Situation Information

Dengue fever is the most common cause of fever in travelers returning from the Caribbean, Central America, and south central Asia.¹ This disease is caused by a virus spread through the bites of infected mosquitoes.

Many countries reported high numbers of dengue infections during 2007. This trend has continued in 2008, with large outbreaks reported in Brazil in March and April and an increase in cases reported in the Caribbean in October.

• March 28, 2008: The Brazilian Ministry of Health reported a national total of 120,570 cases of dengue fever, including 647 cases of dengue hemorrhagic fever and 48 deaths.²
• April 10, 2008: Health officials in Rio de Janeiro reported that 75,399 cases of dengue fever, including 80 deaths, have occurred over the past year.
• November 5, 2008: Health officials in the Netherlands Antilles reported an increase in dengue cases on the islands of St. Maarten, Saba, and Curaçao in late 2008. More than 500 cases of dengue fever have been confirmed on St. Maarten and nine cases of dengue fever have been recorded in Saba. Saba officials say this is the largest number of dengue cases reported on the island in the past 30 years.

Dengue infections have been reported in over 100 countries and are widespread in most tropical countries of the South Pacific, Asia, the Caribbean, the Americas and Africa. See the Distribution of dengue maps for areas where cases have been reported in previous years.

The geographic spread of dengue infections is similar to that of malaria, but unlike malaria dengue infections are often found in the urban areas of tropical nations, including Thailand, Singapore, Taiwan, Indonesia, the Philippines, India and Brazil. Because the main risk of exposure for the traveler is in populated urban and residential areas, travelers are advised to consult CDC (www.cdc.gov/ncidod/dvbid/dengue) and WHO (www.who.int/topics/dengue/en/)websites for outbreak information.

Symptoms and Treatment

Symptoms of dengue include

• fever
• severe headache
• pain behind the eye
• joint and muscle pain,
• rash.

Usually dengue fever causes a mild illness, but it can be severe and even cause dengue hemorrhagic (bleeding) fever (DHF), which can be fatal if not treated. People who have had dengue fever before are more at risk of getting DHF.

No vaccine is available to prevent dengue, and there is no specific medicine to cure dengue. Those who become ill with dengue fever can be given medicine to reduce fever, such as acetaminophen, and may need oral rehydration or intravenous fluids and, in severe cases, treatment to support their blood pressure.

Prevention Measures for Travelers

Travelers can reduce their risk of getting dengue fever by protecting themselves from mosquito bites. The mosquitoes that spread dengue usually bite at dusk and dawn but may bite at any time during the day, especially indoors, in shady areas, or when the weather is cloudy. Unlike malaria, dengue is often spread in cities as well as in rural areas.

Travelers should follow the steps below to protect themselves from mosquito bites:

• Where possible, stay in hotels or resorts that are well screened or air conditioned and that take measures to reduce the mosquito population. If the hotel is not well screened, sleep under bed nets to prevent mosquito bites.
• When outdoors or in a building that is not well screened, use insect repellent on uncovered skin. Always apply sunscreen before insect repellent.
  • Look for a repellent that contains one of the following active ingredients: DEET, picaridin (KBR 3023), Oil of Lemon Eucalyptus/PMD, or IR3535. Always follow the instructions on the label when you use the repellent.
  • In general, repellents protect longer against mosquito bites when they have a higher concentration (percentage) of any of these active ingredients. However, concentrations above 50% do not offer a marked increase in protection time. Products with less than 10% of an active ingredient may offer only limited protection, often no longer than 1-2 hours.
  • The American Academy of Pediatrics approves of the use of repellents with up to 30% DEET on children over 2 months old.
  • Protect babies less than 2 months old by using a carrier draped with mosquito netting with an elastic edge for a tight fit. For more information about the use of repellent on infants and children, please see the “Insect and Other Arthropod Protection” section in Traveling Safely with Infants and Children and the “Children” section of CDC’s Frequently Asked Questions about Repellent Use.
  • For more information on the use of insect repellents, visit Insect and Arthropod Protection in the CDC Health Information for International Travel 2008.
• Wear loose, long-sleeved shirts and long pants when outdoors.
  • Clothing may also be sprayed with repellent containing permethrin or another EPA-registered repellent for greater protection. (Remember: don't use permethrin on skin.)

Information for health-care providers

Proper diagnosis of dengue is important, as many other diseases may mimic dengue. Health-care providers should consider dengue, malaria, and (in south Asia and countries bordering the Indian Ocean) chikungunya in the differential diagnosis of patients who have fever and a history of travel to tropical areas during the 2 weeks before symptom onset.

See Dengue and Dengue Hemorrhagic Fever: Information for Health-Care Practitioners for information regarding reporting dengue cases and instructions for specimen shipping. Serum samples obtained for viral identification and serologic diagnosis can be sent through state or territorial health departments to

CDC Dengue Branch
Division of Vector-Borne Infectious Diseases
National Center for Zoonotic, Vector-Borne and Enteric Diseases
1324 Calle Cañada
San Juan, Puerto Rico 00920-3860
Telephone: 787-706-2399; fax, 787-706-2496.

For more information about dengue and protection measures, see the following links:

• Dengue Fever in CDC Health Information for International Travel 2008
• Insect and Arthropod Protection
• Questions and Answers: Insect Repellent Use and Safety
• Overview of Dengue from CDC Division of Vector-Borne Infectious Diseases

For more information about dengue in travelers, see

• Travel-Associated Dengue—United States, 2005 [MMWR 2006, 55 (25)].
• Travel-Associated Dengue Infections—United States, 2001-2004 [MMWR 2005, 54 (22)]

¹ Freedman DO, Weld LH, Kozarsky PE, Fisk T, Robins R, von Sonnenburg F, et al., for the GeoSentinel Surveillance Network. Spectrum of disease and relation to place of exposure among ill returned travelers. N Engl J Med 2006;354:119-130.

²WHO. Dengue/dengue haemorrhagic fever in Brazil. Disease Outbreak News, April 10, 2008, accessed at http://www.who.int/csr/don/2008_04_10/en/index.html.