(Abstract) In the last two decades, all countries in the tropical regions of Latin America have experienced marked increases in the incidence of both classic dengue and dengue hemorrhagic fever. Major risk factors for the occurrence of dengue in the region, as well as some regional peculiarities in its clinical expression, such as the extensive involvement of older age groups, have been defined. While little information exists on the economic impact of dengue in the region in terms of disease burden, the estimated loss associated with the disease is on the same order of magnitude as tuberculosis, sexually transmitted diseases (excluding HIV/AIDS), Chagas disease, leishmaniasis, or intestinal helminths. Therefore, similar priority should be given in the allocation of resources for dengue research and control.
(Abstract) Dengue is endemic throughout large parts of the Americas and Asia, and is increasingly reported in Africa. More than 2.5 billion people are at high risk of infection in more than 100 endemic countries throughout the tropical and subtropical climate zones. Unplanned urbanization, population migration, and the breakdown of vector control efforts have contributed to the spread of the vector. There is an increase of dengue in its more severe forms, such as dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS), for reasons that are not fully understood. The severe forms, when not properly treated, have become an increasing cause of morbidity and mortality, and are straining the health care systems of many endemic countries. Current treatment of severe disease essentially involves the restoration of fluid, colloid, and electrolyte balances. However, over the past few years, the continuing spread and increasing intensity of the disease, combined with new funding mechanisms for the development and use of vaccines for the developing world, have triggered renewed interest and investment in dengue vaccine research.
(Abstract) Several dengue vaccine candidates have been evaluated in early clinical phase, and some are scheduled for efficacy testing in population-based studies. Given the advancements in dengue vaccine development, there is an increased interest in identifying immunological correlates of protection for these vaccines in order to facilitate their evaluation, further refinement, production and registration. To this end, the WHO Initiative for Vaccine Research (IVR) convened a consultation on primary and secondary immunological correlates of protection induced by dengue vaccines. The meeting was held on the 17th and 18th of November, 2005 at WHO headquarters in Geneva. The consultation was a first dedicated review of the available data in support of establishing correlates. It is concluded that it is not yet possible to define one specific set of correlates, the consultation concluded in recommendations that should help to gather the missing evidence in conjunction with future vaccine trials.
(Abstract) The four dengue viruses are transmitted in tropical countries that circle the globe. All can cause syndromes that are self-limited or severe. The common severe syndrome--dengue haemorrhagic fever/dengue shock syndrome (DHF/DSS)--is characterised by sudden vascular permeability generated by cytokines released when T cells attack dengue-infected cells. Here, I review and discuss data on clinical diagnosis and pathophysiology of vascular permeability and coagulopathy, parenteral treatment of DHF/DSS, and new laboratory tests.
(Abstract) Dengue emerged as a public health burden in Southeast Asia during and following the Second World War and has become increasingly important, with progressively longer and more frequent cyclical epidemics of dengue fever/dengue hemorrhagic fever. Despite this trend, surveillance for this vector-borne viral disease remains largely passive in most Southeast Asian countries, without adequate laboratory support. We review here the factors that may have contributed to the changing epidemiology of dengue in Southeast Asia as well as challenges of disease prevention. We also discuss a regional approach to active dengue virus surveillance, focusing on urban areas where the viruses are maintained, which may be a solution to limited financial resources since most of the countries in the region have developing economies. A regional approach would also result in a greater likelihood of success in disease prevention since the large volume of human travel is a major factor contributing to the geographical spread of dengue viruses.
(Abstract) Dengue viruses have evolved rapidly as they have spread worldwide, and genotypes associated with increased virulence have expanded from South and Southeast Asia into the Pacific and the Americas. This review explores the human, mosquito, and viral factors that contribute to the global spread and persistence of dengue, as well as the interaction between the three spheres, in the context of ecological and climate changes. What is known, as well as gaps in knowledge, is emphasized in light of future prospects for control and prevention of this pandemic disease.
(Abstract) Although the disease burden of dengue is increasing, the impact on the quality of life (QoL) has not been investigated. A study to determine the QoL of confirmed dengue patients using the EuroQol visual thermometer scale was carried out at the University Malaya Medical Center. All patients experienced a drastic decrease in their QoL from the onset of symptoms. The QoL deteriorated to the lowest point (40% of healthy status) between the third and seventh days of illness. The duration of impaired QoL (9 days for ambulatory or 13 days for hospitalized patients) was longer than the duration of fever (5 and 7 days, respectively). Symptomatic dengue has major effects on patients' health.
(Abstract) This document is addressed to national health and regulatory authorities in dengue-endemic countries interested in using vaccines to control the disease. It is also written for vaccine developers and research scientists interested in the development and field evaluation of such vaccines. The guidelines, which were developed with contributions and comments from many individuals from a variety of countries and institutions (see Annex 1), are designed to help identify the basic technical information required to design dengue vaccine field trials. The purposes of the field trials are firstly, to obtain sufficient data on vaccine safety and efficacy to support vaccine licensure, and secondly, to establish that, in post-licensure field studies, the vaccine proves to be safe and provides long-term protection.
(Abstract) Dengue is the most important vector-borne disease in the Americas and threatens the lives of millions of people in developing countries. Imprecise morbidity and mortality statistics underestimate the magnitude of dengue as a regional health problem. As a result, it is considered a low priority by the health sector with no timely steps for effective control. Dengue is perceived as a problem of 'others' (individually, collectively and institutionally), therefore responsibility for its control is passed on to others (neighbors, the community, municipality, health institutions, or other governmental agencies). With no precise risk indicators available there is little opportunity for timely diagnoses, treatment, health interventions or vector control (poor surveillance). Solutions only targeting the vector reduce the impact of interventions and there is no sustainable control. Without political commitment there are insufficient resources to face the problem. This paper discusses the challenges for prevention and control in the Americas.