The chapter discusses the global emergence and resurgence of dengue fever and dengue hemorrhagic fever (DHF) as significant public health issues. It highlights the historical context, factors contributing to the increased incidence, and the clinical, pathological, and diagnostic aspects of the diseases. The text emphasizes the role of demographic and societal changes, urbanization, lack of effective mosquito control, increased air travel, and decay in public health infrastructure in the resurgence of dengue. It also provides an overview of the natural history of dengue viruses, including their transmission cycles, clinical manifestations, and pathogenesis. The chapter details the diagnostic methods for dengue, such as serologic tests, virus isolation, and laboratory techniques, and discusses the prevention and control measures, including vaccine development and active surveillance. The text concludes with a discussion on the importance of raising awareness among healthcare providers in temperate regions to improve early diagnosis and management of dengue cases.The chapter discusses the global emergence and resurgence of dengue fever and dengue hemorrhagic fever (DHF) as significant public health issues. It highlights the historical context, factors contributing to the increased incidence, and the clinical, pathological, and diagnostic aspects of the diseases. The text emphasizes the role of demographic and societal changes, urbanization, lack of effective mosquito control, increased air travel, and decay in public health infrastructure in the resurgence of dengue. It also provides an overview of the natural history of dengue viruses, including their transmission cycles, clinical manifestations, and pathogenesis. The chapter details the diagnostic methods for dengue, such as serologic tests, virus isolation, and laboratory techniques, and discusses the prevention and control measures, including vaccine development and active surveillance. The text concludes with a discussion on the importance of raising awareness among healthcare providers in temperate regions to improve early diagnosis and management of dengue cases.