In subtropical and tropical regions, the dengue virus represents a major threat to human health. The microorganism's natural hosts include mosquitoes, lower primates, and humans. Infection of the human host results in a biphasic fever with the potential to evolve into severe hemorrhagic disease. Over the past few decades, the virus genome structure, viral proteins, and viral antigens have been well characterized. Unfortunately though, the precise mechanisms by which the dengue virus causes disease remain unknown.
Throughout history, major dengue fever epidemics have generally occurred at irregular intervals within the range of the mosquito vector. For instance, in 1922, one such epidemic may have affected between 1 and 2 million people in the southern United States. At present, dengue fever may cause more human morbidity and mortality than any other arthropod-borne viral disease (Henchal & Putnak, 1990, pp. 376-396). The dengue viruses are currently endemic in most tropical areas of the world (Lanciotti, Lewis, Gubler, & Trent, 1994, p. 65). It has been estimated that there could be as many as 100 million cases of dengue infection every year (Halstead, 1988, p. 476).
The only natural hosts for dengue virus infections are mosquitoes, lower primates (e.g., chimpanzees, rhesus monkeys, and macaques), and humans. Although lower primates may develop viremias of a magnitude sufficient to infect mosquitoes, they do not generally manifest "clinically apparent disease" (Henchal & Putnak, 1990, pp. 376-396). The principle mosquito vector is Aedes aegypti. Other mosquito hosts, however, include A. albopictus, A. scutellaris, A. africanus, A. leuteocephalus, A. niveus, A. taylori, and A. furcifer. In Malaysia, Vietnam, and Africa, these arthropods contribute to a forest maintenance cycle (Henchal & Putnak, 1990, pp. 376-396).
The dengue virus belongs to the Flaviviridae family. This group of microorganisms is comprised ...