(Abstract) Dengue is primarily an urban disease of the tropics, and the viruses that cause it are maintained in a cycle that involves humans and Aedes aegypti, a domestic, day-biting mosquito that prefers to feed on humans. Infection with a dengue virus serotype can produce a spectrum of clinical illness, ranging from a nonspecific viral syndrome to severe and fatal hemorrhagic disease. Important risk factors for DHF include the strain and serotype of the virus involved, as well as the age, immune status, and genetic predisposition of the patient.
(Abstract) About two-thirds of the world's population live in areas infested with dengue vectors, mainly Aedes aegypti. All four dengue viruses are circulating, sometimes simultaneously, in most of these areas. It is estimated that up to 80 million persons become infected annually although marked underreporting results in the notification of much smaller figures. Currently dengue is endemic in all continents except Europe and epidemic dengue haemorrhagic fever (DHF) occurs in Asia, the Americas and some Pacific islands. In the Americas, the emergence of epidemic DHF occurred in 1981 almost 30 years after its appearance in Asia, and its incidence is showing a marked upward trend. Presently, all four dengue serotypes are circulating in the Americas, thus increasing the risk for DHF in this region.
(Abstract) Dengue fever, a very old disease, has reemerged in the past 20 years with an expanded geographic distribution of both the viruses and the mosquito vectors, increased epidemic activity, the development of hyperendemicity (the cocirculation of multiple serotypes), and the emergence of dengue hemorrhagic fever in new geographic regions. This paper reviews the changing epidemiology of dengue and dengue hemorrhagic fever by geographic region, the natural history and transmission cycles, clinical diagnosis of both dengue fever and dengue hemorrhagic fever, serologic and virologic laboratory diagnoses, pathogenesis, surveillance, prevention, and control.
(Abstract) Dengue fever (DF) is an old disease that became distributed worldwide in the tropics during the 18th and 19th centuries when the shipping industry and commerce were expanding. The global epidemiology and transmission dynamics of dengue viruses were changed dramatically in Southeast Asia during World War II. The disruption and change in the ecology caused by the war effort expanded the geographical distribution and increased the densities of Ae. aegypti, making many countries in this region highly permissive for epidemic transmission. Modern transportation facilitated and increased the movement of people and commodities within and between regions of the world, leading to increased movement of both the mosquitoes and the viruses. As a result, epidemic DF/DHF spread to the Pacific and the American tropics.
(Abstract) Every year, there are several hundred thousand cases of dengue haemorrhagic fever/dengue shock syndrome (DHF/DSS) resulting in thousands of deaths. The only method currently available to prevent dengue infections is the control of Aedes aegypti, the mosquito vector. This approach has proved expensive and mostly unworkable. Serial infection occurs in most areas of the world where multiple dengue viruses circulate. Dengue vaccines must provide solid and longlasting protection against all four dengue viruses or, in dengue-endemic countries, there is the risk of sensitising recipients to severe disease. Many candidate dengue vaccines are moving towards clinical trials in human beings. These vaccines include several based on the formation of live-attenuated chimeric viruses. Evidence that dengue vaccines should succeed comes from encouraging experience with attenuated vaccines against related viruses such as yellow fever (YF) and Japanese encephalitis (JE), and from a recent successful phase 1 trial of a chimera of these two viruses. This progress is timely, because global dengue morbidity achieved an all time high during 2001–02.
(Abstract) The incidence of dengue and dengue hemorrhagic fever (DF/DHF) has increased significantly over the last decades. Yearly, an estimated 50-100 million cases of DF and about 250,000-500,000 cases of DHF occur worldwide. The epidemiological situation in Latin America now resembles that in Southeast Asia. Here, the main clinical, epidemiological and virological observations in the American region are presented and compared with those previously reported from Southeast Asia.
(Abstract) A survey of policymakers and other influential professionals in four southeast Asian countries (Cambodia, Indonesia, Philippines and Vietnam) was conducted to determine policymakers' views on the public health importance of dengue fever and dengue haemorrhagic fever (DHF), the need for a vaccine and the determinants influencing its potential introduction. Research felt to be key to future decision-making regarding dengue vaccine introduction include: disease surveillance studies, in-country vaccine trials or pilot projects, and studies on the economic burden of dengue and the cost-effectiveness of dengue vaccines. The results suggest favourable conditions for public and private sector markets for dengue vaccines and the need for creative financing strategies to ensure their accessibility to poor children in dengue-endemic countries.
(Abstract) To ascertain the economic feasibility of a pediatric tetravalent dengue vaccine, we developed and calibrated a cost-effectiveness model of vaccinating children at 15 months in Southeast (SE) Asia using a societal perspective.We assumed that full immunization would require two doses at prices of US$ 0.50 and US$ 10 per dose in the public and private sectors, respectively. The gross cost per 1000 population (of all ages) of the vaccination program would be US$ 154. Due to projected savings in dengue treatment, the net cost per capita would be only US$ 17 (89% below the gross cost). The cost per disability adjusted life year (DALY) saved by a pediatric vaccine would be US$ 50, making the potential vaccine highly cost-effective. Eventually, vaccination may be able to replace environmental control as a strategy for dengue prevention and be cost saving.
(Abstract) Dengue fever and dengue hemorrhagic fever constitute a substantial health burden on the population in Thailand. In this study, the impact of symptomatic dengue virus infection on the families of patients hospitalized at the Kamphaeng Phet Provincial Hospital with laboratory-confirmed dengue in 2001 was assessed, and the disability-adjusted life years (DALYs) lost for fatal and non-fatal cases of dengue were calculated using population level data for Thailand. When we accounted for the direct cost of hospitalization, indirect costs due to loss of productivity, and the average number of persons infected per family, we observed a financial loss of approximately US$61 per family, which is more than the average monthly income in Thailand. This figure is of the same order of magnitude as the impact of several diseases currently given priority in southeast Asia, such as the tropical cluster (trypanosomiasis, Chagas disease, schistosomiasis, leishmaniasis, lymphatic filariasis, and onchocerciasis), malaria, meningitis, and hepatitis. These results indicate that dengue prevention, control, and research should be considered equally important as that of diseases currently given priority.
(Abstract) The populations of Southeast Asia (SE Asia) and tropical America are similar, and all four dengue viruses of Asian origin are endemic in both regions. Yet, during comparable 5-year periods, SE Asia experienced 1.16 million cases of dengue hemorrhagic fever (DHF), principally in children, whereas in the Americas there were 2.8 million dengue fever (DF) cases, principally in adults, and only 65,000 DHF cases. This review aims to explain these regional differences.