Dengue is due to a flavivirus transmitted by the bite of the Aedes mosquito. It may be caused by one of four serotypes (possibly five, with a potentially new serotype from Malaysia under study) widely distributed globally between the tropics of Capricorn and Cancer.
Symptoms and Signs
Dengue infection may range from asymptomatic to severe hemorrhagic fever to fatal shock (dengue shock syndrome). Dengue fever is usually a nonspecific, selflimited biphasic febrile illness. More than half of infected children are asymptomatic.
The illness is more severe and begins more suddenly in adults. After an incubation period of 4–5 days, there is a sudden onset of high fever, chills, and “break bone” aching of the head, back, and extremities accompanied by sore throat, prostration, and malaise. There may be conjunctival redness. Initially, the skin appears flushed or blotched, but 3–4 days after the lysis of the fever, a maculopapular rash, which spares palms and soles, appears in over 50% of cases.
As the rash fades, localized clusters of petechiae on the extensor surface of the limbs become apparent. Up to 25% may manifest signs of cardiac involvement. Hepatitis frequently complicates dengue fever with acute fulminant hepatitis in up to 5%.