Dengue fever

Dengue fever is a viral infection that typically causes flu-like symptoms, including fever, muscle aches, joint pains, headaches, nausea, and vomiting, often followed by a rash. Most cases are mild and resolve uneventfully in a few days. However, dengue sometimes causes excessive bleeding (dengue hemorrhagic fever) or a dangerous fall in blood pressure (dengue shock syndrome) that may be fatal. The available evidence indicates that that children under age 15 experiencing a second dengue infection are at greatest risk for severe disease, which implies that adult travelers who have never been exposed to dengue are unlikely to develop these complications.

Dengue is transmitted by Aedes mosquitoes, which bite preferentially during the daytime, especially in the morning and late afternoon (in contrast to Anopheles mosquitoes, the vectors of malaria, which are most active after sundown). Aedes mosquitoes are usually found close to human habitations, often indoors. They breed primarily in man-made water containers, such as jars, barrels, cans, cisterns, metal drums, plastic containers, and discarded tires. As a result, dengue is especially common in densely populated, urban environments, though it occurs in rural areas as well. The disease has been spreading in recent years, due in part to increasing urbanization, and is now endemic in more than one hundred tropical and subtropical countries.

A recent study of dengue in returned travelers showed that the risk peaked at different times of the year in different regions: in June and September for Southeast Asia, in October for south central Asia, in March for South America, and in August and October for the Caribbean (see Seasonality, Annual Trends, and Characteristics of Dengue among Ill Returned Travelers, 1997-2006, Emerging Infectious Diseases, 14 (7) 2008, pp. 1081-1088). In the year 2005, a total of 96 cases of dengue were identified in travelers from the United States, mostly after visits to Mexico, Central America, and the Caribbean. A smaller number occurred after travel to Asia.

There is no treatment for dengue fever except to take analgesics such as acetaminophen (Tylenol) and drink plenty of fluids. Severe cases may require hospitalization for intravenous fluids and supportive care. There is no vaccine at this time. The cornerstone of prevention is insect protection measures, described elsewhere.

From the World Health Organization (WHO)

Dengue fever: the disease

Dengue fever fact sheet

Dengue fever in Southeast Asia

From the Centers for Disease Control (CDC)

Dengue Fever

Travel-Associated Dengue --- United States, 2005

Imported Dengue --- United States, 1999 and 2000

From the Pan American Health Organization

Dengue in the Americas

From the Health Protection Agency (U.K.)

Dengue fever - worldwide update