Outbreak Notice
Update: Dengue, Tropical and Subtropical Regions
This information is current as of today, May 09, 2008 at 18:00
Updated: April 16, 2008
Dengue fever is a common disease caused by a virus that humans get by being bitten by infected mosquitoes (usually Aedes aegypti); it is the most common cause of fever in travelers returned from the Caribbean, Central America, and South Central Asia.1 Symptoms of dengue include fever, severe headache, pain behind the eye (retro-orbital eye pain), joint and muscle pain, and rash. Sometimes dengue fever is 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. Travelers are at risk for getting dengue fever if they travel to or live in areas where dengue virus is present. Travelers can take steps (see below) to reduce their risk of getting sick.
Dengue Risk Areas
The range of areas where dengue virus is located has rapidly grown in recent years. Today it includes many tropical countries in Southeast Asia, the Indian Subcontinent, the South Pacific, the Caribbean, South and Central America, northeastern Australia, and Africa. See the Distribution of dengue maps for areas where cases have been reported in previous years. Risk of getting sick with dengue is related to mosquito bites, which can vary with the season. The mosquitoes that transmit dengue often breed in man-made and natural containers, which are especially common in and around houses; therefore, dengue is common where many houses are clustered.
Many countries reported high numbers of dengue infections during 2007. This trend has continued in 2008, notably with the large outbreak currently being reported in Brazil. As of March 28, 2008, a national total of 120,570 cases of dengue fever, including 647 DHF cases and 48 deaths have been reported by Brazilian Health Authorities.2 As of April 10, 2008, a total of 75,399 cases of dengue fever, including 80 confirmed deaths have been reported in Rio de Janeiro this year.3 In a statement posted on their website on March 19, 2008, the Brazil Ministry of Health announced the creation of a crisis office to handle the outbreak, with support from the state government and the Armed Forces. There is particular concern about this current outbreak in Brazil and travelers to Brazil should take extra precautions. In addition, this outbreak highlights the importance of taking appropriate steps to prevent dengue fever when traveling to all dengue risk areas.
Prevention Measures for Travelers
No vaccine is available to prevent dengue, and there is no specific medicine to cure people who are sick with dengue. Those who become ill with dengue fever can be offered medications (acetaminophen) to reduce fever and may require oral rehydration or intravenous fluids and in severe cases, treatment to support their blood pressure.
Travelers can reduce their risk of getting dengue fever by protecting themselves from mosquito bites. Aedes mosquitoes, the main type of mosquito that spreads dengue, usually are active at dusk and dawn, but may feed at any time during the day, especially indoors, in shady areas, or when the weather is cloudy. Unlike malaria, dengue is often transmitted in urban as well as in rural areas. Recommendations for preventing mosquito bites include:
- Use insect repellent on uncovered skin surfaces when outdoors, especially during the day. When using sunscreen, apply it before insect repellent.
- Repellents containing 30% to 50% DEET (N,N-diethyl-m-toluamide) are recommended for adults and children over 2 months of age and effective for several hours. Repellents with lower amounts of DEET offer shorter-term protection and must be applied more often.
- Repellents containing up to 15% picaridin, which must be applied often, are available in the US. Repellents with higher concentrations of picaridin may be available in some regions outside the US.
- Protect infants less than 2 months of age 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.
- 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.)
- Where possible, stay in hotels or resorts that are well screened or air conditioned and take measures to reduce the mosquito population.
Additional Information
Proper diagnosis of dengue is important; 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's 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:
For more information about dengue in travelers, see
1Freedman 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.
2 WHO. 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.
3 Rio de Janeiro, Brazil. Relatório de casos de dengue – 2008, April 10, 2008, accessed at http://www.saude.rj.gov.br/Docs/Acoes/Dengue/Relatório%20de%20Casos%20de%20Dengue%20(10-04-2008%20-%2011h40m).pdf
