. Second, we will determine the transmission patterns of Dengue virus in urban environments. This aim will test the hypothesis that Dengue outbreaks are associated with the introduction and circulation of new serotypes or genotypes of Dengue virus, and that vector competence of Ae. albopictus varies among Dengue viral serotypes and genotypes, and thus the most favored DENV serotype/genotype may become the epidemic type. The proposed research takes advantage of the unique Dengue epidemiological and vector population situations in Guangzhou, China where frequent Dengue outbreaks have occurred and Ae. albopictus is actively breeding in the urban environment. This research will significantly enhance our understanding of Dengue transmission in urban areas, and contribute to the development of effective surveillance and control programs of Dengue in China.